[PATCH 3.10 221/268] drm/vmwgfx: avoid calling vzalloc with a 0 size in vmw_get_cap_3d_ioctl()

Willy Tarreau
2017-06-19T18:35:48Z

From: Murray McAllister <murray.mcallister@insomniasec.com>

commit 63774069d9527a1aeaa4aa20e929ef5e8e9ecc38 upstream.

In vmw_get_cap_3d_ioctl(), a user can supply 0 for a size that is
used in vzalloc(). This eventually calls dump_stack() (in warn_alloc()),
which can leak useful addresses to dmesg.

Add check to avoid a size of 0.

Signed-off-by: Murray McAllister <murray.mcallister@insomniasec.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
index c509d40..f435b6c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
@@ -90,7 +90,7 @@ int vmw_get_cap_3d_ioctl(struct drm_device *dev, void *data,
void *bounce;
int ret;

- if (unlikely(arg->pad64 != 0)) {
+ if (unlikely(arg->pad64 != 0 || arg->max_size == 0)) {
DRM_ERROR("Illegal GET_3D_CAP argument.\n");
return -EINVAL;
}
--
2.8.0.rc2.1.gbe9624a