diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-08-30 09:29:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-30 15:55:10 -0700 |
| commit | 351050ecd6523374b370341cc29fe61e2201556b (patch) | |
| tree | 5b6c0a72dcf7b3d172c2be867e5bf2fd10030099 | |
| parent | f5c3dd4b5363af997d418174d578a795081aab51 (diff) | |
| download | lwn-351050ecd6523374b370341cc29fe61e2201556b.tar.gz lwn-351050ecd6523374b370341cc29fe61e2201556b.zip | |
kcm: do not attach PF_KCM sockets to avoid deadlock
syzkaller had no problem to trigger a deadlock, attaching a KCM socket
to another one (or itself). (original syzkaller report was a very
confusing lockdep splat during a sendmsg())
It seems KCM claims to only support TCP, but no enforcement is done,
so we might need to add additional checks.
Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/kcm/kcmsock.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index da49191f7ad0..4abf6287d7e1 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1383,6 +1383,10 @@ static int kcm_attach(struct socket *sock, struct socket *csock, if (!csk) return -EINVAL; + /* We must prevent loops or risk deadlock ! */ + if (csk->sk_family == PF_KCM) + return -EOPNOTSUPP; + psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL); if (!psock) return -ENOMEM; |