[dpdk-stable] [16.11 LTS PATCH v2] vhost: fix vring requests validation broken if no FD

[dpdk-stable] [16.11 LTS PATCH v2] vhost: fix vring requests validation broken if no FD

[Maxime Coquelin]

From: Zhike Wang <wangzk320@163.com>

When VHOST_USER_VRING_NOFD_MASK is set, the fd_num is 0,
so validate_msg_fds() will return error. In this case,
the negotiation of vring message between vhost user front end and
back end would fail, and as a result, vhost user link could NOT be up.

How to reproduce:
1.Run dpdk testpmd insides VM, which locates at host with ovs+dpdk.
2.Notice that inside ovs there are endless logs regarding failure to
handle VHOST_USER_SET_VRING_CALL, and link of vm could NOT be up.

Fixes: 1bf11cfb7c7c ("vhost: fix possible denial of service by leaking FDs")
Cc: stable@dpdk.org

Signed-off-by: Zhike Wang <wangzk320@163.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index a6ab131543..1b3e3b178d 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1078,6 +1078,7 @@ vhost_user_msg_handler(int vid, int fd)
 	struct VhostUserMsg msg;
 	int ret;
 	int unlock_required = 0;
+	int expected_fds;
 
 	dev = get_device(vid);
 	if (dev == NULL)
@@ -1236,20 +1237,26 @@ vhost_user_msg_handler(int vid, int fd)
 		break;
 
 	case VHOST_USER_SET_VRING_KICK:
-		if (validate_msg_fds(&msg, 1) != 0)
+		expected_fds =
+			(msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK) ? 0 : 1;
+		if (validate_msg_fds(&msg, expected_fds) != 0)
 			return -1;
 
 		ret = vhost_user_set_vring_kick(dev, &msg);
 		break;
 	case VHOST_USER_SET_VRING_CALL:
-		if (validate_msg_fds(&msg, 1) != 0)
+		expected_fds =
+			(msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK) ? 0 : 1;
+		if (validate_msg_fds(&msg, expected_fds) != 0)
 			return -1;
 
 		vhost_user_set_vring_call(dev, &msg);
 		break;
 
 	case VHOST_USER_SET_VRING_ERR:
-		if (validate_msg_fds(&msg, 1) != 0)
+		expected_fds =
+			(msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK) ? 0 : 1;
+		if (validate_msg_fds(&msg, expected_fds) != 0)
 			return -1;
 
 		if (!(msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK))
-- 
2.21.0

Re: [dpdk-stable] [16.11 LTS PATCH v2] vhost: fix vring requests validation broken if no FD

[Tiwei Bie]

On Fri, Nov 15, 2019 at 11:36:15AM +0100, Maxime Coquelin wrote:
> From: Zhike Wang <wangzk320@163.com>
> 
> When VHOST_USER_VRING_NOFD_MASK is set, the fd_num is 0,
> so validate_msg_fds() will return error. In this case,
> the negotiation of vring message between vhost user front end and
> back end would fail, and as a result, vhost user link could NOT be up.
> 
> How to reproduce:
> 1.Run dpdk testpmd insides VM, which locates at host with ovs+dpdk.
> 2.Notice that inside ovs there are endless logs regarding failure to
> handle VHOST_USER_SET_VRING_CALL, and link of vm could NOT be up.
> 
> Fixes: 1bf11cfb7c7c ("vhost: fix possible denial of service by leaking FDs")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Zhike Wang <wangzk320@163.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/librte_vhost/vhost_user.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)

Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>

Thanks!
Tiwei

Re: [dpdk-stable] [16.11 LTS PATCH v2] vhost: fix vring requests validation broken if no FD

[Luca Boccassi]

On Fri, 2019-11-15 at 20:24 +0800, Tiwei Bie wrote:
> On Fri, Nov 15, 2019 at 11:36:15AM +0100, Maxime Coquelin wrote:
> > From: Zhike Wang <
> > wangzk320@163.com
> > >
> > 
> > When VHOST_USER_VRING_NOFD_MASK is set, the fd_num is 0,
> > so validate_msg_fds() will return error. In this case,
> > the negotiation of vring message between vhost user front end and
> > back end would fail, and as a result, vhost user link could NOT be
> > up.
> > 
> > How to reproduce:
> > 1.Run dpdk testpmd insides VM, which locates at host with ovs+dpdk.
> > 2.Notice that inside ovs there are endless logs regarding failure
> > to
> > handle VHOST_USER_SET_VRING_CALL, and link of vm could NOT be up.
> > 
> > Fixes: 1bf11cfb7c7c ("vhost: fix possible denial of service by
> > leaking FDs")
> > Cc: 
> > stable@dpdk.org
> > 
> > 
> > Signed-off-by: Zhike Wang <
> > wangzk320@163.com
> > >
> > Reviewed-by: Maxime Coquelin <
> > maxime.coquelin@redhat.com
> > >
> > ---
> >  lib/librte_vhost/vhost_user.c | 13 ++++++++++---
> >  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> Reviewed-by: Tiwei Bie <
> tiwei.bie@intel.com
> >
> 
> Thanks!
> Tiwei

Thanks, applied

-- 
Kind regards,
Luca Boccassi