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

Message ID 20210930101941.16546-1-colin.king@canonical.com (mailing list archive)
State New, archived
Headers show
Series [next] drm/virtio: fix potential integer overflow on shift of a int | expand

Commit Message

Colin King Sept. 30, 2021, 10:19 a.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

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 i is 32 or more this can lead to an overflow. Fix
this by shifting the value 1ULL instead.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 8d6b006e1f51 ("drm/virtio: implement context init: handle VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 5618a1d5879c..b3b0557d72cf 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -819,7 +819,7 @@  static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 	if (vfpriv->ring_idx_mask) {
 		valid_ring_mask = 0;
 		for (i = 0; i < vfpriv->num_rings; i++)
-			valid_ring_mask |= 1 << i;
+			valid_ring_mask |= 1ULL << i;
 
 		if (~valid_ring_mask & vfpriv->ring_idx_mask) {
 			ret = -EINVAL;