From 74a335a07a17d131b9263bfdbdcb5e40673ca9ca Mon Sep 17 00:00:00 2001 From: Harold Huang Date: Thu, 3 Mar 2022 10:24:40 +0800 Subject: 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 Suggested-by: Jason Wang Signed-off-by: Harold Huang Acked-by: Jason Wang Link: https://lore.kernel.org/r/20220303022441.383865-1-baymaxhuang@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/tap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/net/tap.c') 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); -- cgit