fs/autofs/inode.c

   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
  13 struct 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                 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->last_used = jiffies;
  33 }
  34
  35 void autofs_free_ino(struct autofs_info *ino)
  36 {
  37         kfree_rcu(ino, rcu);
  38 }
  39
  40 void autofs_kill_sb(struct super_block *sb)
  41 {
  42         struct autofs_sb_info *sbi = autofs_sbi(sb);
  43
  44         /*
  45          * In the event of a failure in get_sb_nodev the superblock
  46          * info is not present so nothing else has been setup, so
  47          * just call kill_anon_super when we are called from
  48          * deactivate_super.
  49          */
  50         if (sbi) {
  51                 /* Free wait queues, close pipe */
  52                 autofs_catatonic_mode(sbi);
  53                 put_pid(sbi->oz_pgrp);
  54         }
  55
  56         pr_debug("shutting down\n");
  57         kill_litter_super(sb);
  58         if (sbi)
  59                 kfree_rcu(sbi, rcu);
  60 }
  61
  62 static int autofs_show_options(struct seq_file *m, struct dentry *root)
  63 {
  64         struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
  65         struct inode *root_inode = d_inode(root->d_sb->s_root);
  66
  67         if (!sbi)
  68                 return 0;
  69
  70         seq_printf(m, ",fd=%d", sbi->pipefd);
  71         if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
  72                 seq_printf(m, ",uid=%u",
  73                         from_kuid_munged(&init_user_ns, root_inode->i_uid));
  74         if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
  75                 seq_printf(m, ",gid=%u",
  76                         from_kgid_munged(&init_user_ns, root_inode->i_gid));
  77         seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
  78         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
  79         seq_printf(m, ",minproto=%d", sbi->min_proto);
  80         seq_printf(m, ",maxproto=%d", sbi->max_proto);
  81
  82         if (autofs_type_offset(sbi->type))
  83                 seq_puts(m, ",offset");
  84         else if (autofs_type_direct(sbi->type))
  85                 seq_puts(m, ",direct");
  86         else
  87                 seq_puts(m, ",indirect");
  88         if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
  89                 seq_puts(m, ",strictexpire");
  90         if (sbi->flags & AUTOFS_SBI_IGNORE)
  91                 seq_puts(m, ",ignore");
  92 #ifdef CONFIG_CHECKPOINT_RESTORE
  93         if (sbi->pipe)
  94                 seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
  95         else
  96                 seq_puts(m, ",pipe_ino=-1");
  97 #endif
  98         return 0;
  99 }
 100
 101 static void autofs_evict_inode(struct inode *inode)
 102 {
 103         clear_inode(inode);
 104         kfree(inode->i_private);
 105 }
 106
 107 static const struct super_operations autofs_sops = {
 108         .statfs         = simple_statfs,
 109         .show_options   = autofs_show_options,
 110         .evict_inode    = autofs_evict_inode,
 111 };
 112
 113 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 114         Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire,
 115         Opt_ignore};
 116
 117 static const match_table_t tokens = {
 118         {Opt_fd, "fd=%u"},
 119         {Opt_uid, "uid=%u"},
 120         {Opt_gid, "gid=%u"},
 121         {Opt_pgrp, "pgrp=%u"},
 122         {Opt_minproto, "minproto=%u"},
 123         {Opt_maxproto, "maxproto=%u"},
 124         {Opt_indirect, "indirect"},
 125         {Opt_direct, "direct"},
 126         {Opt_offset, "offset"},
 127         {Opt_strictexpire, "strictexpire"},
 128         {Opt_ignore, "ignore"},
 129         {Opt_err, NULL}
 130 };
 131
 132 static int parse_options(char *options,
 133                          struct inode *root, int *pgrp, bool *pgrp_set,
 134                          struct autofs_sb_info *sbi)
 135 {
 136         char *p;
 137         substring_t args[MAX_OPT_ARGS];
 138         int option;
 139         int pipefd = -1;
 140         kuid_t uid;
 141         kgid_t gid;
 142
 143         root->i_uid = current_uid();
 144         root->i_gid = current_gid();
 145
 146         sbi->min_proto = AUTOFS_MIN_PROTO_VERSION;
 147         sbi->max_proto = AUTOFS_MAX_PROTO_VERSION;
 148
 149         sbi->pipefd = -1;
 150
 151         if (!options)
 152                 return 1;
 153
 154         while ((p = strsep(&options, ",")) != NULL) {
 155                 int token;
 156
 157                 if (!*p)
 158                         continue;
 159
 160                 token = match_token(p, tokens, args);
 161                 switch (token) {
 162                 case Opt_fd:
 163                         if (match_int(args, &pipefd))
 164                                 return 1;
 165                         sbi->pipefd = pipefd;
 166                         break;
 167                 case Opt_uid:
 168                         if (match_int(args, &option))
 169                                 return 1;
 170                         uid = make_kuid(current_user_ns(), option);
 171                         if (!uid_valid(uid))
 172                                 return 1;
 173                         root->i_uid = uid;
 174                         break;
 175                 case Opt_gid:
 176                         if (match_int(args, &option))
 177                                 return 1;
 178                         gid = make_kgid(current_user_ns(), option);
 179                         if (!gid_valid(gid))
 180                                 return 1;
 181                         root->i_gid = gid;
 182                         break;
 183                 case Opt_pgrp:
 184                         if (match_int(args, &option))
 185                                 return 1;
 186                         *pgrp = option;
 187                         *pgrp_set = true;
 188                         break;
 189                 case Opt_minproto:
 190                         if (match_int(args, &option))
 191                                 return 1;
 192                         sbi->min_proto = option;
 193                         break;
 194                 case Opt_maxproto:
 195                         if (match_int(args, &option))
 196                                 return 1;
 197                         sbi->max_proto = option;
 198                         break;
 199                 case Opt_indirect:
 200                         set_autofs_type_indirect(&sbi->type);
 201                         break;
 202                 case Opt_direct:
 203                         set_autofs_type_direct(&sbi->type);
 204                         break;
 205                 case Opt_offset:
 206                         set_autofs_type_offset(&sbi->type);
 207                         break;
 208                 case Opt_strictexpire:
 209                         sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
 210                         break;
 211                 case Opt_ignore:
 212                         sbi->flags |= AUTOFS_SBI_IGNORE;
 213                         break;
 214                 default:
 215                         return 1;
 216                 }
 217         }
 218         return (sbi->pipefd < 0);
 219 }
 220
 221 int autofs_fill_super(struct super_block *s, void *data, int silent)
 222 {
 223         struct inode *root_inode;
 224         struct dentry *root;
 225         struct file *pipe;
 226         struct autofs_sb_info *sbi;
 227         struct autofs_info *ino;
 228         int pgrp = 0;
 229         bool pgrp_set = false;
 230         int ret = -EINVAL;
 231
 232         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 233         if (!sbi)
 234                 return -ENOMEM;
 235         pr_debug("starting up, sbi = %p\n", sbi);
 236
 237         s->s_fs_info = sbi;
 238         sbi->magic = AUTOFS_SBI_MAGIC;
 239         sbi->pipefd = -1;
 240         sbi->pipe = NULL;
 241         sbi->exp_timeout = 0;
 242         sbi->oz_pgrp = NULL;
 243         sbi->sb = s;
 244         sbi->version = 0;
 245         sbi->sub_version = 0;
 246         sbi->flags = AUTOFS_SBI_CATATONIC;
 247         set_autofs_type_indirect(&sbi->type);
 248         sbi->min_proto = 0;
 249         sbi->max_proto = 0;
 250         mutex_init(&sbi->wq_mutex);
 251         mutex_init(&sbi->pipe_mutex);
 252         spin_lock_init(&sbi->fs_lock);
 253         sbi->queues = NULL;
 254         spin_lock_init(&sbi->lookup_lock);
 255         INIT_LIST_HEAD(&sbi->active_list);
 256         INIT_LIST_HEAD(&sbi->expiring_list);
 257         s->s_blocksize = 1024;
 258         s->s_blocksize_bits = 10;
 259         s->s_magic = AUTOFS_SUPER_MAGIC;
 260         s->s_op = &autofs_sops;
 261         s->s_d_op = &autofs_dentry_operations;
 262         s->s_time_gran = 1;
 263
 264         /*
 265          * Get the root inode and dentry, but defer checking for errors.
 266          */
 267         ino = autofs_new_ino(sbi);
 268         if (!ino) {
 269                 ret = -ENOMEM;
 270                 goto fail_free;
 271         }
 272         root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 273         root = d_make_root(root_inode);
 274         if (!root) {
 275                 ret = -ENOMEM;
 276                 goto fail_ino;
 277         }
 278         pipe = NULL;
 279
 280         root->d_fsdata = ino;
 281
 282         /* Can this call block? */
 283         if (parse_options(data, root_inode, &pgrp, &pgrp_set, sbi)) {
 284                 pr_err("called with bogus options\n");
 285                 goto fail_dput;
 286         }
 287
 288         /* Test versions first */
 289         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 290             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 291                 pr_err("kernel does not match daemon version "
 292                        "daemon (%d, %d) kernel (%d, %d)\n",
 293                        sbi->min_proto, sbi->max_proto,
 294                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 295                 goto fail_dput;
 296         }
 297
 298         /* Establish highest kernel protocol version */
 299         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 300                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 301         else
 302                 sbi->version = sbi->max_proto;
 303         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 304
 305         if (pgrp_set) {
 306                 sbi->oz_pgrp = find_get_pid(pgrp);
 307                 if (!sbi->oz_pgrp) {
 308                         pr_err("could not find process group %d\n",
 309                                 pgrp);
 310                         goto fail_dput;
 311                 }
 312         } else {
 313                 sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
 314         }
 315
 316         if (autofs_type_trigger(sbi->type))
 317                 __managed_dentry_set_managed(root);
 318
 319         root_inode->i_fop = &autofs_root_operations;
 320         root_inode->i_op = &autofs_dir_inode_operations;
 321
 322         pr_debug("pipe fd = %d, pgrp = %u\n",
 323                  sbi->pipefd, pid_nr(sbi->oz_pgrp));
 324         pipe = fget(sbi->pipefd);
 325
 326         if (!pipe) {
 327                 pr_err("could not open pipe file descriptor\n");
 328                 goto fail_put_pid;
 329         }
 330         ret = autofs_prepare_pipe(pipe);
 331         if (ret < 0)
 332                 goto fail_fput;
 333         sbi->pipe = pipe;
 334         sbi->flags &= ~AUTOFS_SBI_CATATONIC;
 335
 336         /*
 337          * Success! Install the root dentry now to indicate completion.
 338          */
 339         s->s_root = root;
 340         return 0;
 341
 342         /*
 343          * Failure ... clean up.
 344          */
 345 fail_fput:
 346         pr_err("pipe file descriptor does not contain proper ops\n");
 347         fput(pipe);
 348 fail_put_pid:
 349         put_pid(sbi->oz_pgrp);
 350 fail_dput:
 351         dput(root);
 352         goto fail_free;
 353 fail_ino:
 354         autofs_free_ino(ino);
 355 fail_free:
 356         kfree(sbi);
 357         s->s_fs_info = NULL;
 358         return ret;
 359 }
 360
 361 struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
 362 {
 363         struct inode *inode = new_inode(sb);
 364
 365         if (inode == NULL)
 366                 return NULL;
 367
 368         inode->i_mode = mode;
 369         if (sb->s_root) {
 370                 inode->i_uid = d_inode(sb->s_root)->i_uid;
 371                 inode->i_gid = d_inode(sb->s_root)->i_gid;
 372         }
 373         inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
 374         inode->i_ino = get_next_ino();
 375
 376         if (S_ISDIR(mode)) {
 377                 set_nlink(inode, 2);
 378                 inode->i_op = &autofs_dir_inode_operations;
 379                 inode->i_fop = &autofs_dir_operations;
 380         } else if (S_ISLNK(mode)) {
 381                 inode->i_op = &autofs_symlink_inode_operations;
 382         } else
 383                 WARN_ON(1);
 384
 385         return inode;
 386 }