From: Xin Long lucien.xin@gmail.com
[ Upstream commit 2eb8d6d2910cfe3dc67dc056f26f3dd9c63d47cd ]
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: 1a66a836da ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/ip_gre.c | 4 ++-- net/ipv6/ip6_gre.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
--- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -589,9 +589,9 @@ static void erspan_fb_xmit(struct sk_buf key = &tun_info->key; if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT)) goto err_free_rt; + if (tun_info->options_len < sizeof(*md)) + goto err_free_rt; md = ip_tunnel_info_opts(tun_info); - if (!md) - goto err_free_rt;
/* ERSPAN has fixed 8 byte GRE header */ version = md->version; --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1000,9 +1000,9 @@ static netdev_tx_t ip6erspan_tunnel_xmit 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) {