Prevent OOB reads for zero-length H264 payloads.

webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc
index 66a19ddf5696a05bf26fae07499655487620bd1c..8fa83010f6f5760282f5ea3b925c57e84fb274d9 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_format_h264_unittest.cc
@@ -537,4 +537,12 @@ TEST_F(RtpDepacketizerH264Test, TestFuA) {
   EXPECT_EQ(kH264FuA, payload.type.Video.codecHeader.H264.packetization_type);
   EXPECT_EQ(kIdr, payload.type.Video.codecHeader.H264.nalu_type);
 }
+
+TEST_F(RtpDepacketizerH264Test, TestEmptyPayload) {

[stefan-webrtc, 2015/06/30 10:20:03]

Seems like we may want to have a few generic tests for the depacketizer and
share some test code, wdyt?

[pbos-webrtc, 2015/06/30 11:22:05]

No, since they are different formats the only thing they would share as input is
zero-length, and that seems like a bunch of boilerplate. :)

+  // Using a wild pointer to crash on accesses from inside the depacketizer.
+  uint8_t* garbage_ptr = reinterpret_cast<uint8_t*>(0x4711);
+  RtpDepacketizer::ParsedPayload payload;
+  EXPECT_FALSE(depacketizer_->Parse(&payload, garbage_ptr, 0));
+}
+
 }  // namespace webrtc