diff options
| -rw-r--r-- | net/unix/af_unix.c | 79 |
1 files changed, 64 insertions, 15 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 4e95bdf973d9..6ced74690eee 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1551,6 +1551,14 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen return err; } +static bool unix_passcred_enabled(const struct socket *sock, + const struct sock *other) +{ + return test_bit(SOCK_PASSCRED, &sock->flags) || + !other->sk_socket || + test_bit(SOCK_PASSCRED, &other->sk_socket->flags); +} + /* * Some apps rely on write() giving SCM_CREDENTIALS * We include credentials if source or destination socket @@ -1561,14 +1569,41 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, { if (UNIXCB(skb).pid) return; - if (test_bit(SOCK_PASSCRED, &sock->flags) || - !other->sk_socket || - test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { + if (unix_passcred_enabled(sock, other)) { UNIXCB(skb).pid = get_pid(task_tgid(current)); current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); } } +static int maybe_init_creds(struct scm_cookie *scm, + struct socket *socket, + const struct sock *other) +{ + int err; + struct msghdr msg = { .msg_controllen = 0 }; + + err = scm_send(socket, &msg, scm, false); + if (err) + return err; + + if (unix_passcred_enabled(socket, other)) { + scm->pid = get_pid(task_tgid(current)); + current_uid_gid(&scm->creds.uid, &scm->creds.gid); + } + return err; +} + +static bool unix_skb_scm_eq(struct sk_buff *skb, + struct scm_cookie *scm) +{ + const struct unix_skb_parms *u = &UNIXCB(skb); + + return u->pid == scm->pid && + uid_eq(u->uid, scm->creds.uid) && + gid_eq(u->gid, scm->creds.gid) && + unix_secdata_eq(scm, skb); +} + /* * Send AF_UNIX data. */ @@ -1884,8 +1919,10 @@ out_err: static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page, int offset, size_t size, int flags) { - int err = 0; - bool send_sigpipe = true; + int err; + bool send_sigpipe = false; + bool init_scm = true; + struct scm_cookie scm; struct sock *other, *sk = socket->sk; struct sk_buff *skb, *newskb = NULL, *tail = NULL; @@ -1903,7 +1940,7 @@ alloc_skb: newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT, &err, 0); if (!newskb) - return err; + goto err; } /* we must acquire readlock as we modify already present @@ -1912,12 +1949,12 @@ alloc_skb: err = mutex_lock_interruptible(&unix_sk(other)->readlock); if (err) { err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS; - send_sigpipe = false; goto err; } if (sk->sk_shutdown & SEND_SHUTDOWN) { err = -EPIPE; + send_sigpipe = true; goto err_unlock; } @@ -1926,17 +1963,27 @@ alloc_skb: if (sock_flag(other, SOCK_DEAD) || other->sk_shutdown & RCV_SHUTDOWN) { err = -EPIPE; + send_sigpipe = true; goto err_state_unlock; } + if (init_scm) { + err = maybe_init_creds(&scm, socket, other); + if (err) + goto err_state_unlock; + init_scm = false; + } + skb = skb_peek_tail(&other->sk_receive_queue); if (tail && tail == skb) { skb = newskb; - } else if (!skb) { - if (newskb) + } else if (!skb || !unix_skb_scm_eq(skb, &scm)) { + if (newskb) { skb = newskb; - else + } else { + tail = skb; goto alloc_skb; + } } else if (newskb) { /* this is fast path, we don't necessarily need to * call to kfree_skb even though with newskb == NULL @@ -1957,6 +2004,9 @@ alloc_skb: atomic_add(size, &sk->sk_wmem_alloc); if (newskb) { + err = unix_scm_to_skb(&scm, skb, false); + if (err) + goto err_state_unlock; spin_lock(&other->sk_receive_queue.lock); __skb_queue_tail(&other->sk_receive_queue, newskb); spin_unlock(&other->sk_receive_queue.lock); @@ -1966,7 +2016,7 @@ alloc_skb: mutex_unlock(&unix_sk(other)->readlock); other->sk_data_ready(other); - + scm_destroy(&scm); return size; err_state_unlock: @@ -1977,6 +2027,8 @@ err: kfree_skb(newskb); if (send_sigpipe && !(flags & MSG_NOSIGNAL)) send_sig(SIGPIPE, current, 0); + if (!init_scm) + scm_destroy(&scm); return err; } @@ -2280,10 +2332,7 @@ unlock: if (check_creds) { /* Never glue messages from different writers */ - if ((UNIXCB(skb).pid != scm.pid) || - !uid_eq(UNIXCB(skb).uid, scm.creds.uid) || - !gid_eq(UNIXCB(skb).gid, scm.creds.gid) || - !unix_secdata_eq(&scm, skb)) + if (!unix_skb_scm_eq(skb, &scm)) break; } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { /* Copy credentials */ |
