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#include <linux/parser.h>
 10
 11#include "autofs_i.h"
 12
 13struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
 14{
 15	struct autofs_info *ino;
 16
 17	ino = kzalloc(sizeof(*ino), GFP_KERNEL);
 18	if (ino) {
 19		INIT_LIST_HEAD(&ino->active);
 20		INIT_LIST_HEAD(&ino->expiring);
 21		ino->last_used = jiffies;
 22		ino->sbi = sbi;
 23	}
 24	return ino;
 25}
 26
 27void 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
 34void autofs_free_ino(struct autofs_info *ino)
 35{
 36	kfree_rcu(ino, rcu);
 37}
 38
 39void 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
 61static 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
100static void autofs_evict_inode(struct inode *inode)
101{
102	clear_inode(inode);
103	kfree(inode->i_private);
104}
105
106static const struct super_operations autofs_sops = {
107	.statfs		= simple_statfs,
108	.show_options	= autofs_show_options,
109	.evict_inode	= autofs_evict_inode,
110};
111
112enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
113	Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire,
114	Opt_ignore};
115
116static const match_table_t tokens = {
117	{Opt_fd, "fd=%u"},
118	{Opt_uid, "uid=%u"},
119	{Opt_gid, "gid=%u"},
120	{Opt_pgrp, "pgrp=%u"},
121	{Opt_minproto, "minproto=%u"},
122	{Opt_maxproto, "maxproto=%u"},
123	{Opt_indirect, "indirect"},
124	{Opt_direct, "direct"},
125	{Opt_offset, "offset"},
126	{Opt_strictexpire, "strictexpire"},
127	{Opt_ignore, "ignore"},
128	{Opt_err, NULL}
129};
130
131static int parse_options(char *options,
132			 struct inode *root, int *pgrp, bool *pgrp_set,
133			 struct autofs_sb_info *sbi)
134{
135	char *p;
136	substring_t args[MAX_OPT_ARGS];
137	int option;
138	int pipefd = -1;
139	kuid_t uid;
140	kgid_t gid;
141
142	root->i_uid = current_uid();
143	root->i_gid = current_gid();
144
145	sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
146	sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
147
148	sbi->pipefd = -1;
149
150	if (!options)
151		return 1;
152
153	while ((p = strsep(&options, ",")) != NULL) {
154		int token;
155
156		if (!*p)
157			continue;
158
159		token = match_token(p, tokens, args);
160		switch (token) {
161		case Opt_fd:
162			if (match_int(args, &pipefd))
163				return 1;
164			sbi->pipefd = pipefd;
165			break;
166		case Opt_uid:
167			if (match_int(args, &option))
168				return 1;
169			uid = make_kuid(current_user_ns(), option);
170			if (!uid_valid(uid))
171				return 1;
172			root->i_uid = uid;
173			break;
174		case Opt_gid:
175			if (match_int(args, &option))
176				return 1;
177			gid = make_kgid(current_user_ns(), option);
178			if (!gid_valid(gid))
179				return 1;
180			root->i_gid = gid;
181			break;
182		case Opt_pgrp:
183			if (match_int(args, &option))
184				return 1;
185			*pgrp = option;
186			*pgrp_set = true;
187			break;
188		case Opt_minproto:
189			if (match_int(args, &option))
190				return 1;
191			sbi->min_proto = option;
192			break;
193		case Opt_maxproto:
194			if (match_int(args, &option))
195				return 1;
196			sbi->max_proto = option;
197			break;
198		case Opt_indirect:
199			set_autofs_type_indirect(&sbi->type);
200			break;
201		case Opt_direct:
202			set_autofs_type_direct(&sbi->type);
203			break;
204		case Opt_offset:
205			set_autofs_type_offset(&sbi->type);
206			break;
207		case Opt_strictexpire:
208			sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
209			break;
210		case Opt_ignore:
211			sbi->flags |= AUTOFS_SBI_IGNORE;
212			break;
213		default:
214			return 1;
215		}
216	}
217	return (sbi->pipefd < 0);
218}
219
220int autofs_fill_super(struct super_block *s, void *data, int silent)
221{
222	struct inode *root_inode;
223	struct dentry *root;
224	struct file *pipe;
225	struct autofs_sb_info *sbi;
226	struct autofs_info *ino;
227	int pgrp = 0;
228	bool pgrp_set = false;
229	int ret = -EINVAL;
230
231	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
232	if (!sbi)
233		return -ENOMEM;
234	pr_debug("starting up, sbi = %p\n", sbi);
235
236	s->s_fs_info = sbi;
237	sbi->magic = AUTOFS_SBI_MAGIC;
238	sbi->pipefd = -1;
239	sbi->pipe = NULL;
240	sbi->exp_timeout = 0;
241	sbi->oz_pgrp = NULL;
242	sbi->sb = s;
243	sbi->version = 0;
244	sbi->sub_version = 0;
245	sbi->flags = AUTOFS_SBI_CATATONIC;
246	set_autofs_type_indirect(&sbi->type);
247	sbi->min_proto = 0;
248	sbi->max_proto = 0;
249	mutex_init(&sbi->wq_mutex);
250	mutex_init(&sbi->pipe_mutex);
251	spin_lock_init(&sbi->fs_lock);
252	sbi->queues = NULL;
253	spin_lock_init(&sbi->lookup_lock);
254	INIT_LIST_HEAD(&sbi->active_list);
255	INIT_LIST_HEAD(&sbi->expiring_list);
256	s->s_blocksize = 1024;
257	s->s_blocksize_bits = 10;
258	s->s_magic = AUTOFS_SUPER_MAGIC;
259	s->s_op = &autofs_sops;
260	s->s_d_op = &autofs_dentry_operations;
261	s->s_time_gran = 1;
262
263	/*
264	 * Get the root inode and dentry, but defer checking for errors.
265	 */
266	ino = autofs_new_ino(sbi);
267	if (!ino) {
268		ret = -ENOMEM;
269		goto fail_free;
270	}
271	root_inode = autofs_get_inode(s, S_IFDIR | 0755);
272	root = d_make_root(root_inode);
273	if (!root) {
274		ret = -ENOMEM;
275		goto fail_ino;
276	}
277	pipe = NULL;
278
279	root->d_fsdata = ino;
280
281	/* Can this call block? */
282	if (parse_options(data, root_inode, &pgrp, &pgrp_set, sbi)) {
283		pr_err("called with bogus options\n");
284		goto fail_dput;
285	}
286
287	/* Test versions first */
288	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
289	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
290		pr_err("kernel does not match daemon version "
291		       "daemon (%d, %d) kernel (%d, %d)\n",
292		       sbi->min_proto, sbi->max_proto,
293		       AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
294		goto fail_dput;
295	}
296
297	/* Establish highest kernel protocol version */
298	if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
299		sbi->version = AUTOFS_MAX_PROTO_VERSION;
300	else
301		sbi->version = sbi->max_proto;
302	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
303
304	if (pgrp_set) {
305		sbi->oz_pgrp = find_get_pid(pgrp);
306		if (!sbi->oz_pgrp) {
307			pr_err("could not find process group %d\n",
308				pgrp);
309			goto fail_dput;
310		}
311	} else {
312		sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
313	}
314
315	if (autofs_type_trigger(sbi->type))
316		__managed_dentry_set_managed(root);
317
318	root_inode->i_fop = &autofs_root_operations;
319	root_inode->i_op = &autofs_dir_inode_operations;
320
321	pr_debug("pipe fd = %d, pgrp = %u\n",
322		 sbi->pipefd, pid_nr(sbi->oz_pgrp));
323	pipe = fget(sbi->pipefd);
324
325	if (!pipe) {
326		pr_err("could not open pipe file descriptor\n");
327		goto fail_put_pid;
328	}
329	ret = autofs_prepare_pipe(pipe);
330	if (ret < 0)
331		goto fail_fput;
332	sbi->pipe = pipe;
333	sbi->flags &= ~AUTOFS_SBI_CATATONIC;
334
335	/*
336	 * Success! Install the root dentry now to indicate completion.
337	 */
338	s->s_root = root;
339	return 0;
340
341	/*
342	 * Failure ... clean up.
343	 */
344fail_fput:
345	pr_err("pipe file descriptor does not contain proper ops\n");
346	fput(pipe);
347fail_put_pid:
348	put_pid(sbi->oz_pgrp);
349fail_dput:
350	dput(root);
351	goto fail_free;
352fail_ino:
353	autofs_free_ino(ino);
354fail_free:
355	kfree(sbi);
356	s->s_fs_info = NULL;
357	return ret;
358}
359
360struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
361{
362	struct inode *inode = new_inode(sb);
363
364	if (inode == NULL)
365		return NULL;
366
367	inode->i_mode = mode;
368	if (sb->s_root) {
369		inode->i_uid = d_inode(sb->s_root)->i_uid;
370		inode->i_gid = d_inode(sb->s_root)->i_gid;
371	}
372	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
373	inode->i_ino = get_next_ino();
374
375	if (S_ISDIR(mode)) {
376		set_nlink(inode, 2);
377		inode->i_op = &autofs_dir_inode_operations;
378		inode->i_fop = &autofs_dir_operations;
379	} else if (S_ISLNK(mode)) {
380		inode->i_op = &autofs_symlink_inode_operations;
381	} else
382		WARN_ON(1);
383
384	return inode;
385}