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Commit 2eb8d6d2 authored Oct 28, 2019 by Xin Long Committed by David S. Miller Oct 29, 2019

erspan: fix the tun_info options_len check for erspan



The check for !md doens't really work for ip_tunnel_info_opts(info) which
only does info + 1. Also to avoid out-of-bounds access on info, it should
ensure options_len is not less than erspan_metadata in both erspan_xmit()
and ip6erspan_tunnel_xmit().

Fixes: 1a66a836 ("gre: add collect_md mode to ERSPAN tunnel")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e56bd641

net/ipv4/ip_gre.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -509,9 +509,9 @@ static void erspan_fb_xmit(struct sk_buff skb, struct net_device dev)
		key = &tun_info->key;
		if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT))
		goto err_free_skb;
		md = ip_tunnel_info_opts(tun_info);
		if (!md)
		if (tun_info->options_len < sizeof(*md))
		goto err_free_skb;
		md = ip_tunnel_info_opts(tun_info);

		/* ERSPAN has fixed 8 byte GRE header */
		version = md->version;

net/ipv6/ip6_gre.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -980,9 +980,9 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct sk_buff *skb,
		dsfield = key->tos;
		if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT))
		goto tx_err;
		md = ip_tunnel_info_opts(tun_info);
		if (!md)
		if (tun_info->options_len < sizeof(*md))
		goto tx_err;
		md = ip_tunnel_info_opts(tun_info);

		tun_id = tunnel_id_to_key32(key->tun_id);
		if (md->version == 1) {