From patchwork Thu Jul 31 20:18:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 4658801 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E06199F377 for ; Thu, 31 Jul 2014 20:22:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AD1D220158 for ; Thu, 31 Jul 2014 20:22:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AC4220149 for ; Thu, 31 Jul 2014 20:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750906AbaGaUWg (ORCPT ); Thu, 31 Jul 2014 16:22:36 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:55124 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750836AbaGaUWf (ORCPT ); Thu, 31 Jul 2014 16:22:35 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1XCwry-0002fU-58; Thu, 31 Jul 2014 14:22:34 -0600 Received: from [98.234.51.111] (helo=x220.int.ebiederm.org.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1XCwrt-0006Tn-HX; Thu, 31 Jul 2014 14:22:33 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linux Containers Cc: Trond Myklebust , linux-nfs@vger.kernel.org, Stanislav Kinsbursky Date: Thu, 31 Jul 2014 13:18:45 -0700 Message-ID: <87mwbpe0yi.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 X-XM-AID: U2FsdGVkX1/PQm+1QXfn8EF92VJmAEBWgSozTLtKn/g= X-SA-Exim-Connect-IP: 98.234.51.111 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-DCC: XMission; sa02 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Linux Containers X-Spam-Relay-Country: Subject: [REVIEW][PATCH] NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 13:58:17 -0700) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The usage of pid_ns->child_reaper->nsproxy->net_ns in nfs_server_list_open and nfs_client_list_open is not safe. /proc for a pid namespace can remain mounted after the all of the process in that pid namespace have exited. There are also times before the initial process in a pid namespace has started or after the initial process in a pid namespace has exited where pid_ns->child_reaper can be NULL or stale. Making the idiom pid_ns->child_reaper->nsproxy a double whammy of problems. Luckily all that needs to happen is to move /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes under /proc/net to /proc/net/nfsfs/servers and /proc/net/nfsfs/volumes and add a symlink from the original location, and to use seq_open_net as it has been designed. Cc: stable@vger.kernel.org Cc: Trond Myklebust Cc: Stanislav Kinsbursky Signed-off-by: "Eric W. Biederman" --- Unless problems are discovered I intend to merge this patch through my namespace tree. fs/nfs/client.c | 95 ++++++++++++++++++++++++++++++++----------------------- fs/nfs/inode.c | 3 +- fs/nfs/internal.h | 9 ++++++ fs/nfs/netns.h | 3 ++ 4 files changed, 69 insertions(+), 41 deletions(-) diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 1d09289c8f0e..180d1ec9c32e 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -1205,7 +1205,7 @@ static const struct file_operations nfs_server_list_fops = { .open = nfs_server_list_open, .read = seq_read, .llseek = seq_lseek, - .release = seq_release, + .release = seq_release_net, .owner = THIS_MODULE, }; @@ -1226,7 +1226,7 @@ static const struct file_operations nfs_volume_list_fops = { .open = nfs_volume_list_open, .read = seq_read, .llseek = seq_lseek, - .release = seq_release, + .release = seq_release_net, .owner = THIS_MODULE, }; @@ -1236,19 +1236,8 @@ static const struct file_operations nfs_volume_list_fops = { */ static int nfs_server_list_open(struct inode *inode, struct file *file) { - struct seq_file *m; - int ret; - struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info; - struct net *net = pid_ns->child_reaper->nsproxy->net_ns; - - ret = seq_open(file, &nfs_server_list_ops); - if (ret < 0) - return ret; - - m = file->private_data; - m->private = net; - - return 0; + return seq_open_net(inode, file, &nfs_server_list_ops, + sizeof(struct seq_net_private)); } /* @@ -1256,7 +1245,7 @@ static int nfs_server_list_open(struct inode *inode, struct file *file) */ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos) { - struct nfs_net *nn = net_generic(m->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id); /* lock the list against modification */ spin_lock(&nn->nfs_client_lock); @@ -1268,7 +1257,7 @@ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos) */ static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos) { - struct nfs_net *nn = net_generic(p->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id); return seq_list_next(v, &nn->nfs_client_list, pos); } @@ -1278,7 +1267,7 @@ static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos) */ static void nfs_server_list_stop(struct seq_file *p, void *v) { - struct nfs_net *nn = net_generic(p->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id); spin_unlock(&nn->nfs_client_lock); } @@ -1289,7 +1278,7 @@ static void nfs_server_list_stop(struct seq_file *p, void *v) static int nfs_server_list_show(struct seq_file *m, void *v) { struct nfs_client *clp; - struct nfs_net *nn = net_generic(m->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id); /* display header on line 1 */ if (v == &nn->nfs_client_list) { @@ -1321,19 +1310,8 @@ static int nfs_server_list_show(struct seq_file *m, void *v) */ static int nfs_volume_list_open(struct inode *inode, struct file *file) { - struct seq_file *m; - int ret; - struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info; - struct net *net = pid_ns->child_reaper->nsproxy->net_ns; - - ret = seq_open(file, &nfs_volume_list_ops); - if (ret < 0) - return ret; - - m = file->private_data; - m->private = net; - - return 0; + return seq_open_net(inode, file, &nfs_server_list_ops, + sizeof(struct seq_net_private)); } /* @@ -1341,7 +1319,7 @@ static int nfs_volume_list_open(struct inode *inode, struct file *file) */ static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos) { - struct nfs_net *nn = net_generic(m->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id); /* lock the list against modification */ spin_lock(&nn->nfs_client_lock); @@ -1353,7 +1331,7 @@ static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos) */ static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos) { - struct nfs_net *nn = net_generic(p->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id); return seq_list_next(v, &nn->nfs_volume_list, pos); } @@ -1363,7 +1341,7 @@ static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos) */ static void nfs_volume_list_stop(struct seq_file *p, void *v) { - struct nfs_net *nn = net_generic(p->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id); spin_unlock(&nn->nfs_client_lock); } @@ -1376,7 +1354,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) struct nfs_server *server; struct nfs_client *clp; char dev[8], fsid[17]; - struct nfs_net *nn = net_generic(m->private, nfs_net_id); + struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id); /* display header on line 1 */ if (v == &nn->nfs_volume_list) { @@ -1407,6 +1385,45 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) return 0; } +int nfs_fs_proc_net_init(struct net *net) +{ + struct nfs_net *nn = net_generic(net, nfs_net_id); + struct proc_dir_entry *p; + + nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net); + if (!nn->proc_nfsfs) + goto error_0; + + /* a file of servers with which we're dealing */ + p = proc_create("servers", S_IFREG|S_IRUGO, + nn->proc_nfsfs, &nfs_server_list_fops); + if (!p) + goto error_1; + + /* a file of volumes that we have mounted */ + p = proc_create("volumes", S_IFREG|S_IRUGO, + nn->proc_nfsfs, &nfs_volume_list_fops); + if (!p) + goto error_2; + return 0; + +error_2: + remove_proc_entry("servers", nn->proc_nfsfs); +error_1: + remove_proc_entry("fs/nfsfs", NULL); +error_0: + return -ENOMEM; +} + +void nfs_fs_proc_net_exit(struct net *net) +{ + struct nfs_net *nn = net_generic(net, nfs_net_id); + + remove_proc_entry("volumes", nn->proc_nfsfs); + remove_proc_entry("servers", nn->proc_nfsfs); + remove_proc_entry("fs/nfsfs", NULL); +} + /* * initialise the /proc/fs/nfsfs/ directory */ @@ -1419,14 +1436,12 @@ int __init nfs_fs_proc_init(void) goto error_0; /* a file of servers with which we're dealing */ - p = proc_create("servers", S_IFREG|S_IRUGO, - proc_fs_nfs, &nfs_server_list_fops); + p = proc_symlink("servers", proc_fs_nfs, "../../net/nfsfs/servers"); if (!p) goto error_1; /* a file of volumes that we have mounted */ - p = proc_create("volumes", S_IFREG|S_IRUGO, - proc_fs_nfs, &nfs_volume_list_fops); + p = proc_symlink("volumes", proc_fs_nfs, "../../net/nfsfs/volumes"); if (!p) goto error_2; return 0; diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 9927913c97c2..a732cbbd4e80 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1840,11 +1840,12 @@ EXPORT_SYMBOL_GPL(nfs_net_id); static int nfs_net_init(struct net *net) { nfs_clients_init(net); - return 0; + return nfs_fs_proc_net_init(net); } static void nfs_net_exit(struct net *net) { + nfs_fs_proc_net_exit(net); nfs_cleanup_cb_ident_idr(net); } diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index f415cbf9f6c3..57b99569d91e 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -195,7 +195,16 @@ extern struct rpc_clnt *nfs4_find_or_create_ds_client(struct nfs_client *, #ifdef CONFIG_PROC_FS extern int __init nfs_fs_proc_init(void); extern void nfs_fs_proc_exit(void); +extern int nfs_fs_proc_net_init(struct net *net); +extern void nfs_fs_proc_net_exit(struct net *net); #else +static inline int nfs_fs_proc_net_init(struct net *net) +{ + return 0; +} +static inline void nfs_fs_proc_exit(struct net *net) +{ +} static inline int nfs_fs_proc_init(void) { return 0; diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h index 8ee1fab83268..ef221fb8a183 100644 --- a/fs/nfs/netns.h +++ b/fs/nfs/netns.h @@ -29,6 +29,9 @@ struct nfs_net { #endif spinlock_t nfs_client_lock; struct timespec boot_time; +#ifdef CONFIG_PROC_FS + struct proc_dir_entry *proc_nfsfs; +#endif }; extern int nfs_net_id;