Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42356 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932953AbeBWSnt (ORCPT ); Fri, 23 Feb 2018 13:43:49 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Eric Biggers Subject: [PATCH 4.9 038/145] binder: check for binder_thread allocation failure in binder_poll() Date: Fri, 23 Feb 2018 19:25:44 +0100 Message-Id: <20180223170729.872536682@linuxfoundation.org> In-Reply-To: <20180223170724.669759283@linuxfoundation.org> References: <20180223170724.669759283@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers 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(+) --- 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;