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[CVE-2017-7294,Trusty] drm/vmwgfx: fix integer overflow in vmw_surface_define_ioctl()

Message ID 1494848395-16587-2-git-send-email-po-hsu.lin@canonical.com
State New
Headers show

Commit Message

Po-Hsu Lin May 15, 2017, 11:39 a.m. UTC 
From: Li Qiang <liq3ea@gmail.com>

In vmw_surface_define_ioctl(), the 'num_sizes' is the sum of the
'req->mip_levels' array. This array can be assigned any value from
the user space. As both the 'num_sizes' and the array is uint32_t,
it is easy to make 'num_sizes' overflow. The later 'mip_levels' is
used as the loop count. This can lead an oob write. Add the check of
'req->mip_levels' to avoid this.

Cc: <stable@vger.kernel.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
(cherry picked from commit e7e11f99564222d82f0ce84bd521e57d78a6b678)
CVE-2017-7294
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index e7af580..5416ff3 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -705,8 +705,11 @@  int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
 			128;
 
 	num_sizes = 0;
-	for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i)
+	for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i) {
+		if (req->mip_levels[i] > DRM_VMW_MAX_MIP_LEVELS)
+			return -EINVAL;
 		num_sizes += req->mip_levels[i];
+	}
 
 	if (num_sizes > DRM_VMW_MAX_SURFACE_FACES *
 	    DRM_VMW_MAX_MIP_LEVELS)