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authorErwin Nindl <nine@wirdorange.org>2007-06-22 13:59:20 +0000
committerErwin Nindl <nine@wirdorange.org>2007-06-22 13:59:20 +0000
commit0275479cb56c7f562f3513fef66c83fc44d1d8c9 (patch)
treef6fbb703cebf62d18b05e2a5e7591ac08c5b6702 /srtp/crypto/hash/hmac.c
parentsatp internet draft 00 final ietf version (diff)
added libsrtp to svn
Diffstat (limited to 'srtp/crypto/hash/hmac.c')
-rw-r--r--srtp/crypto/hash/hmac.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/srtp/crypto/hash/hmac.c b/srtp/crypto/hash/hmac.c
new file mode 100644
index 0000000..4336cf0
--- /dev/null
+++ b/srtp/crypto/hash/hmac.c
@@ -0,0 +1,267 @@
+/*
+ * hmac.c
+ *
+ * implementation of hmac auth_type_t
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+/*
+ *
+ * Copyright(c) 2001-2006 Cisco Systems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 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.
+ *
+ * Neither the name of the Cisco Systems, Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
+ *
+ */
+
+#include "hmac.h"
+#include "alloc.h"
+
+/* the debug module for authentiation */
+
+debug_module_t mod_hmac = {
+ 0, /* debugging is off by default */
+ "hmac sha-1" /* printable name for module */
+};
+
+
+err_status_t
+hmac_alloc(auth_t **a, int key_len, int out_len) {
+ extern auth_type_t hmac;
+ uint8_t *pointer;
+
+ debug_print(mod_hmac, "allocating auth func with key length %d", key_len);
+ debug_print(mod_hmac, " tag length %d", out_len);
+
+ /*
+ * check key length - note that we don't support keys larger
+ * than 20 bytes yet
+ */
+ if (key_len > 20)
+ return err_status_bad_param;
+
+ /* check output length - should be less than 20 bytes */
+ if (out_len > 20)
+ return err_status_bad_param;
+
+ /* allocate memory for auth and hmac_ctx_t structures */
+ pointer = (uint8_t*)crypto_alloc(sizeof(hmac_ctx_t) + sizeof(auth_t));
+ if (pointer == NULL)
+ return err_status_alloc_fail;
+
+ /* set pointers */
+ *a = (auth_t *)pointer;
+ (*a)->type = &hmac;
+ (*a)->state = pointer + sizeof(auth_t);
+ (*a)->out_len = out_len;
+ (*a)->key_len = key_len;
+ (*a)->prefix_len = 0;
+
+ /* increment global count of all hmac uses */
+ hmac.ref_count++;
+
+ return err_status_ok;
+}
+
+err_status_t
+hmac_dealloc(auth_t *a) {
+ extern auth_type_t hmac;
+
+ /* zeroize entire state*/
+ octet_string_set_to_zero((uint8_t *)a,
+ sizeof(hmac_ctx_t) + sizeof(auth_t));
+
+ /* free memory */
+ crypto_free(a);
+
+ /* decrement global count of all hmac uses */
+ hmac.ref_count--;
+
+ return err_status_ok;
+}
+
+err_status_t
+hmac_init(hmac_ctx_t *state, const uint8_t *key, int key_len) {
+ int i;
+ uint8_t ipad[64];
+
+ /*
+ * check key length - note that we don't support keys larger
+ * than 20 bytes yet
+ */
+ if (key_len > 20)
+ return err_status_bad_param;
+
+ /*
+ * set values of ipad and opad by exoring the key into the
+ * appropriate constant values
+ */
+ for (i=0; i < key_len; i++) {
+ ipad[i] = key[i] ^ 0x36;
+ state->opad[i] = key[i] ^ 0x5c;
+ }
+ /* set the rest of ipad, opad to constant values */
+ for ( ; i < 64; i++) {
+ ipad[i] = 0x36;
+ ((uint8_t *)state->opad)[i] = 0x5c;
+ }
+
+ debug_print(mod_hmac, "ipad: %s", octet_string_hex_string(ipad, 64));
+
+ /* initialize sha1 context */
+ sha1_init(&state->init_ctx);
+
+ /* hash ipad ^ key */
+ sha1_update(&state->init_ctx, ipad, 64);
+ memcpy(&state->ctx, &state->init_ctx, sizeof(sha1_ctx_t));
+
+ return err_status_ok;
+}
+
+err_status_t
+hmac_start(hmac_ctx_t *state) {
+
+ memcpy(&state->ctx, &state->init_ctx, sizeof(sha1_ctx_t));
+
+ return err_status_ok;
+}
+
+err_status_t
+hmac_update(hmac_ctx_t *state, const uint8_t *message, int msg_octets) {
+
+ debug_print(mod_hmac, "input: %s",
+ octet_string_hex_string(message, msg_octets));
+
+ /* hash message into sha1 context */
+ sha1_update(&state->ctx, message, msg_octets);
+
+ return err_status_ok;
+}
+
+err_status_t
+hmac_compute(hmac_ctx_t *state, const void *message,
+ int msg_octets, int tag_len, uint8_t *result) {
+ uint32_t hash_value[5];
+ uint32_t H[5];
+ int i;
+
+ /* check tag length, return error if we can't provide the value expected */
+ if (tag_len > 20)
+ return err_status_bad_param;
+
+ /* hash message, copy output into H */
+ hmac_update(state, (const uint8_t*)message, msg_octets);
+ sha1_final(&state->ctx, H);
+
+ /*
+ * note that we don't need to debug_print() the input, since the
+ * function hmac_update() already did that for us
+ */
+ debug_print(mod_hmac, "intermediate state: %s",
+ octet_string_hex_string((uint8_t *)H, 20));
+
+ /* re-initialize hash context */
+ sha1_init(&state->ctx);
+
+ /* hash opad ^ key */
+ sha1_update(&state->ctx, (uint8_t *)state->opad, 64);
+
+ /* hash the result of the inner hash */
+ sha1_update(&state->ctx, (uint8_t *)H, 20);
+
+ /* the result is returned in the array hash_value[] */
+ sha1_final(&state->ctx, hash_value);
+
+ /* copy hash_value to *result */
+ for (i=0; i < tag_len; i++)
+ result[i] = ((uint8_t *)hash_value)[i];
+
+ debug_print(mod_hmac, "output: %s",
+ octet_string_hex_string((uint8_t *)hash_value, tag_len));
+
+ return err_status_ok;
+}
+
+
+/* begin test case 0 */
+
+uint8_t
+hmac_test_case_0_key[20] = {
+ 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+ 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+ 0x0b, 0x0b, 0x0b, 0x0b
+};
+
+uint8_t
+hmac_test_case_0_data[8] = {
+ 0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65 /* "Hi There" */
+};
+
+uint8_t
+hmac_test_case_0_tag[20] = {
+ 0xb6, 0x17, 0x31, 0x86, 0x55, 0x05, 0x72, 0x64,
+ 0xe2, 0x8b, 0xc0, 0xb6, 0xfb, 0x37, 0x8c, 0x8e,
+ 0xf1, 0x46, 0xbe, 0x00
+};
+
+auth_test_case_t
+hmac_test_case_0 = {
+ 20, /* octets in key */
+ hmac_test_case_0_key, /* key */
+ 8, /* octets in data */
+ hmac_test_case_0_data, /* data */
+ 20, /* octets in tag */
+ hmac_test_case_0_tag, /* tag */
+ NULL /* pointer to next testcase */
+};
+
+/* end test case 0 */
+
+char hmac_description[] = "hmac sha-1 authentication function";
+
+/*
+ * auth_type_t hmac is the hmac metaobject
+ */
+
+auth_type_t
+hmac = {
+ (auth_alloc_func) hmac_alloc,
+ (auth_dealloc_func) hmac_dealloc,
+ (auth_init_func) hmac_init,
+ (auth_compute_func) hmac_compute,
+ (auth_update_func) hmac_update,
+ (auth_start_func) hmac_start,
+ (char *) hmac_description,
+ (int) 0, /* instance count */
+ (auth_test_case_t *) &hmac_test_case_0,
+ (debug_module_t *) &mod_hmac
+};
+