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_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 */ 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 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 } 247 248 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 } 272 273 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 } 306 307 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 dentry *root; 313 struct autofs_info *ino; 314 int ret = -ENOMEM; 315 316 pr_debug("starting up, sbi = %p\n", sbi); 317 318 sbi->sb = s; 319 s->s_blocksize = 1024; 320 s->s_blocksize_bits = 10; 321 s->s_magic = AUTOFS_SUPER_MAGIC; 322 s->s_op = &autofs_sops; 323 s->s_d_op = &autofs_dentry_operations; 324 s->s_time_gran = 1; 325 326 /* 327 * Get the root inode and dentry, but defer checking for errors. 328 */ 329 ino = autofs_new_ino(sbi); 330 if (!ino) 331 goto fail; 332 333 root_inode = autofs_get_inode(s, S_IFDIR | 0755); 334 root_inode->i_uid = ctx->uid; 335 root_inode->i_gid = ctx->gid; 336 337 root = d_make_root(root_inode); 338 if (!root) 339 goto fail_ino; 340 341 root->d_fsdata = ino; 342 343 if (ctx->pgrp_set) { 344 sbi->oz_pgrp = find_get_pid(ctx->pgrp); 345 if (!sbi->oz_pgrp) { 346 ret = invalf(fc, "Could not find process group %d", 347 ctx->pgrp); 348 goto fail_dput; 349 } 350 } else { 351 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID); 352 } 353 354 if (autofs_type_trigger(sbi->type)) 355 __managed_dentry_set_managed(root); 356 357 root_inode->i_fop = &autofs_root_operations; 358 root_inode->i_op = &autofs_dir_inode_operations; 359 360 pr_debug("pipe fd = %d, pgrp = %u\n", 361 sbi->pipefd, pid_nr(sbi->oz_pgrp)); 362 363 sbi->flags &= ~AUTOFS_SBI_CATATONIC; 364 365 /* 366 * Success! Install the root dentry now to indicate completion. 367 */ 368 s->s_root = root; 369 return 0; 370 371 /* 372 * Failure ... clean up. 373 */ 374 fail_dput: 375 dput(root); 376 goto fail; 377 fail_ino: 378 autofs_free_ino(ino); 379 fail: 380 return ret; 381 } 382 383 /* 384 * Validate the parameters and then request a superblock. 385 */ 386 static int autofs_get_tree(struct fs_context *fc) 387 { 388 struct autofs_sb_info *sbi = fc->s_fs_info; 389 int ret; 390 391 ret = autofs_validate_protocol(fc); 392 if (ret) 393 return ret; 394 395 if (sbi->pipefd < 0) 396 return invalf(fc, "No control pipe specified"); 397 398 return get_tree_nodev(fc, autofs_fill_super); 399 } 400 401 static void autofs_free_fc(struct fs_context *fc) 402 { 403 struct autofs_fs_context *ctx = fc->fs_private; 404 struct autofs_sb_info *sbi = fc->s_fs_info; 405 406 if (sbi) { 407 if (sbi->pipe) 408 fput(sbi->pipe); 409 kfree(sbi); 410 } 411 kfree(ctx); 412 } 413 414 static const struct fs_context_operations autofs_context_ops = { 415 .free = autofs_free_fc, 416 .parse_param = autofs_parse_param, 417 .get_tree = autofs_get_tree, 418 }; 419 420 /* 421 * Set up the filesystem mount context. 422 */ 423 int autofs_init_fs_context(struct fs_context *fc) 424 { 425 struct autofs_fs_context *ctx; 426 struct autofs_sb_info *sbi; 427 428 ctx = kzalloc(sizeof(struct autofs_fs_context), GFP_KERNEL); 429 if (!ctx) 430 goto nomem; 431 432 ctx->uid = current_uid(); 433 ctx->gid = current_gid(); 434 435 sbi = autofs_alloc_sbi(); 436 if (!sbi) 437 goto nomem_ctx; 438 439 fc->fs_private = ctx; 440 fc->s_fs_info = sbi; 441 fc->ops = &autofs_context_ops; 442 return 0; 443 444 nomem_ctx: 445 kfree(ctx); 446 nomem: 447 return -ENOMEM; 448 } 449 450 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode) 451 { 452 struct inode *inode = new_inode(sb); 453 454 if (inode == NULL) 455 return NULL; 456 457 inode->i_mode = mode; 458 if (sb->s_root) { 459 inode->i_uid = d_inode(sb->s_root)->i_uid; 460 inode->i_gid = d_inode(sb->s_root)->i_gid; 461 } 462 simple_inode_init_ts(inode); 463 inode->i_ino = get_next_ino(); 464 465 if (S_ISDIR(mode)) { 466 set_nlink(inode, 2); 467 inode->i_op = &autofs_dir_inode_operations; 468 inode->i_fop = &autofs_dir_operations; 469 } else if (S_ISLNK(mode)) { 470 inode->i_op = &autofs_symlink_inode_operations; 471 } else 472 WARN_ON(1); 473 474 return inode; 475 } 476