1 files changed, 143 insertions, 0 deletions
diff --git a/third_party/libwebrtc/pc/external_hmac.cc b/third_party/libwebrtc/pc/external_hmac.cc
new file mode 100644
index 0000000000..27b5d0e5ab
--- /dev/null
+++ b/third_party/libwebrtc/pc/external_hmac.cc
@@ -0,0 +1,143 @@
+/*
+ *  Copyright 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "pc/external_hmac.h"
+
+#include <stdlib.h>  // For malloc/free.
+#include <string.h>
+
+#include "rtc_base/logging.h"
+#include "rtc_base/zero_memory.h"
+#include "third_party/libsrtp/include/srtp.h"
+
+// Begin test case 0 */
+static const uint8_t kExternalHmacTestCase0Key[20] = {
+    0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+    0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b};
+
+static const uint8_t kExternalHmacTestCase0Data[8] = {
+    0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65  // "Hi There"
+};
+
+static const uint8_t kExternalHmacFakeTag[10] = {0xba, 0xdd, 0xba, 0xdd, 0xba,
+                                                 0xdd, 0xba, 0xdd, 0xba, 0xdd};
+
+static const srtp_auth_test_case_t kExternalHmacTestCase0 = {
+    20,                                                // Octets in key
+    const_cast<uint8_t*>(kExternalHmacTestCase0Key),   // Key
+    8,                                                 // Octets in data
+    const_cast<uint8_t*>(kExternalHmacTestCase0Data),  // Data
+    10,                                                // Octets in tag
+    const_cast<uint8_t*>(kExternalHmacFakeTag),        // Tag
+    NULL                                               // Pointer to next
+                                                       // testcase
+};
+
+static const char kExternalHmacDescription[] =
+    "external hmac sha-1 authentication";
+
+// srtp_auth_type_t external_hmac is the hmac metaobject
+
+static const srtp_auth_type_t external_hmac = {
+    external_hmac_alloc,
+    external_hmac_dealloc,
+    external_hmac_init,
+    external_hmac_compute,
+    external_hmac_update,
+    external_hmac_start,
+    const_cast<char*>(kExternalHmacDescription),
+    const_cast<srtp_auth_test_case_t*>(&kExternalHmacTestCase0),
+    EXTERNAL_HMAC_SHA1};
+
+srtp_err_status_t external_hmac_alloc(srtp_auth_t** a,
+                                      int key_len,
+                                      int out_len) {
+  uint8_t* pointer;
+
+  // Check key length - note that we don't support keys larger
+  // than 20 bytes yet
+  if (key_len > 20)
+    return srtp_err_status_bad_param;
+
+  // Check output length - should be less than 20 bytes/
+  if (out_len > 20)
+    return srtp_err_status_bad_param;
+
+  // Allocate memory for auth and hmac_ctx_t structures.
+  pointer = new uint8_t[(sizeof(ExternalHmacContext) + sizeof(srtp_auth_t))];
+  if (pointer == NULL)
+    return srtp_err_status_alloc_fail;
+
+  // Set pointers
+  *a = reinterpret_cast<srtp_auth_t*>(pointer);
+  // `external_hmac` is const and libsrtp expects `type` to be non-const.
+  // const conversion is required. `external_hmac` is constant because we don't
+  // want to increase global count in Chrome.
+  (*a)->type = const_cast<srtp_auth_type_t*>(&external_hmac);
+  (*a)->state = pointer + sizeof(srtp_auth_t);
+  (*a)->out_len = out_len;
+  (*a)->key_len = key_len;
+  (*a)->prefix_len = 0;
+
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_hmac_dealloc(srtp_auth_t* a) {
+  rtc::ExplicitZeroMemory(a, sizeof(ExternalHmacContext) + sizeof(srtp_auth_t));
+
+  // Free memory
+  delete[] a;
+
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_hmac_init(void* state,
+                                     const uint8_t* key,
+                                     int key_len) {
+  if (key_len > HMAC_KEY_LENGTH)
+    return srtp_err_status_bad_param;
+
+  ExternalHmacContext* context = static_cast<ExternalHmacContext*>(state);
+  memcpy(context->key, key, key_len);
+  context->key_length = key_len;
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_hmac_start(void* /*state*/) {
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_hmac_update(void* /*state*/,
+                                       const uint8_t* /*message*/,
+                                       int /*msg_octets*/) {
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_hmac_compute(void* /*state*/,
+                                        const uint8_t* /*message*/,
+                                        int /*msg_octets*/,
+                                        int tag_len,
+                                        uint8_t* result) {
+  memcpy(result, kExternalHmacFakeTag, tag_len);
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t external_crypto_init() {
+  // `external_hmac` is const. const_cast is required as libsrtp expects
+  // non-const.
+  srtp_err_status_t status = srtp_replace_auth_type(
+      const_cast<srtp_auth_type_t*>(&external_hmac), EXTERNAL_HMAC_SHA1);
+  if (status) {
+    RTC_LOG(LS_ERROR) << "Error in replacing default auth module, error: "
+                      << status;
+    return srtp_err_status_fail;
+  }
+  return srtp_err_status_ok;
+}