From: Chris Wilson Subject: Re: [PATCH 1/2] drm/i915: fix integer overflow in i915_gem_execbuffer2() Date: Fri, 06 Apr 2012 14:54:05 +0100 Message-ID: <1333720475_271533@CP5-2952> References: <1333717099-32679-1-git-send-email-xi.wang@gmail.com> <1333719431_271283@CP5-2952> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (smtp.fireflyinternet.com [109.228.6.236]) by gabe.freedesktop.org (Postfix) with ESMTP id 9D8D79EEAD for ; Fri, 6 Apr 2012 06:54:41 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Xi Wang Cc: Daniel Vetter , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Fri, 6 Apr 2012 09:46:46 -0400, Xi Wang wrote: > On Apr 6, 2012, at 9:36 AM, Chris Wilson wrote: > > > On Fri, 6 Apr 2012 08:58:18 -0400, Xi Wang wrote: > >> A large args->buffer_count from userspace may overflow the allocation > >> size, leading to out-of-bounds access. > >> > >> Use kmalloc_array() to avoid that. > > > > I can safely say that exec list larger than 4GiB is going to be an > > illegal operation and would rather the ioctl failed outright with > > EINVAL. > > On 32-bit platform? On any platform. The largest it can legally be is a few tens of megabytes. -Chris -- Chris Wilson, Intel Open Source Technology Centre