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