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From:   Colin King <colin.king@canonical.com>
To:     David Airlie <airlied@linux.ie>, Gerd Hoffmann <kraxel@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Lingfeng Yang <lfy@google.com>,
        Anthoine Bourgeois <anthoine.bourgeois@gmail.com>,
        dri-devel@lists.freedesktop.org,
        virtualization@lists.linux-foundation.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] drm/virtio: fix another potential integer overflow on shift of a int
Date:   Thu, 30 Sep 2021 11:27:48 +0100
Message-Id: <20210930102748.16922-1-colin.king@canonical.com>
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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 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 <colin.king@canonical.com>
---
 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