On Thu, Nov 14, 2019 at 04:16:01PM +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>
> ---
>
> Backport not tested yet.
>
> lib/librte_vhost/vhost_user.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index a6ab131543..5aeb0c1691 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)
> @@ -1236,12 +1237,16 @@ 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:
> + expected_fds =
> + (msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK) ? 0 : 1;
> if (validate_msg_fds(&msg, 1) != 0)
Typo, s/1/expected_fds/
> return -1;
>
> @@ -1249,6 +1254,8 @@ vhost_user_msg_handler(int vid, int fd)
> break;
>
> case VHOST_USER_SET_VRING_ERR:
> + expected_fds =
> + (msg.payload.u64 & VHOST_USER_VRING_NOFD_MASK) ? 0 : 1;
> if (validate_msg_fds(&msg, 1) != 0)
Ditto.
Thanks,
Tiwei
> return -1;
>
> --
> 2.21.0
>