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-rw-r--r--plugins/sudoers/match_digest.c135
1 files changed, 135 insertions, 0 deletions
diff --git a/plugins/sudoers/match_digest.c b/plugins/sudoers/match_digest.c
new file mode 100644
index 0000000..5c39f52
--- /dev/null
+++ b/plugins/sudoers/match_digest.c
@@ -0,0 +1,135 @@
+/*
+ * 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 <unistd.h>
+
+#include "sudoers.h"
+#include "sudo_digest.h"
+#include <gram.h>
+
+bool
+digest_matches(int fd, const char *path, const char *runchroot,
+ 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;
+ char pathbuf[PATH_MAX];
+ bool matched = false;
+ debug_decl(digest_matches, SUDOERS_DEBUG_MATCH);
+
+ if (TAILQ_EMPTY(digests)) {
+ /* No digest, no problem. */
+ debug_return_bool(true);
+ }
+
+ if (fd == -1) {
+ /* No file, no match. */
+ goto done;
+ }
+
+ if (runchroot != NULL) {
+ const int len =
+ snprintf(pathbuf, sizeof(pathbuf), "%s%s", runchroot, path);
+ if (len >= ssizeof(pathbuf)) {
+ errno = ENAMETOOLONG;
+ debug_return_bool(false);
+ }
+ path = pathbuf;
+ }
+
+ 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. */
+ unsigned int i;
+ for (i = 0; i < digest_len; i++) {
+ const int h = hexchar(&digest->digest_str[i + 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 != digest_len) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+ "incorrect length for digest, expected %zu, got %zu",
+ digest_len, len);
+ goto bad_format;
+ }
+ }
+ if (memcmp(file_digest, sudoers_digest, digest_len) == 0) {
+ matched = true;
+ 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:
+ free(sudoers_digest);
+ free(file_digest);
+ debug_return_bool(matched);
+}