* [PATCH 2/2 v4] vdpa: check that offsets are within bounds
[not found] <20211208103307.GA3778@kili>
@ 2021-12-08 10:33 ` Dan Carpenter
2021-12-09 2:12 ` Jason Wang
2021-12-09 2:35 ` Yongji Xie
0 siblings, 2 replies; 3+ messages in thread
From: Dan Carpenter @ 2021-12-08 10:33 UTC (permalink / raw)
To: Michael S. Tsirkin, Tiwei Bie, Xie Yongji
Cc: Jason Wang, Eugenio Pérez, kvm, virtualization,
kernel-janitors
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(-)
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2 v4] vdpa: check that offsets are within bounds
2021-12-08 10:33 ` [PATCH 2/2 v4] vdpa: check that offsets are within bounds Dan Carpenter
@ 2021-12-09 2:12 ` Jason Wang
2021-12-09 2:35 ` Yongji Xie
1 sibling, 0 replies; 3+ messages in thread
From: Jason Wang @ 2021-12-09 2:12 UTC (permalink / raw)
To: Dan Carpenter
Cc: Michael S. Tsirkin, Tiwei Bie, Xie Yongji, Eugenio Pérez,
kvm, virtualization, kernel-janitors
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
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2 v4] vdpa: check that offsets are within bounds
2021-12-08 10:33 ` [PATCH 2/2 v4] vdpa: check that offsets are within bounds Dan Carpenter
2021-12-09 2:12 ` Jason Wang
@ 2021-12-09 2:35 ` Yongji Xie
1 sibling, 0 replies; 3+ messages in thread
From: Yongji Xie @ 2021-12-09 2:35 UTC (permalink / raw)
To: Dan Carpenter
Cc: Michael S. Tsirkin, Tiwei Bie, Jason Wang, Eugenio Pérez,
kvm, virtualization, kernel-janitors
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-08 10:33 ` [PATCH 2/2 v4] vdpa: check that offsets are within bounds Dan Carpenter
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2021-12-09 2:35 ` Yongji Xie
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