diff mbox series

[2/2,v4] vdpa: check that offsets are within bounds

Message ID 20211208103337.GA4047@kili (mailing list archive)
State New, archived
Headers show
Series None | expand

Commit Message

Dan Carpenter Dec. 8, 2021, 10:33 a.m. UTC
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>
---
v4: split into a separate patch

 drivers/vhost/vdpa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jason Wang Dec. 9, 2021, 2:12 a.m. UTC | #1
On Wed, Dec 8, 2021 at 6:34 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> 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>

Acked-by: Jason Wang <jasowang@redhat.com>

> ---
> v4: split into a separate patch
>
>  drivers/vhost/vdpa.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 29cced1cd277..e3c4f059b21a 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -197,7 +197,7 @@ static int vhost_vdpa_config_validate(struct vhost_vdpa *v,
>         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)
> --
> 2.20.1
>
Yongji Xie Dec. 9, 2021, 2:35 a.m. UTC | #2
On Wed, Dec 8, 2021 at 6:33 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> 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>

Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
diff mbox series

Patch

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 29cced1cd277..e3c4f059b21a 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -197,7 +197,7 @@  static int vhost_vdpa_config_validate(struct vhost_vdpa *v,
 	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)