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Message-ID: <m1r5kbgivt.fsf@fess.ebiederm.org>
Date: Sun, 13 Jun 2010 06:30:14 -0700
From: ebiederm@...ssion.com (Eric W. Biederman)
To: David Miller <davem@...emloft.net>
Cc: Serge Hallyn <serue@...ibm.com>,
Linux Containers <containers@...ts.osdl.org>,
Daniel Lezcano <daniel.lezcano@...e.fr>,
<netdev@...r.kernel.org>, Pavel Emelyanov <xemul@...allels.com>
Subject: [PATCH 4/8] 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@...ssion.com>
---
include/net/sock.h | 3 ++-
net/core/sock.c | 18 ++++++++++++------
net/unix/af_unix.c | 37 ++++++++++++++++++++++++++++---------
3 files changed, 42 insertions(+), 16 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 56df440..5b1eb7d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -290,7 +290,8 @@ struct sock {
unsigned short sk_ack_backlog;
unsigned short sk_max_ack_backlog;
__u32 sk_priority;
- struct ucred sk_peercred;
+ struct pid *sk_peer_pid;
+ const struct cred *sk_peer_cred;
long sk_rcvtimeo;
long sk_sndtimeo;
struct sk_filter *sk_filter;
diff --git a/net/core/sock.c b/net/core/sock.c
index 9e229d8..9d197a6 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -900,11 +900,15 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
break;
case SO_PEERCRED:
- if (len > sizeof(sk->sk_peercred))
- len = sizeof(sk->sk_peercred);
- if (copy_to_user(optval, &sk->sk_peercred, len))
+ {
+ struct ucred peercred;
+ if (len > sizeof(peercred))
+ len = sizeof(peercred);
+ cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred);
+ if (copy_to_user(optval, &peercred, len))
return -EFAULT;
goto lenout;
+ }
case SO_PEERNAME:
{
@@ -1105,6 +1109,9 @@ static void __sk_free(struct sock *sk)
printk(KERN_DEBUG "%s: optmem leakage (%d bytes) detected.\n",
__func__, atomic_read(&sk->sk_omem_alloc));
+ if (sk->sk_peer_cred)
+ put_cred(sk->sk_peer_cred);
+ put_pid(sk->sk_peer_pid);
put_net(sock_net(sk));
sk_prot_free(sk->sk_prot_creator, sk);
}
@@ -1927,9 +1934,8 @@ void sock_init_data(struct socket *sock, struct sock *sk)
sk->sk_sndmsg_page = NULL;
sk->sk_sndmsg_off = 0;
- sk->sk_peercred.pid = 0;
- sk->sk_peercred.uid = -1;
- sk->sk_peercred.gid = -1;
+ sk->sk_peer_pid = NULL;
+ sk->sk_peer_cred = NULL;
sk->sk_write_pending = 0;
sk->sk_rcvlowat = 1;
sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 3d9122e..028fa25 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -449,11 +449,31 @@ static int unix_release_sock(struct sock *sk, int embrion)
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)
@@ -469,12 +489,14 @@ static int unix_listen(struct socket *sock, int backlog)
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;
}
@@ -1139,8 +1161,7 @@ restart:
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_sleep = &newu->peer_wait;
otheru = unix_sk(other);
@@ -1156,7 +1177,7 @@ restart:
}
/* Set credentials */
- sk->sk_peercred = other->sk_peercred;
+ copy_peercred(sk, other);
sock->state = SS_CONNECTED;
sk->sk_state = TCP_ESTABLISHED;
@@ -1198,10 +1219,8 @@ static int unix_socketpair(struct socket *socka, struct socket *sockb)
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;
--
1.6.5.2.143.g8cc62
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