t1_lib.c

/*
 * Copyright 1995-2025 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/core_names.h>
#include <openssl/ocsp.h>
#include <openssl/conf.h>
#include <openssl/x509v3.h>
#include <openssl/dh.h>
#include <openssl/bn.h>
#include <openssl/provider.h>
#include <openssl/param_build.h>
#include "internal/nelem.h"
#include "internal/sizes.h"
#include "internal/tlsgroups.h"
#include "internal/ssl_unwrap.h"
#include "ssl_local.h"
#include "quic/quic_local.h"
#include <openssl/ct.h>

static const SIGALG_LOOKUP *find_sig_alg(SSL_CONNECTION *s, X509 *x, EVP_PKEY *pkey);
static int tls12_sigalg_allowed(const SSL_CONNECTION *s, int op, const SIGALG_LOOKUP *lu);

SSL3_ENC_METHOD const TLSv1_enc_data = {
    tls1_setup_key_block,
    tls1_generate_master_secret,
    tls1_change_cipher_state,
    tls1_final_finish_mac,
    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
    tls1_alert_code,
    tls1_export_keying_material,
    0,
    ssl3_set_handshake_header,
    tls_close_construct_packet,
    ssl3_handshake_write
};

SSL3_ENC_METHOD const TLSv1_1_enc_data = {
    tls1_setup_key_block,
    tls1_generate_master_secret,
    tls1_change_cipher_state,
    tls1_final_finish_mac,
    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
    tls1_alert_code,
    tls1_export_keying_material,
    0,
    ssl3_set_handshake_header,
    tls_close_construct_packet,
    ssl3_handshake_write
};

SSL3_ENC_METHOD const TLSv1_2_enc_data = {
    tls1_setup_key_block,
    tls1_generate_master_secret,
    tls1_change_cipher_state,
    tls1_final_finish_mac,
    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
    tls1_alert_code,
    tls1_export_keying_material,
    SSL_ENC_FLAG_SIGALGS | SSL_ENC_FLAG_SHA256_PRF
        | SSL_ENC_FLAG_TLS1_2_CIPHERS,
    ssl3_set_handshake_header,
    tls_close_construct_packet,
    ssl3_handshake_write
};

SSL3_ENC_METHOD const TLSv1_3_enc_data = {
    tls13_setup_key_block,
    tls13_generate_master_secret,
    tls13_change_cipher_state,
    tls13_final_finish_mac,
    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
    tls13_alert_code,
    tls13_export_keying_material,
    SSL_ENC_FLAG_SIGALGS | SSL_ENC_FLAG_SHA256_PRF,
    ssl3_set_handshake_header,
    tls_close_construct_packet,
    ssl3_handshake_write
};

OSSL_TIME tls1_default_timeout(void)
{
    /*
     * 2 hours, the 24 hours mentioned in the TLSv1 spec is way too long for
     * http, the cache would over fill
     */
    return ossl_seconds2time(60 * 60 * 2);
}

int tls1_new(SSL *s)
{
    if (!ssl3_new(s))
        return 0;
    if (!s->method->ssl_clear(s))
        return 0;

    return 1;
}

void tls1_free(SSL *s)
{
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);

    if (sc == NULL)
        return;

    OPENSSL_free(sc->ext.session_ticket);
    ssl3_free(s);
}

int tls1_clear(SSL *s)
{
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);

    if (sc == NULL)
        return 0;

    if (!ssl3_clear(s))
        return 0;

    if (s->method->version == TLS_ANY_VERSION)
        sc->version = TLS_MAX_VERSION_INTERNAL;
    else
        sc->version = s->method->version;

    return 1;
}

/* Legacy NID to group_id mapping. Only works for groups we know about */
static const struct {
    int nid;
    uint16_t group_id;
} nid_to_group[] = {
    { NID_sect163k1, OSSL_TLS_GROUP_ID_sect163k1 },
    { NID_sect163r1, OSSL_TLS_GROUP_ID_sect163r1 },
    { NID_sect163r2, OSSL_TLS_GROUP_ID_sect163r2 },
    { NID_sect193r1, OSSL_TLS_GROUP_ID_sect193r1 },
    { NID_sect193r2, OSSL_TLS_GROUP_ID_sect193r2 },
    { NID_sect233k1, OSSL_TLS_GROUP_ID_sect233k1 },
    { NID_sect233r1, OSSL_TLS_GROUP_ID_sect233r1 },
    { NID_sect239k1, OSSL_TLS_GROUP_ID_sect239k1 },
    { NID_sect283k1, OSSL_TLS_GROUP_ID_sect283k1 },
    { NID_sect283r1, OSSL_TLS_GROUP_ID_sect283r1 },
    { NID_sect409k1, OSSL_TLS_GROUP_ID_sect409k1 },
    { NID_sect409r1, OSSL_TLS_GROUP_ID_sect409r1 },
    { NID_sect571k1, OSSL_TLS_GROUP_ID_sect571k1 },
    { NID_sect571r1, OSSL_TLS_GROUP_ID_sect571r1 },
    { NID_secp160k1, OSSL_TLS_GROUP_ID_secp160k1 },
    { NID_secp160r1, OSSL_TLS_GROUP_ID_secp160r1 },
    { NID_secp160r2, OSSL_TLS_GROUP_ID_secp160r2 },
    { NID_secp192k1, OSSL_TLS_GROUP_ID_secp192k1 },
    { NID_X9_62_prime192v1, OSSL_TLS_GROUP_ID_secp192r1 },
    { NID_secp224k1, OSSL_TLS_GROUP_ID_secp224k1 },
    { NID_secp224r1, OSSL_TLS_GROUP_ID_secp224r1 },
    { NID_secp256k1, OSSL_TLS_GROUP_ID_secp256k1 },
    { NID_X9_62_prime256v1, OSSL_TLS_GROUP_ID_secp256r1 },
    { NID_secp384r1, OSSL_TLS_GROUP_ID_secp384r1 },
    { NID_secp521r1, OSSL_TLS_GROUP_ID_secp521r1 },
    { NID_brainpoolP256r1, OSSL_TLS_GROUP_ID_brainpoolP256r1 },
    { NID_brainpoolP384r1, OSSL_TLS_GROUP_ID_brainpoolP384r1 },
    { NID_brainpoolP512r1, OSSL_TLS_GROUP_ID_brainpoolP512r1 },
    { EVP_PKEY_X25519, OSSL_TLS_GROUP_ID_x25519 },
    { EVP_PKEY_X448, OSSL_TLS_GROUP_ID_x448 },
    { NID_brainpoolP256r1tls13, OSSL_TLS_GROUP_ID_brainpoolP256r1_tls13 },
    { NID_brainpoolP384r1tls13, OSSL_TLS_GROUP_ID_brainpoolP384r1_tls13 },
    { NID_brainpoolP512r1tls13, OSSL_TLS_GROUP_ID_brainpoolP512r1_tls13 },
    { NID_id_tc26_gost_3410_2012_256_paramSetA, OSSL_TLS_GROUP_ID_gc256A },
    { NID_id_tc26_gost_3410_2012_256_paramSetB, OSSL_TLS_GROUP_ID_gc256B },
    { NID_id_tc26_gost_3410_2012_256_paramSetC, OSSL_TLS_GROUP_ID_gc256C },
    { NID_id_tc26_gost_3410_2012_256_paramSetD, OSSL_TLS_GROUP_ID_gc256D },
    { NID_id_tc26_gost_3410_2012_512_paramSetA, OSSL_TLS_GROUP_ID_gc512A },
    { NID_id_tc26_gost_3410_2012_512_paramSetB, OSSL_TLS_GROUP_ID_gc512B },
    { NID_id_tc26_gost_3410_2012_512_paramSetC, OSSL_TLS_GROUP_ID_gc512C },
    { NID_ffdhe2048, OSSL_TLS_GROUP_ID_ffdhe2048 },
    { NID_ffdhe3072, OSSL_TLS_GROUP_ID_ffdhe3072 },
    { NID_ffdhe4096, OSSL_TLS_GROUP_ID_ffdhe4096 },
    { NID_ffdhe6144, OSSL_TLS_GROUP_ID_ffdhe6144 },
    { NID_ffdhe8192, OSSL_TLS_GROUP_ID_ffdhe8192 }
};

static const unsigned char ecformats_default[] = {
    TLSEXT_ECPOINTFORMAT_uncompressed,
    TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime,
    TLSEXT_ECPOINTFORMAT_ansiX962_compressed_char2
};

/* Group list string of the built-in pseudo group DEFAULT */
#define DEFAULT_GROUP_NAME "DEFAULT"
#define TLS_DEFAULT_GROUP_LIST \
    "?*X25519MLKEM768 / ?*X25519:?secp256r1 / ?X448:?secp384r1:?secp521r1 / ?ffdhe2048:?ffdhe3072"

static const uint16_t suiteb_curves[] = {
    OSSL_TLS_GROUP_ID_secp256r1,
    OSSL_TLS_GROUP_ID_secp384r1,
};

/* Group list string of the built-in pseudo group DEFAULT_SUITE_B */
#define SUITE_B_GROUP_NAME "DEFAULT_SUITE_B"
#define SUITE_B_GROUP_LIST "secp256r1:secp384r1",

struct provider_ctx_data_st {
    SSL_CTX *ctx;
    OSSL_PROVIDER *provider;
};

#define TLS_GROUP_LIST_MALLOC_BLOCK_SIZE 10
static OSSL_CALLBACK add_provider_groups;
static int add_provider_groups(const OSSL_PARAM params[], void *data)
{
    struct provider_ctx_data_st *pgd = data;
    SSL_CTX *ctx = pgd->ctx;
    const OSSL_PARAM *p;
    TLS_GROUP_INFO *ginf = NULL;
    EVP_KEYMGMT *keymgmt;
    unsigned int gid;
    unsigned int is_kem = 0;
    int ret = 0;

    if (ctx->group_list_max_len == ctx->group_list_len) {
        TLS_GROUP_INFO *tmp = NULL;

        if (ctx->group_list_max_len == 0)
            tmp = OPENSSL_malloc(sizeof(TLS_GROUP_INFO)
                * TLS_GROUP_LIST_MALLOC_BLOCK_SIZE);
        else
            tmp = OPENSSL_realloc(ctx->group_list,
                (ctx->group_list_max_len
                    + TLS_GROUP_LIST_MALLOC_BLOCK_SIZE)
                    * sizeof(TLS_GROUP_INFO));
        if (tmp == NULL)
            return 0;
        ctx->group_list = tmp;
        memset(tmp + ctx->group_list_max_len,
            0,
            sizeof(TLS_GROUP_INFO) * TLS_GROUP_LIST_MALLOC_BLOCK_SIZE);
        ctx->group_list_max_len += TLS_GROUP_LIST_MALLOC_BLOCK_SIZE;
    }

    ginf = &ctx->group_list[ctx->group_list_len];

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_NAME);
    if (p == NULL || p->data_type != OSSL_PARAM_UTF8_STRING) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    ginf->tlsname = OPENSSL_strdup(p->data);
    if (ginf->tlsname == NULL)
        goto err;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_NAME_INTERNAL);
    if (p == NULL || p->data_type != OSSL_PARAM_UTF8_STRING) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    ginf->realname = OPENSSL_strdup(p->data);
    if (ginf->realname == NULL)
        goto err;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_ID);
    if (p == NULL || !OSSL_PARAM_get_uint(p, &gid) || gid > UINT16_MAX) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    ginf->group_id = (uint16_t)gid;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_ALG);
    if (p == NULL || p->data_type != OSSL_PARAM_UTF8_STRING) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    ginf->algorithm = OPENSSL_strdup(p->data);
    if (ginf->algorithm == NULL)
        goto err;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_SECURITY_BITS);
    if (p == NULL || !OSSL_PARAM_get_uint(p, &ginf->secbits)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_IS_KEM);
    if (p != NULL && (!OSSL_PARAM_get_uint(p, &is_kem) || is_kem > 1)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    ginf->is_kem = 1 & is_kem;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_MIN_TLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &ginf->mintls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_MAX_TLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &ginf->maxtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_MIN_DTLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &ginf->mindtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_GROUP_MAX_DTLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &ginf->maxdtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    /*
     * Now check that the algorithm is actually usable for our property query
     * string. Regardless of the result we still return success because we have
     * successfully processed this group, even though we may decide not to use
     * it.
     */
    ret = 1;
    ERR_set_mark();
    keymgmt = EVP_KEYMGMT_fetch(ctx->libctx, ginf->algorithm, ctx->propq);
    if (keymgmt != NULL) {
        /* We have successfully fetched the algorithm, we can use the group. */
        ctx->group_list_len++;
        ginf = NULL;
        EVP_KEYMGMT_free(keymgmt);
    }
    ERR_pop_to_mark();
err:
    if (ginf != NULL) {
        OPENSSL_free(ginf->tlsname);
        OPENSSL_free(ginf->realname);
        OPENSSL_free(ginf->algorithm);
        ginf->algorithm = ginf->tlsname = ginf->realname = NULL;
    }
    return ret;
}

static int discover_provider_groups(OSSL_PROVIDER *provider, void *vctx)
{
    struct provider_ctx_data_st pgd;

    pgd.ctx = vctx;
    pgd.provider = provider;
    return OSSL_PROVIDER_get_capabilities(provider, "TLS-GROUP",
        add_provider_groups, &pgd);
}

int ssl_load_groups(SSL_CTX *ctx)
{
    if (!OSSL_PROVIDER_do_all(ctx->libctx, discover_provider_groups, ctx))
        return 0;

    return SSL_CTX_set1_groups_list(ctx, TLS_DEFAULT_GROUP_LIST);
}

static const char *inferred_keytype(const TLS_SIGALG_INFO *sinf)
{
    return (sinf->keytype != NULL
            ? sinf->keytype
            : (sinf->sig_name != NULL
                      ? sinf->sig_name
                      : sinf->sigalg_name));
}

#define TLS_SIGALG_LIST_MALLOC_BLOCK_SIZE 10
static OSSL_CALLBACK add_provider_sigalgs;
static int add_provider_sigalgs(const OSSL_PARAM params[], void *data)
{
    struct provider_ctx_data_st *pgd = data;
    SSL_CTX *ctx = pgd->ctx;
    OSSL_PROVIDER *provider = pgd->provider;
    const OSSL_PARAM *p;
    TLS_SIGALG_INFO *sinf = NULL;
    EVP_KEYMGMT *keymgmt;
    const char *keytype;
    unsigned int code_point = 0;
    int ret = 0;

    if (ctx->sigalg_list_max_len == ctx->sigalg_list_len) {
        TLS_SIGALG_INFO *tmp = NULL;

        if (ctx->sigalg_list_max_len == 0)
            tmp = OPENSSL_malloc(sizeof(TLS_SIGALG_INFO)
                * TLS_SIGALG_LIST_MALLOC_BLOCK_SIZE);
        else
            tmp = OPENSSL_realloc(ctx->sigalg_list,
                (ctx->sigalg_list_max_len
                    + TLS_SIGALG_LIST_MALLOC_BLOCK_SIZE)
                    * sizeof(TLS_SIGALG_INFO));
        if (tmp == NULL)
            return 0;
        ctx->sigalg_list = tmp;
        memset(tmp + ctx->sigalg_list_max_len, 0,
            sizeof(TLS_SIGALG_INFO) * TLS_SIGALG_LIST_MALLOC_BLOCK_SIZE);
        ctx->sigalg_list_max_len += TLS_SIGALG_LIST_MALLOC_BLOCK_SIZE;
    }

    sinf = &ctx->sigalg_list[ctx->sigalg_list_len];

    /* First, mandatory parameters */
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_NAME);
    if (p == NULL || p->data_type != OSSL_PARAM_UTF8_STRING) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    OPENSSL_free(sinf->sigalg_name);
    sinf->sigalg_name = OPENSSL_strdup(p->data);
    if (sinf->sigalg_name == NULL)
        goto err;

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_IANA_NAME);
    if (p == NULL || p->data_type != OSSL_PARAM_UTF8_STRING) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    OPENSSL_free(sinf->name);
    sinf->name = OPENSSL_strdup(p->data);
    if (sinf->name == NULL)
        goto err;

    p = OSSL_PARAM_locate_const(params,
        OSSL_CAPABILITY_TLS_SIGALG_CODE_POINT);
    if (p == NULL
        || !OSSL_PARAM_get_uint(p, &code_point)
        || code_point > UINT16_MAX) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    sinf->code_point = (uint16_t)code_point;

    p = OSSL_PARAM_locate_const(params,
        OSSL_CAPABILITY_TLS_SIGALG_SECURITY_BITS);
    if (p == NULL || !OSSL_PARAM_get_uint(p, &sinf->secbits)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }

    /* Now, optional parameters */
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_OID);
    if (p == NULL) {
        sinf->sigalg_oid = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->sigalg_oid);
        sinf->sigalg_oid = OPENSSL_strdup(p->data);
        if (sinf->sigalg_oid == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_SIG_NAME);
    if (p == NULL) {
        sinf->sig_name = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->sig_name);
        sinf->sig_name = OPENSSL_strdup(p->data);
        if (sinf->sig_name == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_SIG_OID);
    if (p == NULL) {
        sinf->sig_oid = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->sig_oid);
        sinf->sig_oid = OPENSSL_strdup(p->data);
        if (sinf->sig_oid == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_HASH_NAME);
    if (p == NULL) {
        sinf->hash_name = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->hash_name);
        sinf->hash_name = OPENSSL_strdup(p->data);
        if (sinf->hash_name == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_HASH_OID);
    if (p == NULL) {
        sinf->hash_oid = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->hash_oid);
        sinf->hash_oid = OPENSSL_strdup(p->data);
        if (sinf->hash_oid == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_KEYTYPE);
    if (p == NULL) {
        sinf->keytype = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->keytype);
        sinf->keytype = OPENSSL_strdup(p->data);
        if (sinf->keytype == NULL)
            goto err;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_KEYTYPE_OID);
    if (p == NULL) {
        sinf->keytype_oid = NULL;
    } else if (p->data_type != OSSL_PARAM_UTF8_STRING) {
        goto err;
    } else {
        OPENSSL_free(sinf->keytype_oid);
        sinf->keytype_oid = OPENSSL_strdup(p->data);
        if (sinf->keytype_oid == NULL)
            goto err;
    }

    /* Optional, not documented prior to 3.5 */
    sinf->mindtls = sinf->maxdtls = -1;
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_MIN_DTLS);
    if (p != NULL && !OSSL_PARAM_get_int(p, &sinf->mindtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_MAX_DTLS);
    if (p != NULL && !OSSL_PARAM_get_int(p, &sinf->maxdtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    /* DTLS version numbers grow downward */
    if ((sinf->maxdtls != 0) && (sinf->maxdtls != -1) && ((sinf->maxdtls > sinf->mindtls))) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    /* No provider sigalgs are supported in DTLS, reset after checking. */
    sinf->mindtls = sinf->maxdtls = -1;

    /* The remaining parameters below are mandatory again */
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_MIN_TLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &sinf->mintls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    p = OSSL_PARAM_locate_const(params, OSSL_CAPABILITY_TLS_SIGALG_MAX_TLS);
    if (p == NULL || !OSSL_PARAM_get_int(p, &sinf->maxtls)) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    if ((sinf->maxtls != 0) && (sinf->maxtls != -1) && ((sinf->maxtls < sinf->mintls))) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
        goto err;
    }
    if ((sinf->mintls != 0) && (sinf->mintls != -1) && ((sinf->mintls > TLS1_3_VERSION)))
        sinf->mintls = sinf->maxtls = -1;
    if ((sinf->maxtls != 0) && (sinf->maxtls != -1) && ((sinf->maxtls < TLS1_3_VERSION)))
        sinf->mintls = sinf->maxtls = -1;

    /* Ignore unusable sigalgs */
    if (sinf->mintls == -1 && sinf->mindtls == -1) {
        ret = 1;
        goto err;
    }

    /*
     * Now check that the algorithm is actually usable for our property query
     * string. Regardless of the result we still return success because we have
     * successfully processed this signature, even though we may decide not to
     * use it.
     */
    ret = 1;
    ERR_set_mark();
    keytype = inferred_keytype(sinf);
    keymgmt = EVP_KEYMGMT_fetch(ctx->libctx, keytype, ctx->propq);
    if (keymgmt != NULL) {
        /*
         * We have successfully fetched the algorithm - however if the provider
         * doesn't match this one then we ignore it.
         *
         * Note: We're cheating a little here. Technically if the same algorithm
         * is available from more than one provider then it is undefined which
         * implementation you will get back. Theoretically this could be
         * different every time...we assume here that you'll always get the
         * same one back if you repeat the exact same fetch. Is this a reasonable
         * assumption to make (in which case perhaps we should document this
         * behaviour)?
         */
        if (EVP_KEYMGMT_get0_provider(keymgmt) == provider) {
            /*
             * We have a match - so we could use this signature;
             * Check proper object registration first, though.
             * Don't care about return value as this may have been
             * done within providers or previous calls to
             * add_provider_sigalgs.
             */
            OBJ_create(sinf->sigalg_oid, sinf->sigalg_name, NULL);
            /* sanity check: Without successful registration don't use alg */
            if ((OBJ_txt2nid(sinf->sigalg_name) == NID_undef) || (OBJ_nid2obj(OBJ_txt2nid(sinf->sigalg_name)) == NULL)) {
                ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT);
                goto err;
            }
            if (sinf->sig_name != NULL)
                OBJ_create(sinf->sig_oid, sinf->sig_name, NULL);
            if (sinf->keytype != NULL)
                OBJ_create(sinf->keytype_oid, sinf->keytype, NULL);
            if (sinf->hash_name != NULL)
                OBJ_create(sinf->hash_oid, sinf->hash_name, NULL);
            OBJ_add_sigid(OBJ_txt2nid(sinf->sigalg_name),
                (sinf->hash_name != NULL
                        ? OBJ_txt2nid(sinf->hash_name)
                        : NID_undef),
                OBJ_txt2nid(keytype));
            ctx->sigalg_list_len++;
            sinf = NULL;
        }
        EVP_KEYMGMT_free(keymgmt);
    }
    ERR_pop_to_mark();
err:
    if (sinf != NULL) {
        OPENSSL_free(sinf->name);
        sinf->name = NULL;
        OPENSSL_free(sinf->sigalg_name);
        sinf->sigalg_name = NULL;
        OPENSSL_free(sinf->sigalg_oid);
        sinf->sigalg_oid = NULL;
        OPENSSL_free(sinf->sig_name);
        sinf->sig_name = NULL;
        OPENSSL_free(sinf->sig_oid);
        sinf->sig_oid = NULL;
        OPENSSL_free(sinf->hash_name);
        sinf->hash_name = NULL;
        OPENSSL_free(sinf->hash_oid);
        sinf->hash_oid = NULL;
        OPENSSL_free(sinf->keytype);
        sinf->keytype = NULL;
        OPENSSL_free(sinf->keytype_oid);
        sinf->keytype_oid = NULL;
    }
    return ret;
}

static int discover_provider_sigalgs(OSSL_PROVIDER *provider, void *vctx)
{
    struct provider_ctx_data_st pgd;

    pgd.ctx = vctx;
    pgd.provider = provider;
    OSSL_PROVIDER_get_capabilities(provider, "TLS-SIGALG",
        add_provider_sigalgs, &pgd);
    /*
     * Always OK, even if provider doesn't support the capability:
     * Reconsider testing retval when legacy sigalgs are also loaded this way.
     */
    return 1;
}

int ssl_load_sigalgs(SSL_CTX *ctx)
{
    size_t i;
    SSL_CERT_LOOKUP lu;

    if (!OSSL_PROVIDER_do_all(ctx->libctx, discover_provider_sigalgs, ctx))
        return 0;

    /* now populate ctx->ssl_cert_info */
    if (ctx->sigalg_list_len > 0) {
        OPENSSL_free(ctx->ssl_cert_info);
        ctx->ssl_cert_info = OPENSSL_zalloc(sizeof(lu) * ctx->sigalg_list_len);
        if (ctx->ssl_cert_info == NULL)
            return 0;
        for (i = 0; i < ctx->sigalg_list_len; i++) {
            const char *keytype = inferred_keytype(&ctx->sigalg_list[i]);
            ctx->ssl_cert_info[i].pkey_nid = OBJ_txt2nid(keytype);
            ctx->ssl_cert_info[i].amask = SSL_aANY;
        }
    }

    /*
     * For now, leave it at this: legacy sigalgs stay in their own
     * data structures until "legacy cleanup" occurs.
     */

    return 1;
}

static uint16_t tls1_group_name2id(SSL_CTX *ctx, const char *name)
{
    size_t i;

    for (i = 0; i < ctx->group_list_len; i++) {
        if (OPENSSL_strcasecmp(ctx->group_list[i].tlsname, name) == 0
            || OPENSSL_strcasecmp(ctx->group_list[i].realname, name) == 0)
            return ctx->group_list[i].group_id;
    }

    return 0;
}

const TLS_GROUP_INFO *tls1_group_id_lookup(SSL_CTX *ctx, uint16_t group_id)
{
    size_t i;

    for (i = 0; i < ctx->group_list_len; i++) {
        if (ctx->group_list[i].group_id == group_id)
            return &ctx->group_list[i];
    }

    return NULL;
}

const char *tls1_group_id2name(SSL_CTX *ctx, uint16_t group_id)
{
    const TLS_GROUP_INFO *tls_group_info = tls1_group_id_lookup(ctx, group_id);

    if (tls_group_info == NULL)
        return NULL;

    return tls_group_info->tlsname;
}

int tls1_group_id2nid(uint16_t group_id, int include_unknown)
{
    size_t i;

    if (group_id == 0)
        return NID_undef;

    /*
     * Return well known Group NIDs - for backwards compatibility. This won't
     * work for groups we don't know about.
     */
    for (i = 0; i < OSSL_NELEM(nid_to_group); i++) {
        if (nid_to_group[i].group_id == group_id)
            return nid_to_group[i].nid;
    }
    if (!include_unknown)
        return NID_undef;
    return TLSEXT_nid_unknown | (int)group_id;
}

uint16_t tls1_nid2group_id(int nid)
{
    size_t i;

    /*
     * Return well known Group ids - for backwards compatibility. This won't
     * work for groups we don't know about.
     */
    for (i = 0; i < OSSL_NELEM(nid_to_group); i++) {
        if (nid_to_group[i].nid == nid)
            return nid_to_group[i].group_id;
    }

    return 0;
}

/*
 * Set *pgroups to the supported groups list and *pgroupslen to
 * the number of groups supported.
 */
void tls1_get_supported_groups(SSL_CONNECTION *s, const uint16_t **pgroups,
    size_t *pgroupslen)
{
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    /* For Suite B mode only include P-256, P-384 */
    switch (tls1_suiteb(s)) {
    case SSL_CERT_FLAG_SUITEB_128_LOS:
        *pgroups = suiteb_curves;
        *pgroupslen = OSSL_NELEM(suiteb_curves);
        break;

    case SSL_CERT_FLAG_SUITEB_128_LOS_ONLY:
        *pgroups = suiteb_curves;
        *pgroupslen = 1;
        break;

    case SSL_CERT_FLAG_SUITEB_192_LOS:
        *pgroups = suiteb_curves + 1;
        *pgroupslen = 1;
        break;

    default:
        if (s->ext.supportedgroups == NULL) {
            *pgroups = sctx->ext.supportedgroups;
            *pgroupslen = sctx->ext.supportedgroups_len;
        } else {
            *pgroups = s->ext.supportedgroups;
            *pgroupslen = s->ext.supportedgroups_len;
        }
        break;
    }
}

/*
 * Some comments for the function below:
 * s->ext.supportedgroups == NULL means legacy syntax (no [*,/,-]) from built-in group array.
 * In this case, we need to send exactly one key share, which MUST be the first (leftmost)
 * eligible group from the legacy list. Therefore, we provide the entire list of supported
 * groups in this case.
 *
 * A 'flag' to indicate legacy syntax is created by setting the number of key shares to 1,
 * but the groupID to 0.
 * The 'flag' is checked right at the beginning in tls_construct_ctos_key_share and either
 * the "list of requested key share groups" is used, or the "list of supported groups" in
 * combination with setting add_only_one = 1 is applied.
 */
void tls1_get_requested_keyshare_groups(SSL_CONNECTION *s, const uint16_t **pgroups,
    size_t *pgroupslen)
{
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    if (s->ext.supportedgroups == NULL) {
        *pgroups = sctx->ext.supportedgroups;
        *pgroupslen = sctx->ext.supportedgroups_len;
    } else {
        *pgroups = s->ext.keyshares;
        *pgroupslen = s->ext.keyshares_len;
    }
}

void tls1_get_group_tuples(SSL_CONNECTION *s, const size_t **ptuples,
    size_t *ptupleslen)
{
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    if (s->ext.supportedgroups == NULL) {
        *ptuples = sctx->ext.tuples;
        *ptupleslen = sctx->ext.tuples_len;
    } else {
        *ptuples = s->ext.tuples;
        *ptupleslen = s->ext.tuples_len;
    }
}

int tls_valid_group(SSL_CONNECTION *s, uint16_t group_id,
    int minversion, int maxversion,
    int isec, int *okfortls13)
{
    const TLS_GROUP_INFO *ginfo = tls1_group_id_lookup(SSL_CONNECTION_GET_CTX(s),
        group_id);
    int ret;
    int group_minversion, group_maxversion;

    if (okfortls13 != NULL)
        *okfortls13 = 0;

    if (ginfo == NULL)
        return 0;

    group_minversion = SSL_CONNECTION_IS_DTLS(s) ? ginfo->mindtls : ginfo->mintls;
    group_maxversion = SSL_CONNECTION_IS_DTLS(s) ? ginfo->maxdtls : ginfo->maxtls;

    if (group_minversion < 0 || group_maxversion < 0)
        return 0;
    if (group_maxversion == 0)
        ret = 1;
    else
        ret = (ssl_version_cmp(s, minversion, group_maxversion) <= 0);
    if (group_minversion > 0)
        ret &= (ssl_version_cmp(s, maxversion, group_minversion) >= 0);

    if (!SSL_CONNECTION_IS_DTLS(s)) {
        if (ret && okfortls13 != NULL && maxversion == TLS1_3_VERSION)
            *okfortls13 = (group_maxversion == 0)
                || (group_maxversion >= TLS1_3_VERSION);
    }
    ret &= !isec
        || strcmp(ginfo->algorithm, "EC") == 0
        || strcmp(ginfo->algorithm, "X25519") == 0
        || strcmp(ginfo->algorithm, "X448") == 0;

    return ret;
}

/* See if group is allowed by security callback */
int tls_group_allowed(SSL_CONNECTION *s, uint16_t group, int op)
{
    const TLS_GROUP_INFO *ginfo = tls1_group_id_lookup(SSL_CONNECTION_GET_CTX(s),
        group);
    unsigned char gtmp[2];

    if (ginfo == NULL)
        return 0;

    gtmp[0] = group >> 8;
    gtmp[1] = group & 0xff;
    return ssl_security(s, op, ginfo->secbits,
        tls1_group_id2nid(ginfo->group_id, 0), (void *)gtmp);
}

/* Return 1 if "id" is in "list" */
static int tls1_in_list(uint16_t id, const uint16_t *list, size_t listlen)
{
    size_t i;
    for (i = 0; i < listlen; i++)
        if (list[i] == id)
            return 1;
    return 0;
}

typedef struct {
    TLS_GROUP_INFO *grp;
    size_t ix;
} TLS_GROUP_IX;

DEFINE_STACK_OF(TLS_GROUP_IX)

static void free_wrapper(TLS_GROUP_IX *a)
{
    OPENSSL_free(a);
}

static int tls_group_ix_cmp(const TLS_GROUP_IX *const *a,
    const TLS_GROUP_IX *const *b)
{
    int idcmpab = (*a)->grp->group_id < (*b)->grp->group_id;
    int idcmpba = (*b)->grp->group_id < (*a)->grp->group_id;
    int ixcmpab = (*a)->ix < (*b)->ix;
    int ixcmpba = (*b)->ix < (*a)->ix;

    /* Ascending by group id */
    if (idcmpab != idcmpba)
        return (idcmpba - idcmpab);
    /* Ascending by original appearance index */
    return ixcmpba - ixcmpab;
}

int tls1_get0_implemented_groups(int min_proto_version, int max_proto_version,
    TLS_GROUP_INFO *grps, size_t num, long all,
    STACK_OF(OPENSSL_CSTRING) *out)
{
    STACK_OF(TLS_GROUP_IX) *collect = NULL;
    TLS_GROUP_IX *gix;
    uint16_t id = 0;
    int ret = 0;
    size_t ix;

    if (grps == NULL || out == NULL)
        return 0;
    if ((collect = sk_TLS_GROUP_IX_new(tls_group_ix_cmp)) == NULL)
        return 0;
    for (ix = 0; ix < num; ++ix, ++grps) {
        if (grps->mintls > 0 && max_proto_version > 0
            && grps->mintls > max_proto_version)
            continue;
        if (grps->maxtls > 0 && min_proto_version > 0
            && grps->maxtls < min_proto_version)
            continue;

        if ((gix = OPENSSL_malloc(sizeof(*gix))) == NULL)
            goto end;
        gix->grp = grps;
        gix->ix = ix;
        if (sk_TLS_GROUP_IX_push(collect, gix) <= 0) {
            OPENSSL_free(gix);
            goto end;
        }
    }

    sk_TLS_GROUP_IX_sort(collect);
    num = sk_TLS_GROUP_IX_num(collect);
    for (ix = 0; ix < num; ++ix) {
        gix = sk_TLS_GROUP_IX_value(collect, ix);
        if (!all && gix->grp->group_id == id)
            continue;
        id = gix->grp->group_id;
        if (sk_OPENSSL_CSTRING_push(out, gix->grp->tlsname) <= 0)
            goto end;
    }
    ret = 1;

end:
    sk_TLS_GROUP_IX_pop_free(collect, free_wrapper);
    return ret;
}

/*-
 * For nmatch >= 0, return the id of the |nmatch|th shared group or 0
 * if there is no match.
 * For nmatch == -1, return number of matches
 * For nmatch == -2, return the id of the group to use for
 * a tmp key, or 0 if there is no match.
 */
uint16_t tls1_shared_group(SSL_CONNECTION *s, int nmatch)
{
    const uint16_t *pref, *supp;
    size_t num_pref, num_supp, i;
    int k;
    SSL_CTX *ctx = SSL_CONNECTION_GET_CTX(s);

    /* Can't do anything on client side */
    if (s->server == 0)
        return 0;
    if (nmatch == -2) {
        if (tls1_suiteb(s)) {
            /*
             * For Suite B ciphersuite determines curve: we already know
             * these are acceptable due to previous checks.
             */
            unsigned long cid = s->s3.tmp.new_cipher->id;

            if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256)
                return OSSL_TLS_GROUP_ID_secp256r1;
            if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384)
                return OSSL_TLS_GROUP_ID_secp384r1;
            /* Should never happen */
            return 0;
        }
        /* If not Suite B just return first preference shared curve */
        nmatch = 0;
    }
    /*
     * If server preference set, our groups are the preference order
     * otherwise peer decides.
     */
    if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
        tls1_get_supported_groups(s, &pref, &num_pref);
        tls1_get_peer_groups(s, &supp, &num_supp);
    } else {
        tls1_get_peer_groups(s, &pref, &num_pref);
        tls1_get_supported_groups(s, &supp, &num_supp);
    }

    for (k = 0, i = 0; i < num_pref; i++) {
        uint16_t id = pref[i];
        const TLS_GROUP_INFO *inf;
        int minversion, maxversion;

        if (!tls1_in_list(id, supp, num_supp)
            || !tls_group_allowed(s, id, SSL_SECOP_CURVE_SHARED))
            continue;
        inf = tls1_group_id_lookup(ctx, id);
        if (!ossl_assert(inf != NULL))
            return 0;

        minversion = SSL_CONNECTION_IS_DTLS(s)
            ? inf->mindtls
            : inf->mintls;
        maxversion = SSL_CONNECTION_IS_DTLS(s)
            ? inf->maxdtls
            : inf->maxtls;
        if (maxversion == -1)
            continue;
        if ((minversion != 0 && ssl_version_cmp(s, s->version, minversion) < 0)
            || (maxversion != 0
                && ssl_version_cmp(s, s->version, maxversion) > 0))
            continue;

        if (nmatch == k)
            return id;
        k++;
    }
    if (nmatch == -1)
        return k;
    /* Out of range (nmatch > k). */
    return 0;
}

int tls1_set_groups(uint16_t **grpext, size_t *grpextlen,
    uint16_t **ksext, size_t *ksextlen,
    size_t **tplext, size_t *tplextlen,
    int *groups, size_t ngroups)
{
    uint16_t *glist = NULL, *kslist = NULL;
    size_t *tpllist = NULL;
    size_t i;
    /*
     * Bitmap of groups included to detect duplicates: two variables are added
     * to detect duplicates as some values are more than 32.
     */
    unsigned long *dup_list = NULL;
    unsigned long dup_list_egrp = 0;
    unsigned long dup_list_dhgrp = 0;

    if (ngroups == 0) {
        ERR_raise(ERR_LIB_SSL, SSL_R_BAD_LENGTH);
        return 0;
    }
    if ((glist = OPENSSL_malloc(ngroups * sizeof(*glist))) == NULL)
        goto err;
    if ((kslist = OPENSSL_malloc(1 * sizeof(*kslist))) == NULL)
        goto err;
    if ((tpllist = OPENSSL_malloc(1 * sizeof(*tpllist))) == NULL)
        goto err;
    for (i = 0; i < ngroups; i++) {
        unsigned long idmask;
        uint16_t id;
        id = tls1_nid2group_id(groups[i]);
        if ((id & 0x00FF) >= (sizeof(unsigned long) * 8))
            goto err;
        idmask = 1L << (id & 0x00FF);
        dup_list = (id < 0x100) ? &dup_list_egrp : &dup_list_dhgrp;
        if (!id || ((*dup_list) & idmask))
            goto err;
        *dup_list |= idmask;
        glist[i] = id;
    }
    OPENSSL_free(*grpext);
    OPENSSL_free(*ksext);
    OPENSSL_free(*tplext);
    *grpext = glist;
    *grpextlen = ngroups;
    /*
     * No * prefix was used, let tls_construct_ctos_key_share choose a key
     * share. This has the advantage that it will filter unsupported groups
     * before choosing one, which this function does not do. See also the
     * comment for tls1_get_requested_keyshare_groups.
     */
    kslist[0] = 0;
    *ksext = kslist;
    *ksextlen = 1;
    tpllist[0] = ngroups;
    *tplext = tpllist;
    *tplextlen = 1;
    return 1;
err:
    OPENSSL_free(glist);
    OPENSSL_free(kslist);
    OPENSSL_free(tpllist);
    return 0;
}

/*
 * Definition of DEFAULT[_XYZ] pseudo group names.
 * A pseudo group name is actually a full list of groups, including prefixes
 * and or tuple delimiters. It can be hierarchically defined (for potential future use).
 * IMPORTANT REMARK: For ease of use, in the built-in lists of groups, unknown groups or
 * groups not backed by a provider will always silently be ignored, even without '?' prefix
 */
typedef struct {
    const char *list_name; /* The name of this pseudo group */
    const char *group_string; /* The group string of this pseudo group */
} default_group_string_st; /* (can include '?', '*'. '-', '/' as needed) */

/* Built-in pseudo group-names must start with a (D or d) */
static const char *DEFAULT_GROUPNAME_FIRST_CHARACTER = "D";

/* The list of all built-in pseudo-group-name structures */
static const default_group_string_st default_group_strings[] = {
    { DEFAULT_GROUP_NAME, TLS_DEFAULT_GROUP_LIST },
    { SUITE_B_GROUP_NAME, SUITE_B_GROUP_LIST }
};

/*
 * Some GOST names are not resolved by tls1_group_name2id,
 * hence we'll check for those manually
 */
typedef struct {
    const char *group_name;
    uint16_t groupID;
} name2id_st;
static const name2id_st name2id_arr[] = {
    { "GC256A", OSSL_TLS_GROUP_ID_gc256A },
    { "GC256B", OSSL_TLS_GROUP_ID_gc256B },
    { "GC256C", OSSL_TLS_GROUP_ID_gc256C },
    { "GC256D", OSSL_TLS_GROUP_ID_gc256D },
    { "GC512A", OSSL_TLS_GROUP_ID_gc512A },
    { "GC512B", OSSL_TLS_GROUP_ID_gc512B },
    { "GC512C", OSSL_TLS_GROUP_ID_gc512C },
};

/*
 * Group list management:
 * We establish three lists along with their related size counters:
 * 1) List of (unique) groups
 * 2) List of number of groups per group-priority-tuple
 * 3) List of (unique) key share groups
 */
#define GROUPLIST_INCREMENT 32 /* Memory allocation chunk size (64 Bytes chunks ~= cache line) */
#define GROUP_NAME_BUFFER_LENGTH 64 /* Max length of a group name */

/*
 * Preparation of the prefix used to indicate the desire to send a key share,
 * the characters used as separators between groups or tuples of groups, the
 * character to indicate that an unknown group should be ignored, and the
 * character to indicate that a group should be deleted from a list
 */
#ifndef TUPLE_DELIMITER_CHARACTER
/* The prefix characters to indicate group tuple boundaries */
#define TUPLE_DELIMITER_CHARACTER '/'
#endif
#ifndef GROUP_DELIMITER_CHARACTER
/* The prefix characters to indicate group tuple boundaries */
#define GROUP_DELIMITER_CHARACTER ':'
#endif
#ifndef IGNORE_UNKNOWN_GROUP_CHARACTER
/* The prefix character to ignore unknown groups */
#define IGNORE_UNKNOWN_GROUP_CHARACTER '?'
#endif
#ifndef KEY_SHARE_INDICATOR_CHARACTER
/* The prefix character to trigger a key share addition */
#define KEY_SHARE_INDICATOR_CHARACTER '*'
#endif
#ifndef REMOVE_GROUP_INDICATOR_CHARACTER
/* The prefix character to trigger a key share removal */
#define REMOVE_GROUP_INDICATOR_CHARACTER '-'
#endif
static const char prefixes[] = { TUPLE_DELIMITER_CHARACTER,
    GROUP_DELIMITER_CHARACTER,
    IGNORE_UNKNOWN_GROUP_CHARACTER,
    KEY_SHARE_INDICATOR_CHARACTER,
    REMOVE_GROUP_INDICATOR_CHARACTER,
    '\0' };

/*
 * High-level description of how group strings are analyzed:
 * A first call back function (tuple_cb) is used to process group tuples, and a
 * second callback function (gid_cb) is used to process the groups inside a tuple.
 * Those callback functions are (indirectly) called by CONF_parse_list with
 * different separators (nominally ':' or '/'), a variable based on gid_cb_st
 * is used to keep track of the parsing results between the various calls
 */

typedef struct {
    SSL_CTX *ctx;
    /* Variables to hold the three lists (groups, requested keyshares, tuple structure) */
    size_t gidmax; /* The memory allocation chunk size for the group IDs */
    size_t gidcnt; /* Number of groups */
    uint16_t *gid_arr; /* The IDs of the supported groups (flat list) */
    size_t tplmax; /* The memory allocation chunk size for the tuple counters */
    size_t tplcnt; /* Number of tuples */
    size_t *tuplcnt_arr; /* The number of groups inside a tuple */
    size_t ksidmax; /* The memory allocation chunk size */
    size_t ksidcnt; /* Number of key shares */
    uint16_t *ksid_arr; /* The IDs of the key share groups (flat list) */
    /* Variable to keep state between execution of callback or helper functions */
    size_t tuple_mode; /* Keeps track whether tuple_cb called from 'the top' or from gid_cb */
    int ignore_unknown_default; /* Flag such that unknown groups for DEFAULT[_XYZ] are ignored */
} gid_cb_st;

/* Forward declaration of tuple callback function */
static int tuple_cb(const char *tuple, int len, void *arg);

/*
 * Extract and process the individual groups (and their prefixes if present)
 * present in a tuple. Note: The argument 'elem' is a NON-\0-terminated string
 * and must be appended by a \0 if used as \0-terminated string
 */
static int gid_cb(const char *elem, int len, void *arg)
{
    gid_cb_st *garg = arg;
    size_t i, j, k;
    uint16_t gid = 0;
    int found_group = 0;
    char etmp[GROUP_NAME_BUFFER_LENGTH];
    int retval = 1; /* We assume success */
    char *current_prefix;
    int ignore_unknown = 0;
    int add_keyshare = 0;
    int remove_group = 0;
    size_t restored_prefix_index = 0;
    char *restored_default_group_string;
    int continue_while_loop = 1;

    /* Sanity checks */
    if (garg == NULL || elem == NULL || len <= 0) {
        ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_CONFIG_VALUE);
        return 0;
    }

    /* Check the possible prefixes (remark: Leading and trailing spaces already cleared) */
    while (continue_while_loop && len > 0
        && ((current_prefix = strchr(prefixes, elem[0])) != NULL
            || OPENSSL_strncasecmp(current_prefix = (char *)DEFAULT_GROUPNAME_FIRST_CHARACTER, elem, 1) == 0)) {

        switch (*current_prefix) {
        case TUPLE_DELIMITER_CHARACTER:
            /* tuple delimiter not allowed here -> syntax error */
            return -1;
            break;
        case GROUP_DELIMITER_CHARACTER:
            return -1; /* Not a valid prefix for a single group name-> syntax error */
            break;
        case KEY_SHARE_INDICATOR_CHARACTER:
            if (add_keyshare)
                return -1; /* Only single key share prefix allowed -> syntax error */
            add_keyshare = 1;
            ++elem;
            --len;
            break;
        case REMOVE_GROUP_INDICATOR_CHARACTER:
            if (remove_group)
                return -1; /* Only single remove group prefix allowed -> syntax error */
            remove_group = 1;
            ++elem;
            --len;
            break;
        case IGNORE_UNKNOWN_GROUP_CHARACTER:
            if (ignore_unknown)
                return -1; /* Only single ? allowed -> syntax error */
            ignore_unknown = 1;
            ++elem;
            --len;
            break;
        default:
            /*
             * Check whether a DEFAULT[_XYZ] 'pseudo group' (= a built-in
             * list of groups) should be added
             */
            for (i = 0; i < OSSL_NELEM(default_group_strings); i++) {
                if ((size_t)len == (strlen(default_group_strings[i].list_name))
                    && OPENSSL_strncasecmp(default_group_strings[i].list_name, elem, len) == 0) {
                    /*
                     * We're asked to insert an entire list of groups from a
                     * DEFAULT[_XYZ] 'pseudo group' which we do by
                     * recursively calling this function (indirectly via
                     * CONF_parse_list and tuple_cb); essentially, we treat a DEFAULT
                     * group string like a tuple which is appended to the current tuple
                     * rather then starting a new tuple. Variable tuple_mode is the flag which
                     * controls append tuple vs start new tuple.
                     */

                    if (ignore_unknown || remove_group)
                        return -1; /* removal or ignore not allowed here -> syntax error */

                    /*
                     * First, we restore any keyshare prefix in a new zero-terminated string
                     * (if not already present)
                     */
                    restored_default_group_string = OPENSSL_malloc((1 /* max prefix length */ + strlen(default_group_strings[i].group_string) + 1 /* \0 */) * sizeof(char));
                    if (restored_default_group_string == NULL)
                        return 0;
                    if (add_keyshare
                        /* Remark: we tolerate a duplicated keyshare indicator here */
                        && default_group_strings[i].group_string[0]
                            != KEY_SHARE_INDICATOR_CHARACTER)
                        restored_default_group_string[restored_prefix_index++] = KEY_SHARE_INDICATOR_CHARACTER;

                    memcpy(restored_default_group_string + restored_prefix_index,
                        default_group_strings[i].group_string,
                        strlen(default_group_strings[i].group_string));
                    restored_default_group_string[strlen(default_group_strings[i].group_string) + restored_prefix_index] = '\0';
                    /* We execute the recursive call */
                    garg->ignore_unknown_default = 1; /* We ignore unknown groups for DEFAULT_XYZ */
                    /* we enforce group mode (= append tuple) for DEFAULT_XYZ group lists */
                    garg->tuple_mode = 0;
                    /* We use the tuple_cb callback to process the pseudo group tuple */
                    retval = CONF_parse_list(restored_default_group_string,
                        TUPLE_DELIMITER_CHARACTER, 1, tuple_cb, garg);
                    garg->tuple_mode = 1; /* next call to tuple_cb will again start new tuple */
                    garg->ignore_unknown_default = 0; /* reset to original value */
                    /* We don't need the \0-terminated string anymore */
                    OPENSSL_free(restored_default_group_string);

                    return retval;
                }
            }
            /*
             * If we reached this point, a group name started with a 'd' or 'D', but no request
             * for a DEFAULT[_XYZ] 'pseudo group' was detected, hence processing of the group
             * name can continue as usual (= the while loop checking prefixes can end)
             */
            continue_while_loop = 0;
            break;
        }
    }

    if (len == 0)
        return -1; /* Seems we have prefxes without a group name -> syntax error */

    if (garg->ignore_unknown_default == 1) /* Always ignore unknown groups for DEFAULT[_XYZ] */
        ignore_unknown = 1;

    /* Memory management in case more groups are present compared to initial allocation */
    if (garg->gidcnt == garg->gidmax) {
        uint16_t *tmp = OPENSSL_realloc(garg->gid_arr,
            (garg->gidmax + GROUPLIST_INCREMENT) * sizeof(*garg->gid_arr));

        if (tmp == NULL)
            return 0;

        garg->gidmax += GROUPLIST_INCREMENT;
        garg->gid_arr = tmp;
    }
    /* Memory management for key share groups */
    if (garg->ksidcnt == garg->ksidmax) {
        uint16_t *tmp = OPENSSL_realloc(garg->ksid_arr,
            (garg->ksidmax + GROUPLIST_INCREMENT) * sizeof(*garg->ksid_arr));

        if (tmp == NULL)
            return 0;
        garg->ksidmax += GROUPLIST_INCREMENT;
        garg->ksid_arr = tmp;
    }

    if (len > (int)(sizeof(etmp) - 1))
        return -1; /* group name to long  -> syntax error */

    /*
     * Prepare addition or removal of a single group by converting
     * a group name into its groupID equivalent
     */

    /* Create a \0-terminated string and get the gid for this group if possible */
    memcpy(etmp, elem, len);
    etmp[len] = 0;

    /* Get the groupID */
    gid = tls1_group_name2id(garg->ctx, etmp);
    /*
     * Handle the case where no valid groupID was returned
     * e.g. for an unknown group, which we'd ignore (only) if relevant prefix was set
     */
    if (gid == 0) {
        /* Is it one of the GOST groups ? */
        for (i = 0; i < OSSL_NELEM(name2id_arr); i++) {
            if (OPENSSL_strcasecmp(etmp, name2id_arr[i].group_name) == 0) {
                gid = name2id_arr[i].groupID;
                break;
            }
        }
        if (gid == 0) { /* still not found */
            /* Unknown group - ignore if ignore_unknown; trigger error otherwise */
            retval = ignore_unknown;
            goto done;
        }
    }

    /* Make sure that at least one provider is supporting this groupID */
    found_group = 0;
    for (j = 0; j < garg->ctx->group_list_len; j++)
        if (garg->ctx->group_list[j].group_id == gid) {
            found_group = 1;
            break;
        }

    /*
     * No provider supports this group - ignore if
     * ignore_unknown; trigger error otherwise
     */
    if (found_group == 0) {
        retval = ignore_unknown;
        goto done;
    }
    /* Remove group (and keyshare) from anywhere in the list if present, ignore if not present */
    if (remove_group) {
        /* Is the current group specified anywhere in the entire list so far? */
        found_group = 0;
        for (i = 0; i < garg->gidcnt; i++)
            if (garg->gid_arr[i] == gid) {
                found_group = 1;
                break;
            }
        /* The group to remove is at position i in the list of (zero indexed) groups */
        if (found_group) {
            /* We remove that group from its position (which is at i)... */
            for (j = i; j < (garg->gidcnt - 1); j++)
                garg->gid_arr[j] = garg->gid_arr[j + 1]; /* ...shift remaining groups left ... */
            garg->gidcnt--; /* ..and update the book keeping for the number of groups */

            /*
             * We also must update the number of groups either in a previous tuple (which we
             * must identify and check whether it becomes empty due to the deletion) or in
             * the current tuple, pending where the deleted group resides
             */
            k = 0;
            for (j = 0; j < garg->tplcnt; j++) {
                k += garg->tuplcnt_arr[j];
                /* Remark: i is zero-indexed, k is one-indexed */
                if (k > i) { /* remove from one of the previous tuples */
                    garg->tuplcnt_arr[j]--;
                    break; /* We took care not to have group duplicates, hence we can stop here */
                }
            }
            if (k <= i) /* remove from current tuple */
                garg->tuplcnt_arr[j]--;

            /* We also remove the group from the list of keyshares (if present) */
            found_group = 0;
            for (i = 0; i < garg->ksidcnt; i++)
                if (garg->ksid_arr[i] == gid) {
                    found_group = 1;
                    break;
                }
            if (found_group) {
                /* Found, hence we remove that keyshare from its position (which is at i)... */
                for (j = i; j < (garg->ksidcnt - 1); j++)
                    garg->ksid_arr[j] = garg->ksid_arr[j + 1]; /* shift remaining key shares */
                /* ... and update the book keeping */
                garg->ksidcnt--;
            }
        }
    } else { /* Processing addition of a single new group */

        /* Check for duplicates */
        for (i = 0; i < garg->gidcnt; i++)
            if (garg->gid_arr[i] == gid) {
                /* Duplicate group anywhere in the list of groups - ignore */
                goto done;
            }

        /* Add the current group to the 'flat' list of groups */
        garg->gid_arr[garg->gidcnt++] = gid;
        /* and update the book keeping for the number of groups in current tuple */
        garg->tuplcnt_arr[garg->tplcnt]++;

        /* We memorize if needed that we want to add a key share for the current group */
        if (add_keyshare)
            garg->ksid_arr[garg->ksidcnt++] = gid;
    }

done:
    return retval;
}

/* Extract and process a tuple of groups */
static int tuple_cb(const char *tuple, int len, void *arg)
{
    gid_cb_st *garg = arg;
    int retval = 1; /* We assume success */
    char *restored_tuple_string;

    /* Sanity checks */
    if (garg == NULL || tuple == NULL || len <= 0) {
        ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_CONFIG_VALUE);
        return 0;
    }

    /* Memory management for tuples */
    if (garg->tplcnt == garg->tplmax) {
        size_t *tmp = OPENSSL_realloc(garg->tuplcnt_arr,
            (garg->tplmax + GROUPLIST_INCREMENT) * sizeof(*garg->tuplcnt_arr));

        if (tmp == NULL)
            return 0;
        garg->tplmax += GROUPLIST_INCREMENT;
        garg->tuplcnt_arr = tmp;
    }

    /* Convert to \0-terminated string */
    restored_tuple_string = OPENSSL_malloc((len + 1 /* \0 */) * sizeof(char));
    if (restored_tuple_string == NULL)
        return 0;
    memcpy(restored_tuple_string, tuple, len);
    restored_tuple_string[len] = '\0';

    /* Analyze group list of this tuple */
    retval = CONF_parse_list(restored_tuple_string, GROUP_DELIMITER_CHARACTER, 1, gid_cb, arg);

    /* We don't need the \o-terminated string anymore */
    OPENSSL_free(restored_tuple_string);

    if (garg->tuplcnt_arr[garg->tplcnt] > 0) { /* Some valid groups are present in current tuple... */
        if (garg->tuple_mode) {
            /* We 'close' the tuple */
            garg->tplcnt++;
            garg->tuplcnt_arr[garg->tplcnt] = 0; /* Next tuple is initialized to be empty */
            garg->tuple_mode = 1; /* next call will start a tuple (unless overridden in gid_cb) */
        }
    }

    return retval;
}

/*
 * Set groups and prepare generation of keyshares based on a string of groupnames,
 * names separated by the group or the tuple delimiter, with per-group prefixes to
 * (1) add a key share for this group, (2) ignore the group if unknown to the current
 * context, (3) delete a previous occurrence of the group in the current tuple.
 *
 * The list parsing is done in two hierarchical steps: The top-level step extracts the
 * string of a tuple using tuple_cb, while the next lower step uses gid_cb to
 * parse and process the groups inside a tuple
 */
int tls1_set_groups_list(SSL_CTX *ctx,
    uint16_t **grpext, size_t *grpextlen,
    uint16_t **ksext, size_t *ksextlen,
    size_t **tplext, size_t *tplextlen,
    const char *str)
{
    size_t i = 0, j;
    int ret = 0, parse_ret = 0;
    gid_cb_st gcb;

    /* Sanity check */
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_SSL, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }

    memset(&gcb, 0, sizeof(gcb));
    gcb.tuple_mode = 1; /* We prepare to collect the first tuple */
    gcb.ignore_unknown_default = 0;
    gcb.gidmax = GROUPLIST_INCREMENT;
    gcb.tplmax = GROUPLIST_INCREMENT;
    gcb.ksidmax = GROUPLIST_INCREMENT;
    gcb.ctx = ctx;

    /* Prepare initial chunks of memory for groups, tuples and keyshares groupIDs */
    gcb.gid_arr = OPENSSL_malloc(gcb.gidmax * sizeof(*gcb.gid_arr));
    if (gcb.gid_arr == NULL)
        goto end;
    gcb.tuplcnt_arr = OPENSSL_malloc(gcb.tplmax * sizeof(*gcb.tuplcnt_arr));
    if (gcb.tuplcnt_arr == NULL)
        goto end;
    gcb.tuplcnt_arr[0] = 0;
    gcb.ksid_arr = OPENSSL_malloc(gcb.ksidmax * sizeof(*gcb.ksid_arr));
    if (gcb.ksid_arr == NULL)
        goto end;

    while (str[0] != '\0' && isspace((unsigned char)*str))
        str++;
    if (str[0] == '\0')
        goto empty_list;

    /*
     * Start the (potentially recursive) tuple processing by calling CONF_parse_list
     * with the TUPLE_DELIMITER_CHARACTER (which will call tuple_cb after cleaning spaces)
     */
    parse_ret = CONF_parse_list(str, TUPLE_DELIMITER_CHARACTER, 1, tuple_cb, &gcb);

    if (parse_ret == 0)
        goto end;
    if (parse_ret == -1) {
        ERR_raise_data(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT,
            "Syntax error in '%s'", str);
        goto end;
    }

    /*
     * We check whether a tuple was completely emptied by using "-" prefix
     * excessively, in which case we remove the tuple
     */
    for (i = j = 0; j < gcb.tplcnt; j++) {
        if (gcb.tuplcnt_arr[j] == 0)
            continue;
        /* If there's a gap, move to first unfilled slot */
        if (j == i)
            ++i;
        else
            gcb.tuplcnt_arr[i++] = gcb.tuplcnt_arr[j];
    }
    gcb.tplcnt = i;

    if (gcb.ksidcnt > OPENSSL_CLIENT_MAX_KEY_SHARES) {
        ERR_raise_data(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT,
            "To many keyshares requested in '%s' (max = %d)",
            str, OPENSSL_CLIENT_MAX_KEY_SHARES);
        goto end;
    }

    /*
     * For backward compatibility we let the rest of the code know that a key share
     * for the first valid group should be added if no "*" prefix was used anywhere
     */
    if (gcb.gidcnt > 0 && gcb.ksidcnt == 0) {
        /*
         * No key share group prefix character was used, hence we indicate that a single
         * key share should be sent and flag that it should come from the supported_groups list
         */
        gcb.ksidcnt = 1;
        gcb.ksid_arr[0] = 0;
    }

empty_list:
    /*
     * A call to tls1_set_groups_list with any of the args (other than ctx) set
     * to NULL only does a syntax check, hence we're done here and report success
     */
    if (grpext == NULL || ksext == NULL || tplext == NULL || grpextlen == NULL || ksextlen == NULL || tplextlen == NULL) {
        ret = 1;
        goto end;
    }

    /*
     * tuple_cb and gid_cb combo ensures there are no duplicates or unknown groups so we
     * can just go ahead and set the results (after disposing the existing)
     */
    OPENSSL_free(*grpext);
    *grpext = gcb.gid_arr;
    *grpextlen = gcb.gidcnt;
    OPENSSL_free(*ksext);
    *ksext = gcb.ksid_arr;
    *ksextlen = gcb.ksidcnt;
    OPENSSL_free(*tplext);
    *tplext = gcb.tuplcnt_arr;
    *tplextlen = gcb.tplcnt;

    return 1;

end:
    OPENSSL_free(gcb.gid_arr);
    OPENSSL_free(gcb.tuplcnt_arr);
    OPENSSL_free(gcb.ksid_arr);
    return ret;
}

/* Check a group id matches preferences */
int tls1_check_group_id(SSL_CONNECTION *s, uint16_t group_id,
    int check_own_groups)
{
    const uint16_t *groups;
    size_t groups_len;

    if (group_id == 0)
        return 0;

    /* Check for Suite B compliance */
    if (tls1_suiteb(s) && s->s3.tmp.new_cipher != NULL) {
        unsigned long cid = s->s3.tmp.new_cipher->id;

        if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256) {
            if (group_id != OSSL_TLS_GROUP_ID_secp256r1)
                return 0;
        } else if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384) {
            if (group_id != OSSL_TLS_GROUP_ID_secp384r1)
                return 0;
        } else {
            /* Should never happen */
            return 0;
        }
    }

    if (check_own_groups) {
        /* Check group is one of our preferences */
        tls1_get_supported_groups(s, &groups, &groups_len);
        if (!tls1_in_list(group_id, groups, groups_len))
            return 0;
    }

    if (!tls_group_allowed(s, group_id, SSL_SECOP_CURVE_CHECK))
        return 0;

    /* For clients, nothing more to check */
    if (!s->server)
        return 1;

    /* Check group is one of peers preferences */
    tls1_get_peer_groups(s, &groups, &groups_len);

    /*
     * RFC 4492 does not require the supported elliptic curves extension
     * so if it is not sent we can just choose any curve.
     * It is invalid to send an empty list in the supported groups
     * extension, so groups_len == 0 always means no extension.
     */
    if (groups_len == 0)
        return 1;
    return tls1_in_list(group_id, groups, groups_len);
}

void tls1_get_formatlist(SSL_CONNECTION *s, const unsigned char **pformats,
    size_t *num_formats)
{
    /*
     * If we have a custom point format list use it otherwise use default
     */
    if (s->ext.ecpointformats) {
        *pformats = s->ext.ecpointformats;
        *num_formats = s->ext.ecpointformats_len;
    } else {
        *pformats = ecformats_default;
        /* For Suite B we don't support char2 fields */
        if (tls1_suiteb(s))
            *num_formats = sizeof(ecformats_default) - 1;
        else
            *num_formats = sizeof(ecformats_default);
    }
}

/* Check a key is compatible with compression extension */
static int tls1_check_pkey_comp(SSL_CONNECTION *s, EVP_PKEY *pkey)
{
    unsigned char comp_id;
    size_t i;
    int point_conv;

    /* If not an EC key nothing to check */
    if (!EVP_PKEY_is_a(pkey, "EC"))
        return 1;

    /* Get required compression id */
    point_conv = EVP_PKEY_get_ec_point_conv_form(pkey);
    if (point_conv == 0)
        return 0;
    if (point_conv == POINT_CONVERSION_UNCOMPRESSED) {
        comp_id = TLSEXT_ECPOINTFORMAT_uncompressed;
    } else if (SSL_CONNECTION_IS_TLS13(s)) {
        /*
         * ec_point_formats extension is not used in TLSv1.3 so we ignore
         * this check.
         */
        return 1;
    } else {
        int field_type = EVP_PKEY_get_field_type(pkey);

        if (field_type == NID_X9_62_prime_field)
            comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime;
        else if (field_type == NID_X9_62_characteristic_two_field)
            comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_char2;
        else
            return 0;
    }
    /*
     * If point formats extension present check it, otherwise everything is
     * supported (see RFC4492).
     */
    if (s->ext.peer_ecpointformats == NULL)
        return 1;

    for (i = 0; i < s->ext.peer_ecpointformats_len; i++) {
        if (s->ext.peer_ecpointformats[i] == comp_id)
            return 1;
    }
    return 0;
}

/* Return group id of a key */
static uint16_t tls1_get_group_id(EVP_PKEY *pkey)
{
    int curve_nid = ssl_get_EC_curve_nid(pkey);

    if (curve_nid == NID_undef)
        return 0;
    return tls1_nid2group_id(curve_nid);
}

/*
 * Check cert parameters compatible with extensions: currently just checks EC
 * certificates have compatible curves and compression.
 */
static int tls1_check_cert_param(SSL_CONNECTION *s, X509 *x, int check_ee_md)
{
    uint16_t group_id;
    EVP_PKEY *pkey;
    pkey = X509_get0_pubkey(x);
    if (pkey == NULL)
        return 0;
    /* If not EC nothing to do */
    if (!EVP_PKEY_is_a(pkey, "EC"))
        return 1;
    /* Check compression */
    if (!tls1_check_pkey_comp(s, pkey))
        return 0;
    group_id = tls1_get_group_id(pkey);
    /*
     * For a server we allow the certificate to not be in our list of supported
     * groups.
     */
    if (!tls1_check_group_id(s, group_id, !s->server))
        return 0;
    /*
     * Special case for suite B. We *MUST* sign using SHA256+P-256 or
     * SHA384+P-384.
     */
    if (check_ee_md && tls1_suiteb(s)) {
        int check_md;
        size_t i;

        /* Check to see we have necessary signing algorithm */
        if (group_id == OSSL_TLS_GROUP_ID_secp256r1)
            check_md = NID_ecdsa_with_SHA256;
        else if (group_id == OSSL_TLS_GROUP_ID_secp384r1)
            check_md = NID_ecdsa_with_SHA384;
        else
            return 0; /* Should never happen */
        for (i = 0; i < s->shared_sigalgslen; i++) {
            if (check_md == s->shared_sigalgs[i]->sigandhash)
                return 1;
        }
        return 0;
    }
    return 1;
}

/*
 * tls1_check_ec_tmp_key - Check EC temporary key compatibility
 * @s: SSL connection
 * @cid: Cipher ID we're considering using
 *
 * Checks that the kECDHE cipher suite we're considering using
 * is compatible with the client extensions.
 *
 * Returns 0 when the cipher can't be used or 1 when it can.
 */
int tls1_check_ec_tmp_key(SSL_CONNECTION *s, unsigned long cid)
{
    /* If not Suite B just need a shared group */
    if (!tls1_suiteb(s))
        return tls1_shared_group(s, 0) != 0;
    /*
     * If Suite B, AES128 MUST use P-256 and AES256 MUST use P-384, no other
     * curves permitted.
     */
    if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256)
        return tls1_check_group_id(s, OSSL_TLS_GROUP_ID_secp256r1, 1);
    if (cid == TLS1_CK_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384)
        return tls1_check_group_id(s, OSSL_TLS_GROUP_ID_secp384r1, 1);

    return 0;
}

/* Default sigalg schemes */
static const uint16_t tls12_sigalgs[] = {
    TLSEXT_SIGALG_mldsa65,
    TLSEXT_SIGALG_mldsa87,
    TLSEXT_SIGALG_mldsa44,
    TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
    TLSEXT_SIGALG_ecdsa_secp384r1_sha384,
    TLSEXT_SIGALG_ecdsa_secp521r1_sha512,
    TLSEXT_SIGALG_ed25519,
    TLSEXT_SIGALG_ed448,
    TLSEXT_SIGALG_ecdsa_brainpoolP256r1_sha256,
    TLSEXT_SIGALG_ecdsa_brainpoolP384r1_sha384,
    TLSEXT_SIGALG_ecdsa_brainpoolP512r1_sha512,

    TLSEXT_SIGALG_rsa_pss_pss_sha256,
    TLSEXT_SIGALG_rsa_pss_pss_sha384,
    TLSEXT_SIGALG_rsa_pss_pss_sha512,
    TLSEXT_SIGALG_rsa_pss_rsae_sha256,
    TLSEXT_SIGALG_rsa_pss_rsae_sha384,
    TLSEXT_SIGALG_rsa_pss_rsae_sha512,

    TLSEXT_SIGALG_rsa_pkcs1_sha256,
    TLSEXT_SIGALG_rsa_pkcs1_sha384,
    TLSEXT_SIGALG_rsa_pkcs1_sha512,

    TLSEXT_SIGALG_ecdsa_sha224,
    TLSEXT_SIGALG_ecdsa_sha1,

    TLSEXT_SIGALG_rsa_pkcs1_sha224,
    TLSEXT_SIGALG_rsa_pkcs1_sha1,

    TLSEXT_SIGALG_dsa_sha224,
    TLSEXT_SIGALG_dsa_sha1,

    TLSEXT_SIGALG_dsa_sha256,
    TLSEXT_SIGALG_dsa_sha384,
    TLSEXT_SIGALG_dsa_sha512,

#ifndef OPENSSL_NO_GOST
    TLSEXT_SIGALG_gostr34102012_256_intrinsic,
    TLSEXT_SIGALG_gostr34102012_512_intrinsic,
    TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256,
    TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512,
    TLSEXT_SIGALG_gostr34102001_gostr3411,
#endif
};

static const uint16_t suiteb_sigalgs[] = {
    TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
    TLSEXT_SIGALG_ecdsa_secp384r1_sha384
};

static const SIGALG_LOOKUP sigalg_lookup_tbl[] = {
    { TLSEXT_SIGALG_ecdsa_secp256r1_sha256_name,
        "ECDSA+SHA256", TLSEXT_SIGALG_ecdsa_secp256r1_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA256, NID_X9_62_prime256v1, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_ecdsa_secp384r1_sha384_name,
        "ECDSA+SHA384", TLSEXT_SIGALG_ecdsa_secp384r1_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA384, NID_secp384r1, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_ecdsa_secp521r1_sha512_name,
        "ECDSA+SHA512", TLSEXT_SIGALG_ecdsa_secp521r1_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA512, NID_secp521r1, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },

    { TLSEXT_SIGALG_ed25519_name,
        NULL, TLSEXT_SIGALG_ed25519,
        NID_undef, -1, EVP_PKEY_ED25519, SSL_PKEY_ED25519,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_ed448_name,
        NULL, TLSEXT_SIGALG_ed448,
        NID_undef, -1, EVP_PKEY_ED448, SSL_PKEY_ED448,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },

    { TLSEXT_SIGALG_ecdsa_sha224_name,
        "ECDSA+SHA224", TLSEXT_SIGALG_ecdsa_sha224,
        NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA224, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_ecdsa_sha1_name,
        "ECDSA+SHA1", TLSEXT_SIGALG_ecdsa_sha1,
        NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA1, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },

    { TLSEXT_SIGALG_ecdsa_brainpoolP256r1_sha256_name,
        TLSEXT_SIGALG_ecdsa_brainpoolP256r1_sha256_alias,
        TLSEXT_SIGALG_ecdsa_brainpoolP256r1_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA256, NID_brainpoolP256r1, 1, 0,
        TLS1_3_VERSION, 0, -1, -1 },
    { TLSEXT_SIGALG_ecdsa_brainpoolP384r1_sha384_name,
        TLSEXT_SIGALG_ecdsa_brainpoolP384r1_sha384_alias,
        TLSEXT_SIGALG_ecdsa_brainpoolP384r1_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA384, NID_brainpoolP384r1, 1, 0,
        TLS1_3_VERSION, 0, -1, -1 },
    { TLSEXT_SIGALG_ecdsa_brainpoolP512r1_sha512_name,
        TLSEXT_SIGALG_ecdsa_brainpoolP512r1_sha512_alias,
        TLSEXT_SIGALG_ecdsa_brainpoolP512r1_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_EC, SSL_PKEY_ECC,
        NID_ecdsa_with_SHA512, NID_brainpoolP512r1, 1, 0,
        TLS1_3_VERSION, 0, -1, -1 },

    { TLSEXT_SIGALG_rsa_pss_rsae_sha256_name,
        "PSS+SHA256", TLSEXT_SIGALG_rsa_pss_rsae_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pss_rsae_sha384_name,
        "PSS+SHA384", TLSEXT_SIGALG_rsa_pss_rsae_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pss_rsae_sha512_name,
        "PSS+SHA512", TLSEXT_SIGALG_rsa_pss_rsae_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },

    { TLSEXT_SIGALG_rsa_pss_pss_sha256_name,
        NULL, TLSEXT_SIGALG_rsa_pss_pss_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pss_pss_sha384_name,
        NULL, TLSEXT_SIGALG_rsa_pss_pss_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pss_pss_sha512_name,
        NULL, TLSEXT_SIGALG_rsa_pss_pss_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA_PSS, SSL_PKEY_RSA_PSS_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },

    { TLSEXT_SIGALG_rsa_pkcs1_sha256_name,
        "RSA+SHA256", TLSEXT_SIGALG_rsa_pkcs1_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
        NID_sha256WithRSAEncryption, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pkcs1_sha384_name,
        "RSA+SHA384", TLSEXT_SIGALG_rsa_pkcs1_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
        NID_sha384WithRSAEncryption, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },
    { TLSEXT_SIGALG_rsa_pkcs1_sha512_name,
        "RSA+SHA512", TLSEXT_SIGALG_rsa_pkcs1_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
        NID_sha512WithRSAEncryption, NID_undef, 1, 0,
        TLS1_2_VERSION, 0, DTLS1_2_VERSION, 0 },

    { TLSEXT_SIGALG_rsa_pkcs1_sha224_name,
        "RSA+SHA224", TLSEXT_SIGALG_rsa_pkcs1_sha224,
        NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
        NID_sha224WithRSAEncryption, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_rsa_pkcs1_sha1_name,
        "RSA+SHA1", TLSEXT_SIGALG_rsa_pkcs1_sha1,
        NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_RSA, SSL_PKEY_RSA,
        NID_sha1WithRSAEncryption, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },

    { TLSEXT_SIGALG_dsa_sha256_name,
        "DSA+SHA256", TLSEXT_SIGALG_dsa_sha256,
        NID_sha256, SSL_MD_SHA256_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
        NID_dsa_with_SHA256, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_dsa_sha384_name,
        "DSA+SHA384", TLSEXT_SIGALG_dsa_sha384,
        NID_sha384, SSL_MD_SHA384_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_dsa_sha512_name,
        "DSA+SHA512", TLSEXT_SIGALG_dsa_sha512,
        NID_sha512, SSL_MD_SHA512_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_dsa_sha224_name,
        "DSA+SHA224", TLSEXT_SIGALG_dsa_sha224,
        NID_sha224, SSL_MD_SHA224_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_dsa_sha1_name,
        "DSA+SHA1", TLSEXT_SIGALG_dsa_sha1,
        NID_sha1, SSL_MD_SHA1_IDX, EVP_PKEY_DSA, SSL_PKEY_DSA_SIGN,
        NID_dsaWithSHA1, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },

#ifndef OPENSSL_NO_GOST
    { TLSEXT_SIGALG_gostr34102012_256_intrinsic_alias, /* RFC9189 */
        TLSEXT_SIGALG_gostr34102012_256_intrinsic_name,
        TLSEXT_SIGALG_gostr34102012_256_intrinsic,
        NID_id_GostR3411_2012_256, SSL_MD_GOST12_256_IDX,
        NID_id_GostR3410_2012_256, SSL_PKEY_GOST12_256,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_gostr34102012_256_intrinsic_alias, /* RFC9189 */
        TLSEXT_SIGALG_gostr34102012_256_intrinsic_name,
        TLSEXT_SIGALG_gostr34102012_512_intrinsic,
        NID_id_GostR3411_2012_512, SSL_MD_GOST12_512_IDX,
        NID_id_GostR3410_2012_512, SSL_PKEY_GOST12_512,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },

    { TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256_name,
        NULL, TLSEXT_SIGALG_gostr34102012_256_gostr34112012_256,
        NID_id_GostR3411_2012_256, SSL_MD_GOST12_256_IDX,
        NID_id_GostR3410_2012_256, SSL_PKEY_GOST12_256,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512_name,
        NULL, TLSEXT_SIGALG_gostr34102012_512_gostr34112012_512,
        NID_id_GostR3411_2012_512, SSL_MD_GOST12_512_IDX,
        NID_id_GostR3410_2012_512, SSL_PKEY_GOST12_512,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
    { TLSEXT_SIGALG_gostr34102001_gostr3411_name,
        NULL, TLSEXT_SIGALG_gostr34102001_gostr3411,
        NID_id_GostR3411_94, SSL_MD_GOST94_IDX,
        NID_id_GostR3410_2001, SSL_PKEY_GOST01,
        NID_undef, NID_undef, 1, 0,
        TLS1_2_VERSION, TLS1_2_VERSION, DTLS1_2_VERSION, DTLS1_2_VERSION },
#endif
};
/* Legacy sigalgs for TLS < 1.2 RSA TLS signatures */
static const SIGALG_LOOKUP legacy_rsa_sigalg = {
    "rsa_pkcs1_md5_sha1", NULL, 0,
    NID_md5_sha1, SSL_MD_MD5_SHA1_IDX,
    EVP_PKEY_RSA, SSL_PKEY_RSA,
    NID_undef, NID_undef, 1, 0,
    TLS1_VERSION, TLS1_2_VERSION, DTLS1_VERSION, DTLS1_2_VERSION
};

/*
 * Default signature algorithm values used if signature algorithms not present.
 * From RFC5246. Note: order must match certificate index order.
 */
static const uint16_t tls_default_sigalg[] = {
    TLSEXT_SIGALG_rsa_pkcs1_sha1, /* SSL_PKEY_RSA */
    0, /* SSL_PKEY_RSA_PSS_SIGN */
    TLSEXT_SIGALG_dsa_sha1, /* SSL_PKEY_DSA_SIGN */
    TLSEXT_SIGALG_ecdsa_sha1, /* SSL_PKEY_ECC */
    TLSEXT_SIGALG_gostr34102001_gostr3411, /* SSL_PKEY_GOST01 */
    TLSEXT_SIGALG_gostr34102012_256_intrinsic, /* SSL_PKEY_GOST12_256 */
    TLSEXT_SIGALG_gostr34102012_512_intrinsic, /* SSL_PKEY_GOST12_512 */
    0, /* SSL_PKEY_ED25519 */
    0, /* SSL_PKEY_ED448 */
};

int ssl_setup_sigalgs(SSL_CTX *ctx)
{
    size_t i, cache_idx, sigalgs_len, enabled;
    const SIGALG_LOOKUP *lu;
    SIGALG_LOOKUP *cache = NULL;
    uint16_t *tls12_sigalgs_list = NULL;
    EVP_PKEY *tmpkey = EVP_PKEY_new();
    int istls;
    int ret = 0;

    if (ctx == NULL)
        goto err;

    istls = !SSL_CTX_IS_DTLS(ctx);

    sigalgs_len = OSSL_NELEM(sigalg_lookup_tbl) + ctx->sigalg_list_len;

    cache = OPENSSL_zalloc(sizeof(const SIGALG_LOOKUP) * sigalgs_len);
    if (cache == NULL || tmpkey == NULL)
        goto err;

    tls12_sigalgs_list = OPENSSL_zalloc(sizeof(uint16_t) * sigalgs_len);
    if (tls12_sigalgs_list == NULL)
        goto err;

    ERR_set_mark();
    /* First fill cache and tls12_sigalgs list from legacy algorithm list */
    for (i = 0, lu = sigalg_lookup_tbl;
        i < OSSL_NELEM(sigalg_lookup_tbl); lu++, i++) {
        EVP_PKEY_CTX *pctx;

        cache[i] = *lu;

        /*
         * Check hash is available.
         * This test is not perfect. A provider could have support
         * for a signature scheme, but not a particular hash. However the hash
         * could be available from some other loaded provider. In that case it
         * could be that the signature is available, and the hash is available
         * independently - but not as a combination. We ignore this for now.
         */
        if (lu->hash != NID_undef
            && ctx->ssl_digest_methods[lu->hash_idx] == NULL) {
            cache[i].available = 0;
            continue;
        }

        if (!EVP_PKEY_set_type(tmpkey, lu->sig)) {
            cache[i].available = 0;
            continue;
        }
        pctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx, tmpkey, ctx->propq);
        /* If unable to create pctx we assume the sig algorithm is unavailable */
        if (pctx == NULL)
            cache[i].available = 0;
        EVP_PKEY_CTX_free(pctx);
    }

    /* Now complete cache and tls12_sigalgs list with provider sig information */
    cache_idx = OSSL_NELEM(sigalg_lookup_tbl);
    for (i = 0; i < ctx->sigalg_list_len; i++) {
        TLS_SIGALG_INFO si = ctx->sigalg_list[i];
        cache[cache_idx].name = si.name;
        cache[cache_idx].name12 = si.sigalg_name;
        cache[cache_idx].sigalg = si.code_point;
        tls12_sigalgs_list[cache_idx] = si.code_point;
        cache[cache_idx].hash = si.hash_name ? OBJ_txt2nid(si.hash_name) : NID_undef;
        cache[cache_idx].hash_idx = ssl_get_md_idx(cache[cache_idx].hash);
        cache[cache_idx].sig = OBJ_txt2nid(si.sigalg_name);
        cache[cache_idx].sig_idx = i + SSL_PKEY_NUM;
        cache[cache_idx].sigandhash = OBJ_txt2nid(si.sigalg_name);
        cache[cache_idx].curve = NID_undef;
        cache[cache_idx].mintls = TLS1_3_VERSION;
        cache[cache_idx].maxtls = TLS1_3_VERSION;
        cache[cache_idx].mindtls = -1;
        cache[cache_idx].maxdtls = -1;
        /* Compatibility with TLS 1.3 is checked on load */
        cache[cache_idx].available = istls;
        cache[cache_idx].advertise = 0;
        cache_idx++;
    }
    ERR_pop_to_mark();

    enabled = 0;
    for (i = 0; i < OSSL_NELEM(tls12_sigalgs); ++i) {
        SIGALG_LOOKUP *ent = cache;
        size_t j;

        for (j = 0; j < sigalgs_len; ent++, j++) {
            if (ent->sigalg != tls12_sigalgs[i])
                continue;
            /* Dedup by marking cache entry as default enabled. */
            if (ent->available && !ent->advertise) {
                ent->advertise = 1;
                tls12_sigalgs_list[enabled++] = tls12_sigalgs[i];
            }
            break;
        }
    }

    /* Append any provider sigalgs not yet handled */
    for (i = OSSL_NELEM(sigalg_lookup_tbl); i < sigalgs_len; ++i) {
        SIGALG_LOOKUP *ent = &cache[i];

        if (ent->available && !ent->advertise)
            tls12_sigalgs_list[enabled++] = ent->sigalg;
    }

    ctx->sigalg_lookup_cache = cache;
    ctx->sigalg_lookup_cache_len = sigalgs_len;
    ctx->tls12_sigalgs = tls12_sigalgs_list;
    ctx->tls12_sigalgs_len = enabled;
    cache = NULL;
    tls12_sigalgs_list = NULL;

    ret = 1;
err:
    OPENSSL_free(cache);
    OPENSSL_free(tls12_sigalgs_list);
    EVP_PKEY_free(tmpkey);
    return ret;
}

#define SIGLEN_BUF_INCREMENT 100

char *SSL_get1_builtin_sigalgs(OSSL_LIB_CTX *libctx)
{
    size_t i, maxretlen = SIGLEN_BUF_INCREMENT;
    const SIGALG_LOOKUP *lu;
    EVP_PKEY *tmpkey = EVP_PKEY_new();
    char *retval = OPENSSL_malloc(maxretlen);

    if (retval == NULL)
        return NULL;

    /* ensure retval string is NUL terminated */
    retval[0] = (char)0;

    for (i = 0, lu = sigalg_lookup_tbl;
        i < OSSL_NELEM(sigalg_lookup_tbl); lu++, i++) {
        EVP_PKEY_CTX *pctx;
        int enabled = 1;

        ERR_set_mark();
        /* Check hash is available in some provider. */
        if (lu->hash != NID_undef) {
            EVP_MD *hash = EVP_MD_fetch(libctx, OBJ_nid2ln(lu->hash), NULL);

            /* If unable to create we assume the hash algorithm is unavailable */
            if (hash == NULL) {
                enabled = 0;
                ERR_pop_to_mark();
                continue;
            }
            EVP_MD_free(hash);
        }

        if (!EVP_PKEY_set_type(tmpkey, lu->sig)) {
            enabled = 0;
            ERR_pop_to_mark();
            continue;
        }
        pctx = EVP_PKEY_CTX_new_from_pkey(libctx, tmpkey, NULL);
        /* If unable to create pctx we assume the sig algorithm is unavailable */
        if (pctx == NULL)
            enabled = 0;
        ERR_pop_to_mark();
        EVP_PKEY_CTX_free(pctx);

        if (enabled) {
            const char *sa = lu->name;

            if (sa != NULL) {
                if (strlen(sa) + strlen(retval) + 1 >= maxretlen) {
                    char *tmp;

                    maxretlen += SIGLEN_BUF_INCREMENT;
                    tmp = OPENSSL_realloc(retval, maxretlen);
                    if (tmp == NULL) {
                        OPENSSL_free(retval);
                        return NULL;
                    }
                    retval = tmp;
                }
                if (strlen(retval) > 0)
                    OPENSSL_strlcat(retval, ":", maxretlen);
                OPENSSL_strlcat(retval, sa, maxretlen);
            } else {
                /* lu->name must not be NULL */
                ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR);
            }
        }
    }

    EVP_PKEY_free(tmpkey);
    return retval;
}

/* Lookup TLS signature algorithm */
static const SIGALG_LOOKUP *tls1_lookup_sigalg(const SSL_CTX *ctx,
    uint16_t sigalg)
{
    size_t i;
    const SIGALG_LOOKUP *lu = ctx->sigalg_lookup_cache;

    for (i = 0; i < ctx->sigalg_lookup_cache_len; lu++, i++) {
        if (lu->sigalg == sigalg) {
            if (!lu->available)
                return NULL;
            return lu;
        }
    }
    return NULL;
}

/* Lookup hash: return 0 if invalid or not enabled */
int tls1_lookup_md(SSL_CTX *ctx, const SIGALG_LOOKUP *lu, const EVP_MD **pmd)
{
    const EVP_MD *md;

    if (lu == NULL)
        return 0;
    /* lu->hash == NID_undef means no associated digest */
    if (lu->hash == NID_undef) {
        md = NULL;
    } else {
        md = ssl_md(ctx, lu->hash_idx);
        if (md == NULL)
            return 0;
    }
    if (pmd)
        *pmd = md;
    return 1;
}

/*
 * Check if key is large enough to generate RSA-PSS signature.
 *
 * The key must greater than or equal to 2 * hash length + 2.
 * SHA512 has a hash length of 64 bytes, which is incompatible
 * with a 128 byte (1024 bit) key.
 */
#define RSA_PSS_MINIMUM_KEY_SIZE(md) (2 * EVP_MD_get_size(md) + 2)
static int rsa_pss_check_min_key_size(SSL_CTX *ctx, const EVP_PKEY *pkey,
    const SIGALG_LOOKUP *lu)
{
    const EVP_MD *md;

    if (pkey == NULL)
        return 0;
    if (!tls1_lookup_md(ctx, lu, &md) || md == NULL)
        return 0;
    if (EVP_MD_get_size(md) <= 0)
        return 0;
    if (EVP_PKEY_get_size(pkey) < RSA_PSS_MINIMUM_KEY_SIZE(md))
        return 0;
    return 1;
}

/*
 * Returns a signature algorithm when the peer did not send a list of supported
 * signature algorithms. The signature algorithm is fixed for the certificate
 * type. |idx| is a certificate type index (SSL_PKEY_*). When |idx| is -1 the
 * certificate type from |s| will be used.
 * Returns the signature algorithm to use, or NULL on error.
 */
static const SIGALG_LOOKUP *tls1_get_legacy_sigalg(const SSL_CONNECTION *s,
    int idx)
{
    if (idx == -1) {
        if (s->server) {
            size_t i;

            /* Work out index corresponding to ciphersuite */
            for (i = 0; i < s->ssl_pkey_num; i++) {
                const SSL_CERT_LOOKUP *clu
                    = ssl_cert_lookup_by_idx(i, SSL_CONNECTION_GET_CTX(s));

                if (clu == NULL)
                    continue;
                if (clu->amask & s->s3.tmp.new_cipher->algorithm_auth) {
                    idx = i;
                    break;
                }
            }

            /*
             * Some GOST ciphersuites allow more than one signature algorithms
             * */
            if (idx == SSL_PKEY_GOST01 && s->s3.tmp.new_cipher->algorithm_auth != SSL_aGOST01) {
                int real_idx;

                for (real_idx = SSL_PKEY_GOST12_512; real_idx >= SSL_PKEY_GOST01;
                    real_idx--) {
                    if (s->cert->pkeys[real_idx].privatekey != NULL) {
                        idx = real_idx;
                        break;
                    }
                }
            }
            /*
             * As both SSL_PKEY_GOST12_512 and SSL_PKEY_GOST12_256 indices can be used
             * with new (aGOST12-only) ciphersuites, we should find out which one is available really.
             */
            else if (idx == SSL_PKEY_GOST12_256) {
                int real_idx;

                for (real_idx = SSL_PKEY_GOST12_512; real_idx >= SSL_PKEY_GOST12_256;
                    real_idx--) {
                    if (s->cert->pkeys[real_idx].privatekey != NULL) {
                        idx = real_idx;
                        break;
                    }
                }
            }
        } else {
            idx = s->cert->key - s->cert->pkeys;
        }
    }
    if (idx < 0 || idx >= (int)OSSL_NELEM(tls_default_sigalg))
        return NULL;

    if (SSL_USE_SIGALGS(s) || idx != SSL_PKEY_RSA) {
        const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s),
            tls_default_sigalg[idx]);

        if (lu == NULL)
            return NULL;
        if (!tls1_lookup_md(SSL_CONNECTION_GET_CTX(s), lu, NULL))
            return NULL;
        if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SUPPORTED, lu))
            return NULL;
        return lu;
    }
    if (!tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SUPPORTED, &legacy_rsa_sigalg))
        return NULL;
    return &legacy_rsa_sigalg;
}
/* Set peer sigalg based key type */
int tls1_set_peer_legacy_sigalg(SSL_CONNECTION *s, const EVP_PKEY *pkey)
{
    size_t idx;
    const SIGALG_LOOKUP *lu;

    if (ssl_cert_lookup_by_pkey(pkey, &idx, SSL_CONNECTION_GET_CTX(s)) == NULL)
        return 0;
    lu = tls1_get_legacy_sigalg(s, idx);
    if (lu == NULL)
        return 0;
    s->s3.tmp.peer_sigalg = lu;
    return 1;
}

size_t tls12_get_psigalgs(SSL_CONNECTION *s, int sent, const uint16_t **psigs)
{
    /*
     * If Suite B mode use Suite B sigalgs only, ignore any other
     * preferences.
     */
    switch (tls1_suiteb(s)) {
    case SSL_CERT_FLAG_SUITEB_128_LOS:
        *psigs = suiteb_sigalgs;
        return OSSL_NELEM(suiteb_sigalgs);

    case SSL_CERT_FLAG_SUITEB_128_LOS_ONLY:
        *psigs = suiteb_sigalgs;
        return 1;

    case SSL_CERT_FLAG_SUITEB_192_LOS:
        *psigs = suiteb_sigalgs + 1;
        return 1;
    }
    /*
     *  We use client_sigalgs (if not NULL) if we're a server
     *  and sending a certificate request or if we're a client and
     *  determining which shared algorithm to use.
     */
    if ((s->server == sent) && s->cert->client_sigalgs != NULL) {
        *psigs = s->cert->client_sigalgs;
        return s->cert->client_sigalgslen;
    } else if (s->cert->conf_sigalgs) {
        *psigs = s->cert->conf_sigalgs;
        return s->cert->conf_sigalgslen;
    } else {
        *psigs = SSL_CONNECTION_GET_CTX(s)->tls12_sigalgs;
        return SSL_CONNECTION_GET_CTX(s)->tls12_sigalgs_len;
    }
}

/*
 * Called by servers only. Checks that we have a sig alg that supports the
 * specified EC curve.
 */
int tls_check_sigalg_curve(const SSL_CONNECTION *s, int curve)
{
    const uint16_t *sigs;
    size_t siglen, i;

    if (s->cert->conf_sigalgs) {
        sigs = s->cert->conf_sigalgs;
        siglen = s->cert->conf_sigalgslen;
    } else {
        sigs = SSL_CONNECTION_GET_CTX(s)->tls12_sigalgs;
        siglen = SSL_CONNECTION_GET_CTX(s)->tls12_sigalgs_len;
    }

    for (i = 0; i < siglen; i++) {
        const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), sigs[i]);

        if (lu == NULL)
            continue;
        if (lu->sig == EVP_PKEY_EC
            && lu->curve != NID_undef
            && curve == lu->curve)
            return 1;
    }

    return 0;
}

/*
 * Return the number of security bits for the signature algorithm, or 0 on
 * error.
 */
static int sigalg_security_bits(SSL_CTX *ctx, const SIGALG_LOOKUP *lu)
{
    const EVP_MD *md = NULL;
    int secbits = 0;

    if (!tls1_lookup_md(ctx, lu, &md))
        return 0;
    if (md != NULL) {
        int md_type = EVP_MD_get_type(md);

        /* Security bits: half digest bits */
        secbits = EVP_MD_get_size(md) * 4;
        if (secbits <= 0)
            return 0;
        /*
         * SHA1 and MD5 are known to be broken. Reduce security bits so that
         * they're no longer accepted at security level 1. The real values don't
         * really matter as long as they're lower than 80, which is our
         * security level 1.
         * https://eprint.iacr.org/2020/014 puts a chosen-prefix attack for
         * SHA1 at 2^63.4 and MD5+SHA1 at 2^67.2
         * https://documents.epfl.ch/users/l/le/lenstra/public/papers/lat.pdf
         * puts a chosen-prefix attack for MD5 at 2^39.
         */
        if (md_type == NID_sha1)
            secbits = 64;
        else if (md_type == NID_md5_sha1)
            secbits = 67;
        else if (md_type == NID_md5)
            secbits = 39;
    } else {
        /* Values from https://tools.ietf.org/html/rfc8032#section-8.5 */
        if (lu->sigalg == TLSEXT_SIGALG_ed25519)
            secbits = 128;
        else if (lu->sigalg == TLSEXT_SIGALG_ed448)
            secbits = 224;
    }
    /*
     * For provider-based sigalgs we have secbits information available
     * in the (provider-loaded) sigalg_list structure
     */
    if ((secbits == 0) && (lu->sig_idx >= SSL_PKEY_NUM)
        && ((lu->sig_idx - SSL_PKEY_NUM) < (int)ctx->sigalg_list_len)) {
        secbits = ctx->sigalg_list[lu->sig_idx - SSL_PKEY_NUM].secbits;
    }
    return secbits;
}

static int tls_sigalg_compat(SSL_CONNECTION *sc, const SIGALG_LOOKUP *lu)
{
    int minversion, maxversion;
    int minproto, maxproto;

    if (!lu->available)
        return 0;

    if (SSL_CONNECTION_IS_DTLS(sc)) {
        if (sc->ssl.method->version == DTLS_ANY_VERSION) {
            minproto = sc->min_proto_version;
            maxproto = sc->max_proto_version;
        } else {
            maxproto = minproto = sc->version;
        }
        minversion = lu->mindtls;
        maxversion = lu->maxdtls;
    } else {
        if (sc->ssl.method->version == TLS_ANY_VERSION) {
            minproto = sc->min_proto_version;
            maxproto = sc->max_proto_version;
        } else {
            maxproto = minproto = sc->version;
        }
        minversion = lu->mintls;
        maxversion = lu->maxtls;
    }
    if (minversion == -1 || maxversion == -1
        || (minversion != 0 && maxproto != 0
            && ssl_version_cmp(sc, minversion, maxproto) > 0)
        || (maxversion != 0 && minproto != 0
            && ssl_version_cmp(sc, maxversion, minproto) < 0)
        || !tls12_sigalg_allowed(sc, SSL_SECOP_SIGALG_SUPPORTED, lu))
        return 0;
    return 1;
}

/*
 * Check signature algorithm is consistent with sent supported signature
 * algorithms and if so set relevant digest and signature scheme in
 * s.
 */
int tls12_check_peer_sigalg(SSL_CONNECTION *s, uint16_t sig, EVP_PKEY *pkey)
{
    const uint16_t *sent_sigs;
    const EVP_MD *md = NULL;
    char sigalgstr[2];
    size_t sent_sigslen, i, cidx;
    int pkeyid = -1;
    const SIGALG_LOOKUP *lu;
    int secbits = 0;

    pkeyid = EVP_PKEY_get_id(pkey);

    if (SSL_CONNECTION_IS_TLS13(s)) {
        /* Disallow DSA for TLS 1.3 */
        if (pkeyid == EVP_PKEY_DSA) {
            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
            return 0;
        }
        /* Only allow PSS for TLS 1.3 */
        if (pkeyid == EVP_PKEY_RSA)
            pkeyid = EVP_PKEY_RSA_PSS;
    }

    /* Is this code point available and compatible with the protocol */
    lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), sig);
    if (lu == NULL || !tls_sigalg_compat(s, lu)) {
        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }

    /* If we don't know the pkey nid yet go and find it */
    if (pkeyid == EVP_PKEY_KEYMGMT) {
        const SSL_CERT_LOOKUP *scl = ssl_cert_lookup_by_pkey(pkey, NULL, SSL_CONNECTION_GET_CTX(s));

        if (scl == NULL) {
            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
            return 0;
        }
        pkeyid = scl->pkey_nid;
    }

    /* Should never happen */
    if (pkeyid == -1) {
        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
        return -1;
    }

    /*
     * Check sigalgs is known. Disallow SHA1/SHA224 with TLS 1.3. Check key type
     * is consistent with signature: RSA keys can be used for RSA-PSS
     */
    if ((SSL_CONNECTION_IS_TLS13(s)
            && (lu->hash == NID_sha1 || lu->hash == NID_sha224))
        || (pkeyid != lu->sig
            && (lu->sig != EVP_PKEY_RSA_PSS || pkeyid != EVP_PKEY_RSA))) {
        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }
    /* Check the sigalg is consistent with the key OID */
    if (!ssl_cert_lookup_by_nid(
            (pkeyid == EVP_PKEY_RSA_PSS) ? EVP_PKEY_get_id(pkey) : pkeyid,
            &cidx, SSL_CONNECTION_GET_CTX(s))
        || lu->sig_idx != (int)cidx) {
        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }

    if (pkeyid == EVP_PKEY_EC) {

        /* Check point compression is permitted */
        if (!tls1_check_pkey_comp(s, pkey)) {
            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
                SSL_R_ILLEGAL_POINT_COMPRESSION);
            return 0;
        }

        /* For TLS 1.3 or Suite B check curve matches signature algorithm */
        if (SSL_CONNECTION_IS_TLS13(s) || tls1_suiteb(s)) {
            int curve = ssl_get_EC_curve_nid(pkey);

            if (lu->curve != NID_undef && curve != lu->curve) {
                SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_CURVE);
                return 0;
            }
        }
        if (!SSL_CONNECTION_IS_TLS13(s)) {
            /* Check curve matches extensions */
            if (!tls1_check_group_id(s, tls1_get_group_id(pkey), 1)) {
                SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_WRONG_CURVE);
                return 0;
            }
            if (tls1_suiteb(s)) {
                /* Check sigalg matches a permissible Suite B value */
                if (sig != TLSEXT_SIGALG_ecdsa_secp256r1_sha256
                    && sig != TLSEXT_SIGALG_ecdsa_secp384r1_sha384) {
                    SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                        SSL_R_WRONG_SIGNATURE_TYPE);
                    return 0;
                }
            }
        }
    } else if (tls1_suiteb(s)) {
        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }

    /* Check signature matches a type we sent */
    sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);
    for (i = 0; i < sent_sigslen; i++, sent_sigs++) {
        if (sig == *sent_sigs)
            break;
    }
    /* Allow fallback to SHA1 if not strict mode */
    if (i == sent_sigslen && (lu->hash != NID_sha1 || s->cert->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT)) {
        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }
    if (!tls1_lookup_md(SSL_CONNECTION_GET_CTX(s), lu, &md)) {
        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_UNKNOWN_DIGEST);
        return 0;
    }
    /*
     * Make sure security callback allows algorithm. For historical
     * reasons we have to pass the sigalg as a two byte char array.
     */
    sigalgstr[0] = (sig >> 8) & 0xff;
    sigalgstr[1] = sig & 0xff;
    secbits = sigalg_security_bits(SSL_CONNECTION_GET_CTX(s), lu);
    if (secbits == 0 || !ssl_security(s, SSL_SECOP_SIGALG_CHECK, secbits, md != NULL ? EVP_MD_get_type(md) : NID_undef, (void *)sigalgstr)) {
        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_R_WRONG_SIGNATURE_TYPE);
        return 0;
    }
    /* Store the sigalg the peer uses */
    s->s3.tmp.peer_sigalg = lu;
    return 1;
}

int SSL_get_peer_signature_type_nid(const SSL *s, int *pnid)
{
    const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);

    if (sc == NULL)
        return 0;

    if (sc->s3.tmp.peer_sigalg == NULL)
        return 0;
    *pnid = sc->s3.tmp.peer_sigalg->sig;
    return 1;
}

int SSL_get_signature_type_nid(const SSL *s, int *pnid)
{
    const SSL_CONNECTION *sc = SSL_CONNECTION_FROM_CONST_SSL(s);

    if (sc == NULL)
        return 0;

    if (sc->s3.tmp.sigalg == NULL)
        return 0;
    *pnid = sc->s3.tmp.sigalg->sig;
    return 1;
}

/*
 * Set a mask of disabled algorithms: an algorithm is disabled if it isn't
 * supported, doesn't appear in supported signature algorithms, isn't supported
 * by the enabled protocol versions or by the security level.
 *
 * This function should only be used for checking which ciphers are supported
 * by the client.
 *
 * Call ssl_cipher_disabled() to check that it's enabled or not.
 */
int ssl_set_client_disabled(SSL_CONNECTION *s)
{
    s->s3.tmp.mask_a = 0;
    s->s3.tmp.mask_k = 0;
    ssl_set_sig_mask(&s->s3.tmp.mask_a, s, SSL_SECOP_SIGALG_MASK);
    if (ssl_get_min_max_version(s, &s->s3.tmp.min_ver,
            &s->s3.tmp.max_ver, NULL)
        != 0)
        return 0;
#ifndef OPENSSL_NO_PSK
    /* with PSK there must be client callback set */
    if (!s->psk_client_callback) {
        s->s3.tmp.mask_a |= SSL_aPSK;
        s->s3.tmp.mask_k |= SSL_PSK;
    }
#endif /* OPENSSL_NO_PSK */
#ifndef OPENSSL_NO_SRP
    if (!(s->srp_ctx.srp_Mask & SSL_kSRP)) {
        s->s3.tmp.mask_a |= SSL_aSRP;
        s->s3.tmp.mask_k |= SSL_kSRP;
    }
#endif
    return 1;
}

/*
 * ssl_cipher_disabled - check that a cipher is disabled or not
 * @s: SSL connection that you want to use the cipher on
 * @c: cipher to check
 * @op: Security check that you want to do
 * @ecdhe: If set to 1 then TLSv1 ECDHE ciphers are also allowed in SSLv3
 *
 * Returns 1 when it's disabled, 0 when enabled.
 */
int ssl_cipher_disabled(const SSL_CONNECTION *s, const SSL_CIPHER *c,
    int op, int ecdhe)
{
    int minversion = SSL_CONNECTION_IS_DTLS(s) ? c->min_dtls : c->min_tls;
    int maxversion = SSL_CONNECTION_IS_DTLS(s) ? c->max_dtls : c->max_tls;

    if (c->algorithm_mkey & s->s3.tmp.mask_k
        || c->algorithm_auth & s->s3.tmp.mask_a)
        return 1;
    if (s->s3.tmp.max_ver == 0)
        return 1;

    if (SSL_IS_QUIC_INT_HANDSHAKE(s))
        /* For QUIC, only allow these ciphersuites. */
        switch (SSL_CIPHER_get_id(c)) {
        case TLS1_3_CK_AES_128_GCM_SHA256:
        case TLS1_3_CK_AES_256_GCM_SHA384:
        case TLS1_3_CK_CHACHA20_POLY1305_SHA256:
            break;
        default:
            return 1;
        }

    /*
     * For historical reasons we will allow ECHDE to be selected by a server
     * in SSLv3 if we are a client
     */
    if (minversion == TLS1_VERSION
        && ecdhe
        && (c->algorithm_mkey & (SSL_kECDHE | SSL_kECDHEPSK)) != 0)
        minversion = SSL3_VERSION;

    if (ssl_version_cmp(s, minversion, s->s3.tmp.max_ver) > 0
        || ssl_version_cmp(s, maxversion, s->s3.tmp.min_ver) < 0)
        return 1;

    return !ssl_security(s, op, c->strength_bits, 0, (void *)c);
}

int tls_use_ticket(SSL_CONNECTION *s)
{
    if ((s->options & SSL_OP_NO_TICKET))
        return 0;
    return ssl_security(s, SSL_SECOP_TICKET, 0, 0, NULL);
}

int tls1_set_server_sigalgs(SSL_CONNECTION *s)
{
    size_t i;

    /* Clear any shared signature algorithms */
    OPENSSL_free(s->shared_sigalgs);
    s->shared_sigalgs = NULL;
    s->shared_sigalgslen = 0;

    /* Clear certificate validity flags */
    if (s->s3.tmp.valid_flags)
        memset(s->s3.tmp.valid_flags, 0, s->ssl_pkey_num * sizeof(uint32_t));
    else
        s->s3.tmp.valid_flags = OPENSSL_zalloc(s->ssl_pkey_num * sizeof(uint32_t));
    if (s->s3.tmp.valid_flags == NULL)
        return 0;
    /*
     * If peer sent no signature algorithms check to see if we support
     * the default algorithm for each certificate type
     */
    if (s->s3.tmp.peer_cert_sigalgs == NULL
        && s->s3.tmp.peer_sigalgs == NULL) {
        const uint16_t *sent_sigs;
        size_t sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);

        for (i = 0; i < s->ssl_pkey_num; i++) {
            const SIGALG_LOOKUP *lu = tls1_get_legacy_sigalg(s, i);
            size_t j;

            if (lu == NULL)
                continue;
            /* Check default matches a type we sent */
            for (j = 0; j < sent_sigslen; j++) {
                if (lu->sigalg == sent_sigs[j]) {
                    s->s3.tmp.valid_flags[i] = CERT_PKEY_SIGN;
                    break;
                }
            }
        }
        return 1;
    }

    if (!tls1_process_sigalgs(s)) {
        SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
        return 0;
    }
    if (s->shared_sigalgs != NULL)
        return 1;

    /* Fatal error if no shared signature algorithms */
    SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
        SSL_R_NO_SHARED_SIGNATURE_ALGORITHMS);
    return 0;
}

/*-
 * Gets the ticket information supplied by the client if any.
 *
 *   hello: The parsed ClientHello data
 *   ret: (output) on return, if a ticket was decrypted, then this is set to
 *       point to the resulting session.
 */
SSL_TICKET_STATUS tls_get_ticket_from_client(SSL_CONNECTION *s,
    CLIENTHELLO_MSG *hello,
    SSL_SESSION **ret)
{
    size_t size;
    RAW_EXTENSION *ticketext;

    *ret = NULL;
    s->ext.ticket_expected = 0;

    /*
     * If tickets disabled or not supported by the protocol version
     * (e.g. TLSv1.3) behave as if no ticket present to permit stateful
     * resumption.
     */
    if (s->version <= SSL3_VERSION || !tls_use_ticket(s))
        return SSL_TICKET_NONE;

    ticketext = &hello->pre_proc_exts[TLSEXT_IDX_session_ticket];
    if (!ticketext->present)
        return SSL_TICKET_NONE;

    size = PACKET_remaining(&ticketext->data);

    return tls_decrypt_ticket(s, PACKET_data(&ticketext->data), size,
        hello->session_id, hello->session_id_len, ret);
}

/*-
 * tls_decrypt_ticket attempts to decrypt a session ticket.
 *
 * If s->tls_session_secret_cb is set and we're not doing TLSv1.3 then we are
 * expecting a pre-shared key ciphersuite, in which case we have no use for
 * session tickets and one will never be decrypted, nor will
 * s->ext.ticket_expected be set to 1.
 *
 * Side effects:
 *   Sets s->ext.ticket_expected to 1 if the server will have to issue
 *   a new session ticket to the client because the client indicated support
 *   (and s->tls_session_secret_cb is NULL) but the client either doesn't have
 *   a session ticket or we couldn't use the one it gave us, or if
 *   s->ctx->ext.ticket_key_cb asked to renew the client's ticket.
 *   Otherwise, s->ext.ticket_expected is set to 0.
 *
 *   etick: points to the body of the session ticket extension.
 *   eticklen: the length of the session tickets extension.
 *   sess_id: points at the session ID.
 *   sesslen: the length of the session ID.
 *   psess: (output) on return, if a ticket was decrypted, then this is set to
 *       point to the resulting session.
 */
SSL_TICKET_STATUS tls_decrypt_ticket(SSL_CONNECTION *s,
    const unsigned char *etick,
    size_t eticklen,
    const unsigned char *sess_id,
    size_t sesslen, SSL_SESSION **psess)
{
    SSL_SESSION *sess = NULL;
    unsigned char *sdec;
    const unsigned char *p;
    int slen, ivlen, renew_ticket = 0, declen;
    SSL_TICKET_STATUS ret = SSL_TICKET_FATAL_ERR_OTHER;
    size_t mlen;
    unsigned char tick_hmac[EVP_MAX_MD_SIZE];
    SSL_HMAC *hctx = NULL;
    EVP_CIPHER_CTX *ctx = NULL;
    SSL_CTX *tctx = s->session_ctx;
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    if (eticklen == 0) {
        /*
         * The client will accept a ticket but doesn't currently have
         * one (TLSv1.2 and below), or treated as a fatal error in TLSv1.3
         */
        ret = SSL_TICKET_EMPTY;
        goto end;
    }
    if (!SSL_CONNECTION_IS_TLS13(s) && s->ext.session_secret_cb) {
        /*
         * Indicate that the ticket couldn't be decrypted rather than
         * generating the session from ticket now, trigger
         * abbreviated handshake based on external mechanism to
         * calculate the master secret later.
         */
        ret = SSL_TICKET_NO_DECRYPT;
        goto end;
    }

    /* Need at least keyname + iv */
    if (eticklen < TLSEXT_KEYNAME_LENGTH + EVP_MAX_IV_LENGTH) {
        ret = SSL_TICKET_NO_DECRYPT;
        goto end;
    }

    /* Initialize session ticket encryption and HMAC contexts */
    hctx = ssl_hmac_new(tctx);
    if (hctx == NULL) {
        ret = SSL_TICKET_FATAL_ERR_MALLOC;
        goto end;
    }
    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL) {
        ret = SSL_TICKET_FATAL_ERR_MALLOC;
        goto end;
    }
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (tctx->ext.ticket_key_evp_cb != NULL || tctx->ext.ticket_key_cb != NULL)
#else
    if (tctx->ext.ticket_key_evp_cb != NULL)
#endif
    {
        unsigned char *nctick = (unsigned char *)etick;
        int rv = 0;

        if (tctx->ext.ticket_key_evp_cb != NULL)
            rv = tctx->ext.ticket_key_evp_cb(SSL_CONNECTION_GET_USER_SSL(s),
                nctick,
                nctick + TLSEXT_KEYNAME_LENGTH,
                ctx,
                ssl_hmac_get0_EVP_MAC_CTX(hctx),
                0);
#ifndef OPENSSL_NO_DEPRECATED_3_0
        else if (tctx->ext.ticket_key_cb != NULL)
            /* if 0 is returned, write an empty ticket */
            rv = tctx->ext.ticket_key_cb(SSL_CONNECTION_GET_USER_SSL(s), nctick,
                nctick + TLSEXT_KEYNAME_LENGTH,
                ctx, ssl_hmac_get0_HMAC_CTX(hctx), 0);
#endif
        if (rv < 0) {
            ret = SSL_TICKET_FATAL_ERR_OTHER;
            goto end;
        }
        if (rv == 0) {
            ret = SSL_TICKET_NO_DECRYPT;
            goto end;
        }
        if (rv == 2)
            renew_ticket = 1;
    } else {
        EVP_CIPHER *aes256cbc = NULL;

        /* Check key name matches */
        if (memcmp(etick, tctx->ext.tick_key_name,
                TLSEXT_KEYNAME_LENGTH)
            != 0) {
            ret = SSL_TICKET_NO_DECRYPT;
            goto end;
        }

        aes256cbc = EVP_CIPHER_fetch(sctx->libctx, "AES-256-CBC",
            sctx->propq);
        if (aes256cbc == NULL
            || ssl_hmac_init(hctx, tctx->ext.secure->tick_hmac_key,
                   sizeof(tctx->ext.secure->tick_hmac_key),
                   "SHA256")
                <= 0
            || EVP_DecryptInit_ex(ctx, aes256cbc, NULL,
                   tctx->ext.secure->tick_aes_key,
                   etick + TLSEXT_KEYNAME_LENGTH)
                <= 0) {
            EVP_CIPHER_free(aes256cbc);
            ret = SSL_TICKET_FATAL_ERR_OTHER;
            goto end;
        }
        EVP_CIPHER_free(aes256cbc);
        if (SSL_CONNECTION_IS_TLS13(s))
            renew_ticket = 1;
    }
    /*
     * Attempt to process session ticket, first conduct sanity and integrity
     * checks on ticket.
     */
    mlen = ssl_hmac_size(hctx);
    if (mlen == 0) {
        ret = SSL_TICKET_FATAL_ERR_OTHER;
        goto end;
    }

    ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
    if (ivlen < 0) {
        ret = SSL_TICKET_FATAL_ERR_OTHER;
        goto end;
    }

    /* Sanity check ticket length: must exceed keyname + IV + HMAC */
    if (eticklen <= TLSEXT_KEYNAME_LENGTH + ivlen + mlen) {
        ret = SSL_TICKET_NO_DECRYPT;
        goto end;
    }
    eticklen -= mlen;
    /* Check HMAC of encrypted ticket */
    if (ssl_hmac_update(hctx, etick, eticklen) <= 0
        || ssl_hmac_final(hctx, tick_hmac, NULL, sizeof(tick_hmac)) <= 0) {
        ret = SSL_TICKET_FATAL_ERR_OTHER;
        goto end;
    }

    if (CRYPTO_memcmp(tick_hmac, etick + eticklen, mlen)) {
        ret = SSL_TICKET_NO_DECRYPT;
        goto end;
    }
    /* Attempt to decrypt session data */
    /* Move p after IV to start of encrypted ticket, update length */
    p = etick + TLSEXT_KEYNAME_LENGTH + ivlen;
    eticklen -= TLSEXT_KEYNAME_LENGTH + ivlen;
    sdec = OPENSSL_malloc(eticklen);
    if (sdec == NULL || EVP_DecryptUpdate(ctx, sdec, &slen, p, (int)eticklen) <= 0) {
        OPENSSL_free(sdec);
        ret = SSL_TICKET_FATAL_ERR_OTHER;
        goto end;
    }
    if (EVP_DecryptFinal(ctx, sdec + slen, &declen) <= 0) {
        OPENSSL_free(sdec);
        ret = SSL_TICKET_NO_DECRYPT;
        goto end;
    }
    slen += declen;
    p = sdec;

    sess = d2i_SSL_SESSION_ex(NULL, &p, slen, sctx->libctx, sctx->propq);
    slen -= p - sdec;
    OPENSSL_free(sdec);
    if (sess) {
        /* Some additional consistency checks */
        if (slen != 0) {
            SSL_SESSION_free(sess);
            sess = NULL;
            ret = SSL_TICKET_NO_DECRYPT;
            goto end;
        }
        /*
         * The session ID, if non-empty, is used by some clients to detect
         * that the ticket has been accepted. So we copy it to the session
         * structure. If it is empty set length to zero as required by
         * standard.
         */
        if (sesslen) {
            memcpy(sess->session_id, sess_id, sesslen);
            sess->session_id_length = sesslen;
        }
        if (renew_ticket)
            ret = SSL_TICKET_SUCCESS_RENEW;
        else
            ret = SSL_TICKET_SUCCESS;
        goto end;
    }
    ERR_clear_error();
    /*
     * For session parse failure, indicate that we need to send a new ticket.
     */
    ret = SSL_TICKET_NO_DECRYPT;

end:
    EVP_CIPHER_CTX_free(ctx);
    ssl_hmac_free(hctx);

    /*
     * If set, the decrypt_ticket_cb() is called unless a fatal error was
     * detected above. The callback is responsible for checking |ret| before it
     * performs any action
     */
    if (s->session_ctx->decrypt_ticket_cb != NULL
        && (ret == SSL_TICKET_EMPTY
            || ret == SSL_TICKET_NO_DECRYPT
            || ret == SSL_TICKET_SUCCESS
            || ret == SSL_TICKET_SUCCESS_RENEW)) {
        size_t keyname_len = eticklen;
        int retcb;

        if (keyname_len > TLSEXT_KEYNAME_LENGTH)
            keyname_len = TLSEXT_KEYNAME_LENGTH;
        retcb = s->session_ctx->decrypt_ticket_cb(SSL_CONNECTION_GET_SSL(s),
            sess, etick, keyname_len,
            ret,
            s->session_ctx->ticket_cb_data);
        switch (retcb) {
        case SSL_TICKET_RETURN_ABORT:
            ret = SSL_TICKET_FATAL_ERR_OTHER;
            break;

        case SSL_TICKET_RETURN_IGNORE:
            ret = SSL_TICKET_NONE;
            SSL_SESSION_free(sess);
            sess = NULL;
            break;

        case SSL_TICKET_RETURN_IGNORE_RENEW:
            if (ret != SSL_TICKET_EMPTY && ret != SSL_TICKET_NO_DECRYPT)
                ret = SSL_TICKET_NO_DECRYPT;
            /* else the value of |ret| will already do the right thing */
            SSL_SESSION_free(sess);
            sess = NULL;
            break;

        case SSL_TICKET_RETURN_USE:
        case SSL_TICKET_RETURN_USE_RENEW:
            if (ret != SSL_TICKET_SUCCESS
                && ret != SSL_TICKET_SUCCESS_RENEW)
                ret = SSL_TICKET_FATAL_ERR_OTHER;
            else if (retcb == SSL_TICKET_RETURN_USE)
                ret = SSL_TICKET_SUCCESS;
            else
                ret = SSL_TICKET_SUCCESS_RENEW;
            break;

        default:
            ret = SSL_TICKET_FATAL_ERR_OTHER;
        }
    }

    if (s->ext.session_secret_cb == NULL || SSL_CONNECTION_IS_TLS13(s)) {
        switch (ret) {
        case SSL_TICKET_NO_DECRYPT:
        case SSL_TICKET_SUCCESS_RENEW:
        case SSL_TICKET_EMPTY:
            s->ext.ticket_expected = 1;
        }
    }

    *psess = sess;

    return ret;
}

/* Check to see if a signature algorithm is allowed */
static int tls12_sigalg_allowed(const SSL_CONNECTION *s, int op,
    const SIGALG_LOOKUP *lu)
{
    unsigned char sigalgstr[2];
    int secbits;

    if (lu == NULL || !lu->available)
        return 0;
    /* DSA is not allowed in TLS 1.3 */
    if (SSL_CONNECTION_IS_TLS13(s) && lu->sig == EVP_PKEY_DSA)
        return 0;
    /*
     * At some point we should fully axe DSA/etc. in ClientHello as per TLS 1.3
     * spec
     */
    if (!s->server && !SSL_CONNECTION_IS_DTLS(s)
        && s->s3.tmp.min_ver >= TLS1_3_VERSION
        && (lu->sig == EVP_PKEY_DSA || lu->hash_idx == SSL_MD_SHA1_IDX
            || lu->hash_idx == SSL_MD_MD5_IDX
            || lu->hash_idx == SSL_MD_SHA224_IDX))
        return 0;

    /* See if public key algorithm allowed */
    if (ssl_cert_is_disabled(SSL_CONNECTION_GET_CTX(s), lu->sig_idx))
        return 0;

    if (lu->sig == NID_id_GostR3410_2012_256
        || lu->sig == NID_id_GostR3410_2012_512
        || lu->sig == NID_id_GostR3410_2001) {
        /* We never allow GOST sig algs on the server with TLSv1.3 */
        if (s->server && SSL_CONNECTION_IS_TLS13(s))
            return 0;
        if (!s->server
            && SSL_CONNECTION_GET_SSL(s)->method->version == TLS_ANY_VERSION
            && s->s3.tmp.max_ver >= TLS1_3_VERSION) {
            int i, num;
            STACK_OF(SSL_CIPHER) *sk;

            /*
             * We're a client that could negotiate TLSv1.3. We only allow GOST
             * sig algs if we could negotiate TLSv1.2 or below and we have GOST
             * ciphersuites enabled.
             */

            if (s->s3.tmp.min_ver >= TLS1_3_VERSION)
                return 0;

            sk = SSL_get_ciphers(SSL_CONNECTION_GET_SSL(s));
            num = sk != NULL ? sk_SSL_CIPHER_num(sk) : 0;
            for (i = 0; i < num; i++) {
                const SSL_CIPHER *c;

                c = sk_SSL_CIPHER_value(sk, i);
                /* Skip disabled ciphers */
                if (ssl_cipher_disabled(s, c, SSL_SECOP_CIPHER_SUPPORTED, 0))
                    continue;

                if ((c->algorithm_mkey & (SSL_kGOST | SSL_kGOST18)) != 0)
                    break;
            }
            if (i == num)
                return 0;
        }
    }

    /* Finally see if security callback allows it */
    secbits = sigalg_security_bits(SSL_CONNECTION_GET_CTX(s), lu);
    sigalgstr[0] = (lu->sigalg >> 8) & 0xff;
    sigalgstr[1] = lu->sigalg & 0xff;
    return ssl_security(s, op, secbits, lu->hash, (void *)sigalgstr);
}

/*
 * Get a mask of disabled public key algorithms based on supported signature
 * algorithms. For example if no signature algorithm supports RSA then RSA is
 * disabled.
 */

void ssl_set_sig_mask(uint32_t *pmask_a, SSL_CONNECTION *s, int op)
{
    const uint16_t *sigalgs;
    size_t i, sigalgslen;
    uint32_t disabled_mask = SSL_aRSA | SSL_aDSS | SSL_aECDSA;
    /*
     * Go through all signature algorithms seeing if we support any
     * in disabled_mask.
     */
    sigalgslen = tls12_get_psigalgs(s, 1, &sigalgs);
    for (i = 0; i < sigalgslen; i++, sigalgs++) {
        const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), *sigalgs);
        const SSL_CERT_LOOKUP *clu;

        if (lu == NULL)
            continue;

        clu = ssl_cert_lookup_by_idx(lu->sig_idx,
            SSL_CONNECTION_GET_CTX(s));
        if (clu == NULL)
            continue;

        /* If algorithm is disabled see if we can enable it */
        if ((clu->amask & disabled_mask) != 0
            && tls12_sigalg_allowed(s, op, lu))
            disabled_mask &= ~clu->amask;
    }
    *pmask_a |= disabled_mask;
}

int tls12_copy_sigalgs(SSL_CONNECTION *s, WPACKET *pkt,
    const uint16_t *psig, size_t psiglen)
{
    size_t i;
    int rv = 0;

    for (i = 0; i < psiglen; i++, psig++) {
        const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), *psig);

        if (lu == NULL || !tls_sigalg_compat(s, lu))
            continue;
        if (!WPACKET_put_bytes_u16(pkt, *psig))
            return 0;
        /*
         * If TLS 1.3 must have at least one valid TLS 1.3 message
         * signing algorithm: i.e. neither RSA nor SHA1/SHA224
         */
        if (rv == 0 && (!SSL_CONNECTION_IS_TLS13(s) || (lu->sig != EVP_PKEY_RSA && lu->hash != NID_sha1 && lu->hash != NID_sha224)))
            rv = 1;
    }
    if (rv == 0)
        ERR_raise(ERR_LIB_SSL, SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
    return rv;
}

/* Given preference and allowed sigalgs set shared sigalgs */
static size_t tls12_shared_sigalgs(SSL_CONNECTION *s,
    const SIGALG_LOOKUP **shsig,
    const uint16_t *pref, size_t preflen,
    const uint16_t *allow, size_t allowlen)
{
    const uint16_t *ptmp, *atmp;
    size_t i, j, nmatch = 0;
    for (i = 0, ptmp = pref; i < preflen; i++, ptmp++) {
        const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), *ptmp);

        /* Skip disabled hashes or signature algorithms */
        if (lu == NULL
            || !tls12_sigalg_allowed(s, SSL_SECOP_SIGALG_SHARED, lu))
            continue;
        for (j = 0, atmp = allow; j < allowlen; j++, atmp++) {
            if (*ptmp == *atmp) {
                nmatch++;
                if (shsig)
                    *shsig++ = lu;
                break;
            }
        }
    }
    return nmatch;
}

/* Set shared signature algorithms for SSL structures */
static int tls1_set_shared_sigalgs(SSL_CONNECTION *s)
{
    const uint16_t *pref, *allow, *conf;
    size_t preflen, allowlen, conflen;
    size_t nmatch;
    const SIGALG_LOOKUP **salgs = NULL;
    CERT *c = s->cert;
    unsigned int is_suiteb = tls1_suiteb(s);

    OPENSSL_free(s->shared_sigalgs);
    s->shared_sigalgs = NULL;
    s->shared_sigalgslen = 0;
    /* If client use client signature algorithms if not NULL */
    if (!s->server && c->client_sigalgs && !is_suiteb) {
        conf = c->client_sigalgs;
        conflen = c->client_sigalgslen;
    } else if (c->conf_sigalgs && !is_suiteb) {
        conf = c->conf_sigalgs;
        conflen = c->conf_sigalgslen;
    } else
        conflen = tls12_get_psigalgs(s, 0, &conf);
    if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE || is_suiteb) {
        pref = conf;
        preflen = conflen;
        allow = s->s3.tmp.peer_sigalgs;
        allowlen = s->s3.tmp.peer_sigalgslen;
    } else {
        allow = conf;
        allowlen = conflen;
        pref = s->s3.tmp.peer_sigalgs;
        preflen = s->s3.tmp.peer_sigalgslen;
    }
    nmatch = tls12_shared_sigalgs(s, NULL, pref, preflen, allow, allowlen);
    if (nmatch) {
        if ((salgs = OPENSSL_malloc(nmatch * sizeof(*salgs))) == NULL)
            return 0;
        nmatch = tls12_shared_sigalgs(s, salgs, pref, preflen, allow, allowlen);
    } else {
        salgs = NULL;
    }
    s->shared_sigalgs = salgs;
    s->shared_sigalgslen = nmatch;
    return 1;
}

int tls1_save_u16(PACKET *pkt, uint16_t **pdest, size_t *pdestlen)
{
    unsigned int stmp;
    size_t size, i;
    uint16_t *buf;

    size = PACKET_remaining(pkt);

    /* Invalid data length */
    if (size == 0 || (size & 1) != 0)
        return 0;

    size >>= 1;

    if ((buf = OPENSSL_malloc(size * sizeof(*buf))) == NULL)
        return 0;
    for (i = 0; i < size && PACKET_get_net_2(pkt, &stmp); i++)
        buf[i] = stmp;

    if (i != size) {
        OPENSSL_free(buf);
        return 0;
    }

    OPENSSL_free(*pdest);
    *pdest = buf;
    *pdestlen = size;

    return 1;
}

int tls1_save_sigalgs(SSL_CONNECTION *s, PACKET *pkt, int cert)
{
    /* Extension ignored for inappropriate versions */
    if (!SSL_USE_SIGALGS(s))
        return 1;
    /* Should never happen */
    if (s->cert == NULL)
        return 0;

    if (cert)
        return tls1_save_u16(pkt, &s->s3.tmp.peer_cert_sigalgs,
            &s->s3.tmp.peer_cert_sigalgslen);
    else
        return tls1_save_u16(pkt, &s->s3.tmp.peer_sigalgs,
            &s->s3.tmp.peer_sigalgslen);
}

/* Set preferred digest for each key type */

int tls1_process_sigalgs(SSL_CONNECTION *s)
{
    size_t i;
    uint32_t *pvalid = s->s3.tmp.valid_flags;

    if (!tls1_set_shared_sigalgs(s))
        return 0;

    for (i = 0; i < s->ssl_pkey_num; i++)
        pvalid[i] = 0;

    for (i = 0; i < s->shared_sigalgslen; i++) {
        const SIGALG_LOOKUP *sigptr = s->shared_sigalgs[i];
        int idx = sigptr->sig_idx;

        /* Ignore PKCS1 based sig algs in TLSv1.3 */
        if (SSL_CONNECTION_IS_TLS13(s) && sigptr->sig == EVP_PKEY_RSA)
            continue;
        /* If not disabled indicate we can explicitly sign */
        if (pvalid[idx] == 0
            && !ssl_cert_is_disabled(SSL_CONNECTION_GET_CTX(s), idx))
            pvalid[idx] = CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN;
    }
    return 1;
}

int SSL_get_sigalgs(SSL *s, int idx,
    int *psign, int *phash, int *psignhash,
    unsigned char *rsig, unsigned char *rhash)
{
    uint16_t *psig;
    size_t numsigalgs;
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);

    if (sc == NULL)
        return 0;

    psig = sc->s3.tmp.peer_sigalgs;
    numsigalgs = sc->s3.tmp.peer_sigalgslen;

    if (psig == NULL || numsigalgs > INT_MAX)
        return 0;
    if (idx >= 0) {
        const SIGALG_LOOKUP *lu;

        if (idx >= (int)numsigalgs)
            return 0;
        psig += idx;
        if (rhash != NULL)
            *rhash = (unsigned char)((*psig >> 8) & 0xff);
        if (rsig != NULL)
            *rsig = (unsigned char)(*psig & 0xff);
        lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(sc), *psig);
        if (psign != NULL)
            *psign = lu != NULL ? lu->sig : NID_undef;
        if (phash != NULL)
            *phash = lu != NULL ? lu->hash : NID_undef;
        if (psignhash != NULL)
            *psignhash = lu != NULL ? lu->sigandhash : NID_undef;
    }
    return (int)numsigalgs;
}

int SSL_get_shared_sigalgs(SSL *s, int idx,
    int *psign, int *phash, int *psignhash,
    unsigned char *rsig, unsigned char *rhash)
{
    const SIGALG_LOOKUP *shsigalgs;
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);

    if (sc == NULL)
        return 0;

    if (sc->shared_sigalgs == NULL
        || idx < 0
        || idx >= (int)sc->shared_sigalgslen
        || sc->shared_sigalgslen > INT_MAX)
        return 0;
    shsigalgs = sc->shared_sigalgs[idx];
    if (phash != NULL)
        *phash = shsigalgs->hash;
    if (psign != NULL)
        *psign = shsigalgs->sig;
    if (psignhash != NULL)
        *psignhash = shsigalgs->sigandhash;
    if (rsig != NULL)
        *rsig = (unsigned char)(shsigalgs->sigalg & 0xff);
    if (rhash != NULL)
        *rhash = (unsigned char)((shsigalgs->sigalg >> 8) & 0xff);
    return (int)sc->shared_sigalgslen;
}

/* Maximum possible number of unique entries in sigalgs array */
#define TLS_MAX_SIGALGCNT (OSSL_NELEM(sigalg_lookup_tbl) * 2)

typedef struct {
    size_t sigalgcnt;
    /* TLSEXT_SIGALG_XXX values */
    uint16_t sigalgs[TLS_MAX_SIGALGCNT];
    SSL_CTX *ctx;
} sig_cb_st;

static void get_sigorhash(int *psig, int *phash, const char *str)
{
    if (OPENSSL_strcasecmp(str, "RSA") == 0) {
        *psig = EVP_PKEY_RSA;
    } else if (OPENSSL_strcasecmp(str, "RSA-PSS") == 0
        || OPENSSL_strcasecmp(str, "PSS") == 0) {
        *psig = EVP_PKEY_RSA_PSS;
    } else if (OPENSSL_strcasecmp(str, "DSA") == 0) {
        *psig = EVP_PKEY_DSA;
    } else if (OPENSSL_strcasecmp(str, "ECDSA") == 0) {
        *psig = EVP_PKEY_EC;
    } else {
        *phash = OBJ_sn2nid(str);
        if (*phash == NID_undef)
            *phash = OBJ_ln2nid(str);
    }
}
/* Maximum length of a signature algorithm string component */
#define TLS_MAX_SIGSTRING_LEN 40

static int sig_cb(const char *elem, int len, void *arg)
{
    sig_cb_st *sarg = arg;
    size_t i = 0;
    const SIGALG_LOOKUP *s;
    char etmp[TLS_MAX_SIGSTRING_LEN], *p;
    const char *iana, *alias;
    int sig_alg = NID_undef, hash_alg = NID_undef;
    int ignore_unknown = 0;

    if (elem == NULL)
        return 0;
    if (elem[0] == '?') {
        ignore_unknown = 1;
        ++elem;
        --len;
    }
    if (sarg->sigalgcnt == TLS_MAX_SIGALGCNT)
        return 0;
    if (len > (int)(sizeof(etmp) - 1))
        return 0;
    memcpy(etmp, elem, len);
    etmp[len] = 0;
    p = strchr(etmp, '+');
    /*
     * We only allow SignatureSchemes listed in the sigalg_lookup_tbl;
     * if there's no '+' in the provided name, look for the new-style combined
     * name.  If not, match both sig+hash to find the needed SIGALG_LOOKUP.
     * Just sig+hash is not unique since TLS 1.3 adds rsa_pss_pss_* and
     * rsa_pss_rsae_* that differ only by public key OID; in such cases
     * we will pick the _rsae_ variant, by virtue of them appearing earlier
     * in the table.
     */
    if (p == NULL) {
        if (sarg->ctx != NULL) {
            for (i = 0; i < sarg->ctx->sigalg_lookup_cache_len; i++) {
                iana = sarg->ctx->sigalg_lookup_cache[i].name;
                alias = sarg->ctx->sigalg_lookup_cache[i].name12;
                if ((alias != NULL && OPENSSL_strcasecmp(etmp, alias) == 0)
                    || OPENSSL_strcasecmp(etmp, iana) == 0) {
                    /* Ignore known, but unavailable sigalgs. */
                    if (!sarg->ctx->sigalg_lookup_cache[i].available)
                        return 1;
                    sarg->sigalgs[sarg->sigalgcnt++] = sarg->ctx->sigalg_lookup_cache[i].sigalg;
                    goto found;
                }
            }
        } else {
            /* Syntax checks use the built-in sigalgs */
            for (i = 0, s = sigalg_lookup_tbl;
                i < OSSL_NELEM(sigalg_lookup_tbl); i++, s++) {
                iana = s->name;
                alias = s->name12;
                if ((alias != NULL && OPENSSL_strcasecmp(etmp, alias) == 0)
                    || OPENSSL_strcasecmp(etmp, iana) == 0) {
                    sarg->sigalgs[sarg->sigalgcnt++] = s->sigalg;
                    goto found;
                }
            }
        }
    } else {
        *p = 0;
        p++;
        if (*p == 0)
            return 0;
        get_sigorhash(&sig_alg, &hash_alg, etmp);
        get_sigorhash(&sig_alg, &hash_alg, p);
        if (sig_alg != NID_undef && hash_alg != NID_undef) {
            if (sarg->ctx != NULL) {
                for (i = 0; i < sarg->ctx->sigalg_lookup_cache_len; i++) {
                    s = &sarg->ctx->sigalg_lookup_cache[i];
                    if (s->hash == hash_alg && s->sig == sig_alg) {
                        /* Ignore known, but unavailable sigalgs. */
                        if (!sarg->ctx->sigalg_lookup_cache[i].available)
                            return 1;
                        sarg->sigalgs[sarg->sigalgcnt++] = s->sigalg;
                        goto found;
                    }
                }
            } else {
                for (i = 0; i < OSSL_NELEM(sigalg_lookup_tbl); i++) {
                    s = &sigalg_lookup_tbl[i];
                    if (s->hash == hash_alg && s->sig == sig_alg) {
                        sarg->sigalgs[sarg->sigalgcnt++] = s->sigalg;
                        goto found;
                    }
                }
            }
        }
    }
    /* Ignore unknown algorithms if ignore_unknown */
    return ignore_unknown;

found:
    /* Ignore duplicates */
    for (i = 0; i < sarg->sigalgcnt - 1; i++) {
        if (sarg->sigalgs[i] == sarg->sigalgs[sarg->sigalgcnt - 1]) {
            sarg->sigalgcnt--;
            return 1;
        }
    }
    return 1;
}

/*
 * Set supported signature algorithms based on a colon separated list of the
 * form sig+hash e.g. RSA+SHA512:DSA+SHA512
 */
int tls1_set_sigalgs_list(SSL_CTX *ctx, CERT *c, const char *str, int client)
{
    sig_cb_st sig;
    sig.sigalgcnt = 0;

    if (ctx != NULL)
        sig.ctx = ctx;
    if (!CONF_parse_list(str, ':', 1, sig_cb, &sig))
        return 0;
    if (sig.sigalgcnt == 0) {
        ERR_raise_data(ERR_LIB_SSL, ERR_R_PASSED_INVALID_ARGUMENT,
            "No valid signature algorithms in '%s'", str);
        return 0;
    }
    if (c == NULL)
        return 1;
    return tls1_set_raw_sigalgs(c, sig.sigalgs, sig.sigalgcnt, client);
}

int tls1_set_raw_sigalgs(CERT *c, const uint16_t *psigs, size_t salglen,
    int client)
{
    uint16_t *sigalgs;

    if ((sigalgs = OPENSSL_malloc(salglen * sizeof(*sigalgs))) == NULL)
        return 0;
    memcpy(sigalgs, psigs, salglen * sizeof(*sigalgs));

    if (client) {
        OPENSSL_free(c->client_sigalgs);
        c->client_sigalgs = sigalgs;
        c->client_sigalgslen = salglen;
    } else {
        OPENSSL_free(c->conf_sigalgs);
        c->conf_sigalgs = sigalgs;
        c->conf_sigalgslen = salglen;
    }

    return 1;
}

int tls1_set_sigalgs(CERT *c, const int *psig_nids, size_t salglen, int client)
{
    uint16_t *sigalgs, *sptr;
    size_t i;

    if (salglen & 1)
        return 0;
    if ((sigalgs = OPENSSL_malloc((salglen / 2) * sizeof(*sigalgs))) == NULL)
        return 0;
    for (i = 0, sptr = sigalgs; i < salglen; i += 2) {
        size_t j;
        const SIGALG_LOOKUP *curr;
        int md_id = *psig_nids++;
        int sig_id = *psig_nids++;

        for (j = 0, curr = sigalg_lookup_tbl; j < OSSL_NELEM(sigalg_lookup_tbl);
            j++, curr++) {
            if (curr->hash == md_id && curr->sig == sig_id) {
                *sptr++ = curr->sigalg;
                break;
            }
        }

        if (j == OSSL_NELEM(sigalg_lookup_tbl))
            goto err;
    }

    if (client) {
        OPENSSL_free(c->client_sigalgs);
        c->client_sigalgs = sigalgs;
        c->client_sigalgslen = salglen / 2;
    } else {
        OPENSSL_free(c->conf_sigalgs);
        c->conf_sigalgs = sigalgs;
        c->conf_sigalgslen = salglen / 2;
    }

    return 1;

err:
    OPENSSL_free(sigalgs);
    return 0;
}

static int tls1_check_sig_alg(SSL_CONNECTION *s, X509 *x, int default_nid)
{
    int sig_nid, use_pc_sigalgs = 0;
    size_t i;
    const SIGALG_LOOKUP *sigalg;
    size_t sigalgslen;

    /*-
     * RFC 8446, section 4.2.3:
     *
     * The signatures on certificates that are self-signed or certificates
     * that are trust anchors are not validated, since they begin a
     * certification path (see [RFC5280], Section 3.2).  A certificate that
     * begins a certification path MAY use a signature algorithm that is not
     * advertised as being supported in the "signature_algorithms"
     * extension.
     */
    if (default_nid == -1 || X509_self_signed(x, 0))
        return 1;
    sig_nid = X509_get_signature_nid(x);
    if (default_nid)
        return sig_nid == default_nid ? 1 : 0;

    if (SSL_CONNECTION_IS_TLS13(s) && s->s3.tmp.peer_cert_sigalgs != NULL) {
        /*
         * If we're in TLSv1.3 then we only get here if we're checking the
         * chain. If the peer has specified peer_cert_sigalgs then we use them
         * otherwise we default to normal sigalgs.
         */
        sigalgslen = s->s3.tmp.peer_cert_sigalgslen;
        use_pc_sigalgs = 1;
    } else {
        sigalgslen = s->shared_sigalgslen;
    }
    for (i = 0; i < sigalgslen; i++) {
        int mdnid, pknid;

        sigalg = use_pc_sigalgs
            ? tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s),
                  s->s3.tmp.peer_cert_sigalgs[i])
            : s->shared_sigalgs[i];
        if (sigalg == NULL)
            continue;
        if (sig_nid == sigalg->sigandhash)
            return 1;
        if (sigalg->sig != EVP_PKEY_RSA_PSS)
            continue;
        /*
         * Accept RSA PKCS#1 signatures in certificates when the signature
         * algorithms include RSA-PSS with a matching digest algorithm.
         *
         * When a TLS 1.3 peer inadvertently omits the legacy RSA PKCS#1 code
         * points, and we're doing strict checking of the certificate chain (in
         * a cert_cb via SSL_check_chain()) we may then reject RSA signed
         * certificates in the chain, but the TLS requirement on PSS should not
         * extend to certificates.  Though the peer can in fact list the legacy
         * sigalgs for just this purpose, it is not likely that a better chain
         * signed with RSA-PSS is available.
         */
        if (!OBJ_find_sigid_algs(sig_nid, &mdnid, &pknid))
            continue;
        if (pknid == EVP_PKEY_RSA && mdnid == sigalg->hash)
            return 1;
    }
    return 0;
}

/* Check to see if a certificate issuer name matches list of CA names */
static int ssl_check_ca_name(STACK_OF(X509_NAME) *names, X509 *x)
{
    const X509_NAME *nm;
    int i;
    nm = X509_get_issuer_name(x);
    for (i = 0; i < sk_X509_NAME_num(names); i++) {
        if (!X509_NAME_cmp(nm, sk_X509_NAME_value(names, i)))
            return 1;
    }
    return 0;
}

/*
 * Check certificate chain is consistent with TLS extensions and is usable by
 * server. This servers two purposes: it allows users to check chains before
 * passing them to the server and it allows the server to check chains before
 * attempting to use them.
 */

/* Flags which need to be set for a certificate when strict mode not set */

#define CERT_PKEY_VALID_FLAGS \
    (CERT_PKEY_EE_SIGNATURE | CERT_PKEY_EE_PARAM)
/* Strict mode flags */
#define CERT_PKEY_STRICT_FLAGS                                           \
    (CERT_PKEY_VALID_FLAGS | CERT_PKEY_CA_SIGNATURE | CERT_PKEY_CA_PARAM \
        | CERT_PKEY_ISSUER_NAME | CERT_PKEY_CERT_TYPE)

int tls1_check_chain(SSL_CONNECTION *s, X509 *x, EVP_PKEY *pk,
    STACK_OF(X509) *chain, int idx)
{
    int i;
    int rv = 0;
    int check_flags = 0, strict_mode;
    CERT_PKEY *cpk = NULL;
    CERT *c = s->cert;
    uint32_t *pvalid;
    unsigned int suiteb_flags = tls1_suiteb(s);

    /*
     * Meaning of idx:
     * idx == -1 means SSL_check_chain() invocation
     * idx == -2 means checking client certificate chains
     * idx >= 0 means checking SSL_PKEY index
     *
     * For RPK, where there may be no cert, we ignore -1
     */
    if (idx != -1) {
        if (idx == -2) {
            cpk = c->key;
            idx = (int)(cpk - c->pkeys);
        } else
            cpk = c->pkeys + idx;
        pvalid = s->s3.tmp.valid_flags + idx;
        x = cpk->x509;
        pk = cpk->privatekey;
        chain = cpk->chain;
        strict_mode = c->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT;
        if (tls12_rpk_and_privkey(s, idx)) {
            if (EVP_PKEY_is_a(pk, "EC") && !tls1_check_pkey_comp(s, pk))
                return 0;
            *pvalid = rv = CERT_PKEY_RPK;
            return rv;
        }
        /* If no cert or key, forget it */
        if (x == NULL || pk == NULL)
            goto end;
    } else {
        size_t certidx;

        if (x == NULL || pk == NULL)
            return 0;

        if (ssl_cert_lookup_by_pkey(pk, &certidx,
                SSL_CONNECTION_GET_CTX(s))
            == NULL)
            return 0;
        idx = certidx;
        pvalid = s->s3.tmp.valid_flags + idx;

        if (c->cert_flags & SSL_CERT_FLAGS_CHECK_TLS_STRICT)
            check_flags = CERT_PKEY_STRICT_FLAGS;
        else
            check_flags = CERT_PKEY_VALID_FLAGS;
        strict_mode = 1;
    }

    if (suiteb_flags) {
        int ok;
        if (check_flags)
            check_flags |= CERT_PKEY_SUITEB;
        ok = X509_chain_check_suiteb(NULL, x, chain, suiteb_flags);
        if (ok == X509_V_OK)
            rv |= CERT_PKEY_SUITEB;
        else if (!check_flags)
            goto end;
    }

    /*
     * Check all signature algorithms are consistent with signature
     * algorithms extension if TLS 1.2 or later and strict mode.
     */
    if (TLS1_get_version(SSL_CONNECTION_GET_SSL(s)) >= TLS1_2_VERSION
        && strict_mode) {
        int default_nid;
        int rsign = 0;

        if (s->s3.tmp.peer_cert_sigalgs != NULL
            || s->s3.tmp.peer_sigalgs != NULL) {
            default_nid = 0;
            /* If no sigalgs extension use defaults from RFC5246 */
        } else {
            switch (idx) {
            case SSL_PKEY_RSA:
                rsign = EVP_PKEY_RSA;
                default_nid = NID_sha1WithRSAEncryption;
                break;

            case SSL_PKEY_DSA_SIGN:
                rsign = EVP_PKEY_DSA;
                default_nid = NID_dsaWithSHA1;
                break;

            case SSL_PKEY_ECC:
                rsign = EVP_PKEY_EC;
                default_nid = NID_ecdsa_with_SHA1;
                break;

            case SSL_PKEY_GOST01:
                rsign = NID_id_GostR3410_2001;
                default_nid = NID_id_GostR3411_94_with_GostR3410_2001;
                break;

            case SSL_PKEY_GOST12_256:
                rsign = NID_id_GostR3410_2012_256;
                default_nid = NID_id_tc26_signwithdigest_gost3410_2012_256;
                break;

            case SSL_PKEY_GOST12_512:
                rsign = NID_id_GostR3410_2012_512;
                default_nid = NID_id_tc26_signwithdigest_gost3410_2012_512;
                break;

            default:
                default_nid = -1;
                break;
            }
        }
        /*
         * If peer sent no signature algorithms extension and we have set
         * preferred signature algorithms check we support sha1.
         */
        if (default_nid > 0 && c->conf_sigalgs) {
            size_t j;
            const uint16_t *p = c->conf_sigalgs;
            for (j = 0; j < c->conf_sigalgslen; j++, p++) {
                const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s), *p);

                if (lu != NULL && lu->hash == NID_sha1 && lu->sig == rsign)
                    break;
            }
            if (j == c->conf_sigalgslen) {
                if (check_flags)
                    goto skip_sigs;
                else
                    goto end;
            }
        }
        /* Check signature algorithm of each cert in chain */
        if (SSL_CONNECTION_IS_TLS13(s)) {
            /*
             * We only get here if the application has called SSL_check_chain(),
             * so check_flags is always set.
             */
            if (find_sig_alg(s, x, pk) != NULL)
                rv |= CERT_PKEY_EE_SIGNATURE;
        } else if (!tls1_check_sig_alg(s, x, default_nid)) {
            if (!check_flags)
                goto end;
        } else
            rv |= CERT_PKEY_EE_SIGNATURE;
        rv |= CERT_PKEY_CA_SIGNATURE;
        for (i = 0; i < sk_X509_num(chain); i++) {
            if (!tls1_check_sig_alg(s, sk_X509_value(chain, i), default_nid)) {
                if (check_flags) {
                    rv &= ~CERT_PKEY_CA_SIGNATURE;
                    break;
                } else
                    goto end;
            }
        }
    }
    /* Else not TLS 1.2, so mark EE and CA signing algorithms OK */
    else if (check_flags)
        rv |= CERT_PKEY_EE_SIGNATURE | CERT_PKEY_CA_SIGNATURE;
skip_sigs:
    /* Check cert parameters are consistent */
    if (tls1_check_cert_param(s, x, 1))
        rv |= CERT_PKEY_EE_PARAM;
    else if (!check_flags)
        goto end;
    if (!s->server)
        rv |= CERT_PKEY_CA_PARAM;
    /* In strict mode check rest of chain too */
    else if (strict_mode) {
        rv |= CERT_PKEY_CA_PARAM;
        for (i = 0; i < sk_X509_num(chain); i++) {
            X509 *ca = sk_X509_value(chain, i);
            if (!tls1_check_cert_param(s, ca, 0)) {
                if (check_flags) {
                    rv &= ~CERT_PKEY_CA_PARAM;
                    break;
                } else
                    goto end;
            }
        }
    }
    if (!s->server && strict_mode) {
        STACK_OF(X509_NAME) *ca_dn;
        int check_type = 0;

        if (EVP_PKEY_is_a(pk, "RSA"))
            check_type = TLS_CT_RSA_SIGN;
        else if (EVP_PKEY_is_a(pk, "DSA"))
            check_type = TLS_CT_DSS_SIGN;
        else if (EVP_PKEY_is_a(pk, "EC"))
            check_type = TLS_CT_ECDSA_SIGN;

        if (check_type) {
            const uint8_t *ctypes = s->s3.tmp.ctype;
            size_t j;

            for (j = 0; j < s->s3.tmp.ctype_len; j++, ctypes++) {
                if (*ctypes == check_type) {
                    rv |= CERT_PKEY_CERT_TYPE;
                    break;
                }
            }
            if (!(rv & CERT_PKEY_CERT_TYPE) && !check_flags)
                goto end;
        } else {
            rv |= CERT_PKEY_CERT_TYPE;
        }

        ca_dn = s->s3.tmp.peer_ca_names;

        if (ca_dn == NULL
            || sk_X509_NAME_num(ca_dn) == 0
            || ssl_check_ca_name(ca_dn, x))
            rv |= CERT_PKEY_ISSUER_NAME;
        else
            for (i = 0; i < sk_X509_num(chain); i++) {
                X509 *xtmp = sk_X509_value(chain, i);

                if (ssl_check_ca_name(ca_dn, xtmp)) {
                    rv |= CERT_PKEY_ISSUER_NAME;
                    break;
                }
            }

        if (!check_flags && !(rv & CERT_PKEY_ISSUER_NAME))
            goto end;
    } else
        rv |= CERT_PKEY_ISSUER_NAME | CERT_PKEY_CERT_TYPE;

    if (!check_flags || (rv & check_flags) == check_flags)
        rv |= CERT_PKEY_VALID;

end:

    if (TLS1_get_version(SSL_CONNECTION_GET_SSL(s)) >= TLS1_2_VERSION)
        rv |= *pvalid & (CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN);
    else
        rv |= CERT_PKEY_SIGN | CERT_PKEY_EXPLICIT_SIGN;

    /*
     * When checking a CERT_PKEY structure all flags are irrelevant if the
     * chain is invalid.
     */
    if (!check_flags) {
        if (rv & CERT_PKEY_VALID) {
            *pvalid = rv;
        } else {
            /* Preserve sign and explicit sign flag, clear rest */
            *pvalid &= CERT_PKEY_EXPLICIT_SIGN | CERT_PKEY_SIGN;
            return 0;
        }
    }
    return rv;
}

/* Set validity of certificates in an SSL structure */
void tls1_set_cert_validity(SSL_CONNECTION *s)
{
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_RSA);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_RSA_PSS_SIGN);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_DSA_SIGN);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ECC);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST01);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST12_256);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_GOST12_512);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ED25519);
    tls1_check_chain(s, NULL, NULL, NULL, SSL_PKEY_ED448);
}

/* User level utility function to check a chain is suitable */
int SSL_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain)
{
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(s);

    if (sc == NULL)
        return 0;

    return tls1_check_chain(sc, x, pk, chain, -1);
}

EVP_PKEY *ssl_get_auto_dh(SSL_CONNECTION *s)
{
    EVP_PKEY *dhp = NULL;
    BIGNUM *p;
    int dh_secbits = 80, sec_level_bits;
    EVP_PKEY_CTX *pctx = NULL;
    OSSL_PARAM_BLD *tmpl = NULL;
    OSSL_PARAM *params = NULL;
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    if (s->cert->dh_tmp_auto != 2) {
        if (s->s3.tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aPSK)) {
            if (s->s3.tmp.new_cipher->strength_bits == 256)
                dh_secbits = 128;
            else
                dh_secbits = 80;
        } else {
            if (s->s3.tmp.cert == NULL)
                return NULL;
            dh_secbits = EVP_PKEY_get_security_bits(s->s3.tmp.cert->privatekey);
        }
    }

    /* Do not pick a prime that is too weak for the current security level */
    sec_level_bits = ssl_get_security_level_bits(SSL_CONNECTION_GET_SSL(s),
        NULL, NULL);
    if (dh_secbits < sec_level_bits)
        dh_secbits = sec_level_bits;

    if (dh_secbits >= 192)
        p = BN_get_rfc3526_prime_8192(NULL);
    else if (dh_secbits >= 152)
        p = BN_get_rfc3526_prime_4096(NULL);
    else if (dh_secbits >= 128)
        p = BN_get_rfc3526_prime_3072(NULL);
    else if (dh_secbits >= 112)
        p = BN_get_rfc3526_prime_2048(NULL);
    else
        p = BN_get_rfc2409_prime_1024(NULL);
    if (p == NULL)
        goto err;

    pctx = EVP_PKEY_CTX_new_from_name(sctx->libctx, "DH", sctx->propq);
    if (pctx == NULL
        || EVP_PKEY_fromdata_init(pctx) != 1)
        goto err;

    tmpl = OSSL_PARAM_BLD_new();
    if (tmpl == NULL
        || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P, p)
        || !OSSL_PARAM_BLD_push_uint(tmpl, OSSL_PKEY_PARAM_FFC_G, 2))
        goto err;

    params = OSSL_PARAM_BLD_to_param(tmpl);
    if (params == NULL
        || EVP_PKEY_fromdata(pctx, &dhp, EVP_PKEY_KEY_PARAMETERS, params) != 1)
        goto err;

err:
    OSSL_PARAM_free(params);
    OSSL_PARAM_BLD_free(tmpl);
    EVP_PKEY_CTX_free(pctx);
    BN_free(p);
    return dhp;
}

static int ssl_security_cert_key(SSL_CONNECTION *s, SSL_CTX *ctx, X509 *x,
    int op)
{
    int secbits = -1;
    EVP_PKEY *pkey = X509_get0_pubkey(x);

    if (pkey) {
        /*
         * If no parameters this will return -1 and fail using the default
         * security callback for any non-zero security level. This will
         * reject keys which omit parameters but this only affects DSA and
         * omission of parameters is never (?) done in practice.
         */
        secbits = EVP_PKEY_get_security_bits(pkey);
    }
    if (s != NULL)
        return ssl_security(s, op, secbits, 0, x);
    else
        return ssl_ctx_security(ctx, op, secbits, 0, x);
}

static int ssl_security_cert_sig(SSL_CONNECTION *s, SSL_CTX *ctx, X509 *x,
    int op)
{
    /* Lookup signature algorithm digest */
    int secbits, nid, pknid;

    /* Don't check signature if self signed */
    if ((X509_get_extension_flags(x) & EXFLAG_SS) != 0)
        return 1;
    if (!X509_get_signature_info(x, &nid, &pknid, &secbits, NULL))
        secbits = -1;
    /* If digest NID not defined use signature NID */
    if (nid == NID_undef)
        nid = pknid;
    if (s != NULL)
        return ssl_security(s, op, secbits, nid, x);
    else
        return ssl_ctx_security(ctx, op, secbits, nid, x);
}

int ssl_security_cert(SSL_CONNECTION *s, SSL_CTX *ctx, X509 *x, int vfy,
    int is_ee)
{
    if (vfy)
        vfy = SSL_SECOP_PEER;
    if (is_ee) {
        if (!ssl_security_cert_key(s, ctx, x, SSL_SECOP_EE_KEY | vfy))
            return SSL_R_EE_KEY_TOO_SMALL;
    } else {
        if (!ssl_security_cert_key(s, ctx, x, SSL_SECOP_CA_KEY | vfy))
            return SSL_R_CA_KEY_TOO_SMALL;
    }
    if (!ssl_security_cert_sig(s, ctx, x, SSL_SECOP_CA_MD | vfy))
        return SSL_R_CA_MD_TOO_WEAK;
    return 1;
}

/*
 * Check security of a chain, if |sk| includes the end entity certificate then
 * |x| is NULL. If |vfy| is 1 then we are verifying a peer chain and not sending
 * one to the peer. Return values: 1 if ok otherwise error code to use
 */

int ssl_security_cert_chain(SSL_CONNECTION *s, STACK_OF(X509) *sk,
    X509 *x, int vfy)
{
    int rv, start_idx, i;

    if (x == NULL) {
        x = sk_X509_value(sk, 0);
        if (x == NULL)
            return ERR_R_INTERNAL_ERROR;
        start_idx = 1;
    } else
        start_idx = 0;

    rv = ssl_security_cert(s, NULL, x, vfy, 1);
    if (rv != 1)
        return rv;

    for (i = start_idx; i < sk_X509_num(sk); i++) {
        x = sk_X509_value(sk, i);
        rv = ssl_security_cert(s, NULL, x, vfy, 0);
        if (rv != 1)
            return rv;
    }
    return 1;
}

/*
 * For TLS 1.2 servers check if we have a certificate which can be used
 * with the signature algorithm "lu" and return index of certificate.
 */

static int tls12_get_cert_sigalg_idx(const SSL_CONNECTION *s,
    const SIGALG_LOOKUP *lu)
{
    int sig_idx = lu->sig_idx;
    const SSL_CERT_LOOKUP *clu = ssl_cert_lookup_by_idx(sig_idx,
        SSL_CONNECTION_GET_CTX(s));

    /* If not recognised or not supported by cipher mask it is not suitable */
    if (clu == NULL
        || (clu->amask & s->s3.tmp.new_cipher->algorithm_auth) == 0
        || (clu->pkey_nid == EVP_PKEY_RSA_PSS
            && (s->s3.tmp.new_cipher->algorithm_mkey & SSL_kRSA) != 0))
        return -1;

    /* If doing RPK, the CERT_PKEY won't be "valid" */
    if (tls12_rpk_and_privkey(s, sig_idx))
        return s->s3.tmp.valid_flags[sig_idx] & CERT_PKEY_RPK ? sig_idx : -1;

    return s->s3.tmp.valid_flags[sig_idx] & CERT_PKEY_VALID ? sig_idx : -1;
}

/*
 * Checks the given cert against signature_algorithm_cert restrictions sent by
 * the peer (if any) as well as whether the hash from the sigalg is usable with
 * the key.
 * Returns true if the cert is usable and false otherwise.
 */
static int check_cert_usable(SSL_CONNECTION *s, const SIGALG_LOOKUP *sig,
    X509 *x, EVP_PKEY *pkey)
{
    const SIGALG_LOOKUP *lu;
    int mdnid, pknid, supported;
    size_t i;
    const char *mdname = NULL;
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    /*
     * If the given EVP_PKEY cannot support signing with this digest,
     * the answer is simply 'no'.
     */
    if (sig->hash != NID_undef)
        mdname = OBJ_nid2sn(sig->hash);
    supported = EVP_PKEY_digestsign_supports_digest(pkey, sctx->libctx,
        mdname,
        sctx->propq);
    if (supported <= 0)
        return 0;

    /*
     * The TLS 1.3 signature_algorithms_cert extension places restrictions
     * on the sigalg with which the certificate was signed (by its issuer).
     */
    if (s->s3.tmp.peer_cert_sigalgs != NULL) {
        if (!X509_get_signature_info(x, &mdnid, &pknid, NULL, NULL))
            return 0;
        for (i = 0; i < s->s3.tmp.peer_cert_sigalgslen; i++) {
            lu = tls1_lookup_sigalg(SSL_CONNECTION_GET_CTX(s),
                s->s3.tmp.peer_cert_sigalgs[i]);
            if (lu == NULL)
                continue;

            /*
             * This does not differentiate between the
             * rsa_pss_pss_* and rsa_pss_rsae_* schemes since we do not
             * have a chain here that lets us look at the key OID in the
             * signing certificate.
             */
            if (mdnid == lu->hash && pknid == lu->sig)
                return 1;
        }
        return 0;
    }

    /*
     * Without signat_algorithms_cert, any certificate for which we have
     * a viable public key is permitted.
     */
    return 1;
}

/*
 * Returns true if |s| has a usable certificate configured for use
 * with signature scheme |sig|.
 * "Usable" includes a check for presence as well as applying
 * the signature_algorithm_cert restrictions sent by the peer (if any).
 * Returns false if no usable certificate is found.
 */
static int has_usable_cert(SSL_CONNECTION *s, const SIGALG_LOOKUP *sig, int idx)
{
    /* TLS 1.2 callers can override sig->sig_idx, but not TLS 1.3 callers. */
    if (idx == -1)
        idx = sig->sig_idx;
    if (!ssl_has_cert(s, idx))
        return 0;

    return check_cert_usable(s, sig, s->cert->pkeys[idx].x509,
        s->cert->pkeys[idx].privatekey);
}

/*
 * Returns true if the supplied cert |x| and key |pkey| is usable with the
 * specified signature scheme |sig|, or false otherwise.
 */
static int is_cert_usable(SSL_CONNECTION *s, const SIGALG_LOOKUP *sig, X509 *x,
    EVP_PKEY *pkey)
{
    size_t idx;

    if (ssl_cert_lookup_by_pkey(pkey, &idx, SSL_CONNECTION_GET_CTX(s)) == NULL)
        return 0;

    /* Check the key is consistent with the sig alg */
    if ((int)idx != sig->sig_idx)
        return 0;

    return check_cert_usable(s, sig, x, pkey);
}

/*
 * Find a signature scheme that works with the supplied certificate |x| and key
 * |pkey|. |x| and |pkey| may be NULL in which case we additionally look at our
 * available certs/keys to find one that works.
 */
static const SIGALG_LOOKUP *find_sig_alg(SSL_CONNECTION *s, X509 *x,
    EVP_PKEY *pkey)
{
    const SIGALG_LOOKUP *lu = NULL;
    size_t i;
    int curve = -1;
    EVP_PKEY *tmppkey;
    SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

    /* Look for a shared sigalgs matching possible certificates */
    for (i = 0; i < s->shared_sigalgslen; i++) {
        /* Skip SHA1, SHA224, DSA and RSA if not PSS */
        lu = s->shared_sigalgs[i];
        if (lu->hash == NID_sha1
            || lu->hash == NID_sha224
            || lu->sig == EVP_PKEY_DSA
            || lu->sig == EVP_PKEY_RSA
            || !tls_sigalg_compat(s, lu))
            continue;

        /* Check that we have a cert, and signature_algorithms_cert */
        if (!tls1_lookup_md(sctx, lu, NULL))
            continue;
        if ((pkey == NULL && !has_usable_cert(s, lu, -1))
            || (pkey != NULL && !is_cert_usable(s, lu, x, pkey)))
            continue;

        tmppkey = (pkey != NULL) ? pkey
                                 : s->cert->pkeys[lu->sig_idx].privatekey;

        if (lu->sig == EVP_PKEY_EC) {
            if (curve == -1)
                curve = ssl_get_EC_curve_nid(tmppkey);
            if (lu->curve != NID_undef && curve != lu->curve)
                continue;
        } else if (lu->sig == EVP_PKEY_RSA_PSS) {
            /* validate that key is large enough for the signature algorithm */
            if (!rsa_pss_check_min_key_size(sctx, tmppkey, lu))
                continue;
        }
        break;
    }

    if (i == s->shared_sigalgslen)
        return NULL;

    return lu;
}

/*
 * Choose an appropriate signature algorithm based on available certificates
 * Sets chosen certificate and signature algorithm.
 *
 * For servers if we fail to find a required certificate it is a fatal error,
 * an appropriate error code is set and a TLS alert is sent.
 *
 * For clients fatalerrs is set to 0. If a certificate is not suitable it is not
 * a fatal error: we will either try another certificate or not present one
 * to the server. In this case no error is set.
 */
int tls_choose_sigalg(SSL_CONNECTION *s, int fatalerrs)
{
    const SIGALG_LOOKUP *lu = NULL;
    int sig_idx = -1;

    s->s3.tmp.cert = NULL;
    s->s3.tmp.sigalg = NULL;

    if (SSL_CONNECTION_IS_TLS13(s)) {
        lu = find_sig_alg(s, NULL, NULL);
        if (lu == NULL) {
            if (!fatalerrs)
                return 1;
            SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
            return 0;
        }
    } else {
        /* If ciphersuite doesn't require a cert nothing to do */
        if (!(s->s3.tmp.new_cipher->algorithm_auth & SSL_aCERT))
            return 1;
        if (!s->server && !ssl_has_cert(s, s->cert->key - s->cert->pkeys))
            return 1;

        if (SSL_USE_SIGALGS(s)) {
            size_t i;
            if (s->s3.tmp.peer_sigalgs != NULL) {
                int curve = -1;
                SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);

                /* For Suite B need to match signature algorithm to curve */
                if (tls1_suiteb(s))
                    curve = ssl_get_EC_curve_nid(s->cert->pkeys[SSL_PKEY_ECC]
                            .privatekey);

                /*
                 * Find highest preference signature algorithm matching
                 * cert type
                 */
                for (i = 0; i < s->shared_sigalgslen; i++) {
                    /* Check the sigalg version bounds */
                    lu = s->shared_sigalgs[i];
                    if (!tls_sigalg_compat(s, lu))
                        continue;
                    if (s->server) {
                        if ((sig_idx = tls12_get_cert_sigalg_idx(s, lu)) == -1)
                            continue;
                    } else {
                        int cc_idx = s->cert->key - s->cert->pkeys;

                        sig_idx = lu->sig_idx;
                        if (cc_idx != sig_idx)
                            continue;
                    }
                    /* Check that we have a cert, and sig_algs_cert */
                    if (!has_usable_cert(s, lu, sig_idx))
                        continue;
                    if (lu->sig == EVP_PKEY_RSA_PSS) {
                        /* validate that key is large enough for the signature algorithm */
                        EVP_PKEY *pkey = s->cert->pkeys[sig_idx].privatekey;

                        if (!rsa_pss_check_min_key_size(sctx, pkey, lu))
                            continue;
                    }
                    if (curve == -1 || lu->curve == curve)
                        break;
                }
#ifndef OPENSSL_NO_GOST
                /*
                 * Some Windows-based implementations do not send GOST algorithms indication
                 * in supported_algorithms extension, so when we have GOST-based ciphersuite,
                 * we have to assume GOST support.
                 */
                if (i == s->shared_sigalgslen
                    && (s->s3.tmp.new_cipher->algorithm_auth
                           & (SSL_aGOST01 | SSL_aGOST12))
                        != 0) {
                    if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
                        if (!fatalerrs)
                            return 1;
                        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                            SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
                        return 0;
                    } else {
                        i = 0;
                        sig_idx = lu->sig_idx;
                    }
                }
#endif
                if (i == s->shared_sigalgslen) {
                    if (!fatalerrs)
                        return 1;
                    SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                        SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
                    return 0;
                }
            } else {
                /*
                 * If we have no sigalg use defaults
                 */
                const uint16_t *sent_sigs;
                size_t sent_sigslen;

                if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
                    if (!fatalerrs)
                        return 1;
                    SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                        SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
                    return 0;
                }

                /* Check signature matches a type we sent */
                sent_sigslen = tls12_get_psigalgs(s, 1, &sent_sigs);
                for (i = 0; i < sent_sigslen; i++, sent_sigs++) {
                    if (lu->sigalg == *sent_sigs
                        && has_usable_cert(s, lu, lu->sig_idx))
                        break;
                }
                if (i == sent_sigslen) {
                    if (!fatalerrs)
                        return 1;
                    SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
                        SSL_R_WRONG_SIGNATURE_TYPE);
                    return 0;
                }
            }
        } else {
            if ((lu = tls1_get_legacy_sigalg(s, -1)) == NULL) {
                if (!fatalerrs)
                    return 1;
                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                    SSL_R_NO_SUITABLE_SIGNATURE_ALGORITHM);
                return 0;
            }
        }
    }
    if (sig_idx == -1)
        sig_idx = lu->sig_idx;
    s->s3.tmp.cert = &s->cert->pkeys[sig_idx];
    s->cert->key = s->s3.tmp.cert;
    s->s3.tmp.sigalg = lu;
    return 1;
}

int SSL_CTX_set_tlsext_max_fragment_length(SSL_CTX *ctx, uint8_t mode)
{
    if (mode != TLSEXT_max_fragment_length_DISABLED
        && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
        ERR_raise(ERR_LIB_SSL, SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
        return 0;
    }

    ctx->ext.max_fragment_len_mode = mode;
    return 1;
}

int SSL_set_tlsext_max_fragment_length(SSL *ssl, uint8_t mode)
{
    SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL(ssl);

    if (sc == NULL
        || (IS_QUIC(ssl) && mode != TLSEXT_max_fragment_length_DISABLED))
        return 0;

    if (mode != TLSEXT_max_fragment_length_DISABLED
        && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
        ERR_raise(ERR_LIB_SSL, SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
        return 0;
    }

    sc->ext.max_fragment_len_mode = mode;
    return 1;
}

uint8_t SSL_SESSION_get_max_fragment_length(const SSL_SESSION *session)
{
    if (session->ext.max_fragment_len_mode == TLSEXT_max_fragment_length_UNSPECIFIED)
        return TLSEXT_max_fragment_length_DISABLED;
    return session->ext.max_fragment_len_mode;
}

/*
 * Helper functions for HMAC access with legacy support included.
 */
SSL_HMAC *ssl_hmac_new(const SSL_CTX *ctx)
{
    SSL_HMAC *ret = OPENSSL_zalloc(sizeof(*ret));
    EVP_MAC *mac = NULL;

    if (ret == NULL)
        return NULL;
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (ctx->ext.ticket_key_evp_cb == NULL
        && ctx->ext.ticket_key_cb != NULL) {
        if (!ssl_hmac_old_new(ret))
            goto err;
        return ret;
    }
#endif
    mac = EVP_MAC_fetch(ctx->libctx, "HMAC", ctx->propq);
    if (mac == NULL || (ret->ctx = EVP_MAC_CTX_new(mac)) == NULL)
        goto err;
    EVP_MAC_free(mac);
    return ret;
err:
    EVP_MAC_CTX_free(ret->ctx);
    EVP_MAC_free(mac);
    OPENSSL_free(ret);
    return NULL;
}

void ssl_hmac_free(SSL_HMAC *ctx)
{
    if (ctx != NULL) {
        EVP_MAC_CTX_free(ctx->ctx);
#ifndef OPENSSL_NO_DEPRECATED_3_0
        ssl_hmac_old_free(ctx);
#endif
        OPENSSL_free(ctx);
    }
}

EVP_MAC_CTX *ssl_hmac_get0_EVP_MAC_CTX(SSL_HMAC *ctx)
{
    return ctx->ctx;
}

int ssl_hmac_init(SSL_HMAC *ctx, void *key, size_t len, char *md)
{
    OSSL_PARAM params[2], *p = params;

    if (ctx->ctx != NULL) {
        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST, md, 0);
        *p = OSSL_PARAM_construct_end();
        if (EVP_MAC_init(ctx->ctx, key, len, params))
            return 1;
    }
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (ctx->old_ctx != NULL)
        return ssl_hmac_old_init(ctx, key, len, md);
#endif
    return 0;
}

int ssl_hmac_update(SSL_HMAC *ctx, const unsigned char *data, size_t len)
{
    if (ctx->ctx != NULL)
        return EVP_MAC_update(ctx->ctx, data, len);
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (ctx->old_ctx != NULL)
        return ssl_hmac_old_update(ctx, data, len);
#endif
    return 0;
}

int ssl_hmac_final(SSL_HMAC *ctx, unsigned char *md, size_t *len,
    size_t max_size)
{
    if (ctx->ctx != NULL)
        return EVP_MAC_final(ctx->ctx, md, len, max_size);
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (ctx->old_ctx != NULL)
        return ssl_hmac_old_final(ctx, md, len);
#endif
    return 0;
}

size_t ssl_hmac_size(const SSL_HMAC *ctx)
{
    if (ctx->ctx != NULL)
        return EVP_MAC_CTX_get_mac_size(ctx->ctx);
#ifndef OPENSSL_NO_DEPRECATED_3_0
    if (ctx->old_ctx != NULL)
        return ssl_hmac_old_size(ctx);
#endif
    return 0;
}

int ssl_get_EC_curve_nid(const EVP_PKEY *pkey)
{
    char gname[OSSL_MAX_NAME_SIZE];

    if (EVP_PKEY_get_group_name(pkey, gname, sizeof(gname), NULL) > 0)
        return OBJ_txt2nid(gname);

    return NID_undef;
}

__owur int tls13_set_encoded_pub_key(EVP_PKEY *pkey,
    const unsigned char *enckey,
    size_t enckeylen)
{
    if (EVP_PKEY_is_a(pkey, "DH")) {
        int bits = EVP_PKEY_get_bits(pkey);

        if (bits <= 0 || enckeylen != (size_t)bits / 8)
            /* the encoded key must be padded to the length of the p */
            return 0;
    } else if (EVP_PKEY_is_a(pkey, "EC")) {
        if (enckeylen < 3 /* point format and at least 1 byte for x and y */
            || enckey[0] != 0x04)
            return 0;
    }

    return EVP_PKEY_set1_encoded_public_key(pkey, enckey, enckeylen);
}