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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/proc/root.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * proc root directory handling functions
8 */
9
10#include <linux/uaccess.h>
11
12#include <linux/errno.h>
13#include <linux/time.h>
14#include <linux/proc_fs.h>
15#include <linux/stat.h>
16#include <linux/init.h>
17#include <linux/sched.h>
18#include <linux/sched/stat.h>
19#include <linux/module.h>
20#include <linux/bitops.h>
21#include <linux/user_namespace.h>
22#include <linux/mount.h>
23#include <linux/pid_namespace.h>
24#include <linux/parser.h>
25#include <linux/cred.h>
26
27#include "internal.h"
28
29enum {
30 Opt_gid, Opt_hidepid, Opt_err,
31};
32
33static const match_table_t tokens = {
34 {Opt_hidepid, "hidepid=%u"},
35 {Opt_gid, "gid=%u"},
36 {Opt_err, NULL},
37};
38
39int proc_parse_options(char *options, struct pid_namespace *pid)
40{
41 char *p;
42 substring_t args[MAX_OPT_ARGS];
43 int option;
44
45 if (!options)
46 return 1;
47
48 while ((p = strsep(&options, ",")) != NULL) {
49 int token;
50 if (!*p)
51 continue;
52
53 args[0].to = args[0].from = NULL;
54 token = match_token(p, tokens, args);
55 switch (token) {
56 case Opt_gid:
57 if (match_int(&args[0], &option))
58 return 0;
59 pid->pid_gid = make_kgid(current_user_ns(), option);
60 break;
61 case Opt_hidepid:
62 if (match_int(&args[0], &option))
63 return 0;
64 if (option < HIDEPID_OFF ||
65 option > HIDEPID_INVISIBLE) {
66 pr_err("proc: hidepid value must be between 0 and 2.\n");
67 return 0;
68 }
69 pid->hide_pid = option;
70 break;
71 default:
72 pr_err("proc: unrecognized mount option \"%s\" "
73 "or missing value\n", p);
74 return 0;
75 }
76 }
77
78 return 1;
79}
80
81int proc_remount(struct super_block *sb, int *flags, char *data)
82{
83 struct pid_namespace *pid = sb->s_fs_info;
84
85 sync_filesystem(sb);
86 return !proc_parse_options(data, pid);
87}
88
89static struct dentry *proc_mount(struct file_system_type *fs_type,
90 int flags, const char *dev_name, void *data)
91{
92 struct pid_namespace *ns;
93
94 if (flags & SB_KERNMOUNT) {
95 ns = data;
96 data = NULL;
97 } else {
98 ns = task_active_pid_ns(current);
99 }
100
101 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
102}
103
104static void proc_kill_sb(struct super_block *sb)
105{
106 struct pid_namespace *ns;
107
108 ns = (struct pid_namespace *)sb->s_fs_info;
109 if (ns->proc_self)
110 dput(ns->proc_self);
111 if (ns->proc_thread_self)
112 dput(ns->proc_thread_self);
113 kill_anon_super(sb);
114 put_pid_ns(ns);
115}
116
117static struct file_system_type proc_fs_type = {
118 .name = "proc",
119 .mount = proc_mount,
120 .kill_sb = proc_kill_sb,
121 .fs_flags = FS_USERNS_MOUNT,
122};
123
124void __init proc_root_init(void)
125{
126 proc_init_kmemcache();
127 set_proc_pid_nlink();
128 proc_self_init();
129 proc_thread_self_init();
130 proc_symlink("mounts", NULL, "self/mounts");
131
132 proc_net_init();
133 proc_mkdir("fs", NULL);
134 proc_mkdir("driver", NULL);
135 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
136#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
137 /* just give it a mountpoint */
138 proc_create_mount_point("openprom");
139#endif
140 proc_tty_init();
141 proc_mkdir("bus", NULL);
142 proc_sys_init();
143
144 register_filesystem(&proc_fs_type);
145}
146
147static int proc_root_getattr(const struct path *path, struct kstat *stat,
148 u32 request_mask, unsigned int query_flags)
149{
150 generic_fillattr(d_inode(path->dentry), stat);
151 stat->nlink = proc_root.nlink + nr_processes();
152 return 0;
153}
154
155static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
156{
157 if (!proc_pid_lookup(dir, dentry, flags))
158 return NULL;
159
160 return proc_lookup(dir, dentry, flags);
161}
162
163static int proc_root_readdir(struct file *file, struct dir_context *ctx)
164{
165 if (ctx->pos < FIRST_PROCESS_ENTRY) {
166 int error = proc_readdir(file, ctx);
167 if (unlikely(error <= 0))
168 return error;
169 ctx->pos = FIRST_PROCESS_ENTRY;
170 }
171
172 return proc_pid_readdir(file, ctx);
173}
174
175/*
176 * The root /proc directory is special, as it has the
177 * <pid> directories. Thus we don't use the generic
178 * directory handling functions for that..
179 */
180static const struct file_operations proc_root_operations = {
181 .read = generic_read_dir,
182 .iterate_shared = proc_root_readdir,
183 .llseek = generic_file_llseek,
184};
185
186/*
187 * proc root can do almost nothing..
188 */
189static const struct inode_operations proc_root_inode_operations = {
190 .lookup = proc_root_lookup,
191 .getattr = proc_root_getattr,
192};
193
194/*
195 * This is the root "inode" in the /proc tree..
196 */
197struct proc_dir_entry proc_root = {
198 .low_ino = PROC_ROOT_INO,
199 .namelen = 5,
200 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
201 .nlink = 2,
202 .refcnt = REFCOUNT_INIT(1),
203 .proc_iops = &proc_root_inode_operations,
204 .proc_fops = &proc_root_operations,
205 .parent = &proc_root,
206 .subdir = RB_ROOT,
207 .name = proc_root.inline_name,
208 .inline_name = "/proc",
209};
210
211int pid_ns_prepare_proc(struct pid_namespace *ns)
212{
213 struct vfsmount *mnt;
214
215 mnt = kern_mount_data(&proc_fs_type, ns);
216 if (IS_ERR(mnt))
217 return PTR_ERR(mnt);
218
219 ns->proc_mnt = mnt;
220 return 0;
221}
222
223void pid_ns_release_proc(struct pid_namespace *ns)
224{
225 kern_unmount(ns->proc_mnt);
226}
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}