[PATCH 5.16 0104/1039] drm/virtio: fix another potential integer overflow on shift of a int

From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 18:29:42 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

[ Upstream commit 74c1bda2f3fa79a93e1c910008649b49b02dc09d ]

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@xxxxxxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20210930102748.16922-1-colin.king@xxxxxxxxxxxxx
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 5e8103a197a96..c708bab555c6b 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;
}
--
2.34.1