1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
4 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
5 */
6
7 #include <linux/seq_file.h>
8 #include <linux/pagemap.h>
9
10 #include "autofs_i.h"
11
12 struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
13 {
14 struct autofs_info *ino;
15
16 ino = kzalloc(sizeof(*ino), GFP_KERNEL);
17 if (ino) {
18 INIT_LIST_HEAD(&ino->active);
19 INIT_LIST_HEAD(&ino->expiring);
20 ino->last_used = jiffies;
21 ino->sbi = sbi;
22 ino->count = 1;
23 }
24 return ino;
25 }
26
27 void autofs_clean_ino(struct autofs_info *ino)
28 {
29 ino->uid = GLOBAL_ROOT_UID;
30 ino->gid = GLOBAL_ROOT_GID;
31 ino->last_used = jiffies;
32 }
33
34 void autofs_free_ino(struct autofs_info *ino)
35 {
36 kfree_rcu(ino, rcu);
37 }
38
39 void autofs_kill_sb(struct super_block *sb)
40 {
41 struct autofs_sb_info *sbi = autofs_sbi(sb);
42
43 /*
44 * In the event of a failure in get_sb_nodev the superblock
45 * info is not present so nothing else has been setup, so
46 * just call kill_anon_super when we are called from
47 * deactivate_super.
48 */
49 if (sbi) {
50 /* Free wait queues, close pipe */
51 autofs_catatonic_mode(sbi);
52 put_pid(sbi->oz_pgrp);
53 }
54
55 pr_debug("shutting down\n");
56 kill_litter_super(sb);
57 if (sbi)
58 kfree_rcu(sbi, rcu);
59 }
60
61 static int autofs_show_options(struct seq_file *m, struct dentry *root)
62 {
63 struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
64 struct inode *root_inode = d_inode(root->d_sb->s_root);
65
66 if (!sbi)
67 return 0;
68
69 seq_printf(m, ",fd=%d", sbi->pipefd);
70 if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
71 seq_printf(m, ",uid=%u",
72 from_kuid_munged(&init_user_ns, root_inode->i_uid));
73 if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
74 seq_printf(m, ",gid=%u",
75 from_kgid_munged(&init_user_ns, root_inode->i_gid));
76 seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
77 seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
78 seq_printf(m, ",minproto=%d", sbi->min_proto);
79 seq_printf(m, ",maxproto=%d", sbi->max_proto);
80
81 if (autofs_type_offset(sbi->type))
82 seq_puts(m, ",offset");
83 else if (autofs_type_direct(sbi->type))
84 seq_puts(m, ",direct");
85 else
86 seq_puts(m, ",indirect");
87 if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
88 seq_puts(m, ",strictexpire");
89 if (sbi->flags & AUTOFS_SBI_IGNORE)
90 seq_puts(m, ",ignore");
91 #ifdef CONFIG_CHECKPOINT_RESTORE
92 if (sbi->pipe)
93 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
94 else
95 seq_puts(m, ",pipe_ino=-1");
96 #endif
97 return 0;
98 }
99
100 static void autofs_evict_inode(struct inode *inode)
101 {
102 clear_inode(inode);
103 kfree(inode->i_private);
104 }
105
106 static const struct super_operations autofs_sops = {
107 .statfs = simple_statfs,
108 .show_options = autofs_show_options,
109 .evict_inode = autofs_evict_inode,
110 };
111
112 enum {
113 Opt_direct,
114 Opt_fd,
115 Opt_gid,
116 Opt_ignore,
117 Opt_indirect,
118 Opt_maxproto,
119 Opt_minproto,
120 Opt_offset,
121 Opt_pgrp,
122 Opt_strictexpire,
123 Opt_uid,
124 };
125
126 const struct fs_parameter_spec autofs_param_specs[] = {
127 fsparam_flag ("direct", Opt_direct),
128 fsparam_fd ("fd", Opt_fd),
129 fsparam_gid ("gid", Opt_gid),
130 fsparam_flag ("ignore", Opt_ignore),
131 fsparam_flag ("indirect", Opt_indirect),
132 fsparam_u32 ("maxproto", Opt_maxproto),
133 fsparam_u32 ("minproto", Opt_minproto),
134 fsparam_flag ("offset", Opt_offset),
135 fsparam_u32 ("pgrp", Opt_pgrp),
136 fsparam_flag ("strictexpire", Opt_strictexpire),
137 fsparam_uid ("uid", Opt_uid),
138 {}
139 };
140
141 struct autofs_fs_context {
142 kuid_t uid;
143 kgid_t gid;
144 int pgrp;
145 bool pgrp_set;
146 };
147
148 /*
149 * Open the fd. We do it here rather than in get_tree so that it's done in the
150 * context of the system call that passed the data and not the one that
151 * triggered the superblock creation, lest the fd gets reassigned.
152 */
153 static int autofs_parse_fd(struct fs_context *fc, struct autofs_sb_info *sbi,
154 struct fs_parameter *param,
155 struct fs_parse_result *result)
156 {
157 struct file *pipe;
158 int ret;
159
160 if (param->type == fs_value_is_file) {
161 /* came through the new api */
162 pipe = param->file;
163 param->file = NULL;
164 } else {
165 pipe = fget(result->uint_32);
166 }
167 if (!pipe) {
168 errorf(fc, "could not open pipe file descriptor");
169 return -EBADF;
170 }
171
172 ret = autofs_check_pipe(pipe);
173 if (ret < 0) {
174 errorf(fc, "Invalid/unusable pipe");
175 if (param->type != fs_value_is_file)
176 fput(pipe);
177 return -EBADF;
178 }
179
180 autofs_set_packet_pipe_flags(pipe);
181
182 if (sbi->pipe)
183 fput(sbi->pipe);
184
185 sbi->pipefd = result->uint_32;
186 sbi->pipe = pipe;
187
188 return 0;
189 }
190
191 static int autofs_parse_param(struct fs_context *fc, struct fs_parameter *param)
192 {
193 struct autofs_fs_context *ctx = fc->fs_private;
194 struct autofs_sb_info *sbi = fc->s_fs_info;
195 struct fs_parse_result result;
196 int opt;
197
198 opt = fs_parse(fc, autofs_param_specs, param, &result);
199 if (opt < 0)
200 return opt;
201
202 switch (opt) {
203 case Opt_fd:
204 return autofs_parse_fd(fc, sbi, param, &result);
205 case Opt_uid:
206 ctx->uid = result.uid;
207 break;
208 case Opt_gid:
209 ctx->gid = result.gid;
210 break;
211 case Opt_pgrp:
212 ctx->pgrp = result.uint_32;
213 ctx->pgrp_set = true;
214 break;
215 case Opt_minproto:
216 sbi->min_proto = result.uint_32;
217 break;
218 case Opt_maxproto:
219 sbi->max_proto = result.uint_32;
220 break;
221 case Opt_indirect:
222 set_autofs_type_indirect(&sbi->type);
223 break;
224 case Opt_direct:
225 set_autofs_type_direct(&sbi->type);
226 break;
227 case Opt_offset:
228 set_autofs_type_offset(&sbi->type);
229 break;
230 case Opt_strictexpire:
231 sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
232 break;
233 case Opt_ignore:
234 sbi->flags |= AUTOFS_SBI_IGNORE;
235 }
236
237 return 0;
238 }
239
240 static struct autofs_sb_info *autofs_alloc_sbi(void)
241 {
242 struct autofs_sb_info *sbi;
243
244 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
245 if (!sbi)
246 return NULL;
247
248 sbi->magic = AUTOFS_SBI_MAGIC;
249 sbi->flags = AUTOFS_SBI_CATATONIC;
250 sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
251 sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
252 sbi->pipefd = -1;
253
254 set_autofs_type_indirect(&sbi->type);
255 mutex_init(&sbi->wq_mutex);
256 mutex_init(&sbi->pipe_mutex);
257 spin_lock_init(&sbi->fs_lock);
258 spin_lock_init(&sbi->lookup_lock);
259 INIT_LIST_HEAD(&sbi->active_list);
260 INIT_LIST_HEAD(&sbi->expiring_list);
261
262 return sbi;
263 }
264
265 static int autofs_validate_protocol(struct fs_context *fc)
266 {
267 struct autofs_sb_info *sbi = fc->s_fs_info;
268
269 /* Test versions first */
270 if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
271 sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
272 errorf(fc, "kernel does not match daemon version "
273 "daemon (%d, %d) kernel (%d, %d)\n",
274 sbi->min_proto, sbi->max_proto,
275 AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
276 return -EINVAL;
277 }
278
279 /* Establish highest kernel protocol version */
280 if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
281 sbi->version = AUTOFS_MAX_PROTO_VERSION;
282 else
283 sbi->version = sbi->max_proto;
284
285 switch (sbi->version) {
286 case 4:
287 sbi->sub_version = 7;
288 break;
289 case 5:
290 sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
291 break;
292 default:
293 sbi->sub_version = 0;
294 }
295
296 return 0;
297 }
298
299 static int autofs_fill_super(struct super_block *s, struct fs_context *fc)
300 {
301 struct autofs_fs_context *ctx = fc->fs_private;
302 struct autofs_sb_info *sbi = s->s_fs_info;
303 struct inode *root_inode;
304 struct autofs_info *ino;
305
306 pr_debug("starting up, sbi = %p\n", sbi);
307
308 sbi->sb = s;
309 s->s_blocksize = 1024;
310 s->s_blocksize_bits = 10;
311 s->s_magic = AUTOFS_SUPER_MAGIC;
312 s->s_op = &autofs_sops;
313 s->s_d_op = &autofs_dentry_operations;
314 s->s_time_gran = 1;
315
316 /*
317 * Get the root inode and dentry, but defer checking for errors.
318 */
319 ino = autofs_new_ino(sbi);
320 if (!ino)
321 return -ENOMEM;
322
323 root_inode = autofs_get_inode(s, S_IFDIR | 0755);
324 if (!root_inode)
325 return -ENOMEM;
326
327 root_inode->i_uid = ctx->uid;
328 root_inode->i_gid = ctx->gid;
329 root_inode->i_fop = &autofs_root_operations;
330 root_inode->i_op = &autofs_dir_inode_operations;
331
332 s->s_root = d_make_root(root_inode);
333 if (unlikely(!s->s_root)) {
334 autofs_free_ino(ino);
335 return -ENOMEM;
336 }
337 s->s_root->d_fsdata = ino;
338
339 if (ctx->pgrp_set) {
340 sbi->oz_pgrp = find_get_pid(ctx->pgrp);
341 if (!sbi->oz_pgrp)
342 return invalf(fc, "Could not find process group %d",
343 ctx->pgrp);
344 } else
345 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
346
347 if (autofs_type_trigger(sbi->type))
348 /* s->s_root won't be contended so there's little to
349 * be gained by not taking the d_lock when setting
350 * d_flags, even when a lot mounts are being done.
351 */
352 managed_dentry_set_managed(s->s_root);
353
354 pr_debug("pipe fd = %d, pgrp = %u\n",
355 sbi->pipefd, pid_nr(sbi->oz_pgrp));
356
357 sbi->flags &= ~AUTOFS_SBI_CATATONIC;
358 return 0;
359 }
360
361 /*
362 * Validate the parameters and then request a superblock.
363 */
364 static int autofs_get_tree(struct fs_context *fc)
365 {
366 struct autofs_sb_info *sbi = fc->s_fs_info;
367 int ret;
368
369 ret = autofs_validate_protocol(fc);
370 if (ret)
371 return ret;
372
373 if (sbi->pipefd < 0)
374 return invalf(fc, "No control pipe specified");
375
376 return get_tree_nodev(fc, autofs_fill_super);
377 }
378
379 static void autofs_free_fc(struct fs_context *fc)
380 {
381 struct autofs_fs_context *ctx = fc->fs_private;
382 struct autofs_sb_info *sbi = fc->s_fs_info;
383
384 if (sbi) {
385 if (sbi->pipe)
386 fput(sbi->pipe);
387 kfree(sbi);
388 }
389 kfree(ctx);
390 }
391
392 static const struct fs_context_operations autofs_context_ops = {
393 .free = autofs_free_fc,
394 .parse_param = autofs_parse_param,
395 .get_tree = autofs_get_tree,
396 };
397
398 /*
399 * Set up the filesystem mount context.
400 */
401 int autofs_init_fs_context(struct fs_context *fc)
402 {
403 struct autofs_fs_context *ctx;
404 struct autofs_sb_info *sbi;
405
406 ctx = kzalloc(sizeof(struct autofs_fs_context), GFP_KERNEL);
407 if (!ctx)
408 goto nomem;
409
410 ctx->uid = current_uid();
411 ctx->gid = current_gid();
412
413 sbi = autofs_alloc_sbi();
414 if (!sbi)
415 goto nomem_ctx;
416
417 fc->fs_private = ctx;
418 fc->s_fs_info = sbi;
419 fc->ops = &autofs_context_ops;
420 return 0;
421
422 nomem_ctx:
423 kfree(ctx);
424 nomem:
425 return -ENOMEM;
426 }
427
428 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
429 {
430 struct inode *inode = new_inode(sb);
431
432 if (inode == NULL)
433 return NULL;
434
435 inode->i_mode = mode;
436 if (sb->s_root) {
437 inode->i_uid = d_inode(sb->s_root)->i_uid;
438 inode->i_gid = d_inode(sb->s_root)->i_gid;
439 }
440 simple_inode_init_ts(inode);
441 inode->i_ino = get_next_ino();
442
443 if (S_ISDIR(mode)) {
444 set_nlink(inode, 2);
445 inode->i_op = &autofs_dir_inode_operations;
446 inode->i_fop = &autofs_dir_operations;
447 } else if (S_ISLNK(mode)) {
448 inode->i_op = &autofs_symlink_inode_operations;
449 } else
450 WARN_ON(1);
451
452 return inode;
453 }
454
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