From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757164Ab3CYB1o (ORCPT ); Sun, 24 Mar 2013 21:27:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34033 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756098Ab3CYBQG (ORCPT ); Sun, 24 Mar 2013 21:16:06 -0400 Message-Id: <20130325010529.933837586@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 25 Mar 2013 01:06:21 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Kees Cook , Chris Wilson , Daniel Vetter Subject: [ 057/104] drm/i915: bounds check execbuffer relocation count Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In-Reply-To: <20130325010524.240972766@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:f137:78a:b654:affb X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 3118a4f652c7b12c752f3222af0447008f9b2368 upstream. It is possible to wrap the counter used to allocate the buffer for relocation copies. This could lead to heap writing overflows. CVE-2013-0913 v3: collapse test, improve comment v2: move check into validate_exec_list Signed-off-by: Kees Cook Reported-by: Pinkie Pie Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter Signed-off-by: Ben Hutchings --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -907,15 +907,20 @@ validate_exec_list(struct drm_i915_gem_e int count) { int i; + int relocs_total = 0; + int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry); for (i = 0; i < count; i++) { char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr; int length; /* limited by fault_in_pages_readable() */ - /* First check for malicious input causing overflow */ - if (exec[i].relocation_count > - INT_MAX / sizeof(struct drm_i915_gem_relocation_entry)) + /* First check for malicious input causing overflow in + * the worst case where we need to allocate the entire + * relocation tree as a single array. + */ + if (exec[i].relocation_count > relocs_max - relocs_total) return -EINVAL; + relocs_total += exec[i].relocation_count; length = exec[i].relocation_count * sizeof(struct drm_i915_gem_relocation_entry);