phonet/pep: refuse to enable an unbound pipe

This ioctl() implicitly assumed that the socket was already bound to
a valid local socket name, i.e. Phonet object. If the socket was not
bound, two separate problems would occur:

1) We'd send an pipe enablement request with an invalid source object.
2) Later socket calls could BUG on the socket unexpectedly being
   connected yet not bound to a valid object.

Reported-by: syzbot+2dc91e7fc3dea88b1e8a@syzkaller.appspotmail.com
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index b4f90af..65d463a 100644 (file)
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -947,6 +947,8 @@ static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
                        ret =  -EBUSY;
                else if (sk->sk_state == TCP_ESTABLISHED)
                        ret = -EISCONN;
+               else if (!pn->pn_sk.sobject)
+                       ret = -EADDRNOTAVAIL;
                else
                        ret = pep_sock_enable(sk, NULL, 0);
                release_sock(sk);