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 output's size is zero, dereference of 0'th element results

[wtc, 2013/03/14 00:38:08]

output's => the size of output_

because "output_'s" looks strange.

[ramant (doing other things), 2013/03/14 03:05:15]

Deleted this comment

[ramant (doing other things), 2013/03/14 03:26:20]

Added the comment.

+  // in a crash. C++11 solves this problem by passing std::vector's data.

[wtc, 2013/03/14 00:38:08]

This should read:
  C++11 solves this problem by adding a data() getter method
  to std::vector.

In fact, can you try if we can replace
  &output_[j]
by
  output_.data() + j
?

Perhaps the data() method is already available in MSVC, gcc,
and clang.

You can do this experiment after committing this CL.

[ramant (doing other things), 2013/03/14 03:05:15]

Changed the code to use output_.data() + j. Thanks for the fix.
Done.

[ramant (doing other things), 2013/03/14 03:26:20]

Added the comment. output_.data() + j is not supported on Android.

Added your comments

+  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