56 lines
2.0 KiB
Diff
56 lines
2.0 KiB
Diff
From: Vasiliy Kulikov <segoon@openwall.com>
|
|
Date: Thu, 14 Apr 2011 16:55:16 +0000 (+0400)
|
|
Subject: agp: fix arbitrary kernel memory writes
|
|
X-Git-Tag: v2.6.39-rc5~29^2
|
|
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=194b3da873fd334ef183806db751473512af29ce
|
|
|
|
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>
|
|
---
|
|
|
|
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
|
|
index 850a643..b072648 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 */
|