From: Eric Biggers ebiggers@google.com

If the kzalloc() in binder_get_thread() fails, binder_poll() dereferences the resulting NULL pointer.

Fix it by returning POLLERR if the memory allocation failed.

This bug was found by syzkaller using fault injection.

Reported-by: syzbot syzkaller@googlegroups.com Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c index abf05aa..ed23507 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4289,6 +4289,8 @@ static unsigned int binder_poll(struct file *filp, bool wait_for_proc_work;

thread = binder_get_thread(proc); + if (!thread) + return POLLERR;

binder_inner_proc_lock(thread->proc); thread->looper |= BINDER_LOOPER_STATE_POLL;