Commit 74a335a0 authored Mar 03, 2022 by Harold Huang Committed by Jakub Kicinski Mar 02, 2022

tuntap: add sanity checks about msg_controllen in sendmsg

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@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>

parent fa452e0a

drivers/net/tap.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

drivers/net/tun.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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;

drivers/vhost/net.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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");