diff options
| author | Vasiliy Kulikov <segoon@openwall.com> | 2011-04-14 20:55:16 +0400 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2011-06-26 12:47:16 -0400 |
| commit | 5c4f9f27afea8cca11111e19c581ed6f42321177 (patch) | |
| tree | 12cb33f1334372943a59e9c059eb45c85f32ee1f | |
| parent | 9fc10a22e5020046d6a904743720b41647a54120 (diff) | |
agp: fix arbitrary kernel memory writes
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 <segoon@openwall.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.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 fb86708e47ed..13a344625011 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -1124,8 +1124,8 @@ 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; @@ -1159,7 +1159,7 @@ 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) @@ -1171,6 +1171,11 @@ 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 */ |