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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 | ||
076ccb76 | 21 | static __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; |
0226f492 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 | } |
0226f492 AV |
36 | |
37 | return res; | |
38 | } | |
39 | ||
1e88c420 | 40 | struct proc_fs_opts { |
0226f492 AV |
41 | int flag; |
42 | const char *str; | |
43 | }; | |
44 | ||
45 | static 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 | ||
64 | static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) | |
65 | { | |
1e88c420 | 66 | static const struct proc_fs_opts mnt_opts[] = { |
0226f492 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" }, | |
73 | { 0, NULL } | |
74 | }; | |
1e88c420 | 75 | const struct proc_fs_opts *fs_infop; |
0226f492 | 76 | |
1e88c420 | 77 | for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) { |
0226f492 AV |
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); | |
c7eb6869 | 91 | if (sb->s_subtype) { |
0226f492 AV |
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); | |
d861c630 | 124 | if (sb->s_op->show_options) |
34c80b1d | 125 | err = sb->s_op->show_options(m, mnt_path.dentry); |
0226f492 AV |
126 | seq_puts(m, " 0 0\n"); |
127 | out: | |
128 | return err; | |
129 | } | |
130 | ||
131 | static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt) | |
132 | { | |
ede1bf0d | 133 | struct proc_mounts *p = m->private; |
0226f492 AV |
134 | 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 }; | |
6ce4bca0 | 137 | int err; |
0226f492 AV |
138 | |
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)); | |
6ce4bca0 | 141 | if (sb->s_op->show_path) { |
a6322de6 | 142 | err = sb->s_op->show_path(m, mnt->mnt_root); |
6ce4bca0 DL |
143 | if (err) |
144 | goto out; | |
145 | } else { | |
0226f492 | 146 | seq_dentry(m, mnt->mnt_root, " \t\n\\"); |
6ce4bca0 | 147 | } |
0226f492 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\\"); |
0226f492 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"); |
0226f492 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'); |
189 | out: | |
190 | return err; | |
191 | } | |
192 | ||
193 | static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) | |
194 | { | |
ede1bf0d | 195 | struct proc_mounts *p = m->private; |
0226f492 AV |
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 | 234 | out: |
0226f492 AV |
235 | return err; |
236 | } | |
237 | ||
238 | static 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 | 281 | p->show = show; |
9f6c61f9 MS |
282 | INIT_LIST_HEAD(&p->cursor.mnt_list); |
283 | p->cursor.mnt.mnt_flags = MNT_CURSOR; | |
0226f492 AV |
284 | |
285 | return 0; | |
286 | ||
0226f492 AV |
287 | err_put_path: |
288 | path_put(&root); | |
289 | err_put_ns: | |
290 | put_mnt_ns(ns); | |
291 | err: | |
292 | return ret; | |
293 | } | |
294 | ||
295 | static int mounts_release(struct inode *inode, struct file *file) | |
296 | { | |
ede1bf0d YD |
297 | struct seq_file *m = file->private_data; |
298 | struct proc_mounts *p = m->private; | |
0226f492 | 299 | path_put(&p->root); |
9f6c61f9 | 300 | mnt_cursor_del(p->ns, &p->cursor); |
0226f492 | 301 | put_mnt_ns(p->ns); |
ede1bf0d | 302 | return seq_release_private(inode, file); |
0226f492 AV |
303 | } |
304 | ||
305 | static int mounts_open(struct inode *inode, struct file *file) | |
306 | { | |
307 | return mounts_open_common(inode, file, show_vfsmnt); | |
308 | } | |
309 | ||
310 | static int mountinfo_open(struct inode *inode, struct file *file) | |
311 | { | |
312 | return mounts_open_common(inode, file, show_mountinfo); | |
313 | } | |
314 | ||
315 | static int mountstats_open(struct inode *inode, struct file *file) | |
316 | { | |
317 | return mounts_open_common(inode, file, show_vfsstat); | |
318 | } | |
319 | ||
320 | const struct file_operations proc_mounts_operations = { | |
321 | .open = mounts_open, | |
322 | .read = seq_read, | |
323 | .llseek = seq_lseek, | |
324 | .release = mounts_release, | |
325 | .poll = mounts_poll, | |
326 | }; | |
327 | ||
328 | const struct file_operations proc_mountinfo_operations = { | |
329 | .open = mountinfo_open, | |
330 | .read = seq_read, | |
331 | .llseek = seq_lseek, | |
332 | .release = mounts_release, | |
333 | .poll = mounts_poll, | |
334 | }; | |
335 | ||
336 | const struct file_operations proc_mountstats_operations = { | |
337 | .open = mountstats_open, | |
338 | .read = seq_read, | |
339 | .llseek = seq_lseek, | |
340 | .release = mounts_release, | |
341 | }; |