1 files changed, 295 insertions, 0 deletions
diff --git a/modules/pam_timestamp/hmacsha1.c b/modules/pam_timestamp/hmacsha1.c
new file mode 100644
index 0000000..45a3cac
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+++ b/modules/pam_timestamp/hmacsha1.c
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+/* An implementation of HMAC using SHA-1.
+ *
+ * Copyright (c) 2003 Red Hat, Inc.
+ * Written by Nalin Dahyabhai <nalin@redhat.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, and the entire permission notice in its entirety,
+ *    including the disclaimer of warranties.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions.  (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+/* See RFC 2104 for descriptions. */
+#include "config.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <security/pam_ext.h>
+#include "hmacsha1.h"
+#include "sha1.h"
+
+#define MINIMUM_KEY_SIZE SHA1_OUTPUT_SIZE
+#define MAXIMUM_KEY_SIZE SHA1_BLOCK_SIZE
+
+static void
+hmac_key_create(pam_handle_t *pamh, const char *filename, size_t key_size,
+		uid_t owner, gid_t group)
+{
+	int randfd, keyfd, i;
+	size_t count;
+	char *key;
+
+	/* Open the destination file. */
+	keyfd = open(filename,
+		     O_WRONLY | O_CREAT | O_EXCL | O_TRUNC,
+		     S_IRUSR | S_IWUSR);
+	if (keyfd == -1) {
+		pam_syslog(pamh, LOG_ERR, "Cannot create %s: %m", filename);
+		return;
+	}
+
+
+	 if (fchown(keyfd, owner, group) == -1) {
+		pam_syslog(pamh, LOG_ERR, "Cannot chown %s: %m", filename);
+		close(keyfd);
+		return;
+	}
+
+	/* Open the random device to get key data. */
+	randfd = open("/dev/urandom", O_RDONLY);
+	if (randfd == -1) {
+		pam_syslog(pamh, LOG_ERR, "Cannot open /dev/urandom: %m");
+		close(keyfd);
+		return;
+	}
+
+	/* Read random data for use as the key. */
+	key = malloc(key_size);
+	count = 0;
+	if (!key) {
+		close(keyfd);
+		close(randfd);
+		return;
+	}
+	while (count < key_size) {
+		i = read(randfd, key + count, key_size - count);
+		if ((i == 0) || (i == -1)) {
+			break;
+		}
+		count += i;
+	}
+
+	close(randfd);
+
+	/* If we didn't get enough, stop here. */
+	if (count < key_size) {
+		pam_syslog(pamh, LOG_ERR, "Short read on random device");
+		memset(key, 0, key_size);
+		free(key);
+		close(keyfd);
+		return;
+	}
+
+	/* Now write the key. */
+	count = 0;
+	while (count < key_size) {
+		i = write(keyfd, key + count, key_size - count);
+		if ((i == 0) || (i == -1)) {
+			break;
+		}
+		count += i;
+	}
+	memset(key, 0, key_size);
+	free(key);
+	close(keyfd);
+}
+
+static void
+hmac_key_read(pam_handle_t *pamh, const char *filename, size_t default_key_size,
+	      uid_t owner, gid_t group,
+	      void **key, size_t *key_size)
+{
+	char *tmp;
+	int keyfd, i, count;
+	struct stat st;
+
+	tmp = NULL;
+	*key = NULL;
+	*key_size = 0;
+
+	/* Try to open the key file. */
+	keyfd = open(filename, O_RDONLY);
+	if (keyfd == -1) {
+		/* No such thing? Create it. */
+		if (errno == ENOENT) {
+			hmac_key_create(pamh, filename, default_key_size,
+					owner, group);
+			keyfd = open(filename, O_RDONLY);
+		} else {
+			pam_syslog(pamh, LOG_ERR, "Cannot open %s: %m", filename);
+		}
+		if (keyfd == -1)
+			return;
+	}
+
+	/* If we failed to open the file, we're done. */
+	if (fstat(keyfd, &st) == -1) {
+		close(keyfd);
+		return;
+	}
+
+	/* Read the contents of the file. */
+	tmp = malloc(st.st_size);
+	if (!tmp) {
+		close(keyfd);
+		return;
+	}
+
+	count = 0;
+	while (count < st.st_size) {
+		i = read(keyfd, tmp + count, st.st_size - count);
+		if ((i == 0) || (i == -1)) {
+			break;
+		}
+		count += i;
+	}
+	close(keyfd);
+
+	/* Require that we got the expected amount of data. */
+	if (count < st.st_size) {
+		memset(tmp, 0, st.st_size);
+		free(tmp);
+		return;
+	}
+
+	/* Pass the key back. */
+	*key = tmp;
+	*key_size = st.st_size;
+}
+
+static void
+xor_block(unsigned char *p, unsigned char byte, size_t length)
+{
+	size_t i;
+	for (i = 0; i < length; i++) {
+		p[i] = p[i] ^ byte;
+	}
+}
+
+void
+hmac_sha1_generate(void **mac, size_t *mac_length,
+		   const void *raw_key, size_t raw_key_size,
+		   const void *text, size_t text_length)
+{
+	unsigned char key[MAXIMUM_KEY_SIZE], tmp_key[MAXIMUM_KEY_SIZE];
+	size_t maximum_key_size = SHA1_BLOCK_SIZE,
+	       minimum_key_size = SHA1_OUTPUT_SIZE;
+	const unsigned char ipad = 0x36, opad = 0x5c;
+	struct sha1_context sha1;
+	unsigned char inner[SHA1_OUTPUT_SIZE], outer[SHA1_OUTPUT_SIZE];
+
+	*mac = NULL;
+	*mac_length = 0;
+
+#ifndef HMAC_ALLOW_SHORT_KEYS
+	/* If the key is too short, don't bother. */
+	if (raw_key_size < minimum_key_size) {
+		return;
+	}
+#endif
+
+	/* If the key is too long, "compress" it, else copy it and pad it
+	 * out with zero bytes. */
+	memset(key, 0, sizeof(key));
+	if (raw_key_size > maximum_key_size) {
+		sha1_init(&sha1);
+		sha1_update(&sha1, raw_key, raw_key_size);
+		sha1_output(&sha1, key);
+	} else {
+		memmove(key, raw_key, raw_key_size);
+	}
+
+	/* Generate the inner sum. */
+	memcpy(tmp_key, key, sizeof(tmp_key));
+	xor_block(tmp_key, ipad, sizeof(tmp_key));
+
+	sha1_init(&sha1);
+	sha1_update(&sha1, tmp_key, sizeof(tmp_key));
+	sha1_update(&sha1, text, text_length);
+	sha1_output(&sha1, inner);
+
+	/* Generate the outer sum. */
+	memcpy(tmp_key, key, sizeof(tmp_key));
+	xor_block(tmp_key, opad, sizeof(tmp_key));
+
+	sha1_init(&sha1);
+	sha1_update(&sha1, tmp_key, sizeof(tmp_key));
+	sha1_update(&sha1, inner, sizeof(inner));
+	sha1_output(&sha1, outer);
+
+	/* We don't need any of the keys any more. */
+	memset(key, 0, sizeof(key));
+	memset(tmp_key, 0, sizeof(tmp_key));
+
+	/* Allocate space to store the output. */
+	*mac_length = sizeof(outer);
+	*mac = malloc(*mac_length);
+	if (*mac == NULL) {
+		*mac_length = 0;
+		return;
+	}
+
+	memcpy(*mac, outer, *mac_length);
+}
+
+void
+hmac_sha1_generate_file(pam_handle_t *pamh, void **mac, size_t *mac_length,
+			const char *keyfile, uid_t owner, gid_t group,
+			const void *text, size_t text_length)
+{
+	void *key;
+	size_t key_length;
+
+	hmac_key_read(pamh, keyfile,
+		      MAXIMUM_KEY_SIZE, owner, group,
+		      &key, &key_length);
+	if (key == NULL) {
+		*mac = NULL;
+		*mac_length = 0;
+		return;
+	}
+	hmac_sha1_generate(mac, mac_length,
+			   key, key_length,
+			   text, text_length);
+	memset(key, 0, key_length);
+	free(key);
+}
+
+size_t
+hmac_sha1_size(void)
+{
+	return SHA1_OUTPUT_SIZE;
+}