This is a note to let you know that I've just added the patch titled binder: check for binder_thread allocation failure in binder_poll() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: binder-check-for-binder_thread-allocation-failure-in-binder_poll.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f88982679f54f75daa5b8eff3da72508f1e7422f Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers@xxxxxxxxxx> Date: Tue, 30 Jan 2018 23:11:24 -0800 Subject: binder: check for binder_thread allocation failure in binder_poll() From: Eric Biggers <ebiggers@xxxxxxxxxx> 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 <syzkaller@xxxxxxxxxxxxxxxx> Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/android/binder.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2628,6 +2628,8 @@ static unsigned int binder_poll(struct f 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; Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are queue-4.9/crypto-x86-twofish-3way-fix-rbp-usage.patch queue-4.9/binder-check-for-binder_thread-allocation-failure-in-binder_poll.patch queue-4.9/crypto-hash-annotate-algorithms-taking-optional-key.patch queue-4.9/crypto-hash-prevent-using-keyed-hashes-without-setting-key.patch