From: Carlos Llamas <cmllamas@google.com> stable inclusion from stable-v5.10.210 commit a423042052ec2bdbf1e552e621e6a768922363cc category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I93X0G CVE: CVE-2024-26606 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 97830f3c3088638ff90b20dfba2eb4d487bf14d7 upstream. In (e)poll mode, threads often depend on I/O events to determine when data is ready for consumption. Within binder, a thread may initiate a command via BINDER_WRITE_READ without a read buffer and then make use of epoll_wait() or similar to consume any responses afterwards. It is then crucial that epoll threads are signaled via wakeup when they queue their own work. Otherwise, they risk waiting indefinitely for an event leaving their work unhandled. What is worse, subsequent commands won't trigger a wakeup either as the thread has pending work. Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: Arve Hjønnevåg <arve@android.com> Cc: Martijn Coenen <maco@android.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Steven Moreland <smoreland@google.com> Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Carlos Llamas <cmllamas@google.com> Link: https://lore.kernel.org/r/20240131215347.1808751-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> --- drivers/android/binder.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 2aaccb78235b..f484304a2321 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -836,6 +836,16 @@ binder_enqueue_thread_work_ilocked(struct binder_thread *thread, { WARN_ON(!list_empty(&thread->waiting_thread_node)); binder_enqueue_work_ilocked(work, &thread->todo); + + /* (e)poll-based threads require an explicit wakeup signal when + * queuing their own work; they rely on these events to consume + * messages without I/O block. Without it, threads risk waiting + * indefinitely without handling the work. + */ + if (thread->looper & BINDER_LOOPER_STATE_POLL && + thread->pid == current->pid && !thread->process_todo) + wake_up_interruptible_sync(&thread->wait); + thread->process_todo = true; } -- 2.34.1