From 4be5a281048964854c0b1c145e57597e7116ea9f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 30 Jan 2018 23:11:24 -0800 Subject: [PATCH] binder: check for binder_thread allocation failure in binder_poll() commit f88982679f54f75daa5b8eff3da72508f1e7422f upstream. 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 Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 15009b2b33c7..3b6ac80b2127 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2628,6 +2628,8 @@ static unsigned int binder_poll(struct file *filp, binder_lock(__func__); thread = binder_get_thread(proc); + if (!thread) + return POLLERR; wait_for_proc_work = thread->transaction_stack == NULL && list_empty(&thread->todo) && thread->return_error == BR_OK; -- 2.17.1