diff options
| author | Guillaume Nault <g.nault@alphalink.fr> | 2017-03-31 13:02:25 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-01 20:16:41 -0700 |
| commit | 61b9a047729bb230978178bca6729689d0c50ca2 (patch) | |
| tree | f8dfc3ba7bfc78123ad285d0b846c8b7c865129c /net/l2tp/l2tp_ip.c | |
| parent | afe89962ee0799955b606cc7637ac86a296923a6 (diff) | |
l2tp: fix race in l2tp_recv_common()
Taking a reference on sessions in l2tp_recv_common() is racy; this
has to be done by the callers.
To this end, a new function is required (l2tp_session_get()) to
atomically lookup a session and take a reference on it. Callers then
have to manually drop this reference.
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp/l2tp_ip.c')
| -rw-r--r-- | net/l2tp/l2tp_ip.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 7208fbe5856b..4d322c1b7233 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -143,19 +143,19 @@ static int l2tp_ip_recv(struct sk_buff *skb) } /* Ok, this is a data packet. Lookup the session. */ - session = l2tp_session_find(net, NULL, session_id); - if (session == NULL) + session = l2tp_session_get(net, NULL, session_id, true); + if (!session) goto discard; tunnel = session->tunnel; - if (tunnel == NULL) - goto discard; + if (!tunnel) + goto discard_sess; /* Trace packet contents, if enabled */ if (tunnel->debug & L2TP_MSG_DATA) { length = min(32u, skb->len); if (!pskb_may_pull(skb, length)) - goto discard; + goto discard_sess; /* Point to L2TP header */ optr = ptr = skb->data; @@ -165,6 +165,7 @@ static int l2tp_ip_recv(struct sk_buff *skb) } l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook); + l2tp_session_dec_refcount(session); return 0; @@ -203,6 +204,12 @@ pass_up: return sk_receive_skb(sk, skb, 1); +discard_sess: + if (session->deref) + session->deref(session); + l2tp_session_dec_refcount(session); + goto discard; + discard_put: sock_put(sk); |