1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * fs/proc_namespace.c - handling of /proc/<pi 3 * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
4 * 4 *
5 * In fact, that's a piece of procfs; it's *al 5 * In fact, that's a piece of procfs; it's *almost* isolated from
6 * the rest of fs/proc, but has rather close r 6 * the rest of fs/proc, but has rather close relationships with
7 * fs/namespace.c, thus here instead of fs/pro 7 * fs/namespace.c, thus here instead of fs/proc
8 * 8 *
9 */ 9 */
10 #include <linux/mnt_namespace.h> 10 #include <linux/mnt_namespace.h>
11 #include <linux/nsproxy.h> 11 #include <linux/nsproxy.h>
12 #include <linux/security.h> 12 #include <linux/security.h>
13 #include <linux/fs_struct.h> 13 #include <linux/fs_struct.h>
14 #include <linux/sched/task.h> 14 #include <linux/sched/task.h>
15 15
16 #include "<proc/internal.h" /* only for get_pro 16 #include "<proc/internal.h" /* only for get_proc_task() in -?v=linux-5.16.20">a href="source/fs/proc/internal.h?v=linux-5.16.20">proc/internal.h" /* only for get_proc_task() in ->open() */
17 17
18 #include "pnode.h" 18 #include "pnode.h"
19 #include "internal.h" 19 #include "internal.h"
20 20
21 static __poll_t mounts_poll(struct file *file, 21 static __poll_t mounts_poll(struct file *file, poll_table *wait)
22 { 22 {
23 struct seq_file *m = file->private_dat 23 struct seq_file *m = file->private_data;
24 struct proc_mounts *p = m->private; 24 struct proc_mounts *p = m->private;
25 struct mnt_namespace *ns = p->ns; 25 struct mnt_namespace *ns = p->ns;
26 __poll_t res = EPOLLIN | EPOLLRDNORM; 26 __poll_t res = EPOLLIN | EPOLLRDNORM;
27 int event; 27 int event;
28 28
29 poll_wait(file, &p->ns->poll, wait); 29 poll_wait(file, &p->ns->poll, wait);
30 30
31 event = READ_ONCE(ns->event); 31 event = READ_ONCE(ns->event);
32 if (m->poll_event != event) { 32 if (m->poll_event != event) {
33 m->poll_event = event; 33 m->poll_event = event;
34 res |= EPOLLERR | EPOLLPRI; 34 res |= EPOLLERR | EPOLLPRI;
35 } 35 }
36 36
37 return res; 37 return res;
38 } 38 }
39 39
40 struct proc_fs_opts { 40 struct proc_fs_opts {
41 int flag; 41 int flag;
42 const char *str; 42 const char *str;
43 }; 43 };
44 44
45 static int show_sb_opts(struct seq_file *m, st 45 static int show_sb_opts(struct seq_file *m, struct super_block *sb)
46 { 46 {
47 static const struct proc_fs_opts fs_op 47 static const struct proc_fs_opts fs_opts[] = {
48 { SB_SYNCHRONOUS, ",sync" }, 48 { SB_SYNCHRONOUS, ",sync" },
49 { SB_DIRSYNC, ",dirsync" }, 49 { SB_DIRSYNC, ",dirsync" },
50 { SB_MANDLOCK, ",mand" }, 50 { SB_MANDLOCK, ",mand" },
51 { SB_LAZYTIME, ",lazytime" }, 51 { SB_LAZYTIME, ",lazytime" },
52 { 0, NULL } 52 { 0, NULL }
53 }; 53 };
54 const struct proc_fs_opts *fs_infop; 54 const struct proc_fs_opts *fs_infop;
55 55
56 for (fs_infop = fs_opts; fs_infop->fla 56 for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
57 if (sb->s_flags & fs_infop->fl 57 if (sb->s_flags & fs_infop->flag)
58 seq_puts(m, fs_infop-> 58 seq_puts(m, fs_infop->str);
59 } 59 }
60 60
61 return security_sb_show_options(m, sb) 61 return security_sb_show_options(m, sb);
62 } 62 }
63 63
64 static void show_vfsmnt_opts(struct seq_file * !! 64 static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
65 { 65 {
66 static const struct proc_fs_opts mnt_o 66 static const struct proc_fs_opts mnt_opts[] = {
67 { MNT_NOSUID, ",nosuid" }, 67 { MNT_NOSUID, ",nosuid" },
68 { MNT_NODEV, ",nodev" }, 68 { MNT_NODEV, ",nodev" },
69 { MNT_NOEXEC, ",noexec" }, 69 { MNT_NOEXEC, ",noexec" },
70 { MNT_NOATIME, ",noatime" }, 70 { MNT_NOATIME, ",noatime" },
71 { MNT_NODIRATIME, ",nodiratime 71 { MNT_NODIRATIME, ",nodiratime" },
72 { MNT_RELATIME, ",relatime" }, 72 { MNT_RELATIME, ",relatime" },
73 { MNT_NOSYMFOLLOW, ",nosymfoll 73 { MNT_NOSYMFOLLOW, ",nosymfollow" },
74 { 0, NULL } 74 { 0, NULL }
75 }; 75 };
76 const struct proc_fs_opts *fs_infop; 76 const struct proc_fs_opts *fs_infop;
77 77
78 for (fs_infop = mnt_opts; fs_infop->fl 78 for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
79 if (mnt->mnt_flags & fs_infop- 79 if (mnt->mnt_flags & fs_infop->flag)
80 seq_puts(m, fs_infop-> 80 seq_puts(m, fs_infop->str);
81 } 81 }
82 82
83 if (is_idmapped_mnt(mnt)) !! 83 if (mnt_user_ns(mnt) != &init_user_ns)
84 seq_puts(m, ",idmapped"); 84 seq_puts(m, ",idmapped");
85 } 85 }
86 86
87 static inline void mangle(struct seq_file *m, 87 static inline void mangle(struct seq_file *m, const char *s)
88 { 88 {
89 seq_escape(m, s, " \t\n\\#"); !! 89 seq_escape(m, s, " \t\n\\");
90 } 90 }
91 91
92 static void show_type(struct seq_file *m, stru 92 static void show_type(struct seq_file *m, struct super_block *sb)
93 { 93 {
94 mangle(m, sb->s_type->name); 94 mangle(m, sb->s_type->name);
95 if (sb->s_subtype) { 95 if (sb->s_subtype) {
96 seq_putc(m, '.'); 96 seq_putc(m, '.');
97 mangle(m, sb->s_subtype); 97 mangle(m, sb->s_subtype);
98 } 98 }
99 } 99 }
100 100
101 static int show_vfsmnt(struct seq_file *m, str 101 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
102 { 102 {
103 struct proc_mounts *p = m->private; 103 struct proc_mounts *p = m->private;
104 struct mount *r = real_mount(mnt); 104 struct mount *r = real_mount(mnt);
105 struct path mnt_path = { .dentry = mnt 105 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
106 struct super_block *sb = mnt_path.dent 106 struct super_block *sb = mnt_path.dentry->d_sb;
107 int err; 107 int err;
108 108
109 if (sb->s_op->show_devname) { 109 if (sb->s_op->show_devname) {
110 err = sb->s_op->show_devname(m 110 err = sb->s_op->show_devname(m, mnt_path.dentry);
111 if (err) 111 if (err)
112 goto out; 112 goto out;
113 } else { 113 } else {
114 mangle(m, r->mnt_devname ? r-> 114 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
115 } 115 }
116 seq_putc(m, ' '); 116 seq_putc(m, ' ');
117 /* mountpoints outside of chroot jail 117 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
118 err = seq_path_root(m, &mnt_path, &p-> 118 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
119 if (err) 119 if (err)
120 goto out; 120 goto out;
121 seq_putc(m, ' '); 121 seq_putc(m, ' ');
122 show_type(m, sb); 122 show_type(m, sb);
123 seq_puts(m, __mnt_is_readonly(mnt) ? " 123 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
124 err = show_sb_opts(m, sb); 124 err = show_sb_opts(m, sb);
125 if (err) 125 if (err)
126 goto out; 126 goto out;
127 show_vfsmnt_opts(m, mnt); !! 127 show_mnt_opts(m, mnt);
128 if (sb->s_op->show_options) 128 if (sb->s_op->show_options)
129 err = sb->s_op->show_options(m 129 err = sb->s_op->show_options(m, mnt_path.dentry);
130 seq_puts(m, " 0 0\n"); 130 seq_puts(m, " 0 0\n");
131 out: 131 out:
132 return err; 132 return err;
133 } 133 }
134 134
135 static int show_mountinfo(struct seq_file *m, 135 static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
136 { 136 {
137 struct proc_mounts *p = m->private; 137 struct proc_mounts *p = m->private;
138 struct mount *r = real_mount(mnt); 138 struct mount *r = real_mount(mnt);
139 struct super_block *sb = mnt->mnt_sb; 139 struct super_block *sb = mnt->mnt_sb;
140 struct path mnt_path = { .dentry = mnt 140 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
141 int err; 141 int err;
142 142
143 seq_printf(m, "%i %i %u:%u ", r->mnt_i 143 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
144 MAJOR(sb->s_dev), MINOR(sb- 144 MAJOR(sb->s_dev), MINOR(sb->s_dev));
145 err = show_path(m, mnt->mnt_root); !! 145 if (sb->s_op->show_path) {
146 if (err) !! 146 err = sb->s_op->show_path(m, mnt->mnt_root);
147 goto out; !! 147 if (err)
>> 148 goto out;
>> 149 } else {
>> 150 seq_dentry(m, mnt->mnt_root, " \t\n\\");
>> 151 }
148 seq_putc(m, ' '); 152 seq_putc(m, ' ');
149 153
150 /* mountpoints outside of chroot jail 154 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
151 err = seq_path_root(m, &mnt_path, &p-> 155 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
152 if (err) 156 if (err)
153 goto out; 157 goto out;
154 158
155 seq_puts(m, mnt->mnt_flags & MNT_READO 159 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
156 show_vfsmnt_opts(m, mnt); !! 160 show_mnt_opts(m, mnt);
157 161
158 /* Tagged fields ("foo:X" or "bar") */ 162 /* Tagged fields ("foo:X" or "bar") */
159 if (IS_MNT_SHARED(r)) 163 if (IS_MNT_SHARED(r))
160 seq_printf(m, " shared:%i", r- 164 seq_printf(m, " shared:%i", r->mnt_group_id);
161 if (IS_MNT_SLAVE(r)) { 165 if (IS_MNT_SLAVE(r)) {
162 int master = r->mnt_master->mn 166 int master = r->mnt_master->mnt_group_id;
163 int dom = get_dominating_id(r, 167 int dom = get_dominating_id(r, &p->root);
164 seq_printf(m, " master:%i", ma 168 seq_printf(m, " master:%i", master);
165 if (dom && dom != master) 169 if (dom && dom != master)
166 seq_printf(m, " propag 170 seq_printf(m, " propagate_from:%i", dom);
167 } 171 }
168 if (IS_MNT_UNBINDABLE(r)) 172 if (IS_MNT_UNBINDABLE(r))
169 seq_puts(m, " unbindable"); 173 seq_puts(m, " unbindable");
170 174
171 /* Filesystem specific data */ 175 /* Filesystem specific data */
172 seq_puts(m, " - "); 176 seq_puts(m, " - ");
173 show_type(m, sb); 177 show_type(m, sb);
174 seq_putc(m, ' '); 178 seq_putc(m, ' ');
175 if (sb->s_op->show_devname) { 179 if (sb->s_op->show_devname) {
176 err = sb->s_op->show_devname(m 180 err = sb->s_op->show_devname(m, mnt->mnt_root);
177 if (err) 181 if (err)
178 goto out; 182 goto out;
179 } else { 183 } else {
180 mangle(m, r->mnt_devname ? r-> 184 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
181 } 185 }
182 seq_puts(m, sb_rdonly(sb) ? " ro" : " 186 seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
183 err = show_sb_opts(m, sb); 187 err = show_sb_opts(m, sb);
184 if (err) 188 if (err)
185 goto out; 189 goto out;
186 if (sb->s_op->show_options) 190 if (sb->s_op->show_options)
187 err = sb->s_op->show_options(m 191 err = sb->s_op->show_options(m, mnt->mnt_root);
188 seq_putc(m, '\n'); 192 seq_putc(m, '\n');
189 out: 193 out:
190 return err; 194 return err;
191 } 195 }
192 196
193 static int show_vfsstat(struct seq_file *m, st 197 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
194 { 198 {
195 struct proc_mounts *p = m->private; 199 struct proc_mounts *p = m->private;
196 struct mount *r = real_mount(mnt); 200 struct mount *r = real_mount(mnt);
197 struct path mnt_path = { .dentry = mnt 201 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
198 struct super_block *sb = mnt_path.dent 202 struct super_block *sb = mnt_path.dentry->d_sb;
199 int err; 203 int err;
200 204
201 /* device */ 205 /* device */
202 if (sb->s_op->show_devname) { 206 if (sb->s_op->show_devname) {
203 seq_puts(m, "device "); 207 seq_puts(m, "device ");
204 err = sb->s_op->show_devname(m 208 err = sb->s_op->show_devname(m, mnt_path.dentry);
205 if (err) 209 if (err)
206 goto out; 210 goto out;
207 } else { 211 } else {
208 if (r->mnt_devname) { 212 if (r->mnt_devname) {
209 seq_puts(m, "device ") 213 seq_puts(m, "device ");
210 mangle(m, r->mnt_devna 214 mangle(m, r->mnt_devname);
211 } else 215 } else
212 seq_puts(m, "no device 216 seq_puts(m, "no device");
213 } 217 }
214 218
215 /* mount point */ 219 /* mount point */
216 seq_puts(m, " mounted on "); 220 seq_puts(m, " mounted on ");
217 /* mountpoints outside of chroot jail 221 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
218 err = seq_path_root(m, &mnt_path, &p-> 222 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
219 if (err) 223 if (err)
220 goto out; 224 goto out;
221 seq_putc(m, ' '); 225 seq_putc(m, ' ');
222 226
223 /* file system type */ 227 /* file system type */
224 seq_puts(m, "with fstype "); 228 seq_puts(m, "with fstype ");
225 show_type(m, sb); 229 show_type(m, sb);
226 230
227 /* optional statistics */ 231 /* optional statistics */
228 if (sb->s_op->show_stats) { 232 if (sb->s_op->show_stats) {
229 seq_putc(m, ' '); 233 seq_putc(m, ' ');
230 err = sb->s_op->show_stats(m, 234 err = sb->s_op->show_stats(m, mnt_path.dentry);
231 } 235 }
232 236
233 seq_putc(m, '\n'); 237 seq_putc(m, '\n');
234 out: 238 out:
235 return err; 239 return err;
236 } 240 }
237 241
238 static int mounts_open_common(struct inode *in 242 static int mounts_open_common(struct inode *inode, struct file *file,
239 int (*show)(stru 243 int (*show)(struct seq_file *, struct vfsmount *))
240 { 244 {
241 struct task_struct *task = get_proc_ta 245 struct task_struct *task = get_proc_task(inode);
242 struct nsproxy *nsp; 246 struct nsproxy *nsp;
243 struct mnt_namespace *ns = NULL; 247 struct mnt_namespace *ns = NULL;
244 struct path root; 248 struct path root;
245 struct proc_mounts *p; 249 struct proc_mounts *p;
246 struct seq_file *m; 250 struct seq_file *m;
247 int ret = -EINVAL; 251 int ret = -EINVAL;
248 252
249 if (!task) 253 if (!task)
250 goto err; 254 goto err;
251 255
252 task_lock(task); 256 task_lock(task);
253 nsp = task->nsproxy; 257 nsp = task->nsproxy;
254 if (!nsp || !nsp->mnt_ns) { 258 if (!nsp || !nsp->mnt_ns) {
255 task_unlock(task); 259 task_unlock(task);
256 put_task_struct(task); 260 put_task_struct(task);
257 goto err; 261 goto err;
258 } 262 }
259 ns = nsp->mnt_ns; 263 ns = nsp->mnt_ns;
260 get_mnt_ns(ns); 264 get_mnt_ns(ns);
261 if (!task->fs) { 265 if (!task->fs) {
262 task_unlock(task); 266 task_unlock(task);
263 put_task_struct(task); 267 put_task_struct(task);
264 ret = -ENOENT; 268 ret = -ENOENT;
265 goto err_put_ns; 269 goto err_put_ns;
266 } 270 }
267 get_fs_root(task->fs, &root); 271 get_fs_root(task->fs, &root);
268 task_unlock(task); 272 task_unlock(task);
269 put_task_struct(task); 273 put_task_struct(task);
270 274
271 ret = seq_open_private(file, &mounts_o 275 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
272 if (ret) 276 if (ret)
273 goto err_put_path; 277 goto err_put_path;
274 278
275 m = file->private_data; 279 m = file->private_data;
276 m->poll_event = ns->event; 280 m->poll_event = ns->event;
277 281
278 p = m->private; 282 p = m->private;
279 p->ns = ns; 283 p->ns = ns;
280 p->root = root; 284 p->root = root;
281 p->show = show; 285 p->show = show;
>> 286 INIT_LIST_HEAD(&p->cursor.mnt_list);
>> 287 p->cursor.mnt.mnt_flags = MNT_CURSOR;
282 288
283 return 0; 289 return 0;
284 290
285 err_put_path: 291 err_put_path:
286 path_put(&root); 292 path_put(&root);
287 err_put_ns: 293 err_put_ns:
288 put_mnt_ns(ns); 294 put_mnt_ns(ns);
289 err: 295 err:
290 return ret; 296 return ret;
291 } 297 }
292 298
293 static int mounts_release(struct inode *inode, 299 static int mounts_release(struct inode *inode, struct file *file)
294 { 300 {
295 struct seq_file *m = file->private_dat 301 struct seq_file *m = file->private_data;
296 struct proc_mounts *p = m->private; 302 struct proc_mounts *p = m->private;
297 path_put(&p->root); 303 path_put(&p->root);
>> 304 mnt_cursor_del(p->ns, &p->cursor);
298 put_mnt_ns(p->ns); 305 put_mnt_ns(p->ns);
299 return seq_release_private(inode, file 306 return seq_release_private(inode, file);
300 } 307 }
301 308
302 static int mounts_open(struct inode *inode, st 309 static int mounts_open(struct inode *inode, struct file *file)
303 { 310 {
304 return mounts_open_common(inode, file, 311 return mounts_open_common(inode, file, show_vfsmnt);
305 } 312 }
306 313
307 static int mountinfo_open(struct inode *inode, 314 static int mountinfo_open(struct inode *inode, struct file *file)
308 { 315 {
309 return mounts_open_common(inode, file, 316 return mounts_open_common(inode, file, show_mountinfo);
310 } 317 }
311 318
312 static int mountstats_open(struct inode *inode 319 static int mountstats_open(struct inode *inode, struct file *file)
313 { 320 {
314 return mounts_open_common(inode, file, 321 return mounts_open_common(inode, file, show_vfsstat);
315 } 322 }
316 323
317 const struct file_operations proc_mounts_opera 324 const struct file_operations proc_mounts_operations = {
318 .open = mounts_open, 325 .open = mounts_open,
319 .read_iter = seq_read_iter, 326 .read_iter = seq_read_iter,
320 .splice_read = copy_splice_read, !! 327 .splice_read = generic_file_splice_read,
321 .llseek = seq_lseek, 328 .llseek = seq_lseek,
322 .release = mounts_release, 329 .release = mounts_release,
323 .poll = mounts_poll, 330 .poll = mounts_poll,
324 }; 331 };
325 332
326 const struct file_operations proc_mountinfo_op 333 const struct file_operations proc_mountinfo_operations = {
327 .open = mountinfo_open, 334 .open = mountinfo_open,
328 .read_iter = seq_read_iter, 335 .read_iter = seq_read_iter,
329 .splice_read = copy_splice_read, !! 336 .splice_read = generic_file_splice_read,
330 .llseek = seq_lseek, 337 .llseek = seq_lseek,
331 .release = mounts_release, 338 .release = mounts_release,
332 .poll = mounts_poll, 339 .poll = mounts_poll,
333 }; 340 };
334 341
335 const struct file_operations proc_mountstats_o 342 const struct file_operations proc_mountstats_operations = {
336 .open = mountstats_open, 343 .open = mountstats_open,
337 .read_iter = seq_read_iter, 344 .read_iter = seq_read_iter,
338 .splice_read = copy_splice_read, !! 345 .splice_read = generic_file_splice_read,
339 .llseek = seq_lseek, 346 .llseek = seq_lseek,
340 .release = mounts_release, 347 .release = mounts_release,
341 }; 348 };
342 349
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