Jason Wang
2022-Mar-03 03:59 UTC
[PATCH net-next] tuntap: add sanity checks about msg_controllen in sendmsg
? 2022/3/3 ??10:24, Harold Huang ??:> In patch [1], tun_msg_ctl was added to allow pass batched xdp buffers to > tun_sendmsg. Although we donot use msg_controllen in this path, we should > check msg_controllen to make sure the caller pass a valid msg_ctl. > > [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe8dd45bb7556246c6b76277b1ba4296c91c2505 > > Reported-by: Eric Dumazet <eric.dumazet at gmail.com> > Suggested-by: Jason Wang <jasowang at redhat.com> > Signed-off-by: Harold Huang <baymaxhuang at gmail.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > drivers/net/tap.c | 3 ++- > drivers/net/tun.c | 3 ++- > drivers/vhost/net.c | 1 + > 3 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/tap.c b/drivers/net/tap.c > index 8e3a28ba6b28..ba2ef5437e16 100644 > --- a/drivers/net/tap.c > +++ b/drivers/net/tap.c > @@ -1198,7 +1198,8 @@ static int tap_sendmsg(struct socket *sock, struct msghdr *m, > struct xdp_buff *xdp; > int i; > > - if (ctl && (ctl->type == TUN_MSG_PTR)) { > + if (m->msg_controllen == sizeof(struct tun_msg_ctl) && > + ctl && ctl->type == TUN_MSG_PTR) { > for (i = 0; i < ctl->num; i++) { > xdp = &((struct xdp_buff *)ctl->ptr)[i]; > tap_get_user_xdp(q, xdp); > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 969ea69fd29d..2a0d8a5d7aec 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -2501,7 +2501,8 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) > if (!tun) > return -EBADFD; > > - if (ctl && (ctl->type == TUN_MSG_PTR)) { > + if (m->msg_controllen == sizeof(struct tun_msg_ctl) && > + ctl && ctl->type == TUN_MSG_PTR) { > struct tun_page tpage; > int n = ctl->num; > int flush = 0, queued = 0; > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 28ef323882fb..792ab5f23647 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -473,6 +473,7 @@ static void vhost_tx_batch(struct vhost_net *net, > goto signal_used; > > msghdr->msg_control = &ctl; > + msghdr->msg_controllen = sizeof(ctl); > err = sock->ops->sendmsg(sock, msghdr, 0); > if (unlikely(err < 0)) { > vq_err(&nvq->vq, "Fail to batch sending packets\n");