From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754325Ab1G0Al7 (ORCPT ); Tue, 26 Jul 2011 20:41:59 -0400 Received: from mga01.intel.com ([192.55.52.88]:6474 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753387Ab1G0Ae5 (ORCPT ); Tue, 26 Jul 2011 20:34:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,272,1309762800"; d="scan'208";a="34855520" From: Andi Kleen References: <20110726534.972201586@firstfloor.org> In-Reply-To: <20110726534.972201586@firstfloor.org> To: segoon@openwall.com, airlied@redhat.com, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] [5/98] agp: fix arbitrary kernel memory writes Message-Id: <20110727003457.133ED2403FF@tassilo.jf.intel.com> Date: Tue, 26 Jul 2011 17:34:57 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Vasiliy Kulikov [ upstream commit 194b3da873fd334ef183806db751473512af29ce ] 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: Andi Kleen Index: linux-2.6.35.y/drivers/char/agp/generic.c =================================================================== --- linux-2.6.35.y.orig/drivers/char/agp/generic.c +++ linux-2.6.35.y/drivers/char/agp/generic.c @@ -1122,8 +1122,8 @@ 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; @@ -1157,7 +1157,7 @@ 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) @@ -1169,6 +1169,11 @@ 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 */