Only set certificate on DTLS transport if fingerprint is found in SDP.

webrtc/base/sslfingerprint.cc

 /*
  *  Copyright 2012 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 "webrtc/base/sslfingerprint.h"
 
 #include <ctype.h>
 #include <string>
 
 #include "webrtc/base/helpers.h"
+#include "webrtc/base/logging.h"
 #include "webrtc/base/messagedigest.h"
 #include "webrtc/base/stringencode.h"
 
 namespace rtc {
 
 SSLFingerprint* SSLFingerprint::Create(
     const std::string& algorithm, const rtc::SSLIdentity* identity) {
   if (!identity) {
     return NULL;
   }
@@ skipping 28 matching lines @@
                                                    fingerprint.c_str(),
                                                    fingerprint.length(),
                                                    ':');
   if (!value_len)
     return NULL;
 
   return new SSLFingerprint(algorithm, reinterpret_cast<uint8_t*>(value),
                             value_len);
 }
 
+SSLFingerprint* SSLFingerprint::CreateFromCertificate(
+    const RTCCertificate* cert) {
+  std::string digest_alg;
+  if (!cert->ssl_certificate().GetSignatureDigestAlgorithm(&digest_alg)) {
+    LOG(LS_ERROR) << "Failed to retrieve the certificate's digest algorithm";
+    return nullptr;
+  }
+
+  SSLFingerprint* fingerprint = Create(digest_alg, cert->identity());
+  if (!fingerprint) {
+    LOG(LS_ERROR) << "Failed to create identity fingerprint, alg="
+                  << digest_alg;
+  }
+  return fingerprint;
+}
+
 SSLFingerprint::SSLFingerprint(const std::string& algorithm,
                                const uint8_t* digest_in,
                                size_t digest_len)
     : algorithm(algorithm) {
   digest.SetData(digest_in, digest_len);
 }
 
 SSLFingerprint::SSLFingerprint(const SSLFingerprint& from)
     : algorithm(from.algorithm), digest(from.digest) {}
 
@@ skipping 11 matching lines @@
 }
 
 std::string SSLFingerprint::ToString() const {
   std::string fp_str = algorithm;
   fp_str.append(" ");
   fp_str.append(GetRfc4572Fingerprint());
   return fp_str;
 }
 
 }  // namespace rtc