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    Subject[PATCH 5.16 0103/1039] drm/virtio: fix potential integer overflow on shift of a int
    Date
    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


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