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authorGuillaume Nault <g.nault@alphalink.fr>2018-06-15 15:39:17 +0200
committerDavid S. Miller <davem@davemloft.net>2018-06-15 09:12:37 -0700
commitde9bada5d389903f4faf33980e6a95a2911c7e6d (patch)
tree3ad1d79de37cb8504ed31107e9ed76e5e05c1d85 /net
parenteab9a2d5f323228405b5bacf2ff3fc4ad9cf81e5 (diff)
l2tp: reject creation of non-PPP sessions on L2TPv2 tunnels
The /proc/net/pppol2tp handlers (pppol2tp_seq_*()) iterate over all L2TPv2 tunnels, and rightfully expect that only PPP sessions can be found there. However, l2tp_netlink accepts creating Ethernet sessions regardless of the underlying tunnel version. This confuses pppol2tp_seq_session_show(), which expects that l2tp_session_priv() returns a pppol2tp_session structure. When the session is an Ethernet pseudo-wire, a struct l2tp_eth_sess is returned instead. This leads to invalid memory access when pppol2tp_session_get_sock() later tries to dereference ps->sk. Fixes: d9e31d17ceba ("l2tp: Add L2TP ethernet pseudowire support") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/l2tp/l2tp_netlink.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 6616c9fd292f..5b9900889e31 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -553,6 +553,12 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
goto out_tunnel;
}
+ /* L2TPv2 only accepts PPP pseudo-wires */
+ if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
+ ret = -EPROTONOSUPPORT;
+ goto out_tunnel;
+ }
+
if (tunnel->version > 2) {
if (info->attrs[L2TP_ATTR_DATA_SEQ])
cfg.data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]);

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