net: unix: fix inflight counting bug in garbage collector

[linux-2.6-omap-h63xx.git] / net / unix / af_unix.c

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 015606b54d9b28325aad62a71ea4fc160b686cd8..eb90f77bb0e294b6358db3361740deaa0bec969e 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1,7 +1,7 @@
 /*
  * NET4:       Implementation of BSD Unix domain sockets.
  *
- * Authors:    Alan Cox, <alan.cox@linux.org>
+ * Authors:    Alan Cox, <alan@lxorguk.ukuu.org.uk>
  *
  *             This program is free software; you can redistribute it and/or
  *             modify it under the terms of the GNU General Public License
@@ -711,28 +711,30 @@ static struct sock *unix_find_other(struct net *net,
                                    int type, unsigned hash, int *error)
 {
        struct sock *u;
-       struct nameidata nd;
+       struct path path;
        int err = 0;
 
        if (sunname->sun_path[0]) {
-               err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd);
+               struct inode *inode;
+               err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
                if (err)
                        goto fail;
-               err = vfs_permission(&nd, MAY_WRITE);
+               inode = path.dentry->d_inode;
+               err = inode_permission(inode, MAY_WRITE);
                if (err)
                        goto put_fail;
 
                err = -ECONNREFUSED;
-               if (!S_ISSOCK(nd.path.dentry->d_inode->i_mode))
+               if (!S_ISSOCK(inode->i_mode))
                        goto put_fail;
-               u = unix_find_socket_byinode(net, nd.path.dentry->d_inode);
+               u = unix_find_socket_byinode(net, inode);
                if (!u)
                        goto put_fail;
 
                if (u->sk_type == type)
-                       touch_atime(nd.path.mnt, nd.path.dentry);
+                       touch_atime(path.mnt, path.dentry);
 
-               path_put(&nd.path);
+               path_put(&path);
 
                err=-EPROTOTYPE;
                if (u->sk_type != type) {
@@ -753,7 +755,7 @@ static struct sock *unix_find_other(struct net *net,
        return u;
 
 put_fail:
-       path_put(&nd.path);
+       path_put(&path);
 fail:
        *error=err;
        return NULL;
@@ -1300,14 +1302,23 @@ static void unix_destruct_fds(struct sk_buff *skb)
        sock_wfree(skb);
 }
 
-static void unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
+static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
 {
        int i;
+
+       /*
+        * Need to duplicate file references for the sake of garbage
+        * collection.  Otherwise a socket in the fps might become a
+        * candidate for GC while the skb is not yet queued.
+        */
+       UNIXCB(skb).fp = scm_fp_dup(scm->fp);
+       if (!UNIXCB(skb).fp)
+               return -ENOMEM;
+
        for (i=scm->fp->count-1; i>=0; i--)
                unix_inflight(scm->fp->fp[i]);
-       UNIXCB(skb).fp = scm->fp;
        skb->destructor = unix_destruct_fds;
-       scm->fp = NULL;
+       return 0;
 }
 
 /*
@@ -1366,8 +1377,11 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
                goto out;
 
        memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
-       if (siocb->scm->fp)
-               unix_attach_fds(siocb->scm, skb);
+       if (siocb->scm->fp) {
+               err = unix_attach_fds(siocb->scm, skb);
+               if (err)
+                       goto out_free;
+       }
        unix_get_secdata(siocb->scm, skb);
 
        skb_reset_transport_header(skb);
@@ -1536,8 +1550,13 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                size = min_t(int, size, skb_tailroom(skb));
 
                memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
-               if (siocb->scm->fp)
-                       unix_attach_fds(siocb->scm, skb);
+               if (siocb->scm->fp) {
+                       err = unix_attach_fds(siocb->scm, skb);
+                       if (err) {
+                               kfree_skb(skb);
+                               goto out_err;
+                       }
+               }
 
                if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) {
                        kfree_skb(skb);
@@ -2211,7 +2230,7 @@ static int unix_net_init(struct net *net)
 #endif
        error = 0;
 out:
-       return 0;
+       return error;
 }
 
 static void unix_net_exit(struct net *net)