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| author | Guillaume Nault <g.nault@alphalink.fr> | 2018-06-13 15:09:19 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-06-15 02:10:19 +0200 |
| commit | 7ac6ab1f8a38ba7f8d97f95475bb6a2575db4658 (patch) | |
| tree | 1f554212a69107c536ef0cb58180deed08be415d /net/l2tp | |
| parent | l2tp: fix pseudo-wire type for sessions created by pppol2tp_connect() (diff) | |
| download | linux-7ac6ab1f8a38ba7f8d97f95475bb6a2575db4658.tar.xz linux-7ac6ab1f8a38ba7f8d97f95475bb6a2575db4658.zip | |
l2tp: only accept PPP sessions in pppol2tp_connect()
l2tp_session_priv() returns a struct pppol2tp_session pointer only for
PPPoL2TP sessions. In particular, if the session is an L2TP_PWTYPE_ETH
pseudo-wire, l2tp_session_priv() returns a pointer to an l2tp_eth_sess
structure, which is much smaller than struct pppol2tp_session. This
leads to invalid memory dereference when trying to lock ps->sk_lock.
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/l2tp')
| -rw-r--r-- | net/l2tp/l2tp_ppp.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 270a0a999eaf..8b3b6947a07d 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -734,6 +734,12 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, session = l2tp_session_get(sock_net(sk), tunnel, session_id); if (session) { drop_refcnt = true; + + if (session->pwtype != L2TP_PWTYPE_PPP) { + error = -EPROTOTYPE; + goto end; + } + ps = l2tp_session_priv(session); /* Using a pre-existing session is fine as long as it hasn't |