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_obj(*ino); 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->exp_timeout = -1; 23 ino->count = 1; 24 } 25 return ino; 26 } 27 28 void 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 36 void autofs_free_ino(struct autofs_info *ino) 37 { 38 kfree_rcu(ino, rcu); 39 } 40 41 void 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 if (sbi->pipe) { 55 fput(sbi->pipe); 56 sbi->pipe = NULL; 57 } 58 put_pid(sbi->oz_pgrp); 59 } 60 61 pr_debug("shutting down\n"); 62 kill_anon_super(sb); 63 if (sbi) 64 kfree_rcu(sbi, rcu); 65 } 66 67 static int autofs_show_options(struct seq_file *m, struct dentry *root) 68 { 69 struct autofs_sb_info *sbi = autofs_sbi(root->d_sb); 70 struct inode *root_inode = d_inode(root->d_sb->s_root); 71 72 if (!sbi) 73 return 0; 74 75 seq_printf(m, ",fd=%d", sbi->pipefd); 76 if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID)) 77 seq_printf(m, ",uid=%u", 78 from_kuid_munged(&init_user_ns, root_inode->i_uid)); 79 if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID)) 80 seq_printf(m, ",gid=%u", 81 from_kgid_munged(&init_user_ns, root_inode->i_gid)); 82 seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp)); 83 seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ); 84 seq_printf(m, ",minproto=%d", sbi->min_proto); 85 seq_printf(m, ",maxproto=%d", sbi->max_proto); 86 87 if (autofs_type_offset(sbi->type)) 88 seq_puts(m, ",offset"); 89 else if (autofs_type_direct(sbi->type)) 90 seq_puts(m, ",direct"); 91 else 92 seq_puts(m, ",indirect"); 93 if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE) 94 seq_puts(m, ",strictexpire"); 95 if (sbi->flags & AUTOFS_SBI_IGNORE) 96 seq_puts(m, ",ignore"); 97 #ifdef CONFIG_CHECKPOINT_RESTORE 98 if (sbi->pipe) 99 seq_printf(m, ",pipe_ino=%llu", file_inode(sbi->pipe)->i_ino); 100 else 101 seq_puts(m, ",pipe_ino=-1"); 102 #endif 103 return 0; 104 } 105 106 static void autofs_evict_inode(struct inode *inode) 107 { 108 clear_inode(inode); 109 kfree(inode->i_private); 110 } 111 112 static const struct super_operations autofs_sops = { 113 .statfs = simple_statfs, 114 .show_options = autofs_show_options, 115 .evict_inode = autofs_evict_inode, 116 }; 117 118 enum { 119 Opt_direct, 120 Opt_fd, 121 Opt_gid, 122 Opt_ignore, 123 Opt_indirect, 124 Opt_maxproto, 125 Opt_minproto, 126 Opt_offset, 127 Opt_pgrp, 128 Opt_strictexpire, 129 Opt_uid, 130 }; 131 132 const struct fs_parameter_spec autofs_param_specs[] = { 133 fsparam_flag ("direct", Opt_direct), 134 fsparam_fd ("fd", Opt_fd), 135 fsparam_gid ("gid", Opt_gid), 136 fsparam_flag ("ignore", Opt_ignore), 137 fsparam_flag ("indirect", Opt_indirect), 138 fsparam_u32 ("maxproto", Opt_maxproto), 139 fsparam_u32 ("minproto", Opt_minproto), 140 fsparam_flag ("offset", Opt_offset), 141 fsparam_u32 ("pgrp", Opt_pgrp), 142 fsparam_flag ("strictexpire", Opt_strictexpire), 143 fsparam_uid ("uid", Opt_uid), 144 {} 145 }; 146 147 struct autofs_fs_context { 148 kuid_t uid; 149 kgid_t gid; 150 int pgrp; 151 bool pgrp_set; 152 }; 153 154 /* 155 * Open the fd. We do it here rather than in get_tree so that it's done in the 156 * context of the system call that passed the data and not the one that 157 * triggered the superblock creation, lest the fd gets reassigned. 158 */ 159 static int autofs_parse_fd(struct fs_context *fc, struct autofs_sb_info *sbi, 160 struct fs_parameter *param, 161 struct fs_parse_result *result) 162 { 163 struct file *pipe; 164 int ret; 165 166 if (param->type == fs_value_is_file) { 167 /* came through the new api */ 168 pipe = param->file; 169 param->file = NULL; 170 } else { 171 pipe = fget(result->uint_32); 172 } 173 if (!pipe) { 174 errorf(fc, "could not open pipe file descriptor"); 175 return -EBADF; 176 } 177 178 ret = autofs_check_pipe(pipe); 179 if (ret < 0) { 180 errorf(fc, "Invalid/unusable pipe"); 181 fput(pipe); 182 return -EBADF; 183 } 184 185 autofs_set_packet_pipe_flags(pipe); 186 187 if (sbi->pipe) 188 fput(sbi->pipe); 189 190 sbi->pipefd = result->uint_32; 191 sbi->pipe = pipe; 192 193 return 0; 194 } 195 196 static int autofs_parse_param(struct fs_context *fc, struct fs_parameter *param) 197 { 198 struct autofs_fs_context *ctx = fc->fs_private; 199 struct autofs_sb_info *sbi = fc->s_fs_info; 200 struct fs_parse_result result; 201 int opt; 202 203 opt = fs_parse(fc, autofs_param_specs, param, &result); 204 if (opt < 0) 205 return opt; 206 207 switch (opt) { 208 case Opt_fd: 209 return autofs_parse_fd(fc, sbi, param, &result); 210 case Opt_uid: 211 ctx->uid = result.uid; 212 break; 213 case Opt_gid: 214 ctx->gid = result.gid; 215 break; 216 case Opt_pgrp: 217 ctx->pgrp = result.uint_32; 218 ctx->pgrp_set = true; 219 break; 220 case Opt_minproto: 221 sbi->min_proto = result.uint_32; 222 break; 223 case Opt_maxproto: 224 sbi->max_proto = result.uint_32; 225 break; 226 case Opt_indirect: 227 set_autofs_type_indirect(&sbi->type); 228 break; 229 case Opt_direct: 230 set_autofs_type_direct(&sbi->type); 231 break; 232 case Opt_offset: 233 set_autofs_type_offset(&sbi->type); 234 break; 235 case Opt_strictexpire: 236 sbi->flags |= AUTOFS_SBI_STRICTEXPIRE; 237 break; 238 case Opt_ignore: 239 sbi->flags |= AUTOFS_SBI_IGNORE; 240 } 241 242 return 0; 243 } 244 245 static struct autofs_sb_info *autofs_alloc_sbi(void) 246 { 247 struct autofs_sb_info *sbi; 248 249 sbi = kzalloc_obj(*sbi); 250 if (!sbi) 251 return NULL; 252 253 sbi->magic = AUTOFS_SBI_MAGIC; 254 sbi->flags = AUTOFS_SBI_CATATONIC; 255 sbi->min_proto = AUTOFS_MIN_PROTO_VERSION; 256 sbi->max_proto = AUTOFS_MAX_PROTO_VERSION; 257 sbi->pipefd = -1; 258 sbi->mnt_ns_id = to_ns_common(current->nsproxy->mnt_ns)->ns_id; 259 260 set_autofs_type_indirect(&sbi->type); 261 mutex_init(&sbi->wq_mutex); 262 mutex_init(&sbi->pipe_mutex); 263 spin_lock_init(&sbi->fs_lock); 264 spin_lock_init(&sbi->lookup_lock); 265 INIT_LIST_HEAD(&sbi->active_list); 266 INIT_LIST_HEAD(&sbi->expiring_list); 267 268 return sbi; 269 } 270 271 static int autofs_validate_protocol(struct fs_context *fc) 272 { 273 struct autofs_sb_info *sbi = fc->s_fs_info; 274 275 /* Test versions first */ 276 if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION || 277 sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) { 278 errorf(fc, "kernel does not match daemon version " 279 "daemon (%d, %d) kernel (%d, %d)\n", 280 sbi->min_proto, sbi->max_proto, 281 AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION); 282 return -EINVAL; 283 } 284 285 /* Establish highest kernel protocol version */ 286 if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION) 287 sbi->version = AUTOFS_MAX_PROTO_VERSION; 288 else 289 sbi->version = sbi->max_proto; 290 291 switch (sbi->version) { 292 case 4: 293 sbi->sub_version = 7; 294 break; 295 case 5: 296 sbi->sub_version = AUTOFS_PROTO_SUBVERSION; 297 break; 298 default: 299 sbi->sub_version = 0; 300 } 301 302 return 0; 303 } 304 305 static int autofs_fill_super(struct super_block *s, struct fs_context *fc) 306 { 307 struct autofs_fs_context *ctx = fc->fs_private; 308 struct autofs_sb_info *sbi = s->s_fs_info; 309 struct inode *root_inode; 310 struct autofs_info *ino; 311 312 pr_debug("starting up, sbi = %p\n", sbi); 313 314 sbi->sb = s; 315 s->s_blocksize = 1024; 316 s->s_blocksize_bits = 10; 317 s->s_magic = AUTOFS_SUPER_MAGIC; 318 s->s_op = &autofs_sops; 319 set_default_d_op(s, &autofs_dentry_operations); 320 s->s_time_gran = 1; 321 322 /* 323 * Get the root inode and dentry, but defer checking for errors. 324 */ 325 ino = autofs_new_ino(sbi); 326 if (!ino) 327 return -ENOMEM; 328 329 root_inode = autofs_get_inode(s, S_IFDIR | 0755); 330 if (!root_inode) { 331 autofs_free_ino(ino); 332 return -ENOMEM; 333 } 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 */ 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 } 386 387 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 */ 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_obj(struct autofs_fs_context); 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 } 435 436 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