Commit 65b38851 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes 



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 <trond.myklebust@primarydata.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent db181ce0

fs/nfs/client.c

+55 −40
Original line number Diff line number Diff line
@@ -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;

fs/nfs/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

}

fs/nfs/internal.h

+9 −0
Original line number Diff line number Diff line
@@ -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_net_exit(struct net *net)

{

}

static inline int nfs_fs_proc_init(void)

{

	return 0;

fs/nfs/netns.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

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