fs/jffs2/acl.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2006  NEC Corporation
   5  *
   6  * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/fs.h>
  14 #include <linux/sched.h>
  15 #include <linux/time.h>
  16 #include <linux/crc32.h>
  17 #include <linux/jffs2.h>
  18 #include <linux/xattr.h>
  19 #include <linux/posix_acl_xattr.h>
  20 #include <linux/mtd/mtd.h>
  21 #include "nodelist.h"
  22
  23 static size_t jffs2_acl_size(int count)
  24 {
  25         if (count <= 4) {
  26                 return sizeof(struct jffs2_acl_header)
  27                        + count * sizeof(struct jffs2_acl_entry_short);
  28         } else {
  29                 return sizeof(struct jffs2_acl_header)
  30                        + 4 * sizeof(struct jffs2_acl_entry_short)
  31                        + (count - 4) * sizeof(struct jffs2_acl_entry);
  32         }
  33 }
  34
  35 static int jffs2_acl_count(size_t size)
  36 {
  37         size_t s;
  38
  39         size -= sizeof(struct jffs2_acl_header);
  40         s = size - 4 * sizeof(struct jffs2_acl_entry_short);
  41         if (s < 0) {
  42                 if (size % sizeof(struct jffs2_acl_entry_short))
  43                         return -1;
  44                 return size / sizeof(struct jffs2_acl_entry_short);
  45         } else {
  46                 if (s % sizeof(struct jffs2_acl_entry))
  47                         return -1;
  48                 return s / sizeof(struct jffs2_acl_entry) + 4;
  49         }
  50 }
  51
  52 static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
  53 {
  54         void *end = value + size;
  55         struct jffs2_acl_header *header = value;
  56         struct jffs2_acl_entry *entry;
  57         struct posix_acl *acl;
  58         uint32_t ver;
  59         int i, count;
  60
  61         if (!value)
  62                 return NULL;
  63         if (size < sizeof(struct jffs2_acl_header))
  64                 return ERR_PTR(-EINVAL);
  65         ver = je32_to_cpu(header->a_version);
  66         if (ver != JFFS2_ACL_VERSION) {
  67                 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
  68                 return ERR_PTR(-EINVAL);
  69         }
  70
  71         value += sizeof(struct jffs2_acl_header);
  72         count = jffs2_acl_count(size);
  73         if (count < 0)
  74                 return ERR_PTR(-EINVAL);
  75         if (count == 0)
  76                 return NULL;
  77
  78         acl = posix_acl_alloc(count, GFP_KERNEL);
  79         if (!acl)
  80                 return ERR_PTR(-ENOMEM);
  81
  82         for (i=0; i < count; i++) {
  83                 entry = value;
  84                 if (value + sizeof(struct jffs2_acl_entry_short) > end)
  85                         goto fail;
  86                 acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
  87                 acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
  88                 switch (acl->a_entries[i].e_tag) {
  89                         case ACL_USER_OBJ:
  90                         case ACL_GROUP_OBJ:
  91                         case ACL_MASK:
  92                         case ACL_OTHER:
  93                                 value += sizeof(struct jffs2_acl_entry_short);
  94                                 acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
  95                                 break;
  96
  97                         case ACL_USER:
  98                         case ACL_GROUP:
  99                                 value += sizeof(struct jffs2_acl_entry);
 100                                 if (value > end)
 101                                         goto fail;
 102                                 acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);
 103                                 break;
 104
 105                         default:
 106                                 goto fail;
 107                 }
 108         }
 109         if (value != end)
 110                 goto fail;
 111         return acl;
 112  fail:
 113         posix_acl_release(acl);
 114         return ERR_PTR(-EINVAL);
 115 }
 116
 117 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
 118 {
 119         struct jffs2_acl_header *header;
 120         struct jffs2_acl_entry *entry;
 121         void *e;
 122         size_t i;
 123
 124         *size = jffs2_acl_size(acl->a_count);
 125         header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
 126         if (!header)
 127                 return ERR_PTR(-ENOMEM);
 128         header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
 129         e = header + 1;
 130         for (i=0; i < acl->a_count; i++) {
 131                 entry = e;
 132                 entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
 133                 entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
 134                 switch(acl->a_entries[i].e_tag) {
 135                         case ACL_USER:
 136                         case ACL_GROUP:
 137                                 entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
 138                                 e += sizeof(struct jffs2_acl_entry);
 139                                 break;
 140
 141                         case ACL_USER_OBJ:
 142                         case ACL_GROUP_OBJ:
 143                         case ACL_MASK:
 144                         case ACL_OTHER:
 145                                 e += sizeof(struct jffs2_acl_entry_short);
 146                                 break;
 147
 148                         default:
 149                                 goto fail;
 150                 }
 151         }
 152         return header;
 153  fail:
 154         kfree(header);
 155         return ERR_PTR(-EINVAL);
 156 }
 157
 158 static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
 159 {
 160         struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;
 161
 162         spin_lock(&inode->i_lock);
 163         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 164                 acl = posix_acl_dup(*i_acl);
 165         spin_unlock(&inode->i_lock);
 166         return acl;
 167 }
 168
 169 static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
 170 {
 171         spin_lock(&inode->i_lock);
 172         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 173                 posix_acl_release(*i_acl);
 174         *i_acl = posix_acl_dup(acl);
 175         spin_unlock(&inode->i_lock);
 176 }
 177
 178 static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
 179 {
 180         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 181         struct posix_acl *acl;
 182         char *value = NULL;
 183         int rc, xprefix;
 184
 185         switch (type) {
 186         case ACL_TYPE_ACCESS:
 187                 acl = jffs2_iget_acl(inode, &f->i_acl_access);
 188                 if (acl != JFFS2_ACL_NOT_CACHED)
 189                         return acl;
 190                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 191                 break;
 192         case ACL_TYPE_DEFAULT:
 193                 acl = jffs2_iget_acl(inode, &f->i_acl_default);
 194                 if (acl != JFFS2_ACL_NOT_CACHED)
 195                         return acl;
 196                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 197                 break;
 198         default:
 199                 return ERR_PTR(-EINVAL);
 200         }
 201         rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
 202         if (rc > 0) {
 203                 value = kmalloc(rc, GFP_KERNEL);
 204                 if (!value)
 205                         return ERR_PTR(-ENOMEM);
 206                 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
 207         }
 208         if (rc > 0) {
 209                 acl = jffs2_acl_from_medium(value, rc);
 210         } else if (rc == -ENODATA || rc == -ENOSYS) {
 211                 acl = NULL;
 212         } else {
 213                 acl = ERR_PTR(rc);
 214         }
 215         if (value)
 216                 kfree(value);
 217         if (!IS_ERR(acl)) {
 218                 switch (type) {
 219                 case ACL_TYPE_ACCESS:
 220                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 221                         break;
 222                 case ACL_TYPE_DEFAULT:
 223                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 224                         break;
 225                 }
 226         }
 227         return acl;
 228 }
 229
 230 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 231 {
 232         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 233         size_t size = 0;
 234         char *value = NULL;
 235         int rc, xprefix;
 236
 237         if (S_ISLNK(inode->i_mode))
 238                 return -EOPNOTSUPP;
 239
 240         switch (type) {
 241         case ACL_TYPE_ACCESS:
 242                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 243                 if (acl) {
 244                         mode_t mode = inode->i_mode;
 245                         rc = posix_acl_equiv_mode(acl, &mode);
 246                         if (rc < 0)
 247                                 return rc;
 248                         if (inode->i_mode != mode) {
 249                                 inode->i_mode = mode;
 250                                 jffs2_dirty_inode(inode);
 251                         }
 252                         if (rc == 0)
 253                                 acl = NULL;
 254                 }
 255                 break;
 256         case ACL_TYPE_DEFAULT:
 257                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 258                 if (!S_ISDIR(inode->i_mode))
 259                         return acl ? -EACCES : 0;
 260                 break;
 261         default:
 262                 return -EINVAL;
 263         }
 264         if (acl) {
 265                 value = jffs2_acl_to_medium(acl, &size);
 266                 if (IS_ERR(value))
 267                         return PTR_ERR(value);
 268         }
 269
 270         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 271         if (!value && rc == -ENODATA)
 272                 rc = 0;
 273         if (value)
 274                 kfree(value);
 275         if (!rc) {
 276                 switch(type) {
 277                 case ACL_TYPE_ACCESS:
 278                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 279                         break;
 280                 case ACL_TYPE_DEFAULT:
 281                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 282                         break;
 283                 }
 284         }
 285         return rc;
 286 }
 287
 288 static int jffs2_check_acl(struct inode *inode, int mask)
 289 {
 290         struct posix_acl *acl;
 291         int rc;
 292
 293         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 294         if (IS_ERR(acl))
 295                 return PTR_ERR(acl);
 296         if (acl) {
 297                 rc = posix_acl_permission(inode, acl, mask);
 298                 posix_acl_release(acl);
 299                 return rc;
 300         }
 301         return -EAGAIN;
 302 }
 303
 304 int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
 305 {
 306         return generic_permission(inode, mask, jffs2_check_acl);
 307 }
 308
 309 int jffs2_init_acl(struct inode *inode, struct inode *dir)
 310 {
 311         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 312         struct posix_acl *acl = NULL, *clone;
 313         mode_t mode;
 314         int rc = 0;
 315
 316         f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 317         f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 318         if (!S_ISLNK(inode->i_mode)) {
 319                 acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT);
 320                 if (IS_ERR(acl))
 321                         return PTR_ERR(acl);
 322                 if (!acl)
 323                         inode->i_mode &= ~current->fs->umask;
 324         }
 325         if (acl) {
 326                 if (S_ISDIR(inode->i_mode)) {
 327                         rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 328                         if (rc)
 329                                 goto cleanup;
 330                 }
 331                 clone = posix_acl_clone(acl, GFP_KERNEL);
 332                 rc = -ENOMEM;
 333                 if (!clone)
 334                         goto cleanup;
 335                 mode = inode->i_mode;
 336                 rc = posix_acl_create_masq(clone, &mode);
 337                 if (rc >= 0) {
 338                         inode->i_mode = mode;
 339                         if (rc > 0)
 340                                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 341                 }
 342                 posix_acl_release(clone);
 343         }
 344  cleanup:
 345         posix_acl_release(acl);
 346         return rc;
 347 }
 348
 349 void jffs2_clear_acl(struct jffs2_inode_info *f)
 350 {
 351         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 352                 posix_acl_release(f->i_acl_access);
 353                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 354         }
 355         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 356                 posix_acl_release(f->i_acl_default);
 357                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 358         }
 359 }
 360
 361 int jffs2_acl_chmod(struct inode *inode)
 362 {
 363         struct posix_acl *acl, *clone;
 364         int rc;
 365
 366         if (S_ISLNK(inode->i_mode))
 367                 return -EOPNOTSUPP;
 368         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 369         if (IS_ERR(acl) || !acl)
 370                 return PTR_ERR(acl);
 371         clone = posix_acl_clone(acl, GFP_KERNEL);
 372         posix_acl_release(acl);
 373         if (!clone)
 374                 return -ENOMEM;
 375         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 376         if (!rc)
 377                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 378         posix_acl_release(clone);
 379         return rc;
 380 }
 381
 382 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 383                                          const char *name, size_t name_len)
 384 {
 385         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 386
 387         if (list && retlen <= list_size)
 388                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 389         return retlen;
 390 }
 391
 392 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 393                                           const char *name, size_t name_len)
 394 {
 395         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 396
 397         if (list && retlen <= list_size)
 398                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 399         return retlen;
 400 }
 401
 402 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 403 {
 404         struct posix_acl *acl;
 405         int rc;
 406
 407         acl = jffs2_get_acl(inode, type);
 408         if (IS_ERR(acl))
 409                 return PTR_ERR(acl);
 410         if (!acl)
 411                 return -ENODATA;
 412         rc = posix_acl_to_xattr(acl, buffer, size);
 413         posix_acl_release(acl);
 414
 415         return rc;
 416 }
 417
 418 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 419 {
 420         if (name[0] != '\0')
 421                 return -EINVAL;
 422         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 423 }
 424
 425 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 426 {
 427         if (name[0] != '\0')
 428                 return -EINVAL;
 429         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 430 }
 431
 432 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 433 {
 434         struct posix_acl *acl;
 435         int rc;
 436
 437         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
 438                 return -EPERM;
 439
 440         if (value) {
 441                 acl = posix_acl_from_xattr(value, size);
 442                 if (IS_ERR(acl))
 443                         return PTR_ERR(acl);
 444                 if (acl) {
 445                         rc = posix_acl_valid(acl);
 446                         if (rc)
 447                                 goto out;
 448                 }
 449         } else {
 450                 acl = NULL;
 451         }
 452         rc = jffs2_set_acl(inode, type, acl);
 453  out:
 454         posix_acl_release(acl);
 455         return rc;
 456 }
 457
 458 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 459                                      const void *buffer, size_t size, int flags)
 460 {
 461         if (name[0] != '\0')
 462                 return -EINVAL;
 463         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 464 }
 465
 466 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 467                                       const void *buffer, size_t size, int flags)
 468 {
 469         if (name[0] != '\0')
 470                 return -EINVAL;
 471         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 472 }
 473
 474 struct xattr_handler jffs2_acl_access_xattr_handler = {
 475         .prefix = POSIX_ACL_XATTR_ACCESS,
 476         .list   = jffs2_acl_access_listxattr,
 477         .get    = jffs2_acl_access_getxattr,
 478         .set    = jffs2_acl_access_setxattr,
 479 };
 480
 481 struct xattr_handler jffs2_acl_default_xattr_handler = {
 482         .prefix = POSIX_ACL_XATTR_DEFAULT,
 483         .list   = jffs2_acl_default_listxattr,
 484         .get    = jffs2_acl_default_getxattr,
 485         .set    = jffs2_acl_default_setxattr,
 486 };