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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 1996, 1998-2005, 2007-2020
* Todd C. Miller <Todd.Miller@sudo.ws>
*
* 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.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sudoers.h>
#include <sudo_digest.h>
#include <gram.h>
int
digest_matches(int fd, const char *path,
const struct command_digest_list *digests)
{
unsigned int digest_type = SUDO_DIGEST_INVALID;
unsigned char *file_digest = NULL;
unsigned char *sudoers_digest = NULL;
struct command_digest *digest;
size_t digest_len = (size_t)-1;
int matched = DENY;
int fd2 = -1;
debug_decl(digest_matches, SUDOERS_DEBUG_MATCH);
if (TAILQ_EMPTY(digests)) {
/* No digest, no problem. */
debug_return_int(ALLOW);
}
if (fd == -1) {
fd2 = open(path, O_RDONLY|O_NONBLOCK);
if (fd2 == -1) {
/* No file, no match. */
goto done;
}
fd = fd2;
}
TAILQ_FOREACH(digest, digests, entries) {
/* Compute file digest if needed. */
if (digest->digest_type != digest_type) {
free(file_digest);
file_digest = sudo_filedigest(fd, path, digest->digest_type,
&digest_len);
if (lseek(fd, (off_t)0, SEEK_SET) == -1) {
sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
"unable to rewind digest fd");
}
digest_type = digest->digest_type;
}
if (file_digest == NULL) {
/* Warning (if any) printed by sudo_filedigest() */
goto done;
}
/* Convert the command digest from ascii to binary. */
if ((sudoers_digest = malloc(digest_len)) == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
goto done;
}
if (strlen(digest->digest_str) == digest_len * 2) {
/* Convert ascii hex to binary. */
size_t i;
for (i = 0; i < digest_len; i++) {
const int h = sudo_hexchar(&digest->digest_str[2 * i]);
if (h == -1)
goto bad_format;
sudoers_digest[i] = (unsigned char)h;
}
} else {
/* Convert base64 to binary. */
size_t len = base64_decode(digest->digest_str, sudoers_digest, digest_len);
if (len == (size_t)-1)
goto bad_format;
if (len != digest_len) {
sudo_warnx(
U_("digest for %s (%s) bad length %zu, expected %zu"),
path, digest->digest_str, len, digest_len);
goto done;
}
}
if (memcmp(file_digest, sudoers_digest, digest_len) == 0) {
matched = ALLOW;
break;
}
sudo_debug_printf(SUDO_DEBUG_DIAG|SUDO_DEBUG_LINENO,
"%s digest mismatch for %s, expecting %s",
digest_type_to_name(digest->digest_type), path, digest->digest_str);
free(sudoers_digest);
sudoers_digest = NULL;
}
goto done;
bad_format:
sudo_warnx(U_("digest for %s (%s) is not in %s form"), path,
digest->digest_str, digest_type_to_name(digest->digest_type));
done:
if (fd2 != -1)
close(fd2);
free(sudoers_digest);
free(file_digest);
debug_return_int(matched);
}
|
