nx-aes-xcbc.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * AES XCBC routines supporting the Power 7+ Nest Accelerators driver
 *
 * Copyright (C) 2011-2012 International Business Machines Inc.
 *
 * Author: Kent Yoder <[email protected]>
 */

#include <crypto/aes.h>
#include <crypto/internal/hash.h>
#include <linux/atomic.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/string.h>

#include "nx_csbcpb.h"
#include "nx.h"


struct xcbc_state {
	u8 state[AES_BLOCK_SIZE];
};

static int nx_xcbc_set_key(struct crypto_shash *desc,
			   const u8            *in_key,
			   unsigned int         key_len)
{
	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(desc);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;

	switch (key_len) {
	case AES_KEYSIZE_128:
		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
		break;
	default:
		return -EINVAL;
	}

	memcpy(csbcpb->cpb.aes_xcbc.key, in_key, key_len);

	return 0;
}

/*
 * Based on RFC 3566, for a zero-length message:
 *
 * n = 1
 * K1 = E(K, 0x01010101010101010101010101010101)
 * K3 = E(K, 0x03030303030303030303030303030303)
 * E[0] = 0x00000000000000000000000000000000
 * M[1] = 0x80000000000000000000000000000000 (0 length message with padding)
 * E[1] = (K1, M[1] ^ E[0] ^ K3)
 * Tag = M[1]
 */
static int nx_xcbc_empty(struct shash_desc *desc, u8 *out)
{
	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(desc->tfm);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	struct nx_sg *in_sg, *out_sg;
	u8 keys[2][AES_BLOCK_SIZE];
	u8 key[32];
	int rc = 0;
	int len;

	/* Change to ECB mode */
	csbcpb->cpb.hdr.mode = NX_MODE_AES_ECB;
	memcpy(key, csbcpb->cpb.aes_xcbc.key, AES_BLOCK_SIZE);
	memcpy(csbcpb->cpb.aes_ecb.key, key, AES_BLOCK_SIZE);
	NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;

	/* K1 and K3 base patterns */
	memset(keys[0], 0x01, sizeof(keys[0]));
	memset(keys[1], 0x03, sizeof(keys[1]));

	len = sizeof(keys);
	/* Generate K1 and K3 encrypting the patterns */
	in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *) keys, &len,
				 nx_ctx->ap->sglen);

	if (len != sizeof(keys))
		return -EINVAL;

	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *) keys, &len,
				  nx_ctx->ap->sglen);

	if (len != sizeof(keys))
		return -EINVAL;

	nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) * sizeof(struct nx_sg);
	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);

	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op, 0);
	if (rc)
		goto out;
	atomic_inc(&(nx_ctx->stats->aes_ops));

	/* XOr K3 with the padding for a 0 length message */
	keys[1][0] ^= 0x80;

	len = sizeof(keys[1]);

	/* Encrypt the final result */
	memcpy(csbcpb->cpb.aes_ecb.key, keys[0], AES_BLOCK_SIZE);
	in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *) keys[1], &len,
				 nx_ctx->ap->sglen);

	if (len != sizeof(keys[1]))
		return -EINVAL;

	len = AES_BLOCK_SIZE;
	out_sg = nx_build_sg_list(nx_ctx->out_sg, out, &len,
				  nx_ctx->ap->sglen);

	if (len != AES_BLOCK_SIZE)
		return -EINVAL;

	nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) * sizeof(struct nx_sg);
	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);

	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op, 0);
	if (rc)
		goto out;
	atomic_inc(&(nx_ctx->stats->aes_ops));

out:
	/* Restore XCBC mode */
	csbcpb->cpb.hdr.mode = NX_MODE_AES_XCBC_MAC;
	memcpy(csbcpb->cpb.aes_xcbc.key, key, AES_BLOCK_SIZE);
	NX_CPB_FDM(csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;

	return rc;
}

static int nx_crypto_ctx_aes_xcbc_init2(struct crypto_shash *tfm)
{
	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(tfm);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	int err;

	err = nx_crypto_ctx_aes_xcbc_init(tfm);
	if (err)
		return err;

	nx_ctx_init(nx_ctx, HCOP_FC_AES);

	NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
	csbcpb->cpb.hdr.mode = NX_MODE_AES_XCBC_MAC;

	return 0;
}

static int nx_xcbc_init(struct shash_desc *desc)
{
	struct xcbc_state *sctx = shash_desc_ctx(desc);

	memset(sctx, 0, sizeof *sctx);

	return 0;
}

static int nx_xcbc_update(struct shash_desc *desc,
			  const u8          *data,
			  unsigned int       len)
{
	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(desc->tfm);
	struct xcbc_state *sctx = shash_desc_ctx(desc);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	struct nx_sg *in_sg;
	struct nx_sg *out_sg;
	unsigned int max_sg_len;
	unsigned long irq_flags;
	u32 to_process, total;
	int rc = 0;
	int data_len;

	spin_lock_irqsave(&nx_ctx->lock, irq_flags);

	memcpy(csbcpb->cpb.aes_xcbc.out_cv_mac, sctx->state, AES_BLOCK_SIZE);
	NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
	NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;

	total = len;

	in_sg = nx_ctx->in_sg;
	max_sg_len = min_t(u64, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
				nx_ctx->ap->sglen);
	max_sg_len = min_t(u64, max_sg_len,
				nx_ctx->ap->databytelen/NX_PAGE_SIZE);

	data_len = AES_BLOCK_SIZE;
	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
				  &data_len, nx_ctx->ap->sglen);

	if (data_len != AES_BLOCK_SIZE) {
		rc = -EINVAL;
		goto out;
	}

	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);

	do {
		to_process = total & ~(AES_BLOCK_SIZE - 1);

		in_sg = nx_build_sg_list(in_sg,
					(u8 *) data,
					&to_process,
					max_sg_len);

		nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) *
					sizeof(struct nx_sg);

		/* we've hit the nx chip previously and we're updating again,
		 * so copy over the partial digest */
		memcpy(csbcpb->cpb.aes_xcbc.cv,
		       csbcpb->cpb.aes_xcbc.out_cv_mac, AES_BLOCK_SIZE);

		if (!nx_ctx->op.inlen || !nx_ctx->op.outlen) {
			rc = -EINVAL;
			goto out;
		}

		rc = nx_hcall_sync(nx_ctx, &nx_ctx->op, 0);
		if (rc)
			goto out;

		atomic_inc(&(nx_ctx->stats->aes_ops));

		total -= to_process;
		data += to_process;
		in_sg = nx_ctx->in_sg;
	} while (total >= AES_BLOCK_SIZE);

	rc = total;
	memcpy(sctx->state, csbcpb->cpb.aes_xcbc.out_cv_mac, AES_BLOCK_SIZE);

out:
	spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
	return rc;
}

static int nx_xcbc_finup(struct shash_desc *desc, const u8 *src,
			 unsigned int nbytes, u8 *out)
{
	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(desc->tfm);
	struct xcbc_state *sctx = shash_desc_ctx(desc);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	struct nx_sg *in_sg, *out_sg;
	unsigned long irq_flags;
	int rc = 0;
	int len;

	spin_lock_irqsave(&nx_ctx->lock, irq_flags);

	if (nbytes) {
		/* non-zero final, so copy over the partial digest */
		memcpy(csbcpb->cpb.aes_xcbc.cv, sctx->state, AES_BLOCK_SIZE);
	} else {
		/*
		 * we've never seen an update, so this is a 0 byte op. The
		 * hardware cannot handle a 0 byte op, so just ECB to
		 * generate the hash.
		 */
		rc = nx_xcbc_empty(desc, out);
		goto out;
	}

	/* final is represented by continuing the operation and indicating that
	 * this is not an intermediate operation */
	NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;

	len = nbytes;
	in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *)src, &len,
				 nx_ctx->ap->sglen);

	if (len != nbytes) {
		rc = -EINVAL;
		goto out;
	}

	len = AES_BLOCK_SIZE;
	out_sg = nx_build_sg_list(nx_ctx->out_sg, out, &len,
				  nx_ctx->ap->sglen);

	if (len != AES_BLOCK_SIZE) {
		rc = -EINVAL;
		goto out;
	}

	nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) * sizeof(struct nx_sg);
	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);

	if (!nx_ctx->op.outlen) {
		rc = -EINVAL;
		goto out;
	}

	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op, 0);
	if (rc)
		goto out;

	atomic_inc(&(nx_ctx->stats->aes_ops));

	memcpy(out, csbcpb->cpb.aes_xcbc.out_cv_mac, AES_BLOCK_SIZE);
out:
	spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
	return rc;
}

struct shash_alg nx_shash_aes_xcbc_alg = {
	.digestsize = AES_BLOCK_SIZE,
	.init       = nx_xcbc_init,
	.update     = nx_xcbc_update,
	.finup      = nx_xcbc_finup,
	.setkey     = nx_xcbc_set_key,
	.descsize   = sizeof(struct xcbc_state),
	.init_tfm   = nx_crypto_ctx_aes_xcbc_init2,
	.exit_tfm   = nx_crypto_ctx_shash_exit,
	.base       = {
		.cra_name        = "xcbc(aes)",
		.cra_driver_name = "xcbc-aes-nx",
		.cra_priority    = 300,
		.cra_flags	 = CRYPTO_AHASH_ALG_BLOCK_ONLY |
				   CRYPTO_AHASH_ALG_FINAL_NONZERO,
		.cra_blocksize   = AES_BLOCK_SIZE,
		.cra_module      = THIS_MODULE,
		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
	}
};