From patchwork Thu May 26 15:50:29 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [hardy,maverick,CVE,1/1] agp: fix arbitrary kernel memory writes Date: Thu, 26 May 2011 05:50:29 -0000 From: Andy Whitcroft X-Patchwork-Id: 97590 Message-Id: <1306425029-30649-2-git-send-email-apw@canonical.com> To: kernel-team@lists.ubuntu.com From: Vasiliy Kulikov 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 CVE-1011-2022 BugLink: http://bugs.launchpad.net/bugs/788684 (cherry picked from commit 194b3da873fd334ef183806db751473512af29ce) Signed-off-by: Andy Whitcroft Acked-by: Leann Ogasawara --- drivers/char/agp/generic.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c index d2abf51..7858016 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -1122,8 +1122,8 @@ int agp_generic_insert_memory(struct agp_memory * mem, off_t pg_start, int type) 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_memory *mem, off_t pg_start, int type) { 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_memory *mem, off_t pg_start, int type) 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 */