blob: e16fb8f2049e76dafdd533158fa534dc321d6dbc [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Al Viro0226f492011-12-06 12:21:54 -05002/*
3 * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
4 *
5 * In fact, that's a piece of procfs; it's *almost* isolated from
6 * the rest of fs/proc, but has rather close relationships with
7 * fs/namespace.c, thus here instead of fs/proc
8 *
9 */
10#include <linux/mnt_namespace.h>
11#include <linux/nsproxy.h>
12#include <linux/security.h>
13#include <linux/fs_struct.h>
Ingo Molnarf719ff9b2017-02-06 10:57:33 +010014#include <linux/sched/task.h>
15
Al Viro0226f492011-12-06 12:21:54 -050016#include "proc/internal.h" /* only for get_proc_task() in ->open() */
17
18#include "pnode.h"
19#include "internal.h"
20
Al Viro076ccb72017-07-03 01:02:18 -040021static __poll_t mounts_poll(struct file *file, poll_table *wait)
Al Viro0226f492011-12-06 12:21:54 -050022{
Yann Droneaudede1bf02015-06-30 14:57:30 -070023 struct seq_file *m = file->private_data;
24 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -050025 struct mnt_namespace *ns = p->ns;
Linus Torvaldsa9a08842018-02-11 14:34:03 -080026 __poll_t res = EPOLLIN | EPOLLRDNORM;
Al Viroaab407f2013-09-29 10:59:59 -040027 int event;
Al Viro0226f492011-12-06 12:21:54 -050028
29 poll_wait(file, &p->ns->poll, wait);
30
Mark Rutland6aa7de02017-10-23 14:07:29 -070031 event = READ_ONCE(ns->event);
Yann Droneaudede1bf02015-06-30 14:57:30 -070032 if (m->poll_event != event) {
33 m->poll_event = event;
Linus Torvaldsa9a08842018-02-11 14:34:03 -080034 res |= EPOLLERR | EPOLLPRI;
Al Viro0226f492011-12-06 12:21:54 -050035 }
Al Viro0226f492011-12-06 12:21:54 -050036
37 return res;
38}
39
40struct proc_fs_info {
41 int flag;
42 const char *str;
43};
44
45static int show_sb_opts(struct seq_file *m, struct super_block *sb)
46{
47 static const struct proc_fs_info fs_info[] = {
Linus Torvalds1751e8a2017-11-27 13:05:09 -080048 { SB_SYNCHRONOUS, ",sync" },
49 { SB_DIRSYNC, ",dirsync" },
50 { SB_MANDLOCK, ",mand" },
51 { SB_LAZYTIME, ",lazytime" },
Al Viro0226f492011-12-06 12:21:54 -050052 { 0, NULL }
53 };
54 const struct proc_fs_info *fs_infop;
55
56 for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
57 if (sb->s_flags & fs_infop->flag)
58 seq_puts(m, fs_infop->str);
59 }
60
61 return security_sb_show_options(m, sb);
62}
63
64static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
65{
66 static const struct proc_fs_info mnt_info[] = {
67 { MNT_NOSUID, ",nosuid" },
68 { MNT_NODEV, ",nodev" },
69 { MNT_NOEXEC, ",noexec" },
70 { MNT_NOATIME, ",noatime" },
71 { MNT_NODIRATIME, ",nodiratime" },
72 { MNT_RELATIME, ",relatime" },
73 { 0, NULL }
74 };
75 const struct proc_fs_info *fs_infop;
76
77 for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
78 if (mnt->mnt_flags & fs_infop->flag)
79 seq_puts(m, fs_infop->str);
80 }
81}
82
83static inline void mangle(struct seq_file *m, const char *s)
84{
85 seq_escape(m, s, " \t\n\\");
86}
87
88static void show_type(struct seq_file *m, struct super_block *sb)
89{
90 mangle(m, sb->s_type->name);
91 if (sb->s_subtype && sb->s_subtype[0]) {
92 seq_putc(m, '.');
93 mangle(m, sb->s_subtype);
94 }
95}
96
97static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
98{
Yann Droneaudede1bf02015-06-30 14:57:30 -070099 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500100 struct mount *r = real_mount(mnt);
Al Viro0226f492011-12-06 12:21:54 -0500101 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Virod861c632011-12-08 21:32:45 -0500102 struct super_block *sb = mnt_path.dentry->d_sb;
Dmitry V. Levin5d9f3c72015-11-19 00:57:52 +0300103 int err;
Al Viro0226f492011-12-06 12:21:54 -0500104
Al Virod861c632011-12-08 21:32:45 -0500105 if (sb->s_op->show_devname) {
106 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500107 if (err)
108 goto out;
109 } else {
110 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
111 }
112 seq_putc(m, ' ');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300113 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
114 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
115 if (err)
116 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500117 seq_putc(m, ' ');
Al Virod861c632011-12-08 21:32:45 -0500118 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500119 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
Al Virod861c632011-12-08 21:32:45 -0500120 err = show_sb_opts(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500121 if (err)
122 goto out;
123 show_mnt_opts(m, mnt);
Al Virod861c632011-12-08 21:32:45 -0500124 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500125 err = sb->s_op->show_options(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500126 seq_puts(m, " 0 0\n");
127out:
128 return err;
129}
130
131static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
132{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700133 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500134 struct mount *r = real_mount(mnt);
135 struct super_block *sb = mnt->mnt_sb;
136 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300137 int err;
Al Viro0226f492011-12-06 12:21:54 -0500138
139 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
140 MAJOR(sb->s_dev), MINOR(sb->s_dev));
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300141 if (sb->s_op->show_path) {
Al Viroa6322de2011-12-08 21:37:57 -0500142 err = sb->s_op->show_path(m, mnt->mnt_root);
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300143 if (err)
144 goto out;
145 } else {
Al Viro0226f492011-12-06 12:21:54 -0500146 seq_dentry(m, mnt->mnt_root, " \t\n\\");
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300147 }
Al Viro0226f492011-12-06 12:21:54 -0500148 seq_putc(m, ' ');
149
150 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
Dmitry V. Levin9ad4dc42012-10-17 20:29:36 +0400151 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
Al Viro0226f492011-12-06 12:21:54 -0500152 if (err)
153 goto out;
154
155 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
156 show_mnt_opts(m, mnt);
157
158 /* Tagged fields ("foo:X" or "bar") */
159 if (IS_MNT_SHARED(r))
160 seq_printf(m, " shared:%i", r->mnt_group_id);
161 if (IS_MNT_SLAVE(r)) {
162 int master = r->mnt_master->mnt_group_id;
163 int dom = get_dominating_id(r, &p->root);
164 seq_printf(m, " master:%i", master);
165 if (dom && dom != master)
166 seq_printf(m, " propagate_from:%i", dom);
167 }
168 if (IS_MNT_UNBINDABLE(r))
169 seq_puts(m, " unbindable");
170
171 /* Filesystem specific data */
172 seq_puts(m, " - ");
173 show_type(m, sb);
174 seq_putc(m, ' ');
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300175 if (sb->s_op->show_devname) {
Al Virod861c632011-12-08 21:32:45 -0500176 err = sb->s_op->show_devname(m, mnt->mnt_root);
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300177 if (err)
178 goto out;
179 } else {
Al Viro0226f492011-12-06 12:21:54 -0500180 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300181 }
David Howellsbc98a422017-07-17 08:45:34 +0100182 seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
Al Viro0226f492011-12-06 12:21:54 -0500183 err = show_sb_opts(m, sb);
184 if (err)
185 goto out;
186 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500187 err = sb->s_op->show_options(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500188 seq_putc(m, '\n');
189out:
190 return err;
191}
192
193static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
194{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700195 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500196 struct mount *r = real_mount(mnt);
197 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro64132372011-12-08 20:51:13 -0500198 struct super_block *sb = mnt_path.dentry->d_sb;
Dmitry V. Levinb896fb32015-11-19 00:58:32 +0300199 int err;
Al Viro0226f492011-12-06 12:21:54 -0500200
201 /* device */
Al Viro64132372011-12-08 20:51:13 -0500202 if (sb->s_op->show_devname) {
Al Viro0226f492011-12-06 12:21:54 -0500203 seq_puts(m, "device ");
Al Virod861c632011-12-08 21:32:45 -0500204 err = sb->s_op->show_devname(m, mnt_path.dentry);
Dmitry V. Levin5f8d4982015-03-19 11:10:54 +0000205 if (err)
206 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500207 } else {
208 if (r->mnt_devname) {
209 seq_puts(m, "device ");
210 mangle(m, r->mnt_devname);
211 } else
212 seq_puts(m, "no device");
213 }
214
215 /* mount point */
216 seq_puts(m, " mounted on ");
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300217 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
218 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
219 if (err)
220 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500221 seq_putc(m, ' ');
222
223 /* file system type */
224 seq_puts(m, "with fstype ");
Al Viro64132372011-12-08 20:51:13 -0500225 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500226
227 /* optional statistics */
Al Viro64132372011-12-08 20:51:13 -0500228 if (sb->s_op->show_stats) {
Al Viro0226f492011-12-06 12:21:54 -0500229 seq_putc(m, ' ');
Dmitry V. Levinb896fb32015-11-19 00:58:32 +0300230 err = sb->s_op->show_stats(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500231 }
232
233 seq_putc(m, '\n');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300234out:
Al Viro0226f492011-12-06 12:21:54 -0500235 return err;
236}
237
238static int mounts_open_common(struct inode *inode, struct file *file,
239 int (*show)(struct seq_file *, struct vfsmount *))
240{
241 struct task_struct *task = get_proc_task(inode);
242 struct nsproxy *nsp;
243 struct mnt_namespace *ns = NULL;
244 struct path root;
245 struct proc_mounts *p;
Yann Droneaudede1bf02015-06-30 14:57:30 -0700246 struct seq_file *m;
Al Viro0226f492011-12-06 12:21:54 -0500247 int ret = -EINVAL;
248
249 if (!task)
250 goto err;
251
Eric W. Biederman728dba32014-02-03 19:13:49 -0800252 task_lock(task);
253 nsp = task->nsproxy;
Axel Lin3d931162014-01-23 15:55:44 -0800254 if (!nsp || !nsp->mnt_ns) {
Eric W. Biederman728dba32014-02-03 19:13:49 -0800255 task_unlock(task);
Al Viro0226f492011-12-06 12:21:54 -0500256 put_task_struct(task);
257 goto err;
258 }
259 ns = nsp->mnt_ns;
Al Viro0226f492011-12-06 12:21:54 -0500260 get_mnt_ns(ns);
Al Viro0226f492011-12-06 12:21:54 -0500261 if (!task->fs) {
262 task_unlock(task);
263 put_task_struct(task);
264 ret = -ENOENT;
265 goto err_put_ns;
266 }
267 get_fs_root(task->fs, &root);
268 task_unlock(task);
269 put_task_struct(task);
270
Yann Droneaudede1bf02015-06-30 14:57:30 -0700271 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
272 if (ret)
Al Viro0226f492011-12-06 12:21:54 -0500273 goto err_put_path;
274
Yann Droneaudede1bf02015-06-30 14:57:30 -0700275 m = file->private_data;
276 m->poll_event = ns->event;
Al Viro0226f492011-12-06 12:21:54 -0500277
Yann Droneaudede1bf02015-06-30 14:57:30 -0700278 p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500279 p->ns = ns;
280 p->root = root;
Al Viro0226f492011-12-06 12:21:54 -0500281 p->show = show;
Al Viroc7999c32014-02-27 14:40:10 -0500282 p->cached_event = ~0ULL;
Al Viro0226f492011-12-06 12:21:54 -0500283
284 return 0;
285
Al Viro0226f492011-12-06 12:21:54 -0500286 err_put_path:
287 path_put(&root);
288 err_put_ns:
289 put_mnt_ns(ns);
290 err:
291 return ret;
292}
293
294static int mounts_release(struct inode *inode, struct file *file)
295{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700296 struct seq_file *m = file->private_data;
297 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500298 path_put(&p->root);
299 put_mnt_ns(p->ns);
Yann Droneaudede1bf02015-06-30 14:57:30 -0700300 return seq_release_private(inode, file);
Al Viro0226f492011-12-06 12:21:54 -0500301}
302
303static int mounts_open(struct inode *inode, struct file *file)
304{
305 return mounts_open_common(inode, file, show_vfsmnt);
306}
307
308static int mountinfo_open(struct inode *inode, struct file *file)
309{
310 return mounts_open_common(inode, file, show_mountinfo);
311}
312
313static int mountstats_open(struct inode *inode, struct file *file)
314{
315 return mounts_open_common(inode, file, show_vfsstat);
316}
317
318const struct file_operations proc_mounts_operations = {
319 .open = mounts_open,
320 .read = seq_read,
321 .llseek = seq_lseek,
322 .release = mounts_release,
323 .poll = mounts_poll,
324};
325
326const struct file_operations proc_mountinfo_operations = {
327 .open = mountinfo_open,
328 .read = seq_read,
329 .llseek = seq_lseek,
330 .release = mounts_release,
331 .poll = mounts_poll,
332};
333
334const struct file_operations proc_mountstats_operations = {
335 .open = mountstats_open,
336 .read = seq_read,
337 .llseek = seq_lseek,
338 .release = mounts_release,
339};