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         s = size - 4 * sizeof(struct jffs2_acl_entry_short);
  42         if (s < 0) {
  43                 if (size % sizeof(struct jffs2_acl_entry_short))
  44                         return -1;
  45                 return size / sizeof(struct jffs2_acl_entry_short);
  46         } else {
  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 type, struct posix_acl *acl)
 232 {
 233         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 234         size_t size = 0;
 235         char *value = NULL;
 236         int rc, xprefix;
 237
 238         if (S_ISLNK(inode->i_mode))
 239                 return -EOPNOTSUPP;
 240
 241         switch (type) {
 242         case ACL_TYPE_ACCESS:
 243                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 244                 if (acl) {
 245                         mode_t mode = inode->i_mode;
 246                         rc = posix_acl_equiv_mode(acl, &mode);
 247                         if (rc < 0)
 248                                 return rc;
 249                         if (inode->i_mode != mode) {
 250                                 inode->i_mode = mode;
 251                                 jffs2_dirty_inode(inode);
 252                         }
 253                         if (rc == 0)
 254                                 acl = NULL;
 255                 }
 256                 break;
 257         case ACL_TYPE_DEFAULT:
 258                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 259                 if (!S_ISDIR(inode->i_mode))
 260                         return acl ? -EACCES : 0;
 261                 break;
 262         default:
 263                 return -EINVAL;
 264         }
 265         if (acl) {
 266                 value = jffs2_acl_to_medium(acl, &size);
 267                 if (IS_ERR(value))
 268                         return PTR_ERR(value);
 269         }
 270
 271         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 272         if (!value && rc == -ENODATA)
 273                 rc = 0;
 274         if (value)
 275                 kfree(value);
 276         if (!rc) {
 277                 switch(type) {
 278                 case ACL_TYPE_ACCESS:
 279                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 280                         break;
 281                 case ACL_TYPE_DEFAULT:
 282                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 283                         break;
 284                 }
 285         }
 286         return rc;
 287 }
 288
 289 static int jffs2_check_acl(struct inode *inode, int mask)
 290 {
 291         struct posix_acl *acl;
 292         int rc;
 293
 294         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 295         if (IS_ERR(acl))
 296                 return PTR_ERR(acl);
 297         if (acl) {
 298                 rc = posix_acl_permission(inode, acl, mask);
 299                 posix_acl_release(acl);
 300                 return rc;
 301         }
 302         return -EAGAIN;
 303 }
 304
 305 int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
 306 {
 307         return generic_permission(inode, mask, jffs2_check_acl);
 308 }
 309
 310 int jffs2_init_acl(struct inode *inode, struct inode *dir)
 311 {
 312         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 313         struct posix_acl *acl = NULL, *clone;
 314         mode_t mode;
 315         int rc = 0;
 316
 317         f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 318         f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 319         if (!S_ISLNK(inode->i_mode)) {
 320                 acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT);
 321                 if (IS_ERR(acl))
 322                         return PTR_ERR(acl);
 323                 if (!acl)
 324                         inode->i_mode &= ~current->fs->umask;
 325         }
 326         if (acl) {
 327                 if (S_ISDIR(inode->i_mode)) {
 328                         rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 329                         if (rc)
 330                                 goto cleanup;
 331                 }
 332                 clone = posix_acl_clone(acl, GFP_KERNEL);
 333                 rc = -ENOMEM;
 334                 if (!clone)
 335                         goto cleanup;
 336                 mode = inode->i_mode;
 337                 rc = posix_acl_create_masq(clone, &mode);
 338                 if (rc >= 0) {
 339                         inode->i_mode = mode;
 340                         if (rc > 0)
 341                                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 342                 }
 343                 posix_acl_release(clone);
 344         }
 345  cleanup:
 346         posix_acl_release(acl);
 347         return rc;
 348 }
 349
 350 void jffs2_clear_acl(struct jffs2_inode_info *f)
 351 {
 352         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 353                 posix_acl_release(f->i_acl_access);
 354                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 355         }
 356         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 357                 posix_acl_release(f->i_acl_default);
 358                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 359         }
 360 }
 361
 362 int jffs2_acl_chmod(struct inode *inode)
 363 {
 364         struct posix_acl *acl, *clone;
 365         int rc;
 366
 367         if (S_ISLNK(inode->i_mode))
 368                 return -EOPNOTSUPP;
 369         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 370         if (IS_ERR(acl) || !acl)
 371                 return PTR_ERR(acl);
 372         clone = posix_acl_clone(acl, GFP_KERNEL);
 373         posix_acl_release(acl);
 374         if (!clone)
 375                 return -ENOMEM;
 376         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 377         if (!rc)
 378                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 379         posix_acl_release(clone);
 380         return rc;
 381 }
 382
 383 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 384                                          const char *name, size_t name_len)
 385 {
 386         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 387
 388         if (list && retlen <= list_size)
 389                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 390         return retlen;
 391 }
 392
 393 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 394                                           const char *name, size_t name_len)
 395 {
 396         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 397
 398         if (list && retlen <= list_size)
 399                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 400         return retlen;
 401 }
 402
 403 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 404 {
 405         struct posix_acl *acl;
 406         int rc;
 407
 408         acl = jffs2_get_acl(inode, type);
 409         if (IS_ERR(acl))
 410                 return PTR_ERR(acl);
 411         if (!acl)
 412                 return -ENODATA;
 413         rc = posix_acl_to_xattr(acl, buffer, size);
 414         posix_acl_release(acl);
 415
 416         return rc;
 417 }
 418
 419 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 420 {
 421         if (name[0] != '\0')
 422                 return -EINVAL;
 423         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 424 }
 425
 426 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 427 {
 428         if (name[0] != '\0')
 429                 return -EINVAL;
 430         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 431 }
 432
 433 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 434 {
 435         struct posix_acl *acl;
 436         int rc;
 437
 438         if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
 439                 return -EPERM;
 440
 441         if (value) {
 442                 acl = posix_acl_from_xattr(value, size);
 443                 if (IS_ERR(acl))
 444                         return PTR_ERR(acl);
 445                 if (acl) {
 446                         rc = posix_acl_valid(acl);
 447                         if (rc)
 448                                 goto out;
 449                 }
 450         } else {
 451                 acl = NULL;
 452         }
 453         rc = jffs2_set_acl(inode, type, acl);
 454  out:
 455         posix_acl_release(acl);
 456         return rc;
 457 }
 458
 459 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 460                                      const void *buffer, size_t size, int flags)
 461 {
 462         if (name[0] != '\0')
 463                 return -EINVAL;
 464         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 465 }
 466
 467 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 468                                       const void *buffer, size_t size, int flags)
 469 {
 470         if (name[0] != '\0')
 471                 return -EINVAL;
 472         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 473 }
 474
 475 struct xattr_handler jffs2_acl_access_xattr_handler = {
 476         .prefix = POSIX_ACL_XATTR_ACCESS,
 477         .list   = jffs2_acl_access_listxattr,
 478         .get    = jffs2_acl_access_getxattr,
 479         .set    = jffs2_acl_access_setxattr,
 480 };
 481
 482 struct xattr_handler jffs2_acl_default_xattr_handler = {
 483         .prefix = POSIX_ACL_XATTR_DEFAULT,
 484         .list   = jffs2_acl_default_listxattr,
 485         .get    = jffs2_acl_default_getxattr,
 486         .set    = jffs2_acl_default_setxattr,
 487 };