It is possible to wrap the counter used to allocate the buffer for
relocation copies. This could lead to heap writing overflows.
CVE-2013-0913
v3: collapse test, improve comment
v2: move check into validate_exec_list
Signed-off-by: Kees Cook <[email protected]>
Reported-by: Pinkie Pie
Cc: [email protected]
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index b3a40ee..094ba41 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -732,6 +732,8 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
int count)
{
int i;
+ int relocs_total = 0;
+ int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
for (i = 0; i < count; i++) {
char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr;
@@ -740,10 +742,13 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
if (exec[i].flags & __EXEC_OBJECT_UNKNOWN_FLAGS)
return -EINVAL;
- /* First check for malicious input causing overflow */
- if (exec[i].relocation_count >
- INT_MAX / sizeof(struct drm_i915_gem_relocation_entry))
+ /* First check for malicious input causing overflow in
+ * the worst case where we need to allocate the entire
+ * relocation tree as a single array.
+ */
+ if (exec[i].relocation_count > relocs_max - relocs_total)
return -EINVAL;
+ relocs_total += exec[i].relocation_count;
length = exec[i].relocation_count *
sizeof(struct drm_i915_gem_relocation_entry);
--
1.7.9.5
--
Kees Cook
Chrome OS Security
On Mon, Mar 11, 2013 at 05:31:45PM -0700, Kees Cook wrote:
> It is possible to wrap the counter used to allocate the buffer for
> relocation copies. This could lead to heap writing overflows.
>
> CVE-2013-0913
>
> v3: collapse test, improve comment
> v2: move check into validate_exec_list
>
> Signed-off-by: Kees Cook <[email protected]>
> Reported-by: Pinkie Pie
> Cc: [email protected]
Looks good to me. The only bikeshed that remains is whether we should
just collapse the two variables into one, but the current 'max - count'
is more idiomatic and so preferrable.
Reviewed-by: Chris Wilson <[email protected]>
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
On Tue, Mar 12, 2013 at 09:07:46AM +0000, Chris Wilson wrote:
> On Mon, Mar 11, 2013 at 05:31:45PM -0700, Kees Cook wrote:
> > It is possible to wrap the counter used to allocate the buffer for
> > relocation copies. This could lead to heap writing overflows.
> >
> > CVE-2013-0913
> >
> > v3: collapse test, improve comment
> > v2: move check into validate_exec_list
> >
> > Signed-off-by: Kees Cook <[email protected]>
> > Reported-by: Pinkie Pie
> > Cc: [email protected]
>
> Looks good to me. The only bikeshed that remains is whether we should
> just collapse the two variables into one, but the current 'max - count'
> is more idiomatic and so preferrable.
> Reviewed-by: Chris Wilson <[email protected]>
Picked up for -fixes, thanks for the patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Mar 13, 2013 at 9:28 PM, Daniel Vetter <[email protected]> wrote:
> On Tue, Mar 12, 2013 at 09:07:46AM +0000, Chris Wilson wrote:
>> On Mon, Mar 11, 2013 at 05:31:45PM -0700, Kees Cook wrote:
>> > It is possible to wrap the counter used to allocate the buffer for
>> > relocation copies. This could lead to heap writing overflows.
>> >
>> > CVE-2013-0913
>> >
>> > v3: collapse test, improve comment
>> > v2: move check into validate_exec_list
>> >
>> > Signed-off-by: Kees Cook <[email protected]>
>> > Reported-by: Pinkie Pie
>> > Cc: [email protected]
>>
>> Looks good to me. The only bikeshed that remains is whether we should
>> just collapse the two variables into one, but the current 'max - count'
>> is more idiomatic and so preferrable.
>> Reviewed-by: Chris Wilson <[email protected]>
>
> Picked up for -fixes, thanks for the patch.
I've forgotten to dump my wishlist: Can I have an i-g-t for this? For
this bug here specifically an execbuf with just one buffer with too
many relocs plus another execbuf with two buffers with relocation so
that the 2nd relocation list will overflow should be sufficient.
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Thu, Mar 14, 2013 at 9:57 AM, Daniel Vetter <[email protected]> wrote:
> On Wed, Mar 13, 2013 at 9:28 PM, Daniel Vetter <[email protected]> wrote:
>> On Tue, Mar 12, 2013 at 09:07:46AM +0000, Chris Wilson wrote:
>>> On Mon, Mar 11, 2013 at 05:31:45PM -0700, Kees Cook wrote:
>>> > It is possible to wrap the counter used to allocate the buffer for
>>> > relocation copies. This could lead to heap writing overflows.
>>> >
>>> > CVE-2013-0913
>>> >
>>> > v3: collapse test, improve comment
>>> > v2: move check into validate_exec_list
>>> >
>>> > Signed-off-by: Kees Cook <[email protected]>
>>> > Reported-by: Pinkie Pie
>>> > Cc: [email protected]
>>>
>>> Looks good to me. The only bikeshed that remains is whether we should
>>> just collapse the two variables into one, but the current 'max - count'
>>> is more idiomatic and so preferrable.
>>> Reviewed-by: Chris Wilson <[email protected]>
>>
>> Picked up for -fixes, thanks for the patch.
>
> I've forgotten to dump my wishlist: Can I have an i-g-t for this? For
> this bug here specifically an execbuf with just one buffer with too
> many relocs plus another execbuf with two buffers with relocation so
> that the 2nd relocation list will overflow should be sufficient.
Sure thing. Where do these live? (Or what docs should I read for
this?) I'm assuming i-g-t means "intel graphics test"? :)
-Kees
--
Kees Cook
Chrome OS Security
On Thu, Mar 14, 2013 at 12:32:00PM -0700, Kees Cook wrote:
> On Thu, Mar 14, 2013 at 9:57 AM, Daniel Vetter <[email protected]> wrote:
> > On Wed, Mar 13, 2013 at 9:28 PM, Daniel Vetter <[email protected]> wrote:
> >> On Tue, Mar 12, 2013 at 09:07:46AM +0000, Chris Wilson wrote:
> >>> On Mon, Mar 11, 2013 at 05:31:45PM -0700, Kees Cook wrote:
> >>> > It is possible to wrap the counter used to allocate the buffer for
> >>> > relocation copies. This could lead to heap writing overflows.
> >>> >
> >>> > CVE-2013-0913
> >>> >
> >>> > v3: collapse test, improve comment
> >>> > v2: move check into validate_exec_list
> >>> >
> >>> > Signed-off-by: Kees Cook <[email protected]>
> >>> > Reported-by: Pinkie Pie
> >>> > Cc: [email protected]
> >>>
> >>> Looks good to me. The only bikeshed that remains is whether we should
> >>> just collapse the two variables into one, but the current 'max - count'
> >>> is more idiomatic and so preferrable.
> >>> Reviewed-by: Chris Wilson <[email protected]>
> >>
> >> Picked up for -fixes, thanks for the patch.
> >
> > I've forgotten to dump my wishlist: Can I have an i-g-t for this? For
> > this bug here specifically an execbuf with just one buffer with too
> > many relocs plus another execbuf with two buffers with relocation so
> > that the 2nd relocation list will overflow should be sufficient.
>
> Sure thing. Where do these live? (Or what docs should I read for
> this?) I'm assuming i-g-t means "intel graphics test"? :)
Close :) GPU Tools. The tests lives in the tests directory of:
http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/
--
Damien