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[PATCH][next] drm/virtio: fix another potential integer overflow on shift of a int

From: Colin King <hidden>
Date: 2021-09-30 10:27:55
Also in: dri-devel, kernel-janitors, lkml
Subsystem: drm drivers, drm drivers and misc gpu patches, the rest, virtio gpu driver · Maintainers: David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds, David Airlie, Gerd Hoffmann, Dmitry Osipenko

From: Colin Ian King <redacted>

The left shift of unsigned int 32 bit integer constant 1 is evaluated
using 32 bit arithmetic and then assigned to a signed 64 bit integer.
In the case where value is 32 or more this can lead to an overflow
(value can be in range 0..MAX_CAPSET_ID (63). Fix this by shifting
the value 1ULL instead.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 4fb530e5caf7 ("drm/virtio: implement context init: support init ioctl")
Signed-off-by: Colin Ian King <redacted>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index b3b0557d72cf..0007e423d885 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -774,7 +774,7 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 				goto out_unlock;
 			}
 
-			if ((vgdev->capset_id_mask & (1 << value)) == 0) {
+			if ((vgdev->capset_id_mask & (1ULL << value)) == 0) {
 				ret = -EINVAL;
 				goto out_unlock;
 			}
-- 
2.32.0

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