fs/jffs2/acl.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 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
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/fs.h>
  15 #include <linux/sched.h>
  16 #include <linux/time.h>
  17 #include <linux/crc32.h>
  18 #include <linux/jffs2.h>
  19 #include <linux/xattr.h>
  20 #include <linux/posix_acl_xattr.h>
  21 #include <linux/mtd/mtd.h>
  22 #include "nodelist.h"
  23
  24 static size_t jffs2_acl_size(int count)
  25 {
  26         if (count <= 4) {
  27                 return sizeof(struct jffs2_acl_header)
  28                        + count * sizeof(struct jffs2_acl_entry_short);
  29         } else {
  30                 return sizeof(struct jffs2_acl_header)
  31                        + 4 * sizeof(struct jffs2_acl_entry_short)
  32                        + (count - 4) * sizeof(struct jffs2_acl_entry);
  33         }
  34 }
  35
  36 static int jffs2_acl_count(size_t size)
  37 {
  38         size_t s;
  39
  40         size -= sizeof(struct jffs2_acl_header);
  41         if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
  42                 if (size % sizeof(struct jffs2_acl_entry_short))
  43                         return -1;
  44                 return size / sizeof(struct jffs2_acl_entry_short);
  45         } else {
  46                 s = size - 4 * sizeof(struct jffs2_acl_entry_short);
  47                 if (s % sizeof(struct jffs2_acl_entry))
  48                         return -1;
  49                 return s / sizeof(struct jffs2_acl_entry) + 4;
  50         }
  51 }
  52
  53 static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
  54 {
  55         void *end = value + size;
  56         struct jffs2_acl_header *header = value;
  57         struct jffs2_acl_entry *entry;
  58         struct posix_acl *acl;
  59         uint32_t ver;
  60         int i, count;
  61
  62         if (!value)
  63                 return NULL;
  64         if (size < sizeof(struct jffs2_acl_header))
  65                 return ERR_PTR(-EINVAL);
  66         ver = je32_to_cpu(header->a_version);
  67         if (ver != JFFS2_ACL_VERSION) {
  68                 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
  69                 return ERR_PTR(-EINVAL);
  70         }
  71
  72         value += sizeof(struct jffs2_acl_header);
  73         count = jffs2_acl_count(size);
  74         if (count < 0)
  75                 return ERR_PTR(-EINVAL);
  76         if (count == 0)
  77                 return NULL;
  78
  79         acl = posix_acl_alloc(count, GFP_KERNEL);
  80         if (!acl)
  81                 return ERR_PTR(-ENOMEM);
  82
  83         for (i=0; i < count; i++) {
  84                 entry = value;
  85                 if (value + sizeof(struct jffs2_acl_entry_short) > end)
  86                         goto fail;
  87                 acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
  88                 acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
  89                 switch (acl->a_entries[i].e_tag) {
  90                         case ACL_USER_OBJ:
  91                         case ACL_GROUP_OBJ:
  92                         case ACL_MASK:
  93                         case ACL_OTHER:
  94                                 value += sizeof(struct jffs2_acl_entry_short);
  95                                 acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
  96                                 break;
  97
  98                         case ACL_USER:
  99                         case ACL_GROUP:
 100                                 value += sizeof(struct jffs2_acl_entry);
 101                                 if (value > end)
 102                                         goto fail;
 103                                 acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);
 104                                 break;
 105
 106                         default:
 107                                 goto fail;
 108                 }
 109         }
 110         if (value != end)
 111                 goto fail;
 112         return acl;
 113  fail:
 114         posix_acl_release(acl);
 115         return ERR_PTR(-EINVAL);
 116 }
 117
 118 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
 119 {
 120         struct jffs2_acl_header *header;
 121         struct jffs2_acl_entry *entry;
 122         void *e;
 123         size_t i;
 124
 125         *size = jffs2_acl_size(acl->a_count);
 126         header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
 127         if (!header)
 128                 return ERR_PTR(-ENOMEM);
 129         header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
 130         e = header + 1;
 131         for (i=0; i < acl->a_count; i++) {
 132                 entry = e;
 133                 entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
 134                 entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
 135                 switch(acl->a_entries[i].e_tag) {
 136                         case ACL_USER:
 137                         case ACL_GROUP:
 138                                 entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
 139                                 e += sizeof(struct jffs2_acl_entry);
 140                                 break;
 141
 142                         case ACL_USER_OBJ:
 143                         case ACL_GROUP_OBJ:
 144                         case ACL_MASK:
 145                         case ACL_OTHER:
 146                                 e += sizeof(struct jffs2_acl_entry_short);
 147                                 break;
 148
 149                         default:
 150                                 goto fail;
 151                 }
 152         }
 153         return header;
 154  fail:
 155         kfree(header);
 156         return ERR_PTR(-EINVAL);
 157 }
 158
 159 static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
 160 {
 161         struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;
 162
 163         spin_lock(&inode->i_lock);
 164         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 165                 acl = posix_acl_dup(*i_acl);
 166         spin_unlock(&inode->i_lock);
 167         return acl;
 168 }
 169
 170 static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
 171 {
 172         spin_lock(&inode->i_lock);
 173         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 174                 posix_acl_release(*i_acl);
 175         *i_acl = posix_acl_dup(acl);
 176         spin_unlock(&inode->i_lock);
 177 }
 178
 179 static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
 180 {
 181         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 182         struct posix_acl *acl;
 183         char *value = NULL;
 184         int rc, xprefix;
 185
 186         switch (type) {
 187         case ACL_TYPE_ACCESS:
 188                 acl = jffs2_iget_acl(inode, &f->i_acl_access);
 189                 if (acl != JFFS2_ACL_NOT_CACHED)
 190                         return acl;
 191                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 192                 break;
 193         case ACL_TYPE_DEFAULT:
 194                 acl = jffs2_iget_acl(inode, &f->i_acl_default);
 195                 if (acl != JFFS2_ACL_NOT_CACHED)
 196                         return acl;
 197                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 198                 break;
 199         default:
 200                 return ERR_PTR(-EINVAL);
 201         }
 202         rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
 203         if (rc > 0) {
 204                 value = kmalloc(rc, GFP_KERNEL);
 205                 if (!value)
 206                         return ERR_PTR(-ENOMEM);
 207                 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
 208         }
 209         if (rc > 0) {
 210                 acl = jffs2_acl_from_medium(value, rc);
 211         } else if (rc == -ENODATA || rc == -ENOSYS) {
 212                 acl = NULL;
 213         } else {
 214                 acl = ERR_PTR(rc);
 215         }
 216         if (value)
 217                 kfree(value);
 218         if (!IS_ERR(acl)) {
 219                 switch (type) {
 220                 case ACL_TYPE_ACCESS:
 221                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 222                         break;
 223                 case ACL_TYPE_DEFAULT:
 224                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 225                         break;
 226                 }
 227         }
 228         return acl;
 229 }
 230
 231 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
 232 {
 233         char *value = NULL;
 234         size_t size = 0;
 235         int rc;
 236
 237         if (acl) {
 238                 value = jffs2_acl_to_medium(acl, &size);
 239                 if (IS_ERR(value))
 240                         return PTR_ERR(value);
 241         }
 242         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 243         if (!value && rc == -ENODATA)
 244                 rc = 0;
 245         kfree(value);
 246
 247         return rc;
 248 }
 249
 250 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 251 {
 252         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 253         int rc, xprefix;
 254
 255         if (S_ISLNK(inode->i_mode))
 256                 return -EOPNOTSUPP;
 257
 258         switch (type) {
 259         case ACL_TYPE_ACCESS:
 260                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 261                 if (acl) {
 262                         mode_t mode = inode->i_mode;
 263                         rc = posix_acl_equiv_mode(acl, &mode);
 264                         if (rc < 0)
 265                                 return rc;
 266                         if (inode->i_mode != mode) {
 267                                 struct iattr attr;
 268
 269                                 attr.ia_valid = ATTR_MODE;
 270                                 attr.ia_mode = mode;
 271                                 rc = jffs2_do_setattr(inode, &attr);
 272                                 if (rc < 0)
 273                                         return rc;
 274                         }
 275                         if (rc == 0)
 276                                 acl = NULL;
 277                 }
 278                 break;
 279         case ACL_TYPE_DEFAULT:
 280                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 281                 if (!S_ISDIR(inode->i_mode))
 282                         return acl ? -EACCES : 0;
 283                 break;
 284         default:
 285                 return -EINVAL;
 286         }
 287         rc = __jffs2_set_acl(inode, xprefix, acl);
 288         if (!rc) {
 289                 switch(type) {
 290                 case ACL_TYPE_ACCESS:
 291                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 292                         break;
 293                 case ACL_TYPE_DEFAULT:
 294                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 295                         break;
 296                 }
 297         }
 298         return rc;
 299 }
 300
 301 static int jffs2_check_acl(struct inode *inode, int mask)
 302 {
 303         struct posix_acl *acl;
 304         int rc;
 305
 306         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 307         if (IS_ERR(acl))
 308                 return PTR_ERR(acl);
 309         if (acl) {
 310                 rc = posix_acl_permission(inode, acl, mask);
 311                 posix_acl_release(acl);
 312                 return rc;
 313         }
 314         return -EAGAIN;
 315 }
 316
 317 int jffs2_permission(struct inode *inode, int mask)
 318 {
 319         return generic_permission(inode, mask, jffs2_check_acl);
 320 }
 321
 322 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
 323 {
 324         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 325         struct posix_acl *acl, *clone;
 326         int rc;
 327
 328         f->i_acl_default = NULL;
 329         f->i_acl_access = NULL;
 330
 331         if (S_ISLNK(*i_mode))
 332                 return 0;       /* Symlink always has no-ACL */
 333
 334         acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
 335         if (IS_ERR(acl))
 336                 return PTR_ERR(acl);
 337
 338         if (!acl) {
 339                 *i_mode &= ~current_umask();
 340         } else {
 341                 if (S_ISDIR(*i_mode))
 342                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 343
 344                 clone = posix_acl_clone(acl, GFP_KERNEL);
 345                 if (!clone)
 346                         return -ENOMEM;
 347                 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
 348                 if (rc < 0) {
 349                         posix_acl_release(clone);
 350                         return rc;
 351                 }
 352                 if (rc > 0)
 353                         jffs2_iset_acl(inode, &f->i_acl_access, clone);
 354
 355                 posix_acl_release(clone);
 356         }
 357         return 0;
 358 }
 359
 360 int jffs2_init_acl_post(struct inode *inode)
 361 {
 362         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 363         int rc;
 364
 365         if (f->i_acl_default) {
 366                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, f->i_acl_default);
 367                 if (rc)
 368                         return rc;
 369         }
 370
 371         if (f->i_acl_access) {
 372                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, f->i_acl_access);
 373                 if (rc)
 374                         return rc;
 375         }
 376
 377         return 0;
 378 }
 379
 380 void jffs2_clear_acl(struct jffs2_inode_info *f)
 381 {
 382         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 383                 posix_acl_release(f->i_acl_access);
 384                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 385         }
 386         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 387                 posix_acl_release(f->i_acl_default);
 388                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 389         }
 390 }
 391
 392 int jffs2_acl_chmod(struct inode *inode)
 393 {
 394         struct posix_acl *acl, *clone;
 395         int rc;
 396
 397         if (S_ISLNK(inode->i_mode))
 398                 return -EOPNOTSUPP;
 399         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 400         if (IS_ERR(acl) || !acl)
 401                 return PTR_ERR(acl);
 402         clone = posix_acl_clone(acl, GFP_KERNEL);
 403         posix_acl_release(acl);
 404         if (!clone)
 405                 return -ENOMEM;
 406         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 407         if (!rc)
 408                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 409         posix_acl_release(clone);
 410         return rc;
 411 }
 412
 413 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 414                                          const char *name, size_t name_len)
 415 {
 416         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 417
 418         if (list && retlen <= list_size)
 419                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 420         return retlen;
 421 }
 422
 423 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 424                                           const char *name, size_t name_len)
 425 {
 426         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 427
 428         if (list && retlen <= list_size)
 429                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 430         return retlen;
 431 }
 432
 433 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 434 {
 435         struct posix_acl *acl;
 436         int rc;
 437
 438         acl = jffs2_get_acl(inode, type);
 439         if (IS_ERR(acl))
 440                 return PTR_ERR(acl);
 441         if (!acl)
 442                 return -ENODATA;
 443         rc = posix_acl_to_xattr(acl, buffer, size);
 444         posix_acl_release(acl);
 445
 446         return rc;
 447 }
 448
 449 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 450 {
 451         if (name[0] != '\0')
 452                 return -EINVAL;
 453         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 454 }
 455
 456 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 457 {
 458         if (name[0] != '\0')
 459                 return -EINVAL;
 460         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 461 }
 462
 463 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 464 {
 465         struct posix_acl *acl;
 466         int rc;
 467
 468         if (!is_owner_or_cap(inode))
 469                 return -EPERM;
 470
 471         if (value) {
 472                 acl = posix_acl_from_xattr(value, size);
 473                 if (IS_ERR(acl))
 474                         return PTR_ERR(acl);
 475                 if (acl) {
 476                         rc = posix_acl_valid(acl);
 477                         if (rc)
 478                                 goto out;
 479                 }
 480         } else {
 481                 acl = NULL;
 482         }
 483         rc = jffs2_set_acl(inode, type, acl);
 484  out:
 485         posix_acl_release(acl);
 486         return rc;
 487 }
 488
 489 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 490                                      const void *buffer, size_t size, int flags)
 491 {
 492         if (name[0] != '\0')
 493                 return -EINVAL;
 494         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 495 }
 496
 497 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 498                                       const void *buffer, size_t size, int flags)
 499 {
 500         if (name[0] != '\0')
 501                 return -EINVAL;
 502         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 503 }
 504
 505 struct xattr_handler jffs2_acl_access_xattr_handler = {
 506         .prefix = POSIX_ACL_XATTR_ACCESS,
 507         .list   = jffs2_acl_access_listxattr,
 508         .get    = jffs2_acl_access_getxattr,
 509         .set    = jffs2_acl_access_setxattr,
 510 };
 511
 512 struct xattr_handler jffs2_acl_default_xattr_handler = {
 513         .prefix = POSIX_ACL_XATTR_DEFAULT,
 514         .list   = jffs2_acl_default_listxattr,
 515         .get    = jffs2_acl_default_getxattr,
 516         .set    = jffs2_acl_default_setxattr,
 517 };