Land Recent QUIC Changes

crypto/hkdf.cc

Index: crypto/hkdf.cc
diff --git a/crypto/hkdf.cc b/crypto/hkdf.cc
index e621bcb45b0818d64bce70893ba8308f39bca168..48babe25515acd8367d14ea888a7194e71c20ea3 100644
--- a/crypto/hkdf.cc
+++ b/crypto/hkdf.cc
@@ -72,17 +72,25 @@ HKDF::HKDF(const base::StringPiece& secret,
   }
 
   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() {