nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity

af_unix: Allow SO_PEERCRED to work across namespaces.

Browse source 
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>
This commit is contained in:
Eric W. Biederman 2010-06-13 03:30:14 +00:00 committed by David S. Miller
parent 3f551f9436
commit 109f6e39fa
3 changed files with 42 additions and 16 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
include/net/sock.h
View file

@ -295,7 +295,8 @@ 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;

18
net/core/sock.c
View file

@ -915,11 +915,15 @@ 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:
{
@ -1133,6 +1137,9 @@ 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);
}
@ -1968,9 +1975,8 @@ 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;

37
net/unix/af_unix.c
View file

@ -450,11 +450,31 @@ 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)
@ -470,12 +490,14 @@ 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;
}
@ -1140,8 +1162,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
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 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
}
/* 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 @@ 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;