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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 <linux/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
26enum {
27 Opt_gid, Opt_hidepid, Opt_err,
28};
29
30static const match_table_t tokens = {
31 {Opt_hidepid, "hidepid=%u"},
32 {Opt_gid, "gid=%u"},
33 {Opt_err, NULL},
34};
35
36int proc_parse_options(char *options, struct pid_namespace *pid)
37{
38 char *p;
39 substring_t args[MAX_OPT_ARGS];
40 int option;
41
42 if (!options)
43 return 1;
44
45 while ((p = strsep(&options, ",")) != NULL) {
46 int token;
47 if (!*p)
48 continue;
49
50 args[0].to = args[0].from = NULL;
51 token = match_token(p, tokens, args);
52 switch (token) {
53 case Opt_gid:
54 if (match_int(&args[0], &option))
55 return 0;
56 pid->pid_gid = make_kgid(current_user_ns(), option);
57 break;
58 case Opt_hidepid:
59 if (match_int(&args[0], &option))
60 return 0;
61 if (option < 0 || option > 2) {
62 pr_err("proc: hidepid value must be between 0 and 2.\n");
63 return 0;
64 }
65 pid->hide_pid = option;
66 break;
67 default:
68 pr_err("proc: unrecognized mount option \"%s\" "
69 "or missing value\n", p);
70 return 0;
71 }
72 }
73
74 return 1;
75}
76
77int proc_remount(struct super_block *sb, int *flags, char *data)
78{
79 struct pid_namespace *pid = sb->s_fs_info;
80
81 sync_filesystem(sb);
82 return !proc_parse_options(data, pid);
83}
84
85static struct dentry *proc_mount(struct file_system_type *fs_type,
86 int flags, const char *dev_name, void *data)
87{
88 struct pid_namespace *ns;
89
90 if (flags & MS_KERNMOUNT) {
91 ns = data;
92 data = NULL;
93 } else {
94 ns = task_active_pid_ns(current);
95 }
96
97 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
98}
99
100static void proc_kill_sb(struct super_block *sb)
101{
102 struct pid_namespace *ns;
103
104 ns = (struct pid_namespace *)sb->s_fs_info;
105 if (ns->proc_self)
106 dput(ns->proc_self);
107 if (ns->proc_thread_self)
108 dput(ns->proc_thread_self);
109 kill_anon_super(sb);
110 put_pid_ns(ns);
111}
112
113static struct file_system_type proc_fs_type = {
114 .name = "proc",
115 .mount = proc_mount,
116 .kill_sb = proc_kill_sb,
117 .fs_flags = FS_USERNS_MOUNT,
118};
119
120void __init proc_root_init(void)
121{
122 int err;
123
124 proc_init_inodecache();
125 set_proc_pid_nlink();
126 err = register_filesystem(&proc_fs_type);
127 if (err)
128 return;
129
130 proc_self_init();
131 proc_thread_self_init();
132 proc_symlink("mounts", NULL, "self/mounts");
133
134 proc_net_init();
135
136#ifdef CONFIG_SYSVIPC
137 proc_mkdir("sysvipc", NULL);
138#endif
139 proc_mkdir("fs", NULL);
140 proc_mkdir("driver", NULL);
141 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
142#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
143 /* just give it a mountpoint */
144 proc_create_mount_point("openprom");
145#endif
146 proc_tty_init();
147 proc_mkdir("bus", NULL);
148 proc_sys_init();
149}
150
151static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
152)
153{
154 generic_fillattr(d_inode(dentry), stat);
155 stat->nlink = proc_root.nlink + nr_processes();
156 return 0;
157}
158
159static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
160{
161 if (!proc_pid_lookup(dir, dentry, flags))
162 return NULL;
163
164 return proc_lookup(dir, dentry, flags);
165}
166
167static int proc_root_readdir(struct file *file, struct dir_context *ctx)
168{
169 if (ctx->pos < FIRST_PROCESS_ENTRY) {
170 int error = proc_readdir(file, ctx);
171 if (unlikely(error <= 0))
172 return error;
173 ctx->pos = FIRST_PROCESS_ENTRY;
174 }
175
176 return proc_pid_readdir(file, ctx);
177}
178
179/*
180 * The root /proc directory is special, as it has the
181 * <pid> directories. Thus we don't use the generic
182 * directory handling functions for that..
183 */
184static const struct file_operations proc_root_operations = {
185 .read = generic_read_dir,
186 .iterate_shared = proc_root_readdir,
187 .llseek = generic_file_llseek,
188};
189
190/*
191 * proc root can do almost nothing..
192 */
193static const struct inode_operations proc_root_inode_operations = {
194 .lookup = proc_root_lookup,
195 .getattr = proc_root_getattr,
196};
197
198/*
199 * This is the root "inode" in the /proc tree..
200 */
201struct proc_dir_entry proc_root = {
202 .low_ino = PROC_ROOT_INO,
203 .namelen = 5,
204 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
205 .nlink = 2,
206 .count = ATOMIC_INIT(1),
207 .proc_iops = &proc_root_inode_operations,
208 .proc_fops = &proc_root_operations,
209 .parent = &proc_root,
210 .subdir = RB_ROOT,
211 .name = "/proc",
212};
213
214int pid_ns_prepare_proc(struct pid_namespace *ns)
215{
216 struct vfsmount *mnt;
217
218 mnt = kern_mount_data(&proc_fs_type, ns);
219 if (IS_ERR(mnt))
220 return PTR_ERR(mnt);
221
222 ns->proc_mnt = mnt;
223 return 0;
224}
225
226void pid_ns_release_proc(struct pid_namespace *ns)
227{
228 kern_unmount(ns->proc_mnt);
229}