Add current version of libSRTP from CVS.

libsrtp/crypto/hash/hmac.c

+/*
+ * 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,
+  (auth_type_id_t)       HMAC_SHA1
+};
+