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authorVasiliy Kulikov <segoon@openwall.com>2011-04-14 20:55:16 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-02 09:19:47 -0700
commit0b7c6323a28f3fde67a26bc6b2a889d3f23b12c3 (patch)
treec1e0298db6917791d769c2cf72d7a89f3f900321 /drivers/char
parentf0578c398d86a9d69ef59765e55b9b56cbafb93e (diff)
downloadlinux-linaro-android-0b7c6323a28f3fde67a26bc6b2a889d3f23b12c3.tar.gz
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: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/agp/generic.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index 012cba0d6d9..745e7baff3c 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -1089,8 +1089,8 @@ 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;
@@ -1124,7 +1124,7 @@ 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)
@@ -1136,6 +1136,11 @@ 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 */