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