Adding libFuzzer target for UlpFEC receiver.

Bug: none
Change-Id: I20e622455aee2f5aebad835e915d65f3475fbd17
Reviewed-on: https://webrtc-review.googlesource.com/14300
Commit-Queue: Mark Brand <markbrand@google.com>
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20384}

test/fuzzers/BUILD.gn

@@ -139,6 +139,17 @@ webrtc_fuzzer_test("ulpfec_generator_fuzzer") {
   ]
 }
 
+webrtc_fuzzer_test("ulpfec_receiver_fuzzer") {
+  sources = [
+    "ulpfec_receiver_fuzzer.cc",
+  ]
+  deps = [
+    "../../modules/rtp_rtcp",
+    "../../rtc_base:rtc_base_approved",
+  ]
+  libfuzzer_options = [ "max_len=2000" ]
+}
+
 webrtc_fuzzer_test("flexfec_receiver_fuzzer") {
   sources = [
     "flexfec_receiver_fuzzer.cc",

test/fuzzers/ulpfec_receiver_fuzzer.cc

@@ -0,0 +1,79 @@
+/*
+ *  Copyright (c) 2017 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 <algorithm>
+
+#include "modules/rtp_rtcp/include/ulpfec_receiver.h"
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/byte_io.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "rtc_base/basictypes.h"
+
+namespace webrtc {
+
+namespace {
+class DummyCallback : public RecoveredPacketReceiver {
+  void OnRecoveredPacket(const uint8_t* packet, size_t length) override {}
+};
+}  // namespace
+
+void FuzzOneInput(const uint8_t* data, size_t size) {
+  constexpr size_t kMinDataNeeded = 12;
+  if (size < kMinDataNeeded) {
+    return;
+  }
+
+  uint32_t ulpfec_ssrc = ByteReader<uint32_t>::ReadLittleEndian(data + 0);
+  uint16_t ulpfec_seq_num = ByteReader<uint16_t>::ReadLittleEndian(data + 4);
+  uint32_t media_ssrc = ByteReader<uint32_t>::ReadLittleEndian(data + 6);
+  uint16_t media_seq_num = ByteReader<uint16_t>::ReadLittleEndian(data + 10);
+
+  DummyCallback callback;
+  std::unique_ptr<UlpfecReceiver> receiver(
+      UlpfecReceiver::Create(ulpfec_ssrc, &callback));
+
+  std::unique_ptr<uint8_t[]> packet;
+  size_t packet_length;
+  size_t i = kMinDataNeeded;
+  while (i < size) {
+    packet_length = kRtpHeaderSize + data[i++];
+    packet = std::unique_ptr<uint8_t[]>(new uint8_t[packet_length]);
+    if (i + packet_length >= size) {
+      break;
+    }
+    memcpy(packet.get(), data + i, packet_length);
+    i += packet_length;
+    // Overwrite the RTPHeader fields for the sequence number and SSRC with
+    // consistent values for either a received UlpFEC packet or received media
+    // packet. (We're still relying on libfuzzer to manage to generate packet
+    // headers that interact together; this just ensures that we have two
+    // consistent streams).
+    if (i < size && data[i++] % 2 == 0) {
+      // Simulate UlpFEC packet.
+      ByteWriter<uint16_t>::WriteBigEndian(packet.get() + 2, ulpfec_seq_num++);
+      ByteWriter<uint32_t>::WriteBigEndian(packet.get() + 8, ulpfec_ssrc);
+    } else {
+      // Simulate media packet.
+      ByteWriter<uint16_t>::WriteBigEndian(packet.get() + 2, media_seq_num++);
+      ByteWriter<uint32_t>::WriteBigEndian(packet.get() + 8, media_ssrc);
+    }
+    RtpPacketReceived parsed_packet;
+    RTPHeader parsed_header;
+    if (parsed_packet.Parse(packet.get(), packet_length)) {
+      parsed_packet.GetHeader(&parsed_header);
+      receiver->AddReceivedRedPacket(parsed_header, packet.get(),
+                                     packet_length, 0);
+    }
+  }
+
+  receiver->ProcessReceivedFec();
+}
+
+}  // namespace webrtc