From: Harold Huang baymaxhuang@gmail.com
[ Upstream commit 74a335a07a17d131b9263bfdbdcb5e40673ca9ca ]
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/?i...
Reported-by: Eric Dumazet eric.dumazet@gmail.com Suggested-by: Jason Wang jasowang@redhat.com Signed-off-by: Harold Huang baymaxhuang@gmail.com Acked-by: Jason Wang jasowang@redhat.com Link: https://lore.kernel.org/r/20220303022441.383865-1-baymaxhuang@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 fed85447701a..de999e0fedbc 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2489,7 +2489,8 @@ 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; 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");