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| author | Guillaume Nault <g.nault@alphalink.fr> | 2018-06-15 16:39:17 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-06-15 19:12:37 +0300 |
| commit | de9bada5d389903f4faf33980e6a95a2911c7e6d (patch) | |
| tree | 3ad1d79de37cb8504ed31107e9ed76e5e05c1d85 /net | |
| parent | eab9a2d5f323228405b5bacf2ff3fc4ad9cf81e5 (diff) | |
| download | linux-de9bada5d389903f4faf33980e6a95a2911c7e6d.tar.xz | |
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.c | 6 |
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]); |