mirror of https://github.com/sudo-project/sudo.git
135 lines
4.0 KiB
C
135 lines
4.0 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 1996, 1998-2005, 2007-2020
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* Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Sponsored in part by the Defense Advanced Research Projects
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* Agency (DARPA) and Air Force Research Laboratory, Air Force
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* Materiel Command, USAF, under agreement number F39502-99-1-0512.
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*/
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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sudoers.h>
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#include <sudo_digest.h>
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#include <gram.h>
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int
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digest_matches(int fd, const char *path,
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const struct command_digest_list *digests)
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{
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unsigned int digest_type = SUDO_DIGEST_INVALID;
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unsigned char *file_digest = NULL;
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unsigned char *sudoers_digest = NULL;
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struct command_digest *digest;
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size_t digest_len = (size_t)-1;
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int matched = DENY;
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int fd2 = -1;
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debug_decl(digest_matches, SUDOERS_DEBUG_MATCH);
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if (TAILQ_EMPTY(digests)) {
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/* No digest, no problem. */
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debug_return_int(ALLOW);
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}
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if (fd == -1) {
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fd2 = open(path, O_RDONLY|O_NONBLOCK);
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if (fd2 == -1) {
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/* No file, no match. */
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goto done;
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}
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fd = fd2;
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}
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TAILQ_FOREACH(digest, digests, entries) {
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/* Compute file digest if needed. */
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if (digest->digest_type != digest_type) {
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free(file_digest);
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file_digest = sudo_filedigest(fd, path, digest->digest_type,
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&digest_len);
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if (lseek(fd, (off_t)0, SEEK_SET) == -1) {
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sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
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"unable to rewind digest fd");
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}
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digest_type = digest->digest_type;
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}
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if (file_digest == NULL) {
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/* Warning (if any) printed by sudo_filedigest() */
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goto done;
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}
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/* Convert the command digest from ascii to binary. */
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if ((sudoers_digest = malloc(digest_len)) == NULL) {
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sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
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goto done;
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}
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if (strlen(digest->digest_str) == digest_len * 2) {
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/* Convert ascii hex to binary. */
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size_t i;
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for (i = 0; i < digest_len; i++) {
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const int h = sudo_hexchar(&digest->digest_str[2 * i]);
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if (h == -1)
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goto bad_format;
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sudoers_digest[i] = (unsigned char)h;
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}
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} else {
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/* Convert base64 to binary. */
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size_t len = base64_decode(digest->digest_str, sudoers_digest, digest_len);
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if (len == (size_t)-1)
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goto bad_format;
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if (len != digest_len) {
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sudo_warnx(
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U_("digest for %s (%s) bad length %zu, expected %zu"),
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path, digest->digest_str, len, digest_len);
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goto done;
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}
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}
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if (memcmp(file_digest, sudoers_digest, digest_len) == 0) {
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matched = ALLOW;
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break;
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}
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sudo_debug_printf(SUDO_DEBUG_DIAG|SUDO_DEBUG_LINENO,
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"%s digest mismatch for %s, expecting %s",
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digest_type_to_name(digest->digest_type), path, digest->digest_str);
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free(sudoers_digest);
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sudoers_digest = NULL;
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}
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goto done;
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bad_format:
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sudo_warnx(U_("digest for %s (%s) is not in %s form"), path,
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digest->digest_str, digest_type_to_name(digest->digest_type));
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done:
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if (fd2 != -1)
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close(fd2);
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free(sudoers_digest);
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free(file_digest);
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debug_return_int(matched);
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}
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