1/*
  2 *  linux/fs/proc/root.c
  3 *
  4 *  Copyright (C) 1991, 1992 Linus Torvalds
  5 *
  6 *  proc root directory handling functions
  7 */
  8
  9#include <asm/uaccess.h>
 10
 11#include <linux/errno.h>
 12#include <linux/time.h>
 13#include <linux/proc_fs.h>
 14#include <linux/stat.h>
 15#include <linux/init.h>
 16#include <linux/sched.h>
 17#include <linux/module.h>
 18#include <linux/bitops.h>
 19#include <linux/user_namespace.h>
 20#include <linux/mount.h>
 21#include <linux/pid_namespace.h>
 22#include <linux/parser.h>
 23
 24#include "internal.h"
 25
 26static int proc_test_super(struct super_block *sb, void *data)
 27{
 28	return sb->s_fs_info == data;
 29}
 30
 31static int proc_set_super(struct super_block *sb, void *data)
 32{
 33	int err = set_anon_super(sb, NULL);
 34	if (!err) {
 35		struct pid_namespace *ns = (struct pid_namespace *)data;
 36		sb->s_fs_info = get_pid_ns(ns);
 37	}
 38	return err;
 39}
 40
 41enum {
 42	Opt_gid, Opt_hidepid, Opt_err,
 43};
 44
 45static const match_table_t tokens = {
 46	{Opt_hidepid, "hidepid=%u"},
 47	{Opt_gid, "gid=%u"},
 48	{Opt_err, NULL},
 49};
 50
 51static int proc_parse_options(char *options, struct pid_namespace *pid)
 52{
 53	char *p;
 54	substring_t args[MAX_OPT_ARGS];
 55	int option;
 56
 57	if (!options)
 58		return 1;
 59
 60	while ((p = strsep(&options, ",")) != NULL) {
 61		int token;
 62		if (!*p)
 63			continue;
 64
 65		args[0].to = args[0].from = NULL;
 66		token = match_token(p, tokens, args);
 67		switch (token) {
 68		case Opt_gid:
 69			if (match_int(&args[0], &option))
 70				return 0;
 71			pid->pid_gid = make_kgid(current_user_ns(), option);
 72			break;
 73		case Opt_hidepid:
 74			if (match_int(&args[0], &option))
 75				return 0;
 76			if (option < 0 || option > 2) {
 77				pr_err("proc: hidepid value must be between 0 and 2.\n");
 78				return 0;
 79			}
 80			pid->hide_pid = option;
 81			break;
 82		default:
 83			pr_err("proc: unrecognized mount option \"%s\" "
 84			       "or missing value\n", p);
 85			return 0;
 86		}
 87	}
 88
 89	return 1;
 90}
 91
 92int proc_remount(struct super_block *sb, int *flags, char *data)
 93{
 94	struct pid_namespace *pid = sb->s_fs_info;
 95
 96	sync_filesystem(sb);
 97	return !proc_parse_options(data, pid);
 98}
 99
100static struct dentry *proc_mount(struct file_system_type *fs_type,
101	int flags, const char *dev_name, void *data)
102{
103	int err;
104	struct super_block *sb;
105	struct pid_namespace *ns;
106	char *options;
107
108	if (flags & MS_KERNMOUNT) {
109		ns = (struct pid_namespace *)data;
110		options = NULL;
111	} else {
112		ns = task_active_pid_ns(current);
113		options = data;
114
 
 
 
115		/* Does the mounter have privilege over the pid namespace? */
116		if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
117			return ERR_PTR(-EPERM);
118	}
119
120	sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
121	if (IS_ERR(sb))
122		return ERR_CAST(sb);
123
124	if (!proc_parse_options(options, ns)) {
125		deactivate_locked_super(sb);
126		return ERR_PTR(-EINVAL);
127	}
128
129	if (!sb->s_root) {
130		err = proc_fill_super(sb);
131		if (err) {
132			deactivate_locked_super(sb);
133			return ERR_PTR(err);
134		}
135
136		sb->s_flags |= MS_ACTIVE;
137		/* User space would break if executables appear on proc */
138		sb->s_iflags |= SB_I_NOEXEC;
139	}
140
141	return dget(sb->s_root);
142}
143
144static void proc_kill_sb(struct super_block *sb)
145{
146	struct pid_namespace *ns;
147
148	ns = (struct pid_namespace *)sb->s_fs_info;
149	if (ns->proc_self)
150		dput(ns->proc_self);
151	if (ns->proc_thread_self)
152		dput(ns->proc_thread_self);
153	kill_anon_super(sb);
154	put_pid_ns(ns);
155}
156
157static struct file_system_type proc_fs_type = {
158	.name		= "proc",
159	.mount		= proc_mount,
160	.kill_sb	= proc_kill_sb,
161	.fs_flags	= FS_USERNS_VISIBLE | FS_USERNS_MOUNT,
162};
163
164void __init proc_root_init(void)
165{
166	int err;
167
168	proc_init_inodecache();
169	err = register_filesystem(&proc_fs_type);
170	if (err)
171		return;
172
173	proc_self_init();
174	proc_thread_self_init();
175	proc_symlink("mounts", NULL, "self/mounts");
176
177	proc_net_init();
178
179#ifdef CONFIG_SYSVIPC
180	proc_mkdir("sysvipc", NULL);
181#endif
182	proc_mkdir("fs", NULL);
183	proc_mkdir("driver", NULL);
184	proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
185#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
186	/* just give it a mountpoint */
187	proc_create_mount_point("openprom");
188#endif
189	proc_tty_init();
190	proc_mkdir("bus", NULL);
191	proc_sys_init();
192}
193
194static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
195)
196{
197	generic_fillattr(d_inode(dentry), stat);
198	stat->nlink = proc_root.nlink + nr_processes();
199	return 0;
200}
201
202static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
203{
204	if (!proc_pid_lookup(dir, dentry, flags))
205		return NULL;
206	
207	return proc_lookup(dir, dentry, flags);
208}
209
210static int proc_root_readdir(struct file *file, struct dir_context *ctx)
211{
212	if (ctx->pos < FIRST_PROCESS_ENTRY) {
213		int error = proc_readdir(file, ctx);
214		if (unlikely(error <= 0))
215			return error;
216		ctx->pos = FIRST_PROCESS_ENTRY;
217	}
218
219	return proc_pid_readdir(file, ctx);
220}
221
222/*
223 * The root /proc directory is special, as it has the
224 * <pid> directories. Thus we don't use the generic
225 * directory handling functions for that..
226 */
227static const struct file_operations proc_root_operations = {
228	.read		 = generic_read_dir,
229	.iterate	 = proc_root_readdir,
230	.llseek		= default_llseek,
231};
232
233/*
234 * proc root can do almost nothing..
235 */
236static const struct inode_operations proc_root_inode_operations = {
237	.lookup		= proc_root_lookup,
238	.getattr	= proc_root_getattr,
239};
240
241/*
242 * This is the root "inode" in the /proc tree..
243 */
244struct proc_dir_entry proc_root = {
245	.low_ino	= PROC_ROOT_INO, 
246	.namelen	= 5, 
247	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 
248	.nlink		= 2, 
249	.count		= ATOMIC_INIT(1),
250	.proc_iops	= &proc_root_inode_operations, 
251	.proc_fops	= &proc_root_operations,
252	.parent		= &proc_root,
253	.subdir		= RB_ROOT,
254	.name		= "/proc",
255};
256
257int pid_ns_prepare_proc(struct pid_namespace *ns)
258{
259	struct vfsmount *mnt;
260
261	mnt = kern_mount_data(&proc_fs_type, ns);
262	if (IS_ERR(mnt))
263		return PTR_ERR(mnt);
264
265	ns->proc_mnt = mnt;
266	return 0;
267}
268
269void pid_ns_release_proc(struct pid_namespace *ns)
270{
271	kern_unmount(ns->proc_mnt);
272}

  1/*
  2 *  linux/fs/proc/root.c
  3 *
  4 *  Copyright (C) 1991, 1992 Linus Torvalds
  5 *
  6 *  proc root directory handling functions
  7 */
  8
  9#include <asm/uaccess.h>
 10
 11#include <linux/errno.h>
 12#include <linux/time.h>
 13#include <linux/proc_fs.h>
 14#include <linux/stat.h>
 15#include <linux/init.h>
 16#include <linux/sched.h>
 17#include <linux/module.h>
 18#include <linux/bitops.h>
 19#include <linux/user_namespace.h>
 20#include <linux/mount.h>
 21#include <linux/pid_namespace.h>
 22#include <linux/parser.h>
 23
 24#include "internal.h"
 25
 26static int proc_test_super(struct super_block *sb, void *data)
 27{
 28	return sb->s_fs_info == data;
 29}
 30
 31static int proc_set_super(struct super_block *sb, void *data)
 32{
 33	int err = set_anon_super(sb, NULL);
 34	if (!err) {
 35		struct pid_namespace *ns = (struct pid_namespace *)data;
 36		sb->s_fs_info = get_pid_ns(ns);
 37	}
 38	return err;
 39}
 40
 41enum {
 42	Opt_gid, Opt_hidepid, Opt_err,
 43};
 44
 45static const match_table_t tokens = {
 46	{Opt_hidepid, "hidepid=%u"},
 47	{Opt_gid, "gid=%u"},
 48	{Opt_err, NULL},
 49};
 50
 51static int proc_parse_options(char *options, struct pid_namespace *pid)
 52{
 53	char *p;
 54	substring_t args[MAX_OPT_ARGS];
 55	int option;
 56
 57	if (!options)
 58		return 1;
 59
 60	while ((p = strsep(&options, ",")) != NULL) {
 61		int token;
 62		if (!*p)
 63			continue;
 64
 65		args[0].to = args[0].from = NULL;
 66		token = match_token(p, tokens, args);
 67		switch (token) {
 68		case Opt_gid:
 69			if (match_int(&args[0], &option))
 70				return 0;
 71			pid->pid_gid = make_kgid(current_user_ns(), option);
 72			break;
 73		case Opt_hidepid:
 74			if (match_int(&args[0], &option))
 75				return 0;
 76			if (option < 0 || option > 2) {
 77				pr_err("proc: hidepid value must be between 0 and 2.\n");
 78				return 0;
 79			}
 80			pid->hide_pid = option;
 81			break;
 82		default:
 83			pr_err("proc: unrecognized mount option \"%s\" "
 84			       "or missing value\n", p);
 85			return 0;
 86		}
 87	}
 88
 89	return 1;
 90}
 91
 92int proc_remount(struct super_block *sb, int *flags, char *data)
 93{
 94	struct pid_namespace *pid = sb->s_fs_info;
 95
 96	sync_filesystem(sb);
 97	return !proc_parse_options(data, pid);
 98}
 99
100static struct dentry *proc_mount(struct file_system_type *fs_type,
101	int flags, const char *dev_name, void *data)
102{
103	int err;
104	struct super_block *sb;
105	struct pid_namespace *ns;
106	char *options;
107
108	if (flags & MS_KERNMOUNT) {
109		ns = (struct pid_namespace *)data;
110		options = NULL;
111	} else {
112		ns = task_active_pid_ns(current);
113		options = data;
114
115		if (!capable(CAP_SYS_ADMIN) && !fs_fully_visible(fs_type))
116			return ERR_PTR(-EPERM);
117
118		/* Does the mounter have privilege over the pid namespace? */
119		if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
120			return ERR_PTR(-EPERM);
121	}
122
123	sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
124	if (IS_ERR(sb))
125		return ERR_CAST(sb);
126
127	if (!proc_parse_options(options, ns)) {
128		deactivate_locked_super(sb);
129		return ERR_PTR(-EINVAL);
130	}
131
132	if (!sb->s_root) {
133		err = proc_fill_super(sb);
134		if (err) {
135			deactivate_locked_super(sb);
136			return ERR_PTR(err);
137		}
138
139		sb->s_flags |= MS_ACTIVE;
 
 
140	}
141
142	return dget(sb->s_root);
143}
144
145static void proc_kill_sb(struct super_block *sb)
146{
147	struct pid_namespace *ns;
148
149	ns = (struct pid_namespace *)sb->s_fs_info;
150	if (ns->proc_self)
151		dput(ns->proc_self);
 
 
152	kill_anon_super(sb);
153	put_pid_ns(ns);
154}
155
156static struct file_system_type proc_fs_type = {
157	.name		= "proc",
158	.mount		= proc_mount,
159	.kill_sb	= proc_kill_sb,
160	.fs_flags	= FS_USERNS_MOUNT,
161};
162
163void __init proc_root_init(void)
164{
165	int err;
166
167	proc_init_inodecache();
168	err = register_filesystem(&proc_fs_type);
169	if (err)
170		return;
171
172	proc_self_init();
 
173	proc_symlink("mounts", NULL, "self/mounts");
174
175	proc_net_init();
176
177#ifdef CONFIG_SYSVIPC
178	proc_mkdir("sysvipc", NULL);
179#endif
180	proc_mkdir("fs", NULL);
181	proc_mkdir("driver", NULL);
182	proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
183#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
184	/* just give it a mountpoint */
185	proc_mkdir("openprom", NULL);
186#endif
187	proc_tty_init();
188	proc_mkdir("bus", NULL);
189	proc_sys_init();
190}
191
192static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
193)
194{
195	generic_fillattr(dentry->d_inode, stat);
196	stat->nlink = proc_root.nlink + nr_processes();
197	return 0;
198}
199
200static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
201{
202	if (!proc_lookup(dir, dentry, flags))
203		return NULL;
204	
205	return proc_pid_lookup(dir, dentry, flags);
206}
207
208static int proc_root_readdir(struct file *file, struct dir_context *ctx)
209{
210	if (ctx->pos < FIRST_PROCESS_ENTRY) {
211		int error = proc_readdir(file, ctx);
212		if (unlikely(error <= 0))
213			return error;
214		ctx->pos = FIRST_PROCESS_ENTRY;
215	}
216
217	return proc_pid_readdir(file, ctx);
218}
219
220/*
221 * The root /proc directory is special, as it has the
222 * <pid> directories. Thus we don't use the generic
223 * directory handling functions for that..
224 */
225static const struct file_operations proc_root_operations = {
226	.read		 = generic_read_dir,
227	.iterate	 = proc_root_readdir,
228	.llseek		= default_llseek,
229};
230
231/*
232 * proc root can do almost nothing..
233 */
234static const struct inode_operations proc_root_inode_operations = {
235	.lookup		= proc_root_lookup,
236	.getattr	= proc_root_getattr,
237};
238
239/*
240 * This is the root "inode" in the /proc tree..
241 */
242struct proc_dir_entry proc_root = {
243	.low_ino	= PROC_ROOT_INO, 
244	.namelen	= 5, 
245	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 
246	.nlink		= 2, 
247	.count		= ATOMIC_INIT(1),
248	.proc_iops	= &proc_root_inode_operations, 
249	.proc_fops	= &proc_root_operations,
250	.parent		= &proc_root,
 
251	.name		= "/proc",
252};
253
254int pid_ns_prepare_proc(struct pid_namespace *ns)
255{
256	struct vfsmount *mnt;
257
258	mnt = kern_mount_data(&proc_fs_type, ns);
259	if (IS_ERR(mnt))
260		return PTR_ERR(mnt);
261
262	ns->proc_mnt = mnt;
263	return 0;
264}
265
266void pid_ns_release_proc(struct pid_namespace *ns)
267{
268	kern_unmount(ns->proc_mnt);
269}