Land Recent QUIC Changes

crypto/hkdf.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "crypto/hkdf.h"
 
 #include "base/logging.h"
 #include "crypto/hmac.h"
 
 namespace crypto {
@@ skipping 54 matching lines @@
 
     result = hmac.Sign(base::StringPiece(buf.get(), j), digest, sizeof(digest));
     DCHECK(result);
 
     memcpy(&output_[i*sizeof(digest)], digest, sizeof(digest));
     previous = base::StringPiece(reinterpret_cast<char*>(digest),
                                  sizeof(digest));
   }
 
   size_t j = 0;
-  client_write_key_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
-                                        key_bytes_to_generate);
-  j += key_bytes_to_generate;
-  server_write_key_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
-                                        key_bytes_to_generate);
-  j += key_bytes_to_generate;
-  client_write_iv_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
-                                       iv_bytes_to_generate);
-  j += iv_bytes_to_generate;
-  server_write_iv_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
-                                       iv_bytes_to_generate);
+  // On Windows, when the size of output_ is zero, dereference of 0'th element
+  // results in a crash. C++11 solves this problem by adding a data() getter
+  // method to std::vector.
+  if (key_bytes_to_generate > 0) {
+    client_write_key_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
+                                          key_bytes_to_generate);
+    j += key_bytes_to_generate;
+    server_write_key_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
+                                          key_bytes_to_generate);
+    j += key_bytes_to_generate;
+  }
+
+  if (iv_bytes_to_generate > 0) {
+    client_write_iv_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
+                                         iv_bytes_to_generate);
+    j += iv_bytes_to_generate;
+    server_write_iv_ = base::StringPiece(reinterpret_cast<char*>(&output_[j]),
+                                         iv_bytes_to_generate);
+  }
 }
 
 HKDF::~HKDF() {
 }
 
 }  // namespace crypto