Merge tag 'drm-next-2024-05-25' of https://gitlab.freedesktop.org/drm/kernel
[linux-block.git] / fs / proc_namespace.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
0226f492
AV
2/*
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>
f719ff9b
IM
14#include <linux/sched/task.h>
15
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AV
16#include "proc/internal.h" /* only for get_proc_task() in ->open() */
17
18#include "pnode.h"
19#include "internal.h"
20
076ccb76 21static __poll_t mounts_poll(struct file *file, poll_table *wait)
0226f492 22{
ede1bf0d
YD
23 struct seq_file *m = file->private_data;
24 struct proc_mounts *p = m->private;
0226f492 25 struct mnt_namespace *ns = p->ns;
a9a08845 26 __poll_t res = EPOLLIN | EPOLLRDNORM;
aab407fc 27 int event;
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AV
28
29 poll_wait(file, &p->ns->poll, wait);
30
6aa7de05 31 event = READ_ONCE(ns->event);
ede1bf0d
YD
32 if (m->poll_event != event) {
33 m->poll_event = event;
a9a08845 34 res |= EPOLLERR | EPOLLPRI;
0226f492 35 }
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AV
36
37 return res;
38}
39
1e88c420 40struct proc_fs_opts {
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AV
41 int flag;
42 const char *str;
43};
44
45static int show_sb_opts(struct seq_file *m, struct super_block *sb)
46{
1e88c420 47 static const struct proc_fs_opts fs_opts[] = {
1751e8a6
LT
48 { SB_SYNCHRONOUS, ",sync" },
49 { SB_DIRSYNC, ",dirsync" },
50 { SB_MANDLOCK, ",mand" },
51 { SB_LAZYTIME, ",lazytime" },
0226f492
AV
52 { 0, NULL }
53 };
1e88c420 54 const struct proc_fs_opts *fs_infop;
0226f492 55
1e88c420 56 for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
0226f492
AV
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{
1e88c420 66 static const struct proc_fs_opts mnt_opts[] = {
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AV
67 { MNT_NOSUID, ",nosuid" },
68 { MNT_NODEV, ",nodev" },
69 { MNT_NOEXEC, ",noexec" },
70 { MNT_NOATIME, ",noatime" },
71 { MNT_NODIRATIME, ",nodiratime" },
72 { MNT_RELATIME, ",relatime" },
dab741e0 73 { MNT_NOSYMFOLLOW, ",nosymfollow" },
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AV
74 { 0, NULL }
75 };
1e88c420 76 const struct proc_fs_opts *fs_infop;
0226f492 77
1e88c420 78 for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
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AV
79 if (mnt->mnt_flags & fs_infop->flag)
80 seq_puts(m, fs_infop->str);
81 }
9caccd41 82
bb49e9e7 83 if (is_idmapped_mnt(mnt))
9caccd41 84 seq_puts(m, ",idmapped");
0226f492
AV
85}
86
87static inline void mangle(struct seq_file *m, const char *s)
88{
ed5fce76 89 seq_escape(m, s, " \t\n\\#");
0226f492
AV
90}
91
92static void show_type(struct seq_file *m, struct super_block *sb)
93{
94 mangle(m, sb->s_type->name);
c7eb6869 95 if (sb->s_subtype) {
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AV
96 seq_putc(m, '.');
97 mangle(m, sb->s_subtype);
98 }
99}
100
101static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
102{
ede1bf0d 103 struct proc_mounts *p = m->private;
0226f492 104 struct mount *r = real_mount(mnt);
0226f492 105 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
d861c630 106 struct super_block *sb = mnt_path.dentry->d_sb;
5d9f3c7b 107 int err;
0226f492 108
d861c630
AV
109 if (sb->s_op->show_devname) {
110 err = sb->s_op->show_devname(m, mnt_path.dentry);
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AV
111 if (err)
112 goto out;
113 } else {
114 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
115 }
116 seq_putc(m, ' ');
9d4d6574
DL
117 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
118 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
119 if (err)
120 goto out;
0226f492 121 seq_putc(m, ' ');
d861c630 122 show_type(m, sb);
0226f492 123 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
d861c630 124 err = show_sb_opts(m, sb);
0226f492
AV
125 if (err)
126 goto out;
127 show_mnt_opts(m, mnt);
d861c630 128 if (sb->s_op->show_options)
34c80b1d 129 err = sb->s_op->show_options(m, mnt_path.dentry);
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AV
130 seq_puts(m, " 0 0\n");
131out:
132 return err;
133}
134
135static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
136{
ede1bf0d 137 struct proc_mounts *p = m->private;
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AV
138 struct mount *r = real_mount(mnt);
139 struct super_block *sb = mnt->mnt_sb;
140 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
6ce4bca0 141 int err;
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AV
142
143 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
144 MAJOR(sb->s_dev), MINOR(sb->s_dev));
56c94c62
MS
145 err = show_path(m, mnt->mnt_root);
146 if (err)
147 goto out;
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AV
148 seq_putc(m, ' ');
149
150 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
9ad4dc4f 151 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
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AV
152 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, ' ');
6ce4bca0 175 if (sb->s_op->show_devname) {
d861c630 176 err = sb->s_op->show_devname(m, mnt->mnt_root);
6ce4bca0
DL
177 if (err)
178 goto out;
179 } else {
0226f492 180 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
6ce4bca0 181 }
bc98a42c 182 seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
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AV
183 err = show_sb_opts(m, sb);
184 if (err)
185 goto out;
186 if (sb->s_op->show_options)
34c80b1d 187 err = sb->s_op->show_options(m, mnt->mnt_root);
0226f492
AV
188 seq_putc(m, '\n');
189out:
190 return err;
191}
192
193static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
194{
ede1bf0d 195 struct proc_mounts *p = m->private;
0226f492
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196 struct mount *r = real_mount(mnt);
197 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
64132379 198 struct super_block *sb = mnt_path.dentry->d_sb;
b896fb35 199 int err;
0226f492
AV
200
201 /* device */
64132379 202 if (sb->s_op->show_devname) {
0226f492 203 seq_puts(m, "device ");
d861c630 204 err = sb->s_op->show_devname(m, mnt_path.dentry);
5f8d498d
DL
205 if (err)
206 goto out;
0226f492
AV
207 } 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 ");
9d4d6574
DL
217 /* 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;
0226f492
AV
221 seq_putc(m, ' ');
222
223 /* file system type */
224 seq_puts(m, "with fstype ");
64132379 225 show_type(m, sb);
0226f492
AV
226
227 /* optional statistics */
64132379 228 if (sb->s_op->show_stats) {
0226f492 229 seq_putc(m, ' ');
b896fb35 230 err = sb->s_op->show_stats(m, mnt_path.dentry);
0226f492
AV
231 }
232
233 seq_putc(m, '\n');
9d4d6574 234out:
0226f492
AV
235 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;
ede1bf0d 246 struct seq_file *m;
0226f492
AV
247 int ret = -EINVAL;
248
249 if (!task)
250 goto err;
251
728dba3a
EB
252 task_lock(task);
253 nsp = task->nsproxy;
3d93116c 254 if (!nsp || !nsp->mnt_ns) {
728dba3a 255 task_unlock(task);
0226f492
AV
256 put_task_struct(task);
257 goto err;
258 }
259 ns = nsp->mnt_ns;
0226f492 260 get_mnt_ns(ns);
0226f492
AV
261 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
ede1bf0d
YD
271 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
272 if (ret)
0226f492
AV
273 goto err_put_path;
274
ede1bf0d
YD
275 m = file->private_data;
276 m->poll_event = ns->event;
0226f492 277
ede1bf0d 278 p = m->private;
0226f492
AV
279 p->ns = ns;
280 p->root = root;
0226f492
AV
281 p->show = show;
282
283 return 0;
284
0226f492
AV
285 err_put_path:
286 path_put(&root);
287 err_put_ns:
288 put_mnt_ns(ns);
289 err:
290 return ret;
291}
292
293static int mounts_release(struct inode *inode, struct file *file)
294{
ede1bf0d
YD
295 struct seq_file *m = file->private_data;
296 struct proc_mounts *p = m->private;
0226f492
AV
297 path_put(&p->root);
298 put_mnt_ns(p->ns);
ede1bf0d 299 return seq_release_private(inode, file);
0226f492
AV
300}
301
302static int mounts_open(struct inode *inode, struct file *file)
303{
304 return mounts_open_common(inode, file, show_vfsmnt);
305}
306
307static int mountinfo_open(struct inode *inode, struct file *file)
308{
309 return mounts_open_common(inode, file, show_mountinfo);
310}
311
312static int mountstats_open(struct inode *inode, struct file *file)
313{
314 return mounts_open_common(inode, file, show_vfsstat);
315}
316
317const struct file_operations proc_mounts_operations = {
318 .open = mounts_open,
14e3e989 319 .read_iter = seq_read_iter,
b0072734 320 .splice_read = copy_splice_read,
0226f492
AV
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,
14e3e989 328 .read_iter = seq_read_iter,
b0072734 329 .splice_read = copy_splice_read,
0226f492
AV
330 .llseek = seq_lseek,
331 .release = mounts_release,
332 .poll = mounts_poll,
333};
334
335const struct file_operations proc_mountstats_operations = {
336 .open = mountstats_open,
14e3e989 337 .read_iter = seq_read_iter,
b0072734 338 .splice_read = copy_splice_read,
0226f492
AV
339 .llseek = seq_lseek,
340 .release = mounts_release,
341};