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

media/webm/webm_cluster_parser.cc

Index: media/webm/webm_cluster_parser.cc
diff --git a/media/webm/webm_cluster_parser.cc b/media/webm/webm_cluster_parser.cc
index fb1c69b874739719169085cbdcf4278862e95a61..a398e4d17fa95687c2a34164f3b0b98fee5ea62a 100644
--- a/media/webm/webm_cluster_parser.cc
+++ b/media/webm/webm_cluster_parser.cc
@@ -7,7 +7,6 @@
 #include <vector>
 
 #include "base/logging.h"
-#include "base/sys_byteorder.h"
 #include "media/base/data_buffer.h"
 #include "media/base/decrypt_config.h"
 #include "media/webm/webm_constants.h"
@@ -17,9 +16,9 @@ namespace media {
 // Generates a 16 byte CTR counter block. The CTR counter block format is a
 // CTR IV appended with a CTR block counter. |iv| is an 8 byte CTR IV.
 // Returns a string of kDecryptionKeySize bytes.
-static std::string GenerateCounterBlock(uint64 iv) {
-  std::string counter_block(reinterpret_cast<char*>(&iv), sizeof(iv));
-  counter_block.append(DecryptConfig::kDecryptionKeySize - sizeof(iv), 0);
+static std::string GenerateCounterBlock(const uint8* iv, size_t iv_size) {
+  std::string counter_block(reinterpret_cast<const char*>(iv), iv_size);

[ddorwin, 2012/10/13 17:21:27]

Should we counter_block.resize(DecryptConfig::kDecryptionKeySize);?

[fgalligan1, 2012/10/14 16:45:24]

What about this?
std::string counter_block(DecryptConfig::kDecryptionKeySize, 0);
memcpy(&counter_block[0], reinterpret_cast<const char*>(iv), iv_size);

[ddorwin, 2012/10/15 02:32:49]

SGTM

+  counter_block.append(DecryptConfig::kDecryptionKeySize - iv_size, 0);
   return counter_block;
 }
 
@@ -237,10 +236,8 @@ bool WebMClusterParser::OnBlock(int track_num, int timecode,
     std::string counter_block;
 
     if (signal_byte & kWebMFlagEncryptedFrame) {
-      uint64 network_iv;
-      memcpy(&network_iv, data + data_offset, sizeof(network_iv));
-      data_offset += sizeof(network_iv);
-      counter_block = GenerateCounterBlock(base::NetToHost64(network_iv));
+      counter_block = GenerateCounterBlock(data + data_offset, kWebMIvSize);
+      data_offset += kWebMIvSize;
     }
 
     // TODO(fgalligan): Revisit if DecryptConfig needs to be set on unencrypted