Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
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>
14 : #include <linux/sched/task.h>
15 :
16 : #include "proc/internal.h" /* only for get_proc_task() in ->open() */
17 :
18 : #include "pnode.h"
19 : #include "internal.h"
20 :
21 540164 : static __poll_t mounts_poll(struct file *file, poll_table *wait)
22 : {
23 540164 : struct seq_file *m = file->private_data;
24 540164 : struct proc_mounts *p = m->private;
25 540164 : struct mnt_namespace *ns = p->ns;
26 540164 : __poll_t res = EPOLLIN | EPOLLRDNORM;
27 540164 : int event;
28 :
29 540164 : poll_wait(file, &p->ns->poll, wait);
30 :
31 541248 : event = READ_ONCE(ns->event);
32 541248 : if (m->poll_event != event) {
33 272878 : m->poll_event = event;
34 272878 : res |= EPOLLERR | EPOLLPRI;
35 : }
36 :
37 541248 : return res;
38 : }
39 :
40 : struct proc_fs_opts {
41 : int flag;
42 : const char *str;
43 : };
44 :
45 735556122 : static int show_sb_opts(struct seq_file *m, struct super_block *sb)
46 : {
47 735556122 : static const struct proc_fs_opts fs_opts[] = {
48 : { SB_SYNCHRONOUS, ",sync" },
49 : { SB_DIRSYNC, ",dirsync" },
50 : { SB_MANDLOCK, ",mand" },
51 : { SB_LAZYTIME, ",lazytime" },
52 : { 0, NULL }
53 : };
54 735556122 : const struct proc_fs_opts *fs_infop;
55 :
56 3676983317 : for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
57 2940585801 : if (sb->s_flags & fs_infop->flag)
58 4032 : seq_puts(m, fs_infop->str);
59 : }
60 :
61 736397516 : return security_sb_show_options(m, sb);
62 : }
63 :
64 736201174 : static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
65 : {
66 736201174 : static const struct proc_fs_opts mnt_opts[] = {
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 : { MNT_NOSYMFOLLOW, ",nosymfollow" },
74 : { 0, NULL }
75 : };
76 736201174 : const struct proc_fs_opts *fs_infop;
77 :
78 5879518961 : for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
79 5143233471 : if (mnt->mnt_flags & fs_infop->flag)
80 1160994173 : seq_puts(m, fs_infop->str);
81 : }
82 :
83 736285490 : if (is_idmapped_mnt(mnt))
84 1204 : seq_puts(m, ",idmapped");
85 736254282 : }
86 :
87 : static inline void mangle(struct seq_file *m, const char *s)
88 : {
89 677031031 : seq_escape(m, s, " \t\n\\#");
90 677434784 : }
91 :
92 736502296 : static void show_type(struct seq_file *m, struct super_block *sb)
93 : {
94 736502296 : mangle(m, sb->s_type->name);
95 735400560 : if (sb->s_subtype) {
96 0 : seq_putc(m, '.');
97 0 : mangle(m, sb->s_subtype);
98 : }
99 735400560 : }
100 :
101 683812186 : static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
102 : {
103 683812186 : struct proc_mounts *p = m->private;
104 683812186 : struct mount *r = real_mount(mnt);
105 683812186 : struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
106 683812186 : struct super_block *sb = mnt_path.dentry->d_sb;
107 683812186 : int err;
108 :
109 683812186 : if (sb->s_op->show_devname) {
110 60591778 : err = sb->s_op->show_devname(m, mnt_path.dentry);
111 60645869 : if (err)
112 0 : goto out;
113 : } else {
114 623220408 : mangle(m, r->mnt_devname ? r->mnt_devname : "none");
115 : }
116 684209448 : seq_putc(m, ' ');
117 : /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
118 684213469 : err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
119 684769174 : if (err)
120 7419038 : goto out;
121 677350136 : seq_putc(m, ' ');
122 677284079 : show_type(m, sb);
123 961093913 : seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
124 676560304 : err = show_sb_opts(m, sb);
125 677086673 : if (err)
126 0 : goto out;
127 677086673 : show_mnt_opts(m, mnt);
128 677057469 : if (sb->s_op->show_options)
129 647365093 : err = sb->s_op->show_options(m, mnt_path.dentry);
130 676851272 : seq_puts(m, " 0 0\n");
131 684085359 : out:
132 684085359 : return err;
133 : }
134 :
135 59970377 : static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
136 : {
137 59970377 : struct proc_mounts *p = m->private;
138 59970377 : struct mount *r = real_mount(mnt);
139 59970377 : struct super_block *sb = mnt->mnt_sb;
140 59970377 : struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
141 59970377 : int err;
142 :
143 59970377 : seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
144 59970377 : MAJOR(sb->s_dev), MINOR(sb->s_dev));
145 59736914 : if (sb->s_op->show_path) {
146 6466400 : err = sb->s_op->show_path(m, mnt->mnt_root);
147 6464394 : if (err)
148 0 : goto out;
149 : } else {
150 53270514 : seq_dentry(m, mnt->mnt_root, " \t\n\\");
151 : }
152 59765437 : seq_putc(m, ' ');
153 :
154 : /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
155 59760051 : err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
156 59925361 : if (err)
157 629372 : goto out;
158 :
159 83975833 : seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
160 59266432 : show_mnt_opts(m, mnt);
161 :
162 : /* Tagged fields ("foo:X" or "bar") */
163 59198104 : if (IS_MNT_SHARED(r))
164 57784947 : seq_printf(m, " shared:%i", r->mnt_group_id);
165 59246565 : if (IS_MNT_SLAVE(r)) {
166 1403236 : int master = r->mnt_master->mnt_group_id;
167 1403236 : int dom = get_dominating_id(r, &p->root);
168 1403208 : seq_printf(m, " master:%i", master);
169 1403201 : if (dom && dom != master)
170 0 : seq_printf(m, " propagate_from:%i", dom);
171 : }
172 59246530 : if (IS_MNT_UNBINDABLE(r))
173 409 : seq_puts(m, " unbindable");
174 :
175 : /* Filesystem specific data */
176 59246530 : seq_puts(m, " - ");
177 59274027 : show_type(m, sb);
178 58888155 : seq_putc(m, ' ');
179 58999165 : if (sb->s_op->show_devname) {
180 5188542 : err = sb->s_op->show_devname(m, mnt->mnt_root);
181 5213662 : if (err)
182 0 : goto out;
183 : } else {
184 53810623 : mangle(m, r->mnt_devname ? r->mnt_devname : "none");
185 : }
186 118185774 : seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
187 59067127 : err = show_sb_opts(m, sb);
188 59253370 : if (err)
189 0 : goto out;
190 59253370 : if (sb->s_op->show_options)
191 56656864 : err = sb->s_op->show_options(m, mnt->mnt_root);
192 58975106 : seq_putc(m, '\n');
193 59540678 : out:
194 59540678 : return err;
195 : }
196 :
197 0 : static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
198 : {
199 0 : struct proc_mounts *p = m->private;
200 0 : struct mount *r = real_mount(mnt);
201 0 : struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
202 0 : struct super_block *sb = mnt_path.dentry->d_sb;
203 0 : int err;
204 :
205 : /* device */
206 0 : if (sb->s_op->show_devname) {
207 0 : seq_puts(m, "device ");
208 0 : err = sb->s_op->show_devname(m, mnt_path.dentry);
209 0 : if (err)
210 0 : goto out;
211 : } else {
212 0 : if (r->mnt_devname) {
213 0 : seq_puts(m, "device ");
214 0 : mangle(m, r->mnt_devname);
215 : } else
216 0 : seq_puts(m, "no device");
217 : }
218 :
219 : /* mount point */
220 0 : seq_puts(m, " mounted on ");
221 : /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
222 0 : err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
223 0 : if (err)
224 0 : goto out;
225 0 : seq_putc(m, ' ');
226 :
227 : /* file system type */
228 0 : seq_puts(m, "with fstype ");
229 0 : show_type(m, sb);
230 :
231 : /* optional statistics */
232 0 : if (sb->s_op->show_stats) {
233 0 : seq_putc(m, ' ');
234 0 : err = sb->s_op->show_stats(m, mnt_path.dentry);
235 : }
236 :
237 0 : seq_putc(m, '\n');
238 0 : out:
239 0 : return err;
240 : }
241 :
242 8044999 : static int mounts_open_common(struct inode *inode, struct file *file,
243 : int (*show)(struct seq_file *, struct vfsmount *))
244 : {
245 8044999 : struct task_struct *task = get_proc_task(inode);
246 8068649 : struct nsproxy *nsp;
247 8068649 : struct mnt_namespace *ns = NULL;
248 8068649 : struct path root;
249 8068649 : struct proc_mounts *p;
250 8068649 : struct seq_file *m;
251 8068649 : int ret = -EINVAL;
252 :
253 8068649 : if (!task)
254 0 : goto err;
255 :
256 8068649 : task_lock(task);
257 8059015 : nsp = task->nsproxy;
258 8059015 : if (!nsp || !nsp->mnt_ns) {
259 0 : task_unlock(task);
260 0 : put_task_struct(task);
261 0 : goto err;
262 : }
263 8059015 : ns = nsp->mnt_ns;
264 8059015 : get_mnt_ns(ns);
265 8033556 : if (!task->fs) {
266 0 : task_unlock(task);
267 0 : put_task_struct(task);
268 0 : ret = -ENOENT;
269 0 : goto err_put_ns;
270 : }
271 8033556 : get_fs_root(task->fs, &root);
272 8069777 : task_unlock(task);
273 8069679 : put_task_struct(task);
274 :
275 8061884 : ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
276 8059439 : if (ret)
277 0 : goto err_put_path;
278 :
279 8059439 : m = file->private_data;
280 8059439 : m->poll_event = ns->event;
281 :
282 8059439 : p = m->private;
283 8059439 : p->ns = ns;
284 8059439 : p->root = root;
285 8059439 : p->show = show;
286 8059439 : INIT_LIST_HEAD(&p->cursor.mnt_list);
287 8059439 : p->cursor.mnt.mnt_flags = MNT_CURSOR;
288 :
289 8059439 : return 0;
290 :
291 : err_put_path:
292 0 : path_put(&root);
293 0 : err_put_ns:
294 0 : put_mnt_ns(ns);
295 : err:
296 : return ret;
297 : }
298 :
299 8041426 : static int mounts_release(struct inode *inode, struct file *file)
300 : {
301 8041426 : struct seq_file *m = file->private_data;
302 8041426 : struct proc_mounts *p = m->private;
303 8041426 : path_put(&p->root);
304 8060352 : mnt_cursor_del(p->ns, &p->cursor);
305 8069780 : put_mnt_ns(p->ns);
306 8043057 : return seq_release_private(inode, file);
307 : }
308 :
309 7424271 : static int mounts_open(struct inode *inode, struct file *file)
310 : {
311 7424271 : return mounts_open_common(inode, file, show_vfsmnt);
312 : }
313 :
314 631731 : static int mountinfo_open(struct inode *inode, struct file *file)
315 : {
316 631731 : return mounts_open_common(inode, file, show_mountinfo);
317 : }
318 :
319 0 : static int mountstats_open(struct inode *inode, struct file *file)
320 : {
321 0 : return mounts_open_common(inode, file, show_vfsstat);
322 : }
323 :
324 : const struct file_operations proc_mounts_operations = {
325 : .open = mounts_open,
326 : .read_iter = seq_read_iter,
327 : .splice_read = copy_splice_read,
328 : .llseek = seq_lseek,
329 : .release = mounts_release,
330 : .poll = mounts_poll,
331 : };
332 :
333 : const struct file_operations proc_mountinfo_operations = {
334 : .open = mountinfo_open,
335 : .read_iter = seq_read_iter,
336 : .splice_read = copy_splice_read,
337 : .llseek = seq_lseek,
338 : .release = mounts_release,
339 : .poll = mounts_poll,
340 : };
341 :
342 : const struct file_operations proc_mountstats_operations = {
343 : .open = mountstats_open,
344 : .read_iter = seq_read_iter,
345 : .splice_read = copy_splice_read,
346 : .llseek = seq_lseek,
347 : .release = mounts_release,
348 : };
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