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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
Al Viro914e2632006-10-18 13:55:46 -040016#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/module.h>
18#include <linux/bitops.h>
Eric W. Biederman87a8ebd2013-03-24 14:28:27 -070019#include <linux/user_namespace.h>
Eric W. Biedermanf6c7a1f2006-10-02 02:17:07 -070020#include <linux/mount.h>
Pavel Emelyanov07543f52007-10-18 23:40:08 -070021#include <linux/pid_namespace.h>
Vasiliy Kulikov97412952012-01-10 15:11:27 -080022#include <linux/parser.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Adrian Bunkfee781e2006-01-08 01:04:16 -080024#include "internal.h"
25
Pavel Emelyanov07543f52007-10-18 23:40:08 -070026static 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{
Al Viroff78fca2011-06-12 09:42:17 -040033 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;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070039}
40
Vasiliy Kulikov97412952012-01-10 15:11:27 -080041enum {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080042 Opt_gid, Opt_hidepid, Opt_err,
Vasiliy Kulikov97412952012-01-10 15:11:27 -080043};
44
45static const match_table_t tokens = {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080046 {Opt_hidepid, "hidepid=%u"},
47 {Opt_gid, "gid=%u"},
Vasiliy Kulikov97412952012-01-10 15:11:27 -080048 {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];
Vasiliy Kulikov04996802012-01-10 15:11:31 -080055 int option;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080056
57 if (!options)
58 return 1;
59
60 while ((p = strsep(&options, ",")) != NULL) {
61 int token;
62 if (!*p)
63 continue;
64
Sachin Kamat9fb88442012-10-04 17:15:46 -070065 args[0].to = args[0].from = NULL;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080066 token = match_token(p, tokens, args);
67 switch (token) {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080068 case Opt_gid:
69 if (match_int(&args[0], &option))
70 return 0;
Eric W. Biedermandcb0f222012-02-09 08:48:21 -080071 pid->pid_gid = make_kgid(current_user_ns(), option);
Vasiliy Kulikov04996802012-01-10 15:11:31 -080072 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;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080082 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;
Theodore Ts'o02b99842014-03-13 10:14:33 -040095
96 sync_filesystem(sb);
Vasiliy Kulikov97412952012-01-10 15:11:27 -080097 return !proc_parse_options(data, pid);
98}
99
Al Viroaed1d842010-07-26 13:12:54 +0400100static struct dentry *proc_mount(struct file_system_type *fs_type,
101 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102{
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700103 int err;
104 struct super_block *sb;
105 struct pid_namespace *ns;
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800106 char *options;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700107
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800108 if (flags & MS_KERNMOUNT) {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700109 ns = (struct pid_namespace *)data;
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800110 options = NULL;
111 } else {
Eric W. Biederman17cf22c2010-03-02 14:51:53 -0800112 ns = task_active_pid_ns(current);
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800113 options = data;
Eric W. Biederman87a8ebd2013-03-24 14:28:27 -0700114
Eric W. Biedermane51db732013-03-30 19:57:41 -0700115 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))
Eric W. Biederman87a8ebd2013-03-24 14:28:27 -0700120 return ERR_PTR(-EPERM);
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800121 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700122
David Howells9249e172012-06-25 12:55:37 +0100123 sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700124 if (IS_ERR(sb))
Al Viroaed1d842010-07-26 13:12:54 +0400125 return ERR_CAST(sb);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700126
Vasiliy Kulikov99663be2012-04-05 14:25:04 -0700127 if (!proc_parse_options(options, ns)) {
128 deactivate_locked_super(sb);
129 return ERR_PTR(-EINVAL);
130 }
131
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700132 if (!sb->s_root) {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700133 err = proc_fill_super(sb);
134 if (err) {
Al Viro6f5bbff2009-05-06 01:34:22 -0400135 deactivate_locked_super(sb);
Al Viroaed1d842010-07-26 13:12:54 +0400136 return ERR_PTR(err);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700137 }
138
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700139 sb->s_flags |= MS_ACTIVE;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700140 }
141
Al Viroaed1d842010-07-26 13:12:54 +0400142 return dget(sb->s_root);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700143}
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;
Al Viro021ada72013-03-29 19:27:05 -0400150 if (ns->proc_self)
151 dput(ns->proc_self);
Eric W. Biederman00978752014-07-31 03:10:50 -0700152 if (ns->proc_thread_self)
153 dput(ns->proc_thread_self);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700154 kill_anon_super(sb);
155 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156}
157
Alexey Dobriyanc2319542007-11-28 16:21:23 -0800158static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 .name = "proc",
Al Viroaed1d842010-07-26 13:12:54 +0400160 .mount = proc_mount,
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700161 .kill_sb = proc_kill_sb,
Eric W. Biederman4f326c02012-07-27 05:56:48 -0700162 .fs_flags = FS_USERNS_MOUNT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163};
164
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165void __init proc_root_init(void)
166{
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +0400167 int err;
168
169 proc_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 err = register_filesystem(&proc_fs_type);
171 if (err)
172 return;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700173
Eric W. Biedermane656d8a2010-07-10 14:52:49 -0700174 proc_self_init();
Eric W. Biederman00978752014-07-31 03:10:50 -0700175 proc_thread_self_init();
Linus Torvalds155134f2014-08-10 21:24:59 -0700176 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200177
178 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180#ifdef CONFIG_SYSVIPC
181 proc_mkdir("sysvipc", NULL);
182#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700183 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700184 proc_mkdir("driver", NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
186#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
187 /* just give it a mountpoint */
188 proc_mkdir("openprom", NULL);
189#endif
190 proc_tty_init();
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700191 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800192 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193}
194
Al Viro76b61592006-02-08 14:37:40 -0500195static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
196)
197{
198 generic_fillattr(dentry->d_inode, stat);
199 stat->nlink = proc_root.nlink + nr_processes();
200 return 0;
201}
202
Al Viro00cd8dd2012-06-10 17:13:09 -0400203static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
Alexey Dobriyan335eb532014-08-08 14:21:27 -0700205 if (!proc_pid_lookup(dir, dentry, flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
Alexey Dobriyan335eb532014-08-08 14:21:27 -0700208 return proc_lookup(dir, dentry, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209}
210
Al Virof0c3b502013-05-16 12:07:31 -0400211static int proc_root_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
Al Virof0c3b502013-05-16 12:07:31 -0400213 if (ctx->pos < FIRST_PROCESS_ENTRY) {
Richard Genoud94fc5d92013-08-19 18:30:31 +0200214 int error = proc_readdir(file, ctx);
215 if (unlikely(error <= 0))
216 return error;
Al Virof0c3b502013-05-16 12:07:31 -0400217 ctx->pos = FIRST_PROCESS_ENTRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
Al Virof0c3b502013-05-16 12:07:31 -0400220 return proc_pid_readdir(file, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221}
222
223/*
224 * The root /proc directory is special, as it has the
225 * <pid> directories. Thus we don't use the generic
226 * directory handling functions for that..
227 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800228static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 .read = generic_read_dir,
Al Virof0c3b502013-05-16 12:07:31 -0400230 .iterate = proc_root_readdir,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200231 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232};
233
234/*
235 * proc root can do almost nothing..
236 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800237static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500239 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240};
241
242/*
243 * This is the root "inode" in the /proc tree..
244 */
245struct proc_dir_entry proc_root = {
246 .low_ino = PROC_ROOT_INO,
247 .namelen = 5,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
249 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800250 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 .proc_iops = &proc_root_inode_operations,
252 .proc_fops = &proc_root_operations,
253 .parent = &proc_root,
Nicolas Dichtel710585d2014-12-10 15:45:01 -0800254 .subdir = RB_ROOT,
David Howells09570f92011-07-27 21:47:03 +0300255 .name = "/proc",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256};
257
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700258int pid_ns_prepare_proc(struct pid_namespace *ns)
259{
260 struct vfsmount *mnt;
261
262 mnt = kern_mount_data(&proc_fs_type, ns);
263 if (IS_ERR(mnt))
264 return PTR_ERR(mnt);
265
Al Viro579441a2010-07-26 13:09:36 +0400266 ns->proc_mnt = mnt;
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700267 return 0;
268}
269
270void pid_ns_release_proc(struct pid_namespace *ns)
271{
Al Viro905ad262011-12-08 23:20:45 -0500272 kern_unmount(ns->proc_mnt);
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700273}