Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933682Ab1D2TBb (ORCPT ); Fri, 29 Apr 2011 15:01:31 -0400 Received: from kroah.org ([198.145.64.141]:35096 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933626Ab1D2S6t (ORCPT ); Fri, 29 Apr 2011 14:58:49 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Apr 29 11:56:57 2011 Message-Id: <20110429185657.344031011@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Fri, 29 Apr 2011 11:56:12 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Vasiliy Kulikov , Dave Airlie Subject: [49/55] agp: fix arbitrary kernel memory writes In-Reply-To: <20110429185706.GA12824@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2086 Lines: 64 2.6.38-stable review patch. If anyone has any objections, please let us know. ------------------ From: Vasiliy Kulikov commit 194b3da873fd334ef183806db751473512af29ce upstream. pg_start is copied from userspace on AGPIOC_BIND and AGPIOC_UNBIND ioctl cmds of agp_ioctl() and passed to agpioc_bind_wrap(). As said in the comment, (pg_start + mem->page_count) may wrap in case of AGPIOC_BIND, and it is not checked at all in case of AGPIOC_UNBIND. As a result, user with sufficient privileges (usually "video" group) may generate either local DoS or privilege escalation. Signed-off-by: Vasiliy Kulikov Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/char/agp/generic.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -1089,8 +1089,8 @@ int agp_generic_insert_memory(struct agp return -EINVAL; } - /* AK: could wrap */ - if ((pg_start + mem->page_count) > num_entries) + if (((pg_start + mem->page_count) > num_entries) || + ((pg_start + mem->page_count) < pg_start)) return -EINVAL; j = pg_start; @@ -1124,7 +1124,7 @@ int agp_generic_remove_memory(struct agp { size_t i; struct agp_bridge_data *bridge; - int mask_type; + int mask_type, num_entries; bridge = mem->bridge; if (!bridge) @@ -1136,6 +1136,11 @@ int agp_generic_remove_memory(struct agp if (type != mem->type) return -EINVAL; + num_entries = agp_num_entries(); + if (((pg_start + mem->page_count) > num_entries) || + ((pg_start + mem->page_count) < pg_start)) + return -EINVAL; + mask_type = bridge->driver->agp_type_to_mask_type(bridge, type); if (mask_type != 0) { /* The generic routines know nothing of memory types */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/