[PATCH 3.4 49/92] drm: crtc: integer overflow in drm_property_create_blob()

lizf
2016-04-18T10:49:51Z

From: Dan Carpenter <dan.carpenter@oracle.com>

3.4.112-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 9ac0934bbe52290e4e4c2a58ec41cab9b6ca8c96 upstream.

The size here comes from the user via the ioctl, it is a number between
1-u32max so the addition here could overflow on 32 bit systems.

Fixes: f453ba046074 ('DRM: add mode setting support')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/gpu/drm/drm_crtc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index ed4b748..93c5b2f 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2945,7 +2945,7 @@ static struct drm_property_blob *drm_property_create_blob(struct drm_device *dev
struct drm_property_blob *blob;
int ret;

- if (!length || !data)
+ if (!length || length > ULONG_MAX - sizeof(struct drm_property_blob) || !data)
return NULL;

blob = kzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
--
1.9.1