af_unix: Allow SO_PEERCRED to work across namespaces.
Use struct pid and struct cred to store the peer credentials on struct
sock. This gives enough information to convert the peer credential
information to a value relative to whatever namespace the socket is in
at the time.
This removes nasty surprises when using SO_PEERCRED on socket
connetions where the processes on either side are in different pid and
user namespaces.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index fef2cc5..e1f1349 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -450,11 +450,31 @@
return 0;
}
+static void init_peercred(struct sock *sk)
+{
+ put_pid(sk->sk_peer_pid);
+ if (sk->sk_peer_cred)
+ put_cred(sk->sk_peer_cred);
+ sk->sk_peer_pid = get_pid(task_tgid(current));
+ sk->sk_peer_cred = get_current_cred();
+}
+
+static void copy_peercred(struct sock *sk, struct sock *peersk)
+{
+ put_pid(sk->sk_peer_pid);
+ if (sk->sk_peer_cred)
+ put_cred(sk->sk_peer_cred);
+ sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
+ sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
+}
+
static int unix_listen(struct socket *sock, int backlog)
{
int err;
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
+ struct pid *old_pid = NULL;
+ const struct cred *old_cred = NULL;
err = -EOPNOTSUPP;
if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
@@ -470,12 +490,14 @@
sk->sk_max_ack_backlog = backlog;
sk->sk_state = TCP_LISTEN;
/* set credentials so connect can copy them */
- sk->sk_peercred.pid = task_tgid_vnr(current);
- current_euid_egid(&sk->sk_peercred.uid, &sk->sk_peercred.gid);
+ init_peercred(sk);
err = 0;
out_unlock:
unix_state_unlock(sk);
+ put_pid(old_pid);
+ if (old_cred)
+ put_cred(old_cred);
out:
return err;
}
@@ -1140,8 +1162,7 @@
unix_peer(newsk) = sk;
newsk->sk_state = TCP_ESTABLISHED;
newsk->sk_type = sk->sk_type;
- newsk->sk_peercred.pid = task_tgid_vnr(current);
- current_euid_egid(&newsk->sk_peercred.uid, &newsk->sk_peercred.gid);
+ init_peercred(newsk);
newu = unix_sk(newsk);
newsk->sk_wq = &newu->peer_wq;
otheru = unix_sk(other);
@@ -1157,7 +1178,7 @@
}
/* Set credentials */
- sk->sk_peercred = other->sk_peercred;
+ copy_peercred(sk, other);
sock->state = SS_CONNECTED;
sk->sk_state = TCP_ESTABLISHED;
@@ -1199,10 +1220,8 @@
sock_hold(skb);
unix_peer(ska) = skb;
unix_peer(skb) = ska;
- ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
- current_euid_egid(&skb->sk_peercred.uid, &skb->sk_peercred.gid);
- ska->sk_peercred.uid = skb->sk_peercred.uid;
- ska->sk_peercred.gid = skb->sk_peercred.gid;
+ init_peercred(ska);
+ init_peercred(skb);
if (ska->sk_type != SOCK_DGRAM) {
ska->sk_state = TCP_ESTABLISHED;