diff options
| author | Vasiliy Kulikov <segoon@openwall.com> | 2011-04-14 20:55:16 +0400 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2011-04-21 12:16:55 +1000 |
| commit | 194b3da873fd334ef183806db751473512af29ce (patch) | |
| tree | cb6ac3d05ba2e0a07c02ea1cef0e41477ea29d2b | |
| parent | b522f02184b413955f3bc952e3776ce41edc6355 (diff) | |
agp: fix arbitrary kernel memory writes
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 <segoon@openwall.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | 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 850a643ad69..b072648dc3f 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -1095,8 +1095,8 @@ 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; @@ -1130,7 +1130,7 @@ 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) @@ -1142,6 +1142,11 @@ 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 */ |