From: Dan Carpenter dan.carpenter@oracle.com
commit 3ed21c1451a14d139e1ceb18f2fa70865ce3195a upstream.
In this function "c->off" is a u32 and "size" is a long. On 64bit systems if "c->off" is greater than "size" then "size - c->off" is a negative and we always return -E2BIG. But on 32bit systems the subtraction is type promoted to a high positive u32 value and basically any "c->len" is accepted.
Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") Reported-by: Xie Yongji xieyongji@bytedance.com Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Link: https://lore.kernel.org/r/20211208103337.GA4047@kili Signed-off-by: Michael S. Tsirkin mst@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vdpa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -197,7 +197,7 @@ static int vhost_vdpa_config_validate(st struct vdpa_device *vdpa = v->vdpa; long size = vdpa->config->get_config_size(vdpa);
- if (c->len == 0) + if (c->len == 0 || c->off > size) return -EINVAL;
if (c->len > size - c->off)