Change WebM parser to treat IVs from encrypted WebM as raw data.

media/crypto/aes_decryptor_unittest.cc

Index: media/crypto/aes_decryptor_unittest.cc
diff --git a/media/crypto/aes_decryptor_unittest.cc b/media/crypto/aes_decryptor_unittest.cc
index 1b9d52e51b24be3322e45c14441b07f60adf2a8c..f2be41cfecd618926011396d204b98cd58caf60e 100644
--- a/media/crypto/aes_decryptor_unittest.cc
+++ b/media/crypto/aes_decryptor_unittest.cc
@@ -92,8 +92,8 @@ const WebmEncryptedData kWebmEncryptedFrames[] = {
       0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40
       }, 16,
     // encrypted_data
-    { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-      0x01, 0x9c, 0x71, 0x26, 0x57, 0x3e, 0x25, 0x37,
+    { 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x00, 0x9c, 0x71, 0x26, 0x57, 0x3e, 0x25, 0x37,
       0xf7, 0x31, 0x81, 0x19, 0x64, 0xce, 0xbc
       }, 23
   },
@@ -164,13 +164,12 @@ static const SubsampleEntry kSubsampleEntries[] = {
 // Returns a 16 byte CTR counter block. The CTR counter block format is a
 // CTR IV appended with a CTR block counter. |iv| is a CTR IV. |iv_size| is
 // the size of |iv| in bytes.
-static std::string GenerateCounterBlock(const uint8* iv, int iv_size) {
-  const int kDecryptionKeySize = 16;
-  CHECK_GT(iv_size, 0);
-  CHECK_LE(iv_size, kDecryptionKeySize);
+static std::string GenerateCounterBlock(const std::string& iv) {
+  CHECK_GT(iv.size(), 0UL);
+  CHECK_LE(iv.size(), static_cast<size_t>(DecryptConfig::kDecryptionKeySize));
 
-  std::string counter_block(reinterpret_cast<const char*>(iv), iv_size);
-  counter_block.append(kDecryptionKeySize - iv_size, 0);
+  std::string counter_block(iv);
+  counter_block.append(DecryptConfig::kDecryptionKeySize - iv.size(), 0);

[ddorwin, 2012/10/13 00:26:17]

Why wasn't the scoping necessary before?

[fgalligan1, 2012/10/13 06:20:31]

The old version defined the value at the top of the function for some reason. We
are including decrypt_config.h so that seems like a better value to use. Also
changed the function to perform one less copy.

   return counter_block;
 }
 
@@ -197,12 +196,10 @@ static scoped_refptr<DecoderBuffer> CreateWebMEncryptedBuffer(
   std::string counter_block_str;
 
   if (signal_byte & kWebMFlagEncryptedFrame) {
-    uint64 network_iv;
-    memcpy(&network_iv, data + data_offset, sizeof(network_iv));
-    const uint64 iv = base::NetToHost64(network_iv);
-    counter_block_str =
-        GenerateCounterBlock(reinterpret_cast<const uint8*>(&iv), sizeof(iv));
-    data_offset += sizeof(iv);
+    const std::string iv(reinterpret_cast<const char*>(data + data_offset),
+                         kWebMIvSize);
+    data_offset += kWebMIvSize;
+    counter_block_str = GenerateCounterBlock(iv);
   }
 
   encrypted_buffer->SetDecryptConfig(
@@ -434,7 +431,6 @@ TEST_F(AesDecryptorTest, MultipleKeysAndFrames) {
   ASSERT_NO_FATAL_FAILURE(DecryptAndExpectToSucceed(encrypted_data1,
                                                     frame1.plain_text,
                                                     frame1.plain_text_size));
-
   scoped_refptr<DecoderBuffer> encrypted_data2 =

[ddorwin, 2012/10/13 00:26:17]

Is there a reason the empty line was removed?

[fgalligan1, 2012/10/13 06:20:31]

No. I'll put it back to make less noise.

       CreateWebMEncryptedBuffer(frame2.encrypted_data,
                                 frame2.encrypted_data_size,