[PATCH] phonet/pep: refuse to enable an unbound pipe

From: remi@remlab.net
To: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] phonet/pep: refuse to enable an unbound pipe
Date: Sun, 19 Dec 2021 19:03:39 +0200	[thread overview]
Message-ID: <20211219170339.630659-1-remi@remlab.net> (raw)

From: Rémi Denis-Courmont <remi@remlab.net>

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>
---
 net/phonet/pep.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index b4f90afb0638..65d463ad8770 100644
--- 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);
-- 
2.34.1

