3 files changed, 22 insertions, 0 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 7f555179bf81..f34d9de802ab 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -699,6 +699,11 @@ static ssize_t __write_ports_addfd(char *buf, struct net *net)
         if (err != 0 || fd < 0)
                 return -EINVAL;
 
+        if (svc_alien_sock(net, fd)) {
+                printk(KERN_ERR "%s: socket net is different to NFSd's one\n", __func__);
+                return -EINVAL;
+        }
+
         err = nfsd_create_serv(net);
         if (err != 0)
                 return err;
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 62fd1b756e99..947009ed5996 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -56,6 +56,7 @@ int		svc_recv(struct svc_rqst *, long);
 int             svc_send(struct svc_rqst *);
 void            svc_drop(struct svc_rqst *);
 void            svc_sock_update_bufs(struct svc_serv *serv);
+bool            svc_alien_sock(struct net *net, int fd);
 int             svc_addsock(struct svc_serv *serv, const int fd,
                                         char *name_return, const size_t len);
 void            svc_init_xprt_sock(void);
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index b6e59f0a9475..d06cb8752dcd 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1397,6 +1397,22 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
         return svsk;
 }
 
+bool svc_alien_sock(struct net *net, int fd)
+{
+        int err;
+        struct socket *sock = sockfd_lookup(fd, &err);
+        bool ret = false;
+
+        if (!sock)
+                goto out;
+        if (sock_net(sock->sk) != net)
+                ret = true;
+        sockfd_put(sock);
+out:
+        return ret;
+}
+EXPORT_SYMBOL_GPL(svc_alien_sock);
+
 /**
  * svc_addsock - add a listener socket to an RPC service
  * @serv: pointer to RPC service to which to add a new listener