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
autofs_new_ino(struct autofs_sb_info * sbi)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
autofs_clean_ino(struct autofs_info * ino)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
autofs_free_ino(struct autofs_info * ino)34 void autofs_free_ino(struct autofs_info *ino)
35 {
36 kfree_rcu(ino, rcu);
37 }
38
autofs_kill_sb(struct super_block * sb)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
autofs_show_options(struct seq_file * m,struct dentry * root)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
autofs_evict_inode(struct inode * inode)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_u32 ("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_u32 ("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 */
autofs_parse_fd(struct fs_context * fc,struct autofs_sb_info * sbi,struct fs_parameter * param,struct fs_parse_result * result)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
autofs_parse_param(struct fs_context * fc,struct fs_parameter * param)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 kuid_t uid;
197 kgid_t gid;
198 int opt;
199
200 opt = fs_parse(fc, autofs_param_specs, param, &result);
201 if (opt < 0)
202 return opt;
203
204 switch (opt) {
205 case Opt_fd:
206 return autofs_parse_fd(fc, sbi, param, &result);
207 case Opt_uid:
208 uid = make_kuid(current_user_ns(), result.uint_32);
209 if (!uid_valid(uid))
210 return invalfc(fc, "Invalid uid");
211 ctx->uid = uid;
212 break;
213 case Opt_gid:
214 gid = make_kgid(current_user_ns(), result.uint_32);
215 if (!gid_valid(gid))
216 return invalfc(fc, "Invalid gid");
217 ctx->gid = gid;
218 break;
219 case Opt_pgrp:
220 ctx->pgrp = result.uint_32;
221 ctx->pgrp_set = true;
222 break;
223 case Opt_minproto:
224 sbi->min_proto = result.uint_32;
225 break;
226 case Opt_maxproto:
227 sbi->max_proto = result.uint_32;
228 break;
229 case Opt_indirect:
230 set_autofs_type_indirect(&sbi->type);
231 break;
232 case Opt_direct:
233 set_autofs_type_direct(&sbi->type);
234 break;
235 case Opt_offset:
236 set_autofs_type_offset(&sbi->type);
237 break;
238 case Opt_strictexpire:
239 sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
240 break;
241 case Opt_ignore:
242 sbi->flags |= AUTOFS_SBI_IGNORE;
243 }
244
245 return 0;
246 }
247
autofs_alloc_sbi(void)248 static struct autofs_sb_info *autofs_alloc_sbi(void)
249 {
250 struct autofs_sb_info *sbi;
251
252 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
253 if (!sbi)
254 return NULL;
255
256 sbi->magic = AUTOFS_SBI_MAGIC;
257 sbi->flags = AUTOFS_SBI_CATATONIC;
258 sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
259 sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
260 sbi->pipefd = -1;
261
262 set_autofs_type_indirect(&sbi->type);
263 mutex_init(&sbi->wq_mutex);
264 mutex_init(&sbi->pipe_mutex);
265 spin_lock_init(&sbi->fs_lock);
266 spin_lock_init(&sbi->lookup_lock);
267 INIT_LIST_HEAD(&sbi->active_list);
268 INIT_LIST_HEAD(&sbi->expiring_list);
269
270 return sbi;
271 }
272
autofs_validate_protocol(struct fs_context * fc)273 static int autofs_validate_protocol(struct fs_context *fc)
274 {
275 struct autofs_sb_info *sbi = fc->s_fs_info;
276
277 /* Test versions first */
278 if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
279 sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
280 errorf(fc, "kernel does not match daemon version "
281 "daemon (%d, %d) kernel (%d, %d)\n",
282 sbi->min_proto, sbi->max_proto,
283 AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
284 return -EINVAL;
285 }
286
287 /* Establish highest kernel protocol version */
288 if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
289 sbi->version = AUTOFS_MAX_PROTO_VERSION;
290 else
291 sbi->version = sbi->max_proto;
292
293 switch (sbi->version) {
294 case 4:
295 sbi->sub_version = 7;
296 break;
297 case 5:
298 sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
299 break;
300 default:
301 sbi->sub_version = 0;
302 }
303
304 return 0;
305 }
306
autofs_fill_super(struct super_block * s,struct fs_context * fc)307 static int autofs_fill_super(struct super_block *s, struct fs_context *fc)
308 {
309 struct autofs_fs_context *ctx = fc->fs_private;
310 struct autofs_sb_info *sbi = s->s_fs_info;
311 struct inode *root_inode;
312 struct autofs_info *ino;
313
314 pr_debug("starting up, sbi = %p\n", sbi);
315
316 sbi->sb = s;
317 s->s_blocksize = 1024;
318 s->s_blocksize_bits = 10;
319 s->s_magic = AUTOFS_SUPER_MAGIC;
320 s->s_op = &autofs_sops;
321 s->s_d_op = &autofs_dentry_operations;
322 s->s_time_gran = 1;
323
324 /*
325 * Get the root inode and dentry, but defer checking for errors.
326 */
327 ino = autofs_new_ino(sbi);
328 if (!ino)
329 return -ENOMEM;
330
331 root_inode = autofs_get_inode(s, S_IFDIR | 0755);
332 if (!root_inode)
333 return -ENOMEM;
334
335 root_inode->i_uid = ctx->uid;
336 root_inode->i_gid = ctx->gid;
337 root_inode->i_fop = &autofs_root_operations;
338 root_inode->i_op = &autofs_dir_inode_operations;
339
340 s->s_root = d_make_root(root_inode);
341 if (unlikely(!s->s_root)) {
342 autofs_free_ino(ino);
343 return -ENOMEM;
344 }
345 s->s_root->d_fsdata = ino;
346
347 if (ctx->pgrp_set) {
348 sbi->oz_pgrp = find_get_pid(ctx->pgrp);
349 if (!sbi->oz_pgrp)
350 return invalf(fc, "Could not find process group %d",
351 ctx->pgrp);
352 } else
353 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
354
355 if (autofs_type_trigger(sbi->type))
356 /* s->s_root won't be contended so there's little to
357 * be gained by not taking the d_lock when setting
358 * d_flags, even when a lot mounts are being done.
359 */
360 managed_dentry_set_managed(s->s_root);
361
362 pr_debug("pipe fd = %d, pgrp = %u\n",
363 sbi->pipefd, pid_nr(sbi->oz_pgrp));
364
365 sbi->flags &= ~AUTOFS_SBI_CATATONIC;
366 return 0;
367 }
368
369 /*
370 * Validate the parameters and then request a superblock.
371 */
autofs_get_tree(struct fs_context * fc)372 static int autofs_get_tree(struct fs_context *fc)
373 {
374 struct autofs_sb_info *sbi = fc->s_fs_info;
375 int ret;
376
377 ret = autofs_validate_protocol(fc);
378 if (ret)
379 return ret;
380
381 if (sbi->pipefd < 0)
382 return invalf(fc, "No control pipe specified");
383
384 return get_tree_nodev(fc, autofs_fill_super);
385 }
386
autofs_free_fc(struct fs_context * fc)387 static void autofs_free_fc(struct fs_context *fc)
388 {
389 struct autofs_fs_context *ctx = fc->fs_private;
390 struct autofs_sb_info *sbi = fc->s_fs_info;
391
392 if (sbi) {
393 if (sbi->pipe)
394 fput(sbi->pipe);
395 kfree(sbi);
396 }
397 kfree(ctx);
398 }
399
400 static const struct fs_context_operations autofs_context_ops = {
401 .free = autofs_free_fc,
402 .parse_param = autofs_parse_param,
403 .get_tree = autofs_get_tree,
404 };
405
406 /*
407 * Set up the filesystem mount context.
408 */
autofs_init_fs_context(struct fs_context * fc)409 int autofs_init_fs_context(struct fs_context *fc)
410 {
411 struct autofs_fs_context *ctx;
412 struct autofs_sb_info *sbi;
413
414 ctx = kzalloc(sizeof(struct autofs_fs_context), GFP_KERNEL);
415 if (!ctx)
416 goto nomem;
417
418 ctx->uid = current_uid();
419 ctx->gid = current_gid();
420
421 sbi = autofs_alloc_sbi();
422 if (!sbi)
423 goto nomem_ctx;
424
425 fc->fs_private = ctx;
426 fc->s_fs_info = sbi;
427 fc->ops = &autofs_context_ops;
428 return 0;
429
430 nomem_ctx:
431 kfree(ctx);
432 nomem:
433 return -ENOMEM;
434 }
435
autofs_get_inode(struct super_block * sb,umode_t mode)436 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
437 {
438 struct inode *inode = new_inode(sb);
439
440 if (inode == NULL)
441 return NULL;
442
443 inode->i_mode = mode;
444 if (sb->s_root) {
445 inode->i_uid = d_inode(sb->s_root)->i_uid;
446 inode->i_gid = d_inode(sb->s_root)->i_gid;
447 }
448 simple_inode_init_ts(inode);
449 inode->i_ino = get_next_ino();
450
451 if (S_ISDIR(mode)) {
452 set_nlink(inode, 2);
453 inode->i_op = &autofs_dir_inode_operations;
454 inode->i_fop = &autofs_dir_operations;
455 } else if (S_ISLNK(mode)) {
456 inode->i_op = &autofs_symlink_inode_operations;
457 } else
458 WARN_ON(1);
459
460 return inode;
461 }
462