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
12struct 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(list: &ino->active);
19 INIT_LIST_HEAD(list: &ino->expiring);
20 ino->last_used = jiffies;
21 ino->sbi = sbi;
22 ino->exp_timeout = -1;
23 ino->count = 1;
24 }
25 return ino;
26}
27
28void autofs_clean_ino(struct autofs_info *ino)
29{
30 ino->uid = GLOBAL_ROOT_UID;
31 ino->gid = GLOBAL_ROOT_GID;
32 ino->exp_timeout = -1;
33 ino->last_used = jiffies;
34}
35
36void autofs_free_ino(struct autofs_info *ino)
37{
38 kfree_rcu(ino, rcu);
39}
40
41void autofs_kill_sb(struct super_block *sb)
42{
43 struct autofs_sb_info *sbi = autofs_sbi(sb);
44
45 /*
46 * In the event of a failure in get_sb_nodev the superblock
47 * info is not present so nothing else has been setup, so
48 * just call kill_anon_super when we are called from
49 * deactivate_super.
50 */
51 if (sbi) {
52 /* Free wait queues, close pipe */
53 autofs_catatonic_mode(sbi);
54 put_pid(pid: sbi->oz_pgrp);
55 }
56
57 pr_debug("shutting down\n");
58 kill_litter_super(sb);
59 if (sbi)
60 kfree_rcu(sbi, rcu);
61}
62
63static int autofs_show_options(struct seq_file *m, struct dentry *root)
64{
65 struct autofs_sb_info *sbi = autofs_sbi(sb: root->d_sb);
66 struct inode *root_inode = d_inode(dentry: root->d_sb->s_root);
67
68 if (!sbi)
69 return 0;
70
71 seq_printf(m, fmt: ",fd=%d", sbi->pipefd);
72 if (!uid_eq(left: root_inode->i_uid, GLOBAL_ROOT_UID))
73 seq_printf(m, ",uid=%u",
74 from_kuid_munged(&init_user_ns, root_inode->i_uid));
75 if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
76 seq_printf(m, ",gid=%u",
77 from_kgid_munged(&init_user_ns, root_inode->i_gid));
78 seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
79 seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
80 seq_printf(m, ",minproto=%d", sbi->min_proto);
81 seq_printf(m, ",maxproto=%d", sbi->max_proto);
82
83 if (autofs_type_offset(sbi->type))
84 seq_puts(m, ",offset");
85 else if (autofs_type_direct(sbi->type))
86 seq_puts(m, ",direct");
87 else
88 seq_puts(m, ",indirect");
89 if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
90 seq_puts(m, ",strictexpire");
91 if (sbi->flags & AUTOFS_SBI_IGNORE)
92 seq_puts(m, ",ignore");
93#ifdef CONFIG_CHECKPOINT_RESTORE
94 if (sbi->pipe)
95 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
96 else
97 seq_puts(m, ",pipe_ino=-1");
98#endif
99 return 0;
100}
101
102static void autofs_evict_inode(struct inode *inode)
103{
104 clear_inode(inode);
105 kfree(objp: inode->i_private);
106}
107
108static const struct super_operations autofs_sops = {
109 .statfs = simple_statfs,
110 .show_options = autofs_show_options,
111 .evict_inode = autofs_evict_inode,
112};
113
114enum {
115 Opt_direct,
116 Opt_fd,
117 Opt_gid,
118 Opt_ignore,
119 Opt_indirect,
120 Opt_maxproto,
121 Opt_minproto,
122 Opt_offset,
123 Opt_pgrp,
124 Opt_strictexpire,
125 Opt_uid,
126};
127
128const struct fs_parameter_spec autofs_param_specs[] = {
129 fsparam_flag ("direct", Opt_direct),
130 fsparam_fd ("fd", Opt_fd),
131 fsparam_gid ("gid", Opt_gid),
132 fsparam_flag ("ignore", Opt_ignore),
133 fsparam_flag ("indirect", Opt_indirect),
134 fsparam_u32 ("maxproto", Opt_maxproto),
135 fsparam_u32 ("minproto", Opt_minproto),
136 fsparam_flag ("offset", Opt_offset),
137 fsparam_u32 ("pgrp", Opt_pgrp),
138 fsparam_flag ("strictexpire", Opt_strictexpire),
139 fsparam_uid ("uid", Opt_uid),
140 {}
141};
142
143struct autofs_fs_context {
144 kuid_t uid;
145 kgid_t gid;
146 int pgrp;
147 bool pgrp_set;
148};
149
150/*
151 * Open the fd. We do it here rather than in get_tree so that it's done in the
152 * context of the system call that passed the data and not the one that
153 * triggered the superblock creation, lest the fd gets reassigned.
154 */
155static int autofs_parse_fd(struct fs_context *fc, struct autofs_sb_info *sbi,
156 struct fs_parameter *param,
157 struct fs_parse_result *result)
158{
159 struct file *pipe;
160 int ret;
161
162 if (param->type == fs_value_is_file) {
163 /* came through the new api */
164 pipe = param->file;
165 param->file = NULL;
166 } else {
167 pipe = fget(fd: result->uint_32);
168 }
169 if (!pipe) {
170 errorf(fc, "could not open pipe file descriptor");
171 return -EBADF;
172 }
173
174 ret = autofs_check_pipe(pipe);
175 if (ret < 0) {
176 errorf(fc, "Invalid/unusable pipe");
177 fput(pipe);
178 return -EBADF;
179 }
180
181 autofs_set_packet_pipe_flags(pipe);
182
183 if (sbi->pipe)
184 fput(sbi->pipe);
185
186 sbi->pipefd = result->uint_32;
187 sbi->pipe = pipe;
188
189 return 0;
190}
191
192static int autofs_parse_param(struct fs_context *fc, struct fs_parameter *param)
193{
194 struct autofs_fs_context *ctx = fc->fs_private;
195 struct autofs_sb_info *sbi = fc->s_fs_info;
196 struct fs_parse_result result;
197 int opt;
198
199 opt = fs_parse(fc, desc: autofs_param_specs, param, result: &result);
200 if (opt < 0)
201 return opt;
202
203 switch (opt) {
204 case Opt_fd:
205 return autofs_parse_fd(fc, sbi, param, result: &result);
206 case Opt_uid:
207 ctx->uid = result.uid;
208 break;
209 case Opt_gid:
210 ctx->gid = result.gid;
211 break;
212 case Opt_pgrp:
213 ctx->pgrp = result.uint_32;
214 ctx->pgrp_set = true;
215 break;
216 case Opt_minproto:
217 sbi->min_proto = result.uint_32;
218 break;
219 case Opt_maxproto:
220 sbi->max_proto = result.uint_32;
221 break;
222 case Opt_indirect:
223 set_autofs_type_indirect(&sbi->type);
224 break;
225 case Opt_direct:
226 set_autofs_type_direct(&sbi->type);
227 break;
228 case Opt_offset:
229 set_autofs_type_offset(&sbi->type);
230 break;
231 case Opt_strictexpire:
232 sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
233 break;
234 case Opt_ignore:
235 sbi->flags |= AUTOFS_SBI_IGNORE;
236 }
237
238 return 0;
239}
240
241static struct autofs_sb_info *autofs_alloc_sbi(void)
242{
243 struct autofs_sb_info *sbi;
244
245 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
246 if (!sbi)
247 return NULL;
248
249 sbi->magic = AUTOFS_SBI_MAGIC;
250 sbi->flags = AUTOFS_SBI_CATATONIC;
251 sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
252 sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
253 sbi->pipefd = -1;
254
255 set_autofs_type_indirect(&sbi->type);
256 mutex_init(&sbi->wq_mutex);
257 mutex_init(&sbi->pipe_mutex);
258 spin_lock_init(&sbi->fs_lock);
259 spin_lock_init(&sbi->lookup_lock);
260 INIT_LIST_HEAD(list: &sbi->active_list);
261 INIT_LIST_HEAD(list: &sbi->expiring_list);
262
263 return sbi;
264}
265
266static int autofs_validate_protocol(struct fs_context *fc)
267{
268 struct autofs_sb_info *sbi = fc->s_fs_info;
269
270 /* Test versions first */
271 if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
272 sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
273 errorf(fc, "kernel does not match daemon version "
274 "daemon (%d, %d) kernel (%d, %d)\n",
275 sbi->min_proto, sbi->max_proto,
276 AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
277 return -EINVAL;
278 }
279
280 /* Establish highest kernel protocol version */
281 if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
282 sbi->version = AUTOFS_MAX_PROTO_VERSION;
283 else
284 sbi->version = sbi->max_proto;
285
286 switch (sbi->version) {
287 case 4:
288 sbi->sub_version = 7;
289 break;
290 case 5:
291 sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
292 break;
293 default:
294 sbi->sub_version = 0;
295 }
296
297 return 0;
298}
299
300static int autofs_fill_super(struct super_block *s, struct fs_context *fc)
301{
302 struct autofs_fs_context *ctx = fc->fs_private;
303 struct autofs_sb_info *sbi = s->s_fs_info;
304 struct inode *root_inode;
305 struct autofs_info *ino;
306
307 pr_debug("starting up, sbi = %p\n", sbi);
308
309 sbi->sb = s;
310 s->s_blocksize = 1024;
311 s->s_blocksize_bits = 10;
312 s->s_magic = AUTOFS_SUPER_MAGIC;
313 s->s_op = &autofs_sops;
314 set_default_d_op(s, &autofs_dentry_operations);
315 s->s_time_gran = 1;
316
317 /*
318 * Get the root inode and dentry, but defer checking for errors.
319 */
320 ino = autofs_new_ino(sbi);
321 if (!ino)
322 return -ENOMEM;
323
324 root_inode = autofs_get_inode(s, S_IFDIR | 0755);
325 if (!root_inode)
326 return -ENOMEM;
327
328 root_inode->i_uid = ctx->uid;
329 root_inode->i_gid = ctx->gid;
330 root_inode->i_fop = &autofs_root_operations;
331 root_inode->i_op = &autofs_dir_inode_operations;
332
333 s->s_root = d_make_root(root_inode);
334 if (unlikely(!s->s_root)) {
335 autofs_free_ino(ino);
336 return -ENOMEM;
337 }
338 s->s_root->d_fsdata = ino;
339
340 if (ctx->pgrp_set) {
341 sbi->oz_pgrp = find_get_pid(nr: ctx->pgrp);
342 if (!sbi->oz_pgrp)
343 return invalf(fc, "Could not find process group %d",
344 ctx->pgrp);
345 } else
346 sbi->oz_pgrp = get_task_pid(current, type: PIDTYPE_PGID);
347
348 if (autofs_type_trigger(type: sbi->type))
349 /* s->s_root won't be contended so there's little to
350 * be gained by not taking the d_lock when setting
351 * d_flags, even when a lot mounts are being done.
352 */
353 managed_dentry_set_managed(dentry: s->s_root);
354
355 pr_debug("pipe fd = %d, pgrp = %u\n",
356 sbi->pipefd, pid_nr(sbi->oz_pgrp));
357
358 sbi->flags &= ~AUTOFS_SBI_CATATONIC;
359 return 0;
360}
361
362/*
363 * Validate the parameters and then request a superblock.
364 */
365static int autofs_get_tree(struct fs_context *fc)
366{
367 struct autofs_sb_info *sbi = fc->s_fs_info;
368 int ret;
369
370 ret = autofs_validate_protocol(fc);
371 if (ret)
372 return ret;
373
374 if (sbi->pipefd < 0)
375 return invalf(fc, "No control pipe specified");
376
377 return get_tree_nodev(fc, fill_super: autofs_fill_super);
378}
379
380static void autofs_free_fc(struct fs_context *fc)
381{
382 struct autofs_fs_context *ctx = fc->fs_private;
383 struct autofs_sb_info *sbi = fc->s_fs_info;
384
385 if (sbi) {
386 if (sbi->pipe)
387 fput(sbi->pipe);
388 kfree(objp: sbi);
389 }
390 kfree(objp: ctx);
391}
392
393static const struct fs_context_operations autofs_context_ops = {
394 .free = autofs_free_fc,
395 .parse_param = autofs_parse_param,
396 .get_tree = autofs_get_tree,
397};
398
399/*
400 * Set up the filesystem mount context.
401 */
402int autofs_init_fs_context(struct fs_context *fc)
403{
404 struct autofs_fs_context *ctx;
405 struct autofs_sb_info *sbi;
406
407 ctx = kzalloc(sizeof(struct autofs_fs_context), GFP_KERNEL);
408 if (!ctx)
409 goto nomem;
410
411 ctx->uid = current_uid();
412 ctx->gid = current_gid();
413
414 sbi = autofs_alloc_sbi();
415 if (!sbi)
416 goto nomem_ctx;
417
418 fc->fs_private = ctx;
419 fc->s_fs_info = sbi;
420 fc->ops = &autofs_context_ops;
421 return 0;
422
423nomem_ctx:
424 kfree(objp: ctx);
425nomem:
426 return -ENOMEM;
427}
428
429struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
430{
431 struct inode *inode = new_inode(sb);
432
433 if (inode == NULL)
434 return NULL;
435
436 inode->i_mode = mode;
437 if (sb->s_root) {
438 inode->i_uid = d_inode(dentry: sb->s_root)->i_uid;
439 inode->i_gid = d_inode(dentry: sb->s_root)->i_gid;
440 }
441 simple_inode_init_ts(inode);
442 inode->i_ino = get_next_ino();
443
444 if (S_ISDIR(mode)) {
445 set_nlink(inode, nlink: 2);
446 inode->i_op = &autofs_dir_inode_operations;
447 inode->i_fop = &autofs_dir_operations;
448 } else if (S_ISLNK(mode)) {
449 inode->i_op = &autofs_symlink_inode_operations;
450 } else
451 WARN_ON(1);
452
453 return inode;
454}
455