From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753660AbcAGPwh (ORCPT ); Thu, 7 Jan 2016 10:52:37 -0500 Received: from kanga.kvack.org ([205.233.56.17]:33257 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752283AbcAGPwf (ORCPT ); Thu, 7 Jan 2016 10:52:35 -0500 Date: Thu, 7 Jan 2016 10:52:34 -0500 From: Benjamin LaHaise To: Dmitry Vyukov Cc: Jan Kara , Alexander Viro , linux-aio , "linux-fsdevel@vger.kernel.org" , LKML , syzkaller , Kostya Serebryany , Alexander Potapenko , Sasha Levin , Andrey Ryabinin Subject: Re: int overflow in io_getevents Message-ID: <20160107155234.GM4439@kvack.org> References: <20151216125618.GA16918@quack.suse.cz> <20160106180158.GE4439@kvack.org> <20160107153132.GL4439@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 07, 2016 at 04:37:43PM +0100, Dmitry Vyukov wrote: > pass ts to the function Yeah, I should have had my morning coffee before hitting send. Updated below, and hopefully final. Checked with a test program to confirm that the huge value of seconds in timespec correctly waits, and that negative or other invalid values fail with EINVAL (download from http://www.kvack.org/~bcrl/aio-io_getevents-timespec.c ). -ben -- "Thought is the essence of where you are now." commit 49b78150bc5762c58cfb8b19a859c354cf1a71ac Author: Benjamin LaHaise Date: Thu Jan 7 10:37:58 2016 -0500 aio: handle integer overflow in io_getevents() timespec usage Dmitry Vyukov reported an integer overflow in io_getevents() when running a fuzzer. Upon investigation, the triggers appears to be that an invalid value for the tv_sec or tv_nsec was passed in which is not handled by timespec_to_ktime(). This patch fixes that by making io_getevents() return -EINVAL when timespec_valid() checks fail. We use timespec_valid() instead of timespec_valid_strict() to avoid issues caused by userspace not knowing the cutoff for KTIME_SEC_MAX. Reported-by: Dmitry Vyukov Signed-off-by: Benjamin LaHaise diff --git a/fs/aio.c b/fs/aio.c index 155f842..e0d5398 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1269,6 +1269,8 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr, if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) return -EFAULT; + if (!timespec_valid(&ts)) + return -EINVAL; until = timespec_to_ktime(ts); }