diff options
author | Ted Meyer <tmathmeyer@chromium.org> | 2022-02-23 01:34:20 +0000 |
---|---|---|
committer | Michael Brüning <michael.bruning@qt.io> | 2022-06-03 11:39:16 +0000 |
commit | ecc2bb74f1f7140fc52650042299be18e826b27b (patch) | |
tree | 1a8ba9ec0a7dcf9617a0ad1f7f979543819b66c3 | |
parent | a7a23ccc69e6756e02583e6871cc37151d89a7c2 (diff) |
[Backport] CVE-2022-0796: Use after free in Media
Manual backport of patch originally reviewed on
https://chromium-review.googlesource.com/c/chromium/src/+/3482463:
Guard BatchingMediaLog::event_handlers_ with lock
It seems that despite MediaLog::OnWebMediaPlayerDestroyed and
MediaLog::AddLogRecord both grabbing a lock,
BatchingMediaLog::AddLogRecordLocked can escape the lock handle by
posting BatchingMediaLog::SendQueuedMediaEvents, causing a race.
When the addition of an event is interrupted by the deletion of a player
due to player culling in MediaInspectorContextImpl, a UAF can occur.
R=​dalecurtis
(cherry picked from commit 34526c3d0a857a22618e4d77c7f63b5ca6f8d3d2)
Bug: 1295786
Change-Id: I77df94988f806e4d98924669d27860e50455299d
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Ted (Chromium) Meyer <tmathmeyer@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#970815}
Auto-Submit: Ted (Chromium) Meyer <tmathmeyer@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/4758@{#1192}
Cr-Branched-From: 4a2cf4baf90326df19c3ee70ff987960d59a386e-refs/heads/main@{#950365}
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
-rw-r--r-- | chromium/content/renderer/media/batching_media_log.cc | 29 | ||||
-rw-r--r-- | chromium/content/renderer/media/batching_media_log.h | 16 |
2 files changed, 22 insertions, 23 deletions
diff --git a/chromium/content/renderer/media/batching_media_log.cc b/chromium/content/renderer/media/batching_media_log.cc index 76ebdf6f7a1..d345a23ccd3 100644 --- a/chromium/content/renderer/media/batching_media_log.cc +++ b/chromium/content/renderer/media/batching_media_log.cc @@ -56,9 +56,9 @@ BatchingMediaLog::BatchingMediaLog( std::vector<std::unique_ptr<EventHandler>> event_handlers) : security_origin_(security_origin), task_runner_(std::move(task_runner)), - event_handlers_(std::move(event_handlers)), tick_clock_(base::DefaultTickClock::GetInstance()), last_ipc_send_time_(tick_clock_->NowTicks()), + event_handlers_(std::move(event_handlers)), ipc_send_pending_(false) { DCHECK(RenderThread::Get()) << "BatchingMediaLog must be constructed on the render thread"; @@ -81,6 +81,7 @@ BatchingMediaLog::~BatchingMediaLog() { } void BatchingMediaLog::OnWebMediaPlayerDestroyedLocked() { + base::AutoLock lock(lock_); for (const auto& handler : event_handlers_) handler->OnWebMediaPlayerDestroyed(); } @@ -200,27 +201,25 @@ std::string BatchingMediaLog::MediaEventToMessageString( void BatchingMediaLog::SendQueuedMediaEvents() { DCHECK(task_runner_->BelongsToCurrentThread()); + base::AutoLock auto_lock(lock_); - std::vector<media::MediaLogRecord> events_to_send; - { - base::AutoLock auto_lock(lock_); - DCHECK(ipc_send_pending_); - ipc_send_pending_ = false; - - if (last_duration_changed_event_) { - queued_media_events_.push_back(*last_duration_changed_event_); - last_duration_changed_event_.reset(); - } + DCHECK(ipc_send_pending_); + ipc_send_pending_ = false; - queued_media_events_.swap(events_to_send); - last_ipc_send_time_ = tick_clock_->NowTicks(); + if (last_duration_changed_event_) { + queued_media_events_.push_back(*last_duration_changed_event_); + last_duration_changed_event_.reset(); } - if (events_to_send.empty()) + last_ipc_send_time_ = tick_clock_->NowTicks(); + + if (queued_media_events_.empty()) return; for (const auto& handler : event_handlers_) - handler->SendQueuedMediaEvents(events_to_send); + handler->SendQueuedMediaEvents(queued_media_events_); + + queued_media_events_.clear(); } void BatchingMediaLog::SetTickClockForTesting( diff --git a/chromium/content/renderer/media/batching_media_log.h b/chromium/content/renderer/media/batching_media_log.h index 32e2bbb87ec..b68535aea42 100644 --- a/chromium/content/renderer/media/batching_media_log.h +++ b/chromium/content/renderer/media/batching_media_log.h @@ -65,9 +65,6 @@ class CONTENT_EXPORT BatchingMediaLog : public media::MediaLog { scoped_refptr<base::SingleThreadTaskRunner> task_runner_; - // impl for sending queued events. - std::vector<std::unique_ptr<EventHandler>> event_handlers_; - // |lock_| protects access to all of the following member variables. It // allows any render process thread to AddEvent(), while preserving their // sequence for throttled send on |task_runner_| and coherent retrieval by @@ -75,15 +72,18 @@ class CONTENT_EXPORT BatchingMediaLog : public media::MediaLog { // guarantees provided by MediaLog, since SendQueuedMediaEvents must also // be synchronized with respect to AddEvent. mutable base::Lock lock_; - const base::TickClock* tick_clock_; - base::TimeTicks last_ipc_send_time_; - std::vector<media::MediaLogRecord> queued_media_events_; + const base::TickClock* tick_clock_ GUARDED_BY(LOCK); + base::TimeTicks last_ipc_send_time_ GUARDED_BY(LOCK); + std::vector<media::MediaLogRecord> queued_media_events_ GUARDED_BY(LOCK); + + // impl for sending queued events. + std::vector<std::unique_ptr<EventHandler>> event_handlers_ GUARDED_BY(LOCK); // For enforcing max 1 pending send. - bool ipc_send_pending_; + bool ipc_send_pending_ GUARDED_BY(LOCK); // Limits the number of events we send over IPC to one. - std::unique_ptr<media::MediaLogRecord> last_duration_changed_event_; + std::unique_ptr<media::MediaLogRecord> last_duration_changed_event_ GUARDED_BY(LOCK); // Holds the earliest MEDIA_ERROR_LOG_ENTRY event added to this log. This is // most likely to contain the most specific information available describing |