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NetEq: Fixing a bug that caused rtc::checked_cast to trigger

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This is a bug that was introduced in
https://codereview.webrtc.org/1230503003, where the variable "int
temp_bufsize" was changed to a size_t. If the packet buffer was
flushed while inserting a packet, temp_bufsize became negative, which
was tested later in an if-statement. Now, with size_t instead, it
would just become very large, and the if-statement would never see a
negative value. The effect was that the packet size in samples could
be updated with a very large positive number, causing an overflow
which triggered rtc::checked_cast in
StatisticsCalculator::GetNetworkStatistics, line 220.

Also adding a test to reproduce the crash. Without the fix, the test
results in the above mentioned checked_cast to trigger. With the fix,
everything works fine.

BUG=chromium:525260

Review URL: https://codereview.webrtc.org/1307893004

Cr-Commit-Position: refs/heads/master@{#9802}
This commit is contained in:
henrik.lundin
2015-08-27 13:14:48 -07:00
committed by Commit bot
parent 9c3efd0052
commit 116c84e1b0
2 changed files with 53 additions and 8 deletions
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40
webrtc/modules/audio_coding/neteq/neteq_impl_unittest.cc
View File

@ -13,6 +13,7 @@
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "webrtc/base/safe_conversions.h"
#include "webrtc/modules/audio_coding/neteq/accelerate.h"
#include "webrtc/modules/audio_coding/neteq/expand.h"
#include "webrtc/modules/audio_coding/neteq/mock/mock_audio_decoder.h"
@ -902,4 +903,43 @@ TEST_F(NetEqImplTest, UnsupportedDecoder) {
EXPECT_EQ(kChannels, num_channels);
}
// This test inserts packets until the buffer is flushed. After that, it asks
// NetEq for the network statistics. The purpose of the test is to make sure
// that even though the buffer size increment is negative (which it becomes when
// the packet causing a flush is inserted), the packet length stored in the
// decision logic remains valid.
TEST_F(NetEqImplTest, FloodBufferAndGetNetworkStats) {
UseNoMocks();
CreateInstance();
const size_t kPayloadLengthSamples = 80;
const size_t kPayloadLengthBytes = 2 * kPayloadLengthSamples; // PCM 16-bit.
const uint8_t kPayloadType = 17; // Just an arbitrary number.
const uint32_t kReceiveTime = 17; // Value doesn't matter for this test.
uint8_t payload[kPayloadLengthBytes] = {0};
WebRtcRTPHeader rtp_header;
rtp_header.header.payloadType = kPayloadType;
rtp_header.header.sequenceNumber = 0x1234;
rtp_header.header.timestamp = 0x12345678;
rtp_header.header.ssrc = 0x87654321;
EXPECT_EQ(NetEq::kOK,
neteq_->RegisterPayloadType(kDecoderPCM16B, kPayloadType));
// Insert packets until the buffer flushes.
for (size_t i = 0; i <= config_.max_packets_in_buffer; ++i) {
EXPECT_EQ(i, packet_buffer_->NumPacketsInBuffer());
EXPECT_EQ(NetEq::kOK,
neteq_->InsertPacket(rtp_header, payload, kPayloadLengthBytes,
kReceiveTime));
rtp_header.header.timestamp +=
rtc::checked_cast<uint32_t>(kPayloadLengthSamples);
++rtp_header.header.sequenceNumber;
}
EXPECT_EQ(1u, packet_buffer_->NumPacketsInBuffer());
// Ask for network statistics. This should not crash.
NetEqNetworkStatistics stats;
EXPECT_EQ(NetEq::kOK, neteq_->NetworkStatistics(&stats));
}
} // namespace webrtc