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/time.h>
  15 #include <linux/crc32.h>
  16 #include <linux/jffs2.h>
  17 #include <linux/xattr.h>
  18 #include <linux/posix_acl_xattr.h>
  19 #include <linux/mtd/mtd.h>
  20 #include "nodelist.h"
  21
  22 static size_t jffs2_acl_size(int count)
  23 {
  24         if (count <= 4) {
  25                 return sizeof(struct jffs2_acl_header)
  26                        + count * sizeof(struct jffs2_acl_entry_short);
  27         } else {
  28                 return sizeof(struct jffs2_acl_header)
  29                        + 4 * sizeof(struct jffs2_acl_entry_short)
  30                        + (count - 4) * sizeof(struct jffs2_acl_entry);
  31         }
  32 }
  33
  34 static int jffs2_acl_count(size_t size)
  35 {
  36         size_t s;
  37
  38         size -= sizeof(struct jffs2_acl_header);
  39         s = size - 4 * sizeof(struct jffs2_acl_entry_short);
  40         if (s < 0) {
  41                 if (size % sizeof(struct jffs2_acl_entry_short))
  42                         return -1;
  43                 return size / sizeof(struct jffs2_acl_entry_short);
  44         } else {
  45                 if (s % sizeof(struct jffs2_acl_entry))
  46                         return -1;
  47                 return s / sizeof(struct jffs2_acl_entry) + 4;
  48         }
  49 }
  50
  51 static struct posix_acl *jffs2_acl_from_medium(const void *value, size_t size)
  52 {
  53         const char *end = (char *)value + size;
  54         struct posix_acl *acl;
  55         uint32_t ver;
  56         int i, count;
  57
  58         if (!value)
  59                 return NULL;
  60         if (size < sizeof(struct jffs2_acl_header))
  61                 return ERR_PTR(-EINVAL);
  62         ver = je32_to_cpu(((struct jffs2_acl_header *)value)->a_version);
  63         if (ver != JFFS2_ACL_VERSION) {
  64                 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
  65                 return ERR_PTR(-EINVAL);
  66         }
  67
  68         value = (char *)value + sizeof(struct jffs2_acl_header);
  69         count = jffs2_acl_count(size);
  70         if (count < 0)
  71                 return ERR_PTR(-EINVAL);
  72         if (count == 0)
  73                 return NULL;
  74
  75         acl = posix_acl_alloc(count, GFP_KERNEL);
  76         if (!acl)
  77                 return ERR_PTR(-ENOMEM);
  78
  79         for (i=0; i < count; i++) {
  80                 struct jffs2_acl_entry *entry = (struct jffs2_acl_entry *)value;
  81                 if ((char *)value + sizeof(struct jffs2_acl_entry_short) > end)
  82                         goto fail;
  83                 acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
  84                 acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
  85                 switch (acl->a_entries[i].e_tag) {
  86                         case ACL_USER_OBJ:
  87                         case ACL_GROUP_OBJ:
  88                         case ACL_MASK:
  89                         case ACL_OTHER:
  90                                 value = (char *)value + sizeof(struct jffs2_acl_entry_short);
  91                                 acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
  92                                 break;
  93
  94                         case ACL_USER:
  95                         case ACL_GROUP:
  96                                 value = (char *)value + sizeof(struct jffs2_acl_entry);
  97                                 if ((char *)value > end)
  98                                         goto fail;
  99                                 acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);
 100                                 break;
 101
 102                         default:
 103                                 goto fail;
 104                 }
 105         }
 106         if (value != end)
 107                 goto fail;
 108         return acl;
 109  fail:
 110         posix_acl_release(acl);
 111         return ERR_PTR(-EINVAL);
 112 }
 113
 114 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
 115 {
 116         struct jffs2_acl_header *jffs2_acl;
 117         char *e;
 118         size_t i;
 119
 120         *size = jffs2_acl_size(acl->a_count);
 121         jffs2_acl = kmalloc(sizeof(struct jffs2_acl_header)
 122                              + acl->a_count * sizeof(struct jffs2_acl_entry),
 123                             GFP_KERNEL);
 124         if (!jffs2_acl)
 125                 return ERR_PTR(-ENOMEM);
 126         jffs2_acl->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
 127         e = (char *)jffs2_acl + sizeof(struct jffs2_acl_header);
 128         for (i=0; i < acl->a_count; i++) {
 129                 struct jffs2_acl_entry *entry = (struct jffs2_acl_entry *)e;
 130                 entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
 131                 entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
 132                 switch(acl->a_entries[i].e_tag) {
 133                         case ACL_USER:
 134                         case ACL_GROUP:
 135                                 entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
 136                                 e += sizeof(struct jffs2_acl_entry);
 137                                 break;
 138
 139                         case ACL_USER_OBJ:
 140                         case ACL_GROUP_OBJ:
 141                         case ACL_MASK:
 142                         case ACL_OTHER:
 143                                 e += sizeof(struct jffs2_acl_entry_short);
 144                                 break;
 145
 146                         default:
 147                                 goto fail;
 148                 }
 149         }
 150         return (char *)jffs2_acl;
 151  fail:
 152         kfree(jffs2_acl);
 153         return ERR_PTR(-EINVAL);
 154 }
 155
 156 static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)
 157 {
 158         struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;
 159
 160         spin_lock(&inode->i_lock);
 161         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 162                 acl = posix_acl_dup(*i_acl);
 163         spin_unlock(&inode->i_lock);
 164         return acl;
 165 }
 166
 167 static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
 168 {
 169         spin_lock(&inode->i_lock);
 170         if (*i_acl != JFFS2_ACL_NOT_CACHED)
 171                 posix_acl_release(*i_acl);
 172         *i_acl = posix_acl_dup(acl);
 173         spin_unlock(&inode->i_lock);
 174 }
 175
 176 static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
 177 {
 178         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 179         struct posix_acl *acl;
 180         char *value = NULL;
 181         int rc, xprefix;
 182
 183         switch (type) {
 184         case ACL_TYPE_ACCESS:
 185                 acl = jffs2_iget_acl(inode, &f->i_acl_access);
 186                 if (acl != JFFS2_ACL_NOT_CACHED)
 187                         return acl;
 188                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 189                 break;
 190         case ACL_TYPE_DEFAULT:
 191                 acl = jffs2_iget_acl(inode, &f->i_acl_default);
 192                 if (acl != JFFS2_ACL_NOT_CACHED)
 193                         return acl;
 194                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 195                 break;
 196         default:
 197                 return ERR_PTR(-EINVAL);
 198         }
 199         rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
 200         if (rc > 0) {
 201                 value = kmalloc(rc, GFP_KERNEL);
 202                 if (!value)
 203                         return ERR_PTR(-ENOMEM);
 204                 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
 205         }
 206         if (rc > 0) {
 207                 acl = jffs2_acl_from_medium(value, rc);
 208         } else if (rc == -ENODATA || rc == -ENOSYS) {
 209                 acl = NULL;
 210         } else {
 211                 acl = ERR_PTR(rc);
 212         }
 213         if (value)
 214                 kfree(value);
 215         if (!IS_ERR(acl)) {
 216                 switch (type) {
 217                 case ACL_TYPE_ACCESS:
 218                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 219                         break;
 220                 case ACL_TYPE_DEFAULT:
 221                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 222                         break;
 223                 }
 224         }
 225         return acl;
 226 }
 227
 228 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 229 {
 230         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 231         size_t size = 0;
 232         char *value = NULL;
 233         int rc, xprefix;
 234
 235         if (S_ISLNK(inode->i_mode))
 236                 return -EOPNOTSUPP;
 237
 238         switch (type) {
 239         case ACL_TYPE_ACCESS:
 240                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 241                 if (acl) {
 242                         mode_t mode = inode->i_mode;
 243                         rc = posix_acl_equiv_mode(acl, &mode);
 244                         if (rc < 0)
 245                                 return rc;
 246                         if (inode->i_mode != mode) {
 247                                 inode->i_mode = mode;
 248                                 jffs2_dirty_inode(inode);
 249                         }
 250                         if (rc == 0)
 251                                 acl = NULL;
 252                 }
 253                 break;
 254         case ACL_TYPE_DEFAULT:
 255                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 256                 if (!S_ISDIR(inode->i_mode))
 257                         return acl ? -EACCES : 0;
 258                 break;
 259         default:
 260                 return -EINVAL;
 261         }
 262         if (acl) {
 263                 value = jffs2_acl_to_medium(acl, &size);
 264                 if (IS_ERR(value))
 265                         return PTR_ERR(value);
 266         }
 267
 268         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 269         if (value)
 270                 kfree(value);
 271         if (!rc) {
 272                 switch(type) {
 273                 case ACL_TYPE_ACCESS:
 274                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 275                         break;
 276                 case ACL_TYPE_DEFAULT:
 277                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 278                         break;
 279                 }
 280         }
 281         return rc;
 282 }
 283
 284 static int jffs2_check_acl(struct inode *inode, int mask)
 285 {
 286         struct posix_acl *acl;
 287         int rc;
 288
 289         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 290         if (IS_ERR(acl))
 291                 return PTR_ERR(acl);
 292         if (acl) {
 293                 rc = posix_acl_permission(inode, acl, mask);
 294                 posix_acl_release(acl);
 295                 return rc;
 296         }
 297         return -EAGAIN;
 298 }
 299
 300 int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
 301 {
 302         return generic_permission(inode, mask, jffs2_check_acl);
 303 }
 304
 305 int jffs2_init_acl(struct inode *inode, struct inode *dir)
 306 {
 307         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 308         struct posix_acl *acl = NULL, *clone;
 309         mode_t mode;
 310         int rc = 0;
 311
 312         f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 313         f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 314         if (!S_ISLNK(inode->i_mode)) {
 315                 acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT);
 316                 if (IS_ERR(acl))
 317                         return PTR_ERR(acl);
 318                 if (!acl)
 319                         inode->i_mode &= ~current->fs->umask;
 320         }
 321         if (acl) {
 322                 if (S_ISDIR(inode->i_mode)) {
 323                         rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 324                         if (rc)
 325                                 goto cleanup;
 326                 }
 327                 clone = posix_acl_clone(acl, GFP_KERNEL);
 328                 rc = -ENOMEM;
 329                 if (!clone)
 330                         goto cleanup;
 331                 mode = inode->i_mode;
 332                 rc = posix_acl_create_masq(clone, &mode);
 333                 if (rc >= 0) {
 334                         inode->i_mode = mode;
 335                         if (rc > 0)
 336                                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 337                 }
 338                 posix_acl_release(clone);
 339         }
 340  cleanup:
 341         posix_acl_release(acl);
 342         return rc;
 343 }
 344
 345 void jffs2_clear_acl(struct inode *inode)
 346 {
 347         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 348
 349         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 350                 posix_acl_release(f->i_acl_access);
 351                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 352         }
 353         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 354                 posix_acl_release(f->i_acl_default);
 355                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 356         }
 357 }
 358
 359 int jffs2_acl_chmod(struct inode *inode)
 360 {
 361         struct posix_acl *acl, *clone;
 362         int rc;
 363
 364         if (S_ISLNK(inode->i_mode))
 365                 return -EOPNOTSUPP;
 366         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 367         if (IS_ERR(acl) || !acl)
 368                 return PTR_ERR(acl);
 369         clone = posix_acl_clone(acl, GFP_KERNEL);
 370         posix_acl_release(acl);
 371         if (!clone)
 372                 return -ENOMEM;
 373         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 374         if (!rc)
 375                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 376         posix_acl_release(clone);
 377         return rc;
 378 }
 379
 380 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 381                                          const char *name, size_t name_len)
 382 {
 383         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 384
 385         if (list && retlen <= list_size)
 386                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 387         return retlen;
 388 }
 389
 390 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 391                                           const char *name, size_t name_len)
 392 {
 393         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 394
 395         if (list && retlen <= list_size)
 396                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 397         return retlen;
 398 }
 399
 400 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 401 {
 402         struct posix_acl *acl;
 403         int rc;
 404
 405         acl = jffs2_get_acl(inode, type);
 406         if (IS_ERR(acl))
 407                 return PTR_ERR(acl);
 408         if (!acl)
 409                 return -ENODATA;
 410         rc = posix_acl_to_xattr(acl, buffer, size);
 411         posix_acl_release(acl);
 412
 413         return rc;
 414 }
 415
 416 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 417 {
 418         if (name[0] != '\0')
 419                 return -EINVAL;
 420         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 421 }
 422
 423 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 424 {
 425         if (name[0] != '\0')
 426                 return -EINVAL;
 427         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 428 }
 429
 430 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 431 {
 432         struct posix_acl *acl;
 433         int rc;
 434
 435         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
 436                 return -EPERM;
 437
 438         if (value) {
 439                 acl = posix_acl_from_xattr(value, size);
 440                 if (IS_ERR(acl))
 441                         return PTR_ERR(acl);
 442                 if (acl) {
 443                         rc = posix_acl_valid(acl);
 444                         if (rc)
 445                                 goto out;
 446                 }
 447         } else {
 448                 acl = NULL;
 449         }
 450         rc = jffs2_set_acl(inode, type, acl);
 451  out:
 452         posix_acl_release(acl);
 453         return rc;
 454 }
 455
 456 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 457                                      const void *buffer, size_t size, int flags)
 458 {
 459         if (name[0] != '\0')
 460                 return -EINVAL;
 461         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 462 }
 463
 464 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 465                                       const void *buffer, size_t size, int flags)
 466 {
 467         if (name[0] != '\0')
 468                 return -EINVAL;
 469         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 470 }
 471
 472 struct xattr_handler jffs2_acl_access_xattr_handler = {
 473         .prefix = POSIX_ACL_XATTR_ACCESS,
 474         .list   = jffs2_acl_access_listxattr,
 475         .get    = jffs2_acl_access_getxattr,
 476         .set    = jffs2_acl_access_setxattr,
 477 };
 478
 479 struct xattr_handler jffs2_acl_default_xattr_handler = {
 480         .prefix = POSIX_ACL_XATTR_DEFAULT,
 481         .list   = jffs2_acl_default_listxattr,
 482         .get    = jffs2_acl_default_getxattr,
 483         .set    = jffs2_acl_default_setxattr,
 484 };