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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 | ||
0226f492 AV |
16 | #include "proc/internal.h" /* only for get_proc_task() in ->open() */ |
17 | ||
18 | #include "pnode.h" | |
19 | #include "internal.h" | |
20 | ||
21 | static unsigned mounts_poll(struct file *file, poll_table *wait) | |
22 | { | |
ede1bf0d YD |
23 | struct seq_file *m = file->private_data; |
24 | struct proc_mounts *p = m->private; | |
0226f492 AV |
25 | struct mnt_namespace *ns = p->ns; |
26 | unsigned res = POLLIN | POLLRDNORM; | |
aab407fc | 27 | int event; |
0226f492 AV |
28 | |
29 | poll_wait(file, &p->ns->poll, wait); | |
30 | ||
aab407fc | 31 | event = ACCESS_ONCE(ns->event); |
ede1bf0d YD |
32 | if (m->poll_event != event) { |
33 | m->poll_event = event; | |
0226f492 AV |
34 | res |= POLLERR | POLLPRI; |
35 | } | |
0226f492 AV |
36 | |
37 | return res; | |
38 | } | |
39 | ||
40 | struct proc_fs_info { | |
41 | int flag; | |
42 | const char *str; | |
43 | }; | |
44 | ||
45 | static int show_sb_opts(struct seq_file *m, struct super_block *sb) | |
46 | { | |
47 | static const struct proc_fs_info fs_info[] = { | |
48 | { MS_SYNCHRONOUS, ",sync" }, | |
49 | { MS_DIRSYNC, ",dirsync" }, | |
50 | { MS_MANDLOCK, ",mand" }, | |
0ae45f63 | 51 | { MS_LAZYTIME, ",lazytime" }, |
0226f492 AV |
52 | { 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 | ||
64 | static 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 | ||
83 | static inline void mangle(struct seq_file *m, const char *s) | |
84 | { | |
85 | seq_escape(m, s, " \t\n\\"); | |
86 | } | |
87 | ||
88 | static 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 | ||
97 | static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt) | |
98 | { | |
ede1bf0d | 99 | struct proc_mounts *p = m->private; |
0226f492 | 100 | struct mount *r = real_mount(mnt); |
0226f492 | 101 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
d861c630 | 102 | struct super_block *sb = mnt_path.dentry->d_sb; |
5d9f3c7b | 103 | int err; |
0226f492 | 104 | |
d861c630 AV |
105 | if (sb->s_op->show_devname) { |
106 | err = sb->s_op->show_devname(m, mnt_path.dentry); | |
0226f492 AV |
107 | if (err) |
108 | goto out; | |
109 | } else { | |
110 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); | |
111 | } | |
112 | seq_putc(m, ' '); | |
9d4d6574 DL |
113 | /* 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; | |
0226f492 | 117 | seq_putc(m, ' '); |
d861c630 | 118 | show_type(m, sb); |
0226f492 | 119 | seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); |
d861c630 | 120 | err = show_sb_opts(m, sb); |
0226f492 AV |
121 | if (err) |
122 | goto out; | |
123 | show_mnt_opts(m, mnt); | |
04e61a5b DR |
124 | if (sb->s_op->show_options2) |
125 | err = sb->s_op->show_options2(mnt, m, mnt_path.dentry); | |
126 | else if (sb->s_op->show_options) | |
34c80b1d | 127 | err = sb->s_op->show_options(m, mnt_path.dentry); |
0226f492 AV |
128 | seq_puts(m, " 0 0\n"); |
129 | out: | |
130 | return err; | |
131 | } | |
132 | ||
133 | static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt) | |
134 | { | |
ede1bf0d | 135 | struct proc_mounts *p = m->private; |
0226f492 AV |
136 | struct mount *r = real_mount(mnt); |
137 | struct super_block *sb = mnt->mnt_sb; | |
138 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; | |
6ce4bca0 | 139 | int err; |
0226f492 AV |
140 | |
141 | seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id, | |
142 | MAJOR(sb->s_dev), MINOR(sb->s_dev)); | |
6ce4bca0 | 143 | if (sb->s_op->show_path) { |
a6322de6 | 144 | err = sb->s_op->show_path(m, mnt->mnt_root); |
6ce4bca0 DL |
145 | if (err) |
146 | goto out; | |
147 | } else { | |
0226f492 | 148 | seq_dentry(m, mnt->mnt_root, " \t\n\\"); |
6ce4bca0 | 149 | } |
0226f492 AV |
150 | seq_putc(m, ' '); |
151 | ||
152 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ | |
9ad4dc4f | 153 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); |
0226f492 AV |
154 | if (err) |
155 | goto out; | |
156 | ||
157 | seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw"); | |
158 | show_mnt_opts(m, mnt); | |
159 | ||
160 | /* Tagged fields ("foo:X" or "bar") */ | |
161 | if (IS_MNT_SHARED(r)) | |
162 | seq_printf(m, " shared:%i", r->mnt_group_id); | |
163 | if (IS_MNT_SLAVE(r)) { | |
164 | int master = r->mnt_master->mnt_group_id; | |
165 | int dom = get_dominating_id(r, &p->root); | |
166 | seq_printf(m, " master:%i", master); | |
167 | if (dom && dom != master) | |
168 | seq_printf(m, " propagate_from:%i", dom); | |
169 | } | |
170 | if (IS_MNT_UNBINDABLE(r)) | |
171 | seq_puts(m, " unbindable"); | |
172 | ||
173 | /* Filesystem specific data */ | |
174 | seq_puts(m, " - "); | |
175 | show_type(m, sb); | |
176 | seq_putc(m, ' '); | |
6ce4bca0 | 177 | if (sb->s_op->show_devname) { |
d861c630 | 178 | err = sb->s_op->show_devname(m, mnt->mnt_root); |
6ce4bca0 DL |
179 | if (err) |
180 | goto out; | |
181 | } else { | |
0226f492 | 182 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
6ce4bca0 | 183 | } |
bc98a42c | 184 | seq_puts(m, sb_rdonly(sb) ? " ro" : " rw"); |
0226f492 AV |
185 | err = show_sb_opts(m, sb); |
186 | if (err) | |
187 | goto out; | |
04e61a5b DR |
188 | if (sb->s_op->show_options2) { |
189 | err = sb->s_op->show_options2(mnt, m, mnt->mnt_root); | |
190 | } else if (sb->s_op->show_options) | |
34c80b1d | 191 | err = sb->s_op->show_options(m, mnt->mnt_root); |
0226f492 AV |
192 | seq_putc(m, '\n'); |
193 | out: | |
194 | return err; | |
195 | } | |
196 | ||
197 | static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) | |
198 | { | |
ede1bf0d | 199 | struct proc_mounts *p = m->private; |
0226f492 AV |
200 | struct mount *r = real_mount(mnt); |
201 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; | |
64132379 | 202 | struct super_block *sb = mnt_path.dentry->d_sb; |
b896fb35 | 203 | int err; |
0226f492 AV |
204 | |
205 | /* device */ | |
64132379 | 206 | if (sb->s_op->show_devname) { |
0226f492 | 207 | seq_puts(m, "device "); |
d861c630 | 208 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
5f8d498d DL |
209 | if (err) |
210 | goto out; | |
0226f492 AV |
211 | } else { |
212 | if (r->mnt_devname) { | |
213 | seq_puts(m, "device "); | |
214 | mangle(m, r->mnt_devname); | |
215 | } else | |
216 | seq_puts(m, "no device"); | |
217 | } | |
218 | ||
219 | /* mount point */ | |
220 | seq_puts(m, " mounted on "); | |
9d4d6574 DL |
221 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
222 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); | |
223 | if (err) | |
224 | goto out; | |
0226f492 AV |
225 | seq_putc(m, ' '); |
226 | ||
227 | /* file system type */ | |
228 | seq_puts(m, "with fstype "); | |
64132379 | 229 | show_type(m, sb); |
0226f492 AV |
230 | |
231 | /* optional statistics */ | |
64132379 | 232 | if (sb->s_op->show_stats) { |
0226f492 | 233 | seq_putc(m, ' '); |
b896fb35 | 234 | err = sb->s_op->show_stats(m, mnt_path.dentry); |
0226f492 AV |
235 | } |
236 | ||
237 | seq_putc(m, '\n'); | |
9d4d6574 | 238 | out: |
0226f492 AV |
239 | return err; |
240 | } | |
241 | ||
242 | static int mounts_open_common(struct inode *inode, struct file *file, | |
243 | int (*show)(struct seq_file *, struct vfsmount *)) | |
244 | { | |
245 | struct task_struct *task = get_proc_task(inode); | |
246 | struct nsproxy *nsp; | |
247 | struct mnt_namespace *ns = NULL; | |
248 | struct path root; | |
249 | struct proc_mounts *p; | |
ede1bf0d | 250 | struct seq_file *m; |
0226f492 AV |
251 | int ret = -EINVAL; |
252 | ||
253 | if (!task) | |
254 | goto err; | |
255 | ||
728dba3a EB |
256 | task_lock(task); |
257 | nsp = task->nsproxy; | |
3d93116c | 258 | if (!nsp || !nsp->mnt_ns) { |
728dba3a | 259 | task_unlock(task); |
0226f492 AV |
260 | put_task_struct(task); |
261 | goto err; | |
262 | } | |
263 | ns = nsp->mnt_ns; | |
0226f492 | 264 | get_mnt_ns(ns); |
0226f492 AV |
265 | if (!task->fs) { |
266 | task_unlock(task); | |
267 | put_task_struct(task); | |
268 | ret = -ENOENT; | |
269 | goto err_put_ns; | |
270 | } | |
271 | get_fs_root(task->fs, &root); | |
272 | task_unlock(task); | |
273 | put_task_struct(task); | |
274 | ||
ede1bf0d YD |
275 | ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts)); |
276 | if (ret) | |
0226f492 AV |
277 | goto err_put_path; |
278 | ||
ede1bf0d YD |
279 | m = file->private_data; |
280 | m->poll_event = ns->event; | |
0226f492 | 281 | |
ede1bf0d | 282 | p = m->private; |
0226f492 AV |
283 | p->ns = ns; |
284 | p->root = root; | |
0226f492 | 285 | p->show = show; |
c7999c36 | 286 | p->cached_event = ~0ULL; |
0226f492 AV |
287 | |
288 | return 0; | |
289 | ||
0226f492 AV |
290 | err_put_path: |
291 | path_put(&root); | |
292 | err_put_ns: | |
293 | put_mnt_ns(ns); | |
294 | err: | |
295 | return ret; | |
296 | } | |
297 | ||
298 | static int mounts_release(struct inode *inode, struct file *file) | |
299 | { | |
ede1bf0d YD |
300 | struct seq_file *m = file->private_data; |
301 | struct proc_mounts *p = m->private; | |
0226f492 AV |
302 | path_put(&p->root); |
303 | put_mnt_ns(p->ns); | |
ede1bf0d | 304 | return seq_release_private(inode, file); |
0226f492 AV |
305 | } |
306 | ||
307 | static int mounts_open(struct inode *inode, struct file *file) | |
308 | { | |
309 | return mounts_open_common(inode, file, show_vfsmnt); | |
310 | } | |
311 | ||
312 | static int mountinfo_open(struct inode *inode, struct file *file) | |
313 | { | |
314 | return mounts_open_common(inode, file, show_mountinfo); | |
315 | } | |
316 | ||
317 | static int mountstats_open(struct inode *inode, struct file *file) | |
318 | { | |
319 | return mounts_open_common(inode, file, show_vfsstat); | |
320 | } | |
321 | ||
322 | const struct file_operations proc_mounts_operations = { | |
323 | .open = mounts_open, | |
324 | .read = seq_read, | |
325 | .llseek = seq_lseek, | |
326 | .release = mounts_release, | |
327 | .poll = mounts_poll, | |
328 | }; | |
329 | ||
330 | const struct file_operations proc_mountinfo_operations = { | |
331 | .open = mountinfo_open, | |
332 | .read = seq_read, | |
333 | .llseek = seq_lseek, | |
334 | .release = mounts_release, | |
335 | .poll = mounts_poll, | |
336 | }; | |
337 | ||
338 | const struct file_operations proc_mountstats_operations = { | |
339 | .open = mountstats_open, | |
340 | .read = seq_read, | |
341 | .llseek = seq_lseek, | |
342 | .release = mounts_release, | |
343 | }; |