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         }
  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 {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
 116 static 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
 131 static 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
 220 int 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          */
 344 fail_fput:
 345         pr_err("pipe file descriptor does not contain proper ops\n");
 346         fput(pipe);
 347 fail_put_pid:
 348         put_pid(sbi->oz_pgrp);
 349 fail_dput:
 350         dput(root);
 351         goto fail_free;
 352 fail_ino:
 353         autofs_free_ino(ino);
 354 fail_free:
 355         kfree(sbi);
 356         s->s_fs_info = NULL;
 357         return ret;
 358 }
 359
 360 struct 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 }