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AGP security fixes 

agp: fix arbitrary kernel memory writes (CVE-2011-1745)
agp: fix OOM and buffer overflow (CVE-2011-1746)
This commit is contained in:
Chuck Ebbert 2011-04-29 13:02:25 -04:00
parent fdc263cb21
commit 29f13318a3
3 changed files with 123 additions and 0 deletions
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55
agp-fix-arbitrary-kernel-memory-writes.patch Normal file
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@ -0,0 +1,55 @@
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 */

56
agp-fix-oom-and-buffer-overflow.patch Normal file
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@ -0,0 +1,56 @@
From: Vasiliy Kulikov <segoon@openwall.com>
Date: Thu, 14 Apr 2011 16:55:19 +0000 (+0400)
Subject: agp: fix OOM and buffer overflow
X-Git-Tag: v2.6.39-rc5~29^2~1
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=b522f02184b413955f3bc952e3776ce41edc6355
agp: fix OOM and buffer overflow
page_count is copied from userspace. agp_allocate_memory() tries to
check whether this number is too big, but doesn't take into account the
wrap case. Also agp_create_user_memory() doesn't check whether
alloc_size is calculated from num_agp_pages variable without overflow.
This may lead to allocation of too small buffer with following buffer
overflow.
Another problem in agp code is not addressed in the patch - kernel memory
exhaustion (AGPIOC_RESERVE and AGPIOC_ALLOCATE ioctls). It is not checked
whether requested pid is a pid of the caller (no check in agpioc_reserve_wrap()).
Each allocation is limited to 16KB, though, there is no per-process limit.
This might lead to OOM situation, which is not even solved in case of the
caller death by OOM killer - the memory is allocated for another (faked) process.
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 012cba0..850a643 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -115,6 +115,9 @@ static struct agp_memory *agp_create_user_memory(unsigned long num_agp_pages)
struct agp_memory *new;
unsigned long alloc_size = num_agp_pages*sizeof(struct page *);
+ if (INT_MAX/sizeof(struct page *) < num_agp_pages)
+ return NULL;
+
new = kzalloc(sizeof(struct agp_memory), GFP_KERNEL);
if (new == NULL)
return NULL;
@@ -234,11 +237,14 @@ struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge,
int scratch_pages;
struct agp_memory *new;
size_t i;
+ int cur_memory;
if (!bridge)
return NULL;
- if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp)
+ cur_memory = atomic_read(&bridge->current_memory_agp);
+ if ((cur_memory + page_count > bridge->max_memory_agp) ||
+ (cur_memory + page_count < page_count))
return NULL;
if (type >= AGP_USER_TYPES) {

12
kernel.spec
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@ -851,6 +851,11 @@ Patch13955: virtio_net-add-schedule-check-to-napi_enable-call.patch
# cve-2011-1079
Patch13956: bluetooth-bnep-fix-buffer-overflow.patch
# cve-2011-1745
Patch13957: agp-fix-arbitrary-kernel-memory-writes.patch
# cve-2011-1746
Patch13958: agp-fix-oom-and-buffer-overflow.patch
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@ -1611,6 +1616,11 @@ ApplyPatch virtio_net-add-schedule-check-to-napi_enable-call.patch
# cve-2011-1079
ApplyPatch bluetooth-bnep-fix-buffer-overflow.patch
# cve-2011-1745
ApplyPatch agp-fix-arbitrary-kernel-memory-writes.patch
# cve-2011-1746
ApplyPatch agp-fix-oom-and-buffer-overflow.patch
# END OF PATCH APPLICATIONS
%endif
@ -2233,6 +2243,8 @@ fi
%changelog
* Fri Apr 29 2011 Chuck Ebbert <cebbert@redhat.com> 2.6.34.9-69
- Bluetooth: bnep: fix buffer overflow (CVE-2011-1079)
- agp: fix arbitrary kernel memory writes (CVE-2011-1745)
- agp: fix OOM and buffer overflow (CVE-2011-1746)
* Sun Apr 17 2011 Chuck Ebbert <cebbert@redhat.com>
- Linux 2.6.34.9