From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754157Ab2BEWom (ORCPT ); Sun, 5 Feb 2012 17:44:42 -0500 Received: from 1wt.eu ([62.212.114.60]:61872 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753749Ab2BEW0U (ORCPT ); Sun, 5 Feb 2012 17:26:20 -0500 Message-Id: <20120205220949.664105202@pcw.home.local> User-Agent: quilt/0.48-1 Date: Sun, 05 Feb 2012 23:09:54 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vasiliy Kulikov , Dave Airlie , Greg KH Subject: [PATCH 05/91] agp: fix OOM and buffer overflow In-Reply-To: <0635750f5f06ed2ca212b91fcb5c4483@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27-longterm review patch. If anyone has any objections, please let us know. ------------------ commit b522f02184b413955f3bc952e3776ce41edc6355 upstream. page_count is copied from userspace. agp_allocate_memory() tries to check whether this number is too big, but doesn't take into account the wrap case. Also agp_create_user_memory() doesn't check whether alloc_size is calculated from num_agp_pages variable without overflow. This may lead to allocation of too small buffer with following buffer overflow. Another problem in agp code is not addressed in the patch - kernel memory exhaustion (AGPIOC_RESERVE and AGPIOC_ALLOCATE ioctls). It is not checked whether requested pid is a pid of the caller (no check in agpioc_reserve_wrap()). Each allocation is limited to 16KB, though, there is no per-process limit. This might lead to OOM situation, which is not even solved in case of the caller death by OOM killer - the memory is allocated for another (faked) process. Signed-off-by: Vasiliy Kulikov Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/char/agp/generic.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) Index: longterm-2.6.27/drivers/char/agp/generic.c =================================================================== --- longterm-2.6.27.orig/drivers/char/agp/generic.c 2012-02-05 22:34:35.500916106 +0100 +++ longterm-2.6.27/drivers/char/agp/generic.c 2012-02-05 22:34:35.639914999 +0100 @@ -123,6 +123,9 @@ struct agp_memory *new; unsigned long alloc_size = num_agp_pages*sizeof(struct page *); + if (INT_MAX/sizeof(struct page *) < num_agp_pages) + return NULL; + new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL); if (new == NULL) return NULL; @@ -236,11 +239,14 @@ int scratch_pages; struct agp_memory *new; size_t i; + int cur_memory; if (!bridge) return NULL; - if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp) + cur_memory = atomic_read(&bridge->current_memory_agp); + if ((cur_memory + page_count > bridge->max_memory_agp) || + (cur_memory + page_count < page_count)) return NULL; if (type >= AGP_USER_TYPES) {