[CVE-2017-7346][PATCH Trusty] drm/vmwgfx: limit the number of mip levels in vmw_gb_surface_define_ioctl()

Po-Hsu Lin po-hsu.lin at canonical.com
Wed Jun 14 09:09:34 UTC 2017

From: Vladis Dronov <vdronov at redhat.com>


The 'req->mip_levels' parameter in vmw_gb_surface_define_ioctl() is
a user-controlled 'uint32_t' value which is used as a loop count limit.
This can lead to a kernel lockup and DoS. Add check for 'req->mip_levels'.


Cc: <stable at vger.kernel.org>
Signed-off-by: Vladis Dronov <vdronov at redhat.com>
Reviewed-by: Sinclair Yeh <syeh at vmware.com>
(backported from commit ee9c4e681ec4f58e42a83cb0c22a0289ade1aacf)

Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 5416ff3..8a98b88 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -1180,6 +1180,9 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
 	const struct svga3d_surface_desc *desc;
 	uint32_t backup_handle;
+	if (req->mip_levels > DRM_VMW_MAX_MIP_LEVELS)
+		return -EINVAL;
 	if (unlikely(vmw_user_surface_size == 0))
 		vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) +

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