Commit 25a80e72 authored Jul 27, 2022 by Zhengchao Shao Committed by Greg Kroah-Hartman Sep 05, 2022

net/af_packet: check len when min_header_len equals to 0

commit dc633700f00f726e027846a318c5ffeb8deaaeda upstream.

User can use AF_PACKET socket to send packets with the length of 0.
When min_header_len equals to 0, packet_snd will call __dev_queue_xmit
to send packets, and sock->type can be any type.

Reported-by: <syzbot+5ea725c25d06fb9114c4@syzkaller.appspotmail.com>
Fixes: fd1894224407 ("bpf: Don't redirect packets with invalid pkt_len")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent fc78b2fc

net/packet/af_packet.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -2960,8 +2960,8 @@ static int packet_snd(struct socket sock, struct msghdr msg, size_t len)
		if (err)
		goto out_free;

		if (sock->type == SOCK_RAW &&
		!dev_validate_header(dev, skb->data, len)) {
		if ((sock->type == SOCK_RAW &&
		!dev_validate_header(dev, skb->data, len)) \|\| !skb->len) {
		err = -EINVAL;
		goto out_free;
		}