Split out digest matching into its own file.

plugins/sudoers/match_digest.c

@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 1996, 1998-2005, 2007-2019
+ *	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 <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+#include <unistd.h>
+
+#include "sudoers.h"
+#include <gram.h>
+
+#ifdef SUDOERS_NAME_MATCH
+bool
+digest_matches(int fd, const char *file, const struct command_digest *digest)
+{
+    debug_decl(digest_matches, SUDOERS_DEBUG_MATCH)
+
+    /* Digests are not supported when matching only by name. */
+
+    debug_return_bool(false);
+}
+#else
+bool
+digest_matches(int fd, const char *file, const struct command_digest *digest)
+{
+    unsigned char *file_digest = NULL;
+    unsigned char *sudoers_digest = NULL;
+    bool matched = false;
+    size_t digest_len;
+    debug_decl(digest_matches, SUDOERS_DEBUG_MATCH)
+
+    file_digest = sudo_filedigest(fd, file, 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");
+    }
+    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;
+    } else {
+	sudo_debug_printf(SUDO_DEBUG_DIAG|SUDO_DEBUG_LINENO,
+	    "%s digest mismatch for %s, expecting %s",
+	    digest_type_to_name(digest->digest_type), file, digest->digest_str);
+    }
+    goto done;
+
+bad_format:
+    sudo_warnx(U_("digest for %s (%s) is not in %s form"), file,
+	digest->digest_str, digest_type_to_name(digest->digest_type));
+done:
+    free(sudoers_digest);
+    free(file_digest);
+    debug_return_bool(matched);
+}
+#endif /* SUDOERS_NAME_MATCH */