file.c

/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 2004-2005, 2007-2022 Todd C. Miller <[email protected]>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>

#include <sudoers.h>
#include <sudo_lbuf.h>
#include <gram.h>

struct sudo_file_handle {
    FILE *fp;
    struct sudoers_parse_tree parse_tree;
};

static int
sudo_file_close(struct sudoers_context *ctx, struct sudo_nss *nss)
{
    debug_decl(sudo_file_close, SUDOERS_DEBUG_NSS);
    struct sudo_file_handle *handle = nss->handle;

    if (handle != NULL) {
	fclose(handle->fp);
	sudoersin = NULL;

	free_parse_tree(&handle->parse_tree);
	free(handle);
	nss->handle = NULL;
    }

    debug_return_int(0);
}

static int
sudo_file_open(struct sudoers_context *ctx, struct sudo_nss *nss)
{
    debug_decl(sudo_file_open, SUDOERS_DEBUG_NSS);
    struct sudo_file_handle *handle;
    char *outfile = NULL;

    /* Note: relies on defaults being initialized early. */
    if (def_ignore_local_sudoers)
	debug_return_int(-1);

    if (nss->handle != NULL) {
	sudo_debug_printf(SUDO_DEBUG_ERROR,
	    "%s: called with non-NULL handle %p", __func__, nss->handle);
	sudo_file_close(ctx, nss);
    }

    handle = malloc(sizeof(*handle));
    if (handle != NULL) {
	init_parser(ctx, NULL);
	handle->fp = open_sudoers(ctx->parser_conf.sudoers_path, &outfile,
	    false, NULL);
	if (handle->fp != NULL) {
	    init_parse_tree(&handle->parse_tree, NULL, NULL, ctx, nss);
	    if (outfile != NULL) {
		/* Update path to open sudoers file. */
		sudo_rcstr_delref(sudoers);
		sudoers = outfile;
	    }
	} else {
	    free(handle);
	    handle = NULL;
	}
    }
    nss->handle = handle;
    debug_return_int(nss->handle ? 0 : -1);
}

/*
 * Parse and return the specified sudoers file.
 */
static struct sudoers_parse_tree *
sudo_file_parse(struct sudoers_context *ctx, const struct sudo_nss *nss)
{
    debug_decl(sudo_file_close, SUDOERS_DEBUG_NSS);
    struct sudo_file_handle *handle = nss->handle;
    int error;

    if (handle == NULL || handle->fp == NULL) {
	sudo_debug_printf(SUDO_DEBUG_ERROR, "%s: called with NULL %s",
	    __func__, handle ? "file pointer" : "handle");
	debug_return_ptr(NULL);
    }

    sudoersin = handle->fp;
    error = sudoersparse();
    if (error || (parse_error && !sudoers_error_recovery())) {
	/* unrecoverable error */
	debug_return_ptr(NULL);
    }

    /* Move parsed sudoers policy to nss handle. */
    reparent_parse_tree(&handle->parse_tree);

    debug_return_ptr(&handle->parse_tree);
}

/*
 * No need for explicit sudoers queries, the parse function handled it.
 */
static int
sudo_file_query(struct sudoers_context *ctx, const struct sudo_nss *nss,
    struct passwd *pw)
{
    debug_decl(sudo_file_query, SUDOERS_DEBUG_NSS);
    debug_return_int(0);
}

/*
 * No need to get defaults for sudoers file, the parse function handled it.
 */
static int
sudo_file_getdefs(struct sudoers_context *ctx, const struct sudo_nss *nss)
{
    debug_decl(sudo_file_getdefs, SUDOERS_DEBUG_NSS);
    debug_return_int(0);
}

/* sudo_nss implementation */
struct sudo_nss sudo_nss_file = {
    { NULL, NULL },
    "sudoers",
    sudo_file_open,
    sudo_file_close,
    sudo_file_parse,
    sudo_file_query,
    sudo_file_getdefs
};