pkcs5_pbkdf2.c
changeset 0 d7ee4e2ed49d
child 10 85496558f3a4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pkcs5_pbkdf2.c	Tue Dec 17 22:16:27 2013 -0500
@@ -0,0 +1,122 @@
+/*	$OpenBSD: pkcs5_pbkdf2.c,v 1.4 2013/06/03 21:07:02 tedu Exp $	*/
+
+/*-
+ * Copyright (c) 2008 Damien Bergamini <damien.bergamini@free.fr>
+ *
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+
+#include <string.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <util.h>
+
+#include "sha1.h"
+
+/*
+ * HMAC-SHA-1 (from RFC 2202).
+ */
+static void
+hmac_sha1(const u_int8_t *text, size_t text_len, const u_int8_t *key,
+    size_t key_len, u_int8_t digest[SHA1_DIGEST_LENGTH])
+{
+	SHA1_CTX ctx;
+	u_int8_t k_pad[SHA1_BLOCK_LENGTH];
+	u_int8_t tk[SHA1_DIGEST_LENGTH];
+	int i;
+
+	if (key_len > SHA1_BLOCK_LENGTH) {
+		SHA1Init(&ctx);
+		SHA1Update(&ctx, key, key_len);
+		SHA1Final(tk, &ctx);
+
+		key = tk;
+		key_len = SHA1_DIGEST_LENGTH;
+	}
+
+	bzero(k_pad, sizeof k_pad);
+	bcopy(key, k_pad, key_len);
+	for (i = 0; i < SHA1_BLOCK_LENGTH; i++)
+		k_pad[i] ^= 0x36;
+
+	SHA1Init(&ctx);
+	SHA1Update(&ctx, k_pad, SHA1_BLOCK_LENGTH);
+	SHA1Update(&ctx, text, text_len);
+	SHA1Final(digest, &ctx);
+
+	bzero(k_pad, sizeof k_pad);
+	bcopy(key, k_pad, key_len);
+	for (i = 0; i < SHA1_BLOCK_LENGTH; i++)
+		k_pad[i] ^= 0x5c;
+
+	SHA1Init(&ctx);
+	SHA1Update(&ctx, k_pad, SHA1_BLOCK_LENGTH);
+	SHA1Update(&ctx, digest, SHA1_DIGEST_LENGTH);
+	SHA1Final(digest, &ctx);
+}
+
+/*
+ * Password-Based Key Derivation Function 2 (PKCS #5 v2.0).
+ * Code based on IEEE Std 802.11-2007, Annex H.4.2.
+ */
+int
+pkcs5_pbkdf2(const char *pass, size_t pass_len, const uint8_t *salt, size_t salt_len,
+    uint8_t *key, size_t key_len, unsigned int rounds)
+{
+	uint8_t *asalt, obuf[SHA1_DIGEST_LENGTH];
+	uint8_t d1[SHA1_DIGEST_LENGTH], d2[SHA1_DIGEST_LENGTH];
+	unsigned int i, j;
+	unsigned int count;
+	size_t r;
+
+	if (rounds < 1 || key_len == 0)
+		return -1;
+	if (salt_len == 0 || salt_len > SIZE_MAX - 4)
+		return -1;
+	if ((asalt = malloc(salt_len + 4)) == NULL)
+		return -1;
+
+	memcpy(asalt, salt, salt_len);
+
+	for (count = 1; key_len > 0; count++) {
+		asalt[salt_len + 0] = (count >> 24) & 0xff;
+		asalt[salt_len + 1] = (count >> 16) & 0xff;
+		asalt[salt_len + 2] = (count >> 8) & 0xff;
+		asalt[salt_len + 3] = count & 0xff;
+		hmac_sha1(asalt, salt_len + 4, (const uint8_t *) pass, pass_len, d1);
+		memcpy(obuf, d1, sizeof(obuf));
+
+		for (i = 1; i < rounds; i++) {
+			hmac_sha1(d1, sizeof(d1), (const uint8_t *) pass, pass_len, d2);
+			memcpy(d1, d2, sizeof(d1));
+			for (j = 0; j < sizeof(obuf); j++)
+				obuf[j] ^= d1[j];
+		}
+
+		r = MIN(key_len, SHA1_DIGEST_LENGTH);
+		memcpy(key, obuf, r);
+		key += r;
+		key_len -= r;
+	};
+	bzero(asalt, salt_len + 4);
+	free(asalt);
+	bzero(d1, sizeof(d1));
+	bzero(d2, sizeof(d2));
+	bzero(obuf, sizeof(obuf));
+
+	return 0;
+}
+