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 = ACL_NOT_CACHED;
 162
 163         spin_lock(&inode->i_lock);
 164         if (*i_acl != 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 != 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 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, &inode->i_acl);
 188                 if (acl != 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, &inode->i_default_acl);
 194                 if (acl != 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, &inode->i_acl, acl);
 221                         break;
 222                 case ACL_TYPE_DEFAULT:
 223                         jffs2_iset_acl(inode, &inode->i_default_acl, acl);
 224                         break;
 225                 }
 226         }
 227         return acl;
 228 }
 229
 230 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
 231 {
 232         char *value = NULL;
 233         size_t size = 0;
 234         int rc;
 235
 236         if (acl) {
 237                 value = jffs2_acl_to_medium(acl, &size);
 238                 if (IS_ERR(value))
 239                         return PTR_ERR(value);
 240         }
 241         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 242         if (!value && rc == -ENODATA)
 243                 rc = 0;
 244         kfree(value);
 245
 246         return rc;
 247 }
 248
 249 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 250 {
 251         int rc, xprefix;
 252
 253         if (S_ISLNK(inode->i_mode))
 254                 return -EOPNOTSUPP;
 255
 256         switch (type) {
 257         case ACL_TYPE_ACCESS:
 258                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 259                 if (acl) {
 260                         mode_t mode = inode->i_mode;
 261                         rc = posix_acl_equiv_mode(acl, &mode);
 262                         if (rc < 0)
 263                                 return rc;
 264                         if (inode->i_mode != mode) {
 265                                 struct iattr attr;
 266
 267                                 attr.ia_valid = ATTR_MODE;
 268                                 attr.ia_mode = mode;
 269                                 rc = jffs2_do_setattr(inode, &attr);
 270                                 if (rc < 0)
 271                                         return rc;
 272                         }
 273                         if (rc == 0)
 274                                 acl = NULL;
 275                 }
 276                 break;
 277         case ACL_TYPE_DEFAULT:
 278                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 279                 if (!S_ISDIR(inode->i_mode))
 280                         return acl ? -EACCES : 0;
 281                 break;
 282         default:
 283                 return -EINVAL;
 284         }
 285         rc = __jffs2_set_acl(inode, xprefix, acl);
 286         if (!rc) {
 287                 switch(type) {
 288                 case ACL_TYPE_ACCESS:
 289                         jffs2_iset_acl(inode, &inode->i_acl, acl);
 290                         break;
 291                 case ACL_TYPE_DEFAULT:
 292                         jffs2_iset_acl(inode, &inode->i_default_acl, acl);
 293                         break;
 294                 }
 295         }
 296         return rc;
 297 }
 298
 299 static int jffs2_check_acl(struct inode *inode, int mask)
 300 {
 301         struct posix_acl *acl;
 302         int rc;
 303
 304         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 305         if (IS_ERR(acl))
 306                 return PTR_ERR(acl);
 307         if (acl) {
 308                 rc = posix_acl_permission(inode, acl, mask);
 309                 posix_acl_release(acl);
 310                 return rc;
 311         }
 312         return -EAGAIN;
 313 }
 314
 315 int jffs2_permission(struct inode *inode, int mask)
 316 {
 317         return generic_permission(inode, mask, jffs2_check_acl);
 318 }
 319
 320 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
 321 {
 322         struct posix_acl *acl, *clone;
 323         int rc;
 324
 325         inode->i_default_acl = NULL;
 326         inode->i_acl = NULL;
 327
 328         if (S_ISLNK(*i_mode))
 329                 return 0;       /* Symlink always has no-ACL */
 330
 331         acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
 332         if (IS_ERR(acl))
 333                 return PTR_ERR(acl);
 334
 335         if (!acl) {
 336                 *i_mode &= ~current_umask();
 337         } else {
 338                 if (S_ISDIR(*i_mode))
 339                         jffs2_iset_acl(inode, &inode->i_default_acl, acl);
 340
 341                 clone = posix_acl_clone(acl, GFP_KERNEL);
 342                 if (!clone)
 343                         return -ENOMEM;
 344                 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
 345                 if (rc < 0) {
 346                         posix_acl_release(clone);
 347                         return rc;
 348                 }
 349                 if (rc > 0)
 350                         jffs2_iset_acl(inode, &inode->i_acl, clone);
 351
 352                 posix_acl_release(clone);
 353         }
 354         return 0;
 355 }
 356
 357 int jffs2_init_acl_post(struct inode *inode)
 358 {
 359         int rc;
 360
 361         if (inode->i_default_acl) {
 362                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
 363                 if (rc)
 364                         return rc;
 365         }
 366
 367         if (inode->i_acl) {
 368                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
 369                 if (rc)
 370                         return rc;
 371         }
 372
 373         return 0;
 374 }
 375
 376 int jffs2_acl_chmod(struct inode *inode)
 377 {
 378         struct posix_acl *acl, *clone;
 379         int rc;
 380
 381         if (S_ISLNK(inode->i_mode))
 382                 return -EOPNOTSUPP;
 383         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 384         if (IS_ERR(acl) || !acl)
 385                 return PTR_ERR(acl);
 386         clone = posix_acl_clone(acl, GFP_KERNEL);
 387         posix_acl_release(acl);
 388         if (!clone)
 389                 return -ENOMEM;
 390         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 391         if (!rc)
 392                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 393         posix_acl_release(clone);
 394         return rc;
 395 }
 396
 397 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 398                                          const char *name, size_t name_len)
 399 {
 400         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 401
 402         if (list && retlen <= list_size)
 403                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 404         return retlen;
 405 }
 406
 407 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 408                                           const char *name, size_t name_len)
 409 {
 410         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 411
 412         if (list && retlen <= list_size)
 413                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 414         return retlen;
 415 }
 416
 417 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 418 {
 419         struct posix_acl *acl;
 420         int rc;
 421
 422         acl = jffs2_get_acl(inode, type);
 423         if (IS_ERR(acl))
 424                 return PTR_ERR(acl);
 425         if (!acl)
 426                 return -ENODATA;
 427         rc = posix_acl_to_xattr(acl, buffer, size);
 428         posix_acl_release(acl);
 429
 430         return rc;
 431 }
 432
 433 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 434 {
 435         if (name[0] != '\0')
 436                 return -EINVAL;
 437         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 438 }
 439
 440 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 441 {
 442         if (name[0] != '\0')
 443                 return -EINVAL;
 444         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 445 }
 446
 447 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 448 {
 449         struct posix_acl *acl;
 450         int rc;
 451
 452         if (!is_owner_or_cap(inode))
 453                 return -EPERM;
 454
 455         if (value) {
 456                 acl = posix_acl_from_xattr(value, size);
 457                 if (IS_ERR(acl))
 458                         return PTR_ERR(acl);
 459                 if (acl) {
 460                         rc = posix_acl_valid(acl);
 461                         if (rc)
 462                                 goto out;
 463                 }
 464         } else {
 465                 acl = NULL;
 466         }
 467         rc = jffs2_set_acl(inode, type, acl);
 468  out:
 469         posix_acl_release(acl);
 470         return rc;
 471 }
 472
 473 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 474                                      const void *buffer, size_t size, int flags)
 475 {
 476         if (name[0] != '\0')
 477                 return -EINVAL;
 478         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 479 }
 480
 481 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 482                                       const void *buffer, size_t size, int flags)
 483 {
 484         if (name[0] != '\0')
 485                 return -EINVAL;
 486         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 487 }
 488
 489 struct xattr_handler jffs2_acl_access_xattr_handler = {
 490         .prefix = POSIX_ACL_XATTR_ACCESS,
 491         .list   = jffs2_acl_access_listxattr,
 492         .get    = jffs2_acl_access_getxattr,
 493         .set    = jffs2_acl_access_setxattr,
 494 };
 495
 496 struct xattr_handler jffs2_acl_default_xattr_handler = {
 497         .prefix = POSIX_ACL_XATTR_DEFAULT,
 498         .list   = jffs2_acl_default_listxattr,
 499         .get    = jffs2_acl_default_getxattr,
 500         .set    = jffs2_acl_default_setxattr,
 501 };