webrtc_m130/media/engine/webrtc_media_engine.cc
Harald Alvestrand b62ee8ce94 Detect and reject illegal RTP header extension modifications.
This is somewhat klugey, because it does the same checks at two
different layers in the stack, in different functions, which runs
the risk of making them out of sync. But it solves the immediate
problem.

Bug: chromium:1249753
Change-Id: I2ad96f0cc9499c15540ff6946a409b40df3e3925
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/235826
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35259}
2021-10-22 11:52:02 +00:00

217 lines
8.1 KiB
C++

/*
* Copyright (c) 2014 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 "media/engine/webrtc_media_engine.h"
#include <map>
#include <memory>
#include <utility>
#include "absl/algorithm/container.h"
#include "absl/strings/match.h"
#include "media/engine/webrtc_voice_engine.h"
#ifdef HAVE_WEBRTC_VIDEO
#include "media/engine/webrtc_video_engine.h"
#else
#include "media/engine/null_webrtc_video_engine.h"
#endif
namespace cricket {
std::unique_ptr<MediaEngineInterface> CreateMediaEngine(
MediaEngineDependencies dependencies) {
// TODO(sprang): Make populating `dependencies.trials` mandatory and remove
// these fallbacks.
std::unique_ptr<webrtc::WebRtcKeyValueConfig> fallback_trials(
dependencies.trials ? nullptr : new webrtc::FieldTrialBasedConfig());
const webrtc::WebRtcKeyValueConfig& trials =
dependencies.trials ? *dependencies.trials : *fallback_trials;
auto audio_engine = std::make_unique<WebRtcVoiceEngine>(
dependencies.task_queue_factory, std::move(dependencies.adm),
std::move(dependencies.audio_encoder_factory),
std::move(dependencies.audio_decoder_factory),
std::move(dependencies.audio_mixer),
std::move(dependencies.audio_processing),
dependencies.audio_frame_processor, trials);
#ifdef HAVE_WEBRTC_VIDEO
auto video_engine = std::make_unique<WebRtcVideoEngine>(
std::move(dependencies.video_encoder_factory),
std::move(dependencies.video_decoder_factory), trials);
#else
auto video_engine = std::make_unique<NullWebRtcVideoEngine>();
#endif
return std::make_unique<CompositeMediaEngine>(std::move(fallback_trials),
std::move(audio_engine),
std::move(video_engine));
}
namespace {
// Remove mutually exclusive extensions with lower priority.
void DiscardRedundantExtensions(
std::vector<webrtc::RtpExtension>* extensions,
rtc::ArrayView<const char* const> extensions_decreasing_prio) {
RTC_DCHECK(extensions);
bool found = false;
for (const char* uri : extensions_decreasing_prio) {
auto it = absl::c_find_if(
*extensions,
[uri](const webrtc::RtpExtension& rhs) { return rhs.uri == uri; });
if (it != extensions->end()) {
if (found) {
extensions->erase(it);
}
found = true;
}
}
}
} // namespace
bool ValidateRtpExtensions(
rtc::ArrayView<const webrtc::RtpExtension> extensions,
rtc::ArrayView<const webrtc::RtpExtension> old_extensions) {
bool id_used[1 + webrtc::RtpExtension::kMaxId] = {false};
for (const auto& extension : extensions) {
if (extension.id < webrtc::RtpExtension::kMinId ||
extension.id > webrtc::RtpExtension::kMaxId) {
RTC_LOG(LS_ERROR) << "Bad RTP extension ID: " << extension.ToString();
return false;
}
if (id_used[extension.id]) {
RTC_LOG(LS_ERROR) << "Duplicate RTP extension ID: "
<< extension.ToString();
return false;
}
id_used[extension.id] = true;
}
// Validate the extension list against the already negotiated extensions.
// Re-registering is OK, re-mapping (either same URL at new ID or same
// ID used with new URL) is an illegal remap.
// This is required in order to avoid a crash when registering an
// extension. A better structure would use the registered extensions
// in the RTPSender. This requires spinning through:
//
// WebRtcVoiceMediaChannel::::WebRtcAudioSendStream::stream_ (pointer)
// AudioSendStream::rtp_rtcp_module_ (pointer)
// ModuleRtpRtcpImpl2::rtp_sender_ (pointer)
// RtpSenderContext::packet_generator (struct member)
// RTPSender::rtp_header_extension_map_ (class member)
//
// Getting at this seems like a hard slog.
if (!old_extensions.empty()) {
absl::string_view urimap[1 + webrtc::RtpExtension::kMaxId];
std::map<absl::string_view, int> idmap;
for (const auto& old_extension : old_extensions) {
urimap[old_extension.id] = old_extension.uri;
idmap[old_extension.uri] = old_extension.id;
}
for (const auto& extension : extensions) {
if (!urimap[extension.id].empty() &&
urimap[extension.id] != extension.uri) {
RTC_LOG(LS_ERROR) << "Extension negotiation failure: " << extension.id
<< " was mapped to " << urimap[extension.id]
<< " but is proposed changed to " << extension.uri;
return false;
}
const auto& it = idmap.find(extension.uri);
if (it != idmap.end() && it->second != extension.id) {
RTC_LOG(LS_ERROR) << "Extension negotation failure: " << extension.uri
<< " was identified by " << it->second
<< " but is proposed changed to " << extension.id;
return false;
}
}
}
return true;
}
std::vector<webrtc::RtpExtension> FilterRtpExtensions(
const std::vector<webrtc::RtpExtension>& extensions,
bool (*supported)(absl::string_view),
bool filter_redundant_extensions,
const webrtc::WebRtcKeyValueConfig& trials) {
// Don't check against old parameters; this should have been done earlier.
RTC_DCHECK(ValidateRtpExtensions(extensions, {}));
RTC_DCHECK(supported);
std::vector<webrtc::RtpExtension> result;
// Ignore any extensions that we don't recognize.
for (const auto& extension : extensions) {
if (supported(extension.uri)) {
result.push_back(extension);
} else {
RTC_LOG(LS_WARNING) << "Unsupported RTP extension: "
<< extension.ToString();
}
}
// Sort by name, ascending (prioritise encryption), so that we don't reset
// extensions if they were specified in a different order (also allows us
// to use std::unique below).
absl::c_sort(result, [](const webrtc::RtpExtension& rhs,
const webrtc::RtpExtension& lhs) {
return rhs.encrypt == lhs.encrypt ? rhs.uri < lhs.uri
: rhs.encrypt > lhs.encrypt;
});
// Remove unnecessary extensions (used on send side).
if (filter_redundant_extensions) {
auto it = std::unique(
result.begin(), result.end(),
[](const webrtc::RtpExtension& rhs, const webrtc::RtpExtension& lhs) {
return rhs.uri == lhs.uri && rhs.encrypt == lhs.encrypt;
});
result.erase(it, result.end());
// Keep just the highest priority extension of any in the following lists.
if (absl::StartsWith(trials.Lookup("WebRTC-FilterAbsSendTimeExtension"),
"Enabled")) {
static const char* const kBweExtensionPriorities[] = {
webrtc::RtpExtension::kTransportSequenceNumberUri,
webrtc::RtpExtension::kAbsSendTimeUri,
webrtc::RtpExtension::kTimestampOffsetUri};
DiscardRedundantExtensions(&result, kBweExtensionPriorities);
} else {
static const char* const kBweExtensionPriorities[] = {
webrtc::RtpExtension::kAbsSendTimeUri,
webrtc::RtpExtension::kTimestampOffsetUri};
DiscardRedundantExtensions(&result, kBweExtensionPriorities);
}
}
return result;
}
webrtc::BitrateConstraints GetBitrateConfigForCodec(const Codec& codec) {
webrtc::BitrateConstraints config;
int bitrate_kbps = 0;
if (codec.GetParam(kCodecParamMinBitrate, &bitrate_kbps) &&
bitrate_kbps > 0) {
config.min_bitrate_bps = bitrate_kbps * 1000;
} else {
config.min_bitrate_bps = 0;
}
if (codec.GetParam(kCodecParamStartBitrate, &bitrate_kbps) &&
bitrate_kbps > 0) {
config.start_bitrate_bps = bitrate_kbps * 1000;
} else {
// Do not reconfigure start bitrate unless it's specified and positive.
config.start_bitrate_bps = -1;
}
if (codec.GetParam(kCodecParamMaxBitrate, &bitrate_kbps) &&
bitrate_kbps > 0) {
config.max_bitrate_bps = bitrate_kbps * 1000;
} else {
config.max_bitrate_bps = -1;
}
return config;
}
} // namespace cricket