diff mbox series

[net-next,5/6] erspan: fix the tun_info options_len check

Message ID df4d06219243295fba75ab6361f0d750a135b7cc.1568617721.git.lucien.xin@gmail.com
State Deferred
Delegated to: David Miller
Headers show
Series net: add support for ip_tun_info options setting | expand

Commit Message

Xin Long Sept. 16, 2019, 7:10 a.m. UTC 
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().

Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/ipv4/ip_gre.c  | 4 ++--
 net/ipv6/ip6_gre.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a53a543..df7149c 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -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 (sizeof(*md) > tun_info->options_len)
 		goto err_free_skb;
+	md = ip_tunnel_info_opts(tun_info);
 
 	/* ERSPAN has fixed 8 byte GRE header */
 	version = md->version;
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index dd2d0b96..4aba9e0 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -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 (sizeof(*md) > tun_info->options_len)
 			goto tx_err;
+		md = ip_tunnel_info_opts(tun_info);
 
 		tun_id = tunnel_id_to_key32(key->tun_id);
 		if (md->version == 1) {