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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 0104/1039] drm/virtio: fix another potential integer overflow on shift of a int
Date:   Mon, 24 Jan 2022 19:31:33 +0100
Message-Id: <20220124184128.650978883@linuxfoundation.org>
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From: Colin Ian King <colin.king@canonical.com>

[ 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@canonical.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210930102748.16922-1-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 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