Fix parsing padding byte in rtp header extension

BUG=chromium:664598

Review-Url: https://codereview.webrtc.org/2498903003
Cr-Commit-Position: refs/heads/master@{#15230}
diff --git a/webrtc/modules/BUILD.gn b/webrtc/modules/BUILD.gn
index 5537829..0996098 100644
--- a/webrtc/modules/BUILD.gn
+++ b/webrtc/modules/BUILD.gn
@@ -473,6 +473,7 @@
       "rtp_rtcp/source/rtp_payload_registry_unittest.cc",
       "rtp_rtcp/source/rtp_rtcp_impl_unittest.cc",
       "rtp_rtcp/source/rtp_sender_unittest.cc",
+      "rtp_rtcp/source/rtp_utility_unittest.cc",
       "rtp_rtcp/source/time_util_unittest.cc",
       "rtp_rtcp/source/ulpfec_generator_unittest.cc",
       "rtp_rtcp/source/ulpfec_header_reader_writer_unittest.cc",
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_utility.cc b/webrtc/modules/rtp_rtcp/source/rtp_utility.cc
index 7dd5973..749539e 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_utility.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_utility.cc
@@ -318,8 +318,13 @@
     const int len = (*ptr & 0x0f);
     ptr++;
 
+    if (id == 0) {
+      // Padding byte, skip ignoring len.
+      continue;
+    }
+
     if (id == 15) {
-      LOG(LS_WARNING)
+      LOG(LS_VERBOSE)
           << "RTP extension header 15 encountered. Terminate parsing.";
       return;
     }
@@ -446,23 +451,8 @@
       }
     }
     ptr += (len + 1);
-    uint8_t num_bytes = ParsePaddingBytes(ptrRTPDataExtensionEnd, ptr);
-    ptr += num_bytes;
   }
 }
 
-uint8_t RtpHeaderParser::ParsePaddingBytes(
-    const uint8_t* ptrRTPDataExtensionEnd,
-    const uint8_t* ptr) const {
-  uint8_t num_zero_bytes = 0;
-  while (ptrRTPDataExtensionEnd - ptr > 0) {
-    if (*ptr != 0) {
-      return num_zero_bytes;
-    }
-    ptr++;
-    num_zero_bytes++;
-  }
-  return num_zero_bytes;
-}
 }  // namespace RtpUtility
 }  // namespace webrtc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_utility.h b/webrtc/modules/rtp_rtcp/source/rtp_utility.h
index 474bc6e..6cab7cb 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_utility.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_utility.h
@@ -59,9 +59,6 @@
                                    const uint8_t* ptrRTPDataExtensionEnd,
                                    const uint8_t* ptr) const;
 
-  uint8_t ParsePaddingBytes(const uint8_t* ptrRTPDataExtensionEnd,
-                            const uint8_t* ptr) const;
-
   const uint8_t* const _ptrRTPDataBegin;
   const uint8_t* const _ptrRTPDataEnd;
 };
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_utility_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_utility_unittest.cc
new file mode 100644
index 0000000..80f22fc
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/rtp_utility_unittest.cc
@@ -0,0 +1,240 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
+#include "webrtc/test/gmock.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::ElementsAreArray;
+using ::testing::make_tuple;
+
+const int8_t kPayloadType = 100;
+const uint32_t kSsrc = 0x12345678;
+const uint16_t kSeqNum = 88;
+const uint32_t kTimestamp = 0x65431278;
+
+}  // namespace
+
+TEST(RtpHeaderParser, ParseMinimum) {
+  // clang-format off
+  const uint8_t kPacket[] = {
+    0x80, kPayloadType, 0x00, kSeqNum,
+    0x65, 0x43, 0x12, 0x78,   // kTimestamp.
+    0x12, 0x34, 0x56, 0x78};  // kSsrc.
+  // clang-format on
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, nullptr));
+
+  EXPECT_EQ(kPayloadType, header.payloadType);
+  EXPECT_EQ(kSeqNum, header.sequenceNumber);
+  EXPECT_EQ(kTimestamp, header.timestamp);
+  EXPECT_EQ(kSsrc, header.ssrc);
+  EXPECT_EQ(0u, header.paddingLength);
+  EXPECT_EQ(sizeof(kPacket), header.headerLength);
+}
+
+TEST(RtpHeaderParser, ParseWithExtension) {
+  // clang-format off
+  const uint8_t kPacket[] = {
+    0x90, kPayloadType, 0x00, kSeqNum,
+    0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+    0x12, 0x34, 0x56, 0x78,  // kSsrc.
+    0xbe, 0xde, 0x00, 0x01,  // Extension block of size 1 x 32bit words.
+    0x12, 0x01, 0x56, 0xce};
+  // clang-format on
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(1);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  EXPECT_EQ(kPayloadType, header.payloadType);
+  EXPECT_EQ(kSeqNum, header.sequenceNumber);
+  EXPECT_EQ(kTimestamp, header.timestamp);
+  EXPECT_EQ(kSsrc, header.ssrc);
+
+  ASSERT_TRUE(header.extension.hasTransmissionTimeOffset);
+  EXPECT_EQ(0x156ce, header.extension.transmissionTimeOffset);
+}
+
+TEST(RtpHeaderParser, ParseWithInvalidSizedExtension) {
+  const size_t kPayloadSize = 7;
+  // clang-format off
+  const uint8_t kPacket[] = {
+      0x90, kPayloadType, 0x00, kSeqNum,
+      0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+      0x12, 0x34, 0x56, 0x78,  // kSsrc.
+      0xbe, 0xde, 0x00, 0x02,  // Extension block of size 2 x 32bit words.
+      0x16,  // (6+1)-bytes, but Transmission Offset expected to be 3-bytes.
+             'e',  'x',  't',
+       'd',  'a',  't',  'a',
+       'p',  'a',  'y',  'l',  'o',  'a',  'd'
+  };
+  // clang-format on
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(1);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  // Extension should be ignored.
+  EXPECT_FALSE(header.extension.hasTransmissionTimeOffset);
+  // But shouldn't prevent reading payload.
+  EXPECT_THAT(sizeof(kPacket) - kPayloadSize, header.headerLength);
+}
+
+TEST(RtpHeaderParser, ParseWithExtensionPadding) {
+  // clang-format off
+  const uint8_t kPacket[] = {
+      0x90, kPayloadType, 0x00, kSeqNum,
+      0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+      0x12, 0x34, 0x56, 0x78,  // kSsrc.
+      0xbe, 0xde, 0x00, 0x02,  // Extension of size 1x32bit word.
+      0x02,  // A byte of (invalid) padding.
+      0x12, 0x1a, 0xda, 0x03,  // TransmissionOffset extension.
+      0x0f, 0x00, 0x03,  // More invalid padding bytes: id=0, but len > 0.
+  };
+  // clang-format on
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(1);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  // Parse should skip padding and read extension.
+  EXPECT_TRUE(header.extension.hasTransmissionTimeOffset);
+  EXPECT_EQ(0x1ada03, header.extension.transmissionTimeOffset);
+  EXPECT_EQ(sizeof(kPacket), header.headerLength);
+}
+
+TEST(RtpHeaderParser, ParseWithOverSizedExtension) {
+  // clang-format off
+  const uint8_t kPacket[] = {
+      0x90, kPayloadType, 0x00, kSeqNum,
+      0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+      0x12, 0x34, 0x56, 0x78,  // kSsrc.
+      0xbe, 0xde, 0x00, 0x01,  // Extension of size 1x32bit word.
+      0x00,  // Add a byte of padding.
+            0x12,  // Extension id 1 size (2+1).
+                  0xda, 0x1a  // Only 2 bytes of extension payload.
+  };
+  // clang-format on
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(1);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  // Parse should ignore extension.
+  EXPECT_FALSE(header.extension.hasTransmissionTimeOffset);
+  EXPECT_EQ(sizeof(kPacket), header.headerLength);
+}
+
+TEST(RtpHeaderParser, ParseAll6Extensions) {
+  const uint8_t kAudioLevel = 0x5a;
+  // clang-format off
+  const uint8_t kPacket[] = {
+      0x90, kPayloadType, 0x00, kSeqNum,
+      0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+      0x12, 0x34, 0x56, 0x78,  // kSsrc.
+      0xbe, 0xde, 0x00, 0x05,  // Extension of size 5x32bit word.
+      0x40, 0x80|kAudioLevel,  // AudioLevel.
+      0x22, 0x01, 0x56, 0xce,  // TransmissionOffset.
+      0x62, 0x12, 0x34, 0x56,  // AbsoluteSendTime.
+      0x81, 0xce, 0xab,        // TransportSequenceNumber.
+      0xa0, 0x03,              // VideoRotation.
+      0xb2, 0x12, 0x48, 0x76,  // PlayoutDelayLimits.
+      0x00,                    // Padding to 32bit boundary.
+  };
+  // clang-format on
+  ASSERT_EQ(sizeof(kPacket) % 4, 0u);
+
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(2);
+  extensions.Register<AudioLevel>(4);
+  extensions.Register<AbsoluteSendTime>(6);
+  extensions.Register<TransportSequenceNumber>(8);
+  extensions.Register<VideoOrientation>(0xa);
+  extensions.Register<PlayoutDelayLimits>(0xb);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  EXPECT_TRUE(header.extension.hasTransmissionTimeOffset);
+  EXPECT_EQ(0x156ce, header.extension.transmissionTimeOffset);
+
+  EXPECT_TRUE(header.extension.hasAudioLevel);
+  EXPECT_TRUE(header.extension.voiceActivity);
+  EXPECT_EQ(kAudioLevel, header.extension.audioLevel);
+
+  EXPECT_TRUE(header.extension.hasAbsoluteSendTime);
+  EXPECT_EQ(0x123456U, header.extension.absoluteSendTime);
+
+  EXPECT_TRUE(header.extension.hasTransportSequenceNumber);
+  EXPECT_EQ(0xceab, header.extension.transportSequenceNumber);
+
+  EXPECT_TRUE(header.extension.hasVideoRotation);
+  EXPECT_EQ(kVideoRotation_270, header.extension.videoRotation);
+
+  EXPECT_EQ(0x124 * PlayoutDelayLimits::kGranularityMs,
+            header.extension.playout_delay.min_ms);
+  EXPECT_EQ(0x876 * PlayoutDelayLimits::kGranularityMs,
+            header.extension.playout_delay.max_ms);
+}
+
+TEST(RtpHeaderParser, ParseWithCsrcsExtensionAndPadding) {
+  const uint8_t kPacketPaddingSize = 8;
+  const uint32_t kCsrcs[] = {0x34567890, 0x32435465};
+  const size_t kPayloadSize = 7;
+  // clang-format off
+  const uint8_t kPacket[] = {
+    0xb2, kPayloadType, 0x00, kSeqNum,
+    0x65, 0x43, 0x12, 0x78,  // kTimestamp.
+    0x12, 0x34, 0x56, 0x78,  // kSsrc.
+    0x34, 0x56, 0x78, 0x90,  // kCsrcs[0].
+    0x32, 0x43, 0x54, 0x65,  // kCsrcs[1].
+    0xbe, 0xde, 0x00, 0x01,  // Extension.
+    0x12, 0x00, 0x56, 0xce,  // TransmissionTimeOffset with id = 1.
+    'p', 'a', 'y', 'l', 'o', 'a', 'd',
+    'p', 'a', 'd', 'd', 'i', 'n', 'g', kPacketPaddingSize};
+  // clang-format on
+  RtpHeaderExtensionMap extensions;
+  extensions.Register<TransmissionOffset>(1);
+  RtpUtility::RtpHeaderParser parser(kPacket, sizeof(kPacket));
+  RTPHeader header;
+
+  EXPECT_TRUE(parser.Parse(&header, &extensions));
+
+  EXPECT_EQ(kPayloadType, header.payloadType);
+  EXPECT_EQ(kSeqNum, header.sequenceNumber);
+  EXPECT_EQ(kTimestamp, header.timestamp);
+  EXPECT_EQ(kSsrc, header.ssrc);
+  EXPECT_THAT(make_tuple(header.arrOfCSRCs, header.numCSRCs),
+              ElementsAreArray(kCsrcs));
+  EXPECT_EQ(kPacketPaddingSize, header.paddingLength);
+  EXPECT_THAT(sizeof(kPacket) - kPayloadSize - kPacketPaddingSize,
+              header.headerLength);
+  EXPECT_TRUE(header.extension.hasTransmissionTimeOffset);
+  EXPECT_EQ(0x56ce, header.extension.transmissionTimeOffset);
+}
+
+}  // namespace webrtc