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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0103/1039] drm/virtio: fix potential integer overflow on shift of a int
Date:   Mon, 24 Jan 2022 19:31:32 +0100
Message-Id: <20220124184128.620812085@linuxfoundation.org>
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From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 8f4502fa284478a5264afa8a5a95511276fa9b80 ]

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>
Link: http://patchwork.freedesktop.org/patch/msgid/20210930101941.16546-1-colin.king@canonical.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 3607646d32295..5e8103a197a96 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;
-- 
2.34.1