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 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                                 struct iattr attr;
 251
 252                                 attr.ia_valid = ATTR_MODE;
 253                                 attr.ia_mode = mode;
 254                                 rc = jffs2_do_setattr(inode, &attr);
 255                                 if (rc < 0)
 256                                         return rc;
 257                         }
 258                         if (rc == 0)
 259                                 acl = NULL;
 260                 }
 261                 break;
 262         case ACL_TYPE_DEFAULT:
 263                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 264                 if (!S_ISDIR(inode->i_mode))
 265                         return acl ? -EACCES : 0;
 266                 break;
 267         default:
 268                 return -EINVAL;
 269         }
 270         if (acl) {
 271                 value = jffs2_acl_to_medium(acl, &size);
 272                 if (IS_ERR(value))
 273                         return PTR_ERR(value);
 274         }
 275
 276         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 277         if (!value && rc == -ENODATA)
 278                 rc = 0;
 279         if (value)
 280                 kfree(value);
 281         if (!rc) {
 282                 switch(type) {
 283                 case ACL_TYPE_ACCESS:
 284                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 285                         break;
 286                 case ACL_TYPE_DEFAULT:
 287                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 288                         break;
 289                 }
 290         }
 291         return rc;
 292 }
 293
 294 static int jffs2_check_acl(struct inode *inode, int mask)
 295 {
 296         struct posix_acl *acl;
 297         int rc;
 298
 299         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 300         if (IS_ERR(acl))
 301                 return PTR_ERR(acl);
 302         if (acl) {
 303                 rc = posix_acl_permission(inode, acl, mask);
 304                 posix_acl_release(acl);
 305                 return rc;
 306         }
 307         return -EAGAIN;
 308 }
 309
 310 int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
 311 {
 312         return generic_permission(inode, mask, jffs2_check_acl);
 313 }
 314
 315 int jffs2_init_acl(struct inode *inode, struct posix_acl *acl)
 316 {
 317         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 318         struct posix_acl *clone;
 319         mode_t mode;
 320         int rc = 0;
 321
 322         f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 323         f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 324
 325         if (acl) {
 326                 if (S_ISDIR(inode->i_mode)) {
 327                         rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
 328                         if (rc)
 329                                 goto cleanup;
 330                 }
 331                 clone = posix_acl_clone(acl, GFP_KERNEL);
 332                 rc = -ENOMEM;
 333                 if (!clone)
 334                         goto cleanup;
 335                 mode = inode->i_mode;
 336                 rc = posix_acl_create_masq(clone, &mode);
 337                 if (rc >= 0) {
 338                         inode->i_mode = mode;
 339                         if (rc > 0)
 340                                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 341                 }
 342                 posix_acl_release(clone);
 343         }
 344  cleanup:
 345         posix_acl_release(acl);
 346         return rc;
 347 }
 348
 349 void jffs2_clear_acl(struct jffs2_inode_info *f)
 350 {
 351         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 352                 posix_acl_release(f->i_acl_access);
 353                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 354         }
 355         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 356                 posix_acl_release(f->i_acl_default);
 357                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 358         }
 359 }
 360
 361 int jffs2_acl_chmod(struct inode *inode)
 362 {
 363         struct posix_acl *acl, *clone;
 364         int rc;
 365
 366         if (S_ISLNK(inode->i_mode))
 367                 return -EOPNOTSUPP;
 368         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 369         if (IS_ERR(acl) || !acl)
 370                 return PTR_ERR(acl);
 371         clone = posix_acl_clone(acl, GFP_KERNEL);
 372         posix_acl_release(acl);
 373         if (!clone)
 374                 return -ENOMEM;
 375         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 376         if (!rc)
 377                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 378         posix_acl_release(clone);
 379         return rc;
 380 }
 381
 382 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 383                                          const char *name, size_t name_len)
 384 {
 385         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 386
 387         if (list && retlen <= list_size)
 388                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 389         return retlen;
 390 }
 391
 392 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 393                                           const char *name, size_t name_len)
 394 {
 395         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 396
 397         if (list && retlen <= list_size)
 398                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 399         return retlen;
 400 }
 401
 402 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 403 {
 404         struct posix_acl *acl;
 405         int rc;
 406
 407         acl = jffs2_get_acl(inode, type);
 408         if (IS_ERR(acl))
 409                 return PTR_ERR(acl);
 410         if (!acl)
 411                 return -ENODATA;
 412         rc = posix_acl_to_xattr(acl, buffer, size);
 413         posix_acl_release(acl);
 414
 415         return rc;
 416 }
 417
 418 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 419 {
 420         if (name[0] != '\0')
 421                 return -EINVAL;
 422         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 423 }
 424
 425 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 426 {
 427         if (name[0] != '\0')
 428                 return -EINVAL;
 429         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 430 }
 431
 432 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 433 {
 434         struct posix_acl *acl;
 435         int rc;
 436
 437         if (!is_owner_or_cap(inode))
 438                 return -EPERM;
 439
 440         if (value) {
 441                 acl = posix_acl_from_xattr(value, size);
 442                 if (IS_ERR(acl))
 443                         return PTR_ERR(acl);
 444                 if (acl) {
 445                         rc = posix_acl_valid(acl);
 446                         if (rc)
 447                                 goto out;
 448                 }
 449         } else {
 450                 acl = NULL;
 451         }
 452         rc = jffs2_set_acl(inode, type, acl);
 453  out:
 454         posix_acl_release(acl);
 455         return rc;
 456 }
 457
 458 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 459                                      const void *buffer, size_t size, int flags)
 460 {
 461         if (name[0] != '\0')
 462                 return -EINVAL;
 463         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 464 }
 465
 466 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 467                                       const void *buffer, size_t size, int flags)
 468 {
 469         if (name[0] != '\0')
 470                 return -EINVAL;
 471         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 472 }
 473
 474 struct xattr_handler jffs2_acl_access_xattr_handler = {
 475         .prefix = POSIX_ACL_XATTR_ACCESS,
 476         .list   = jffs2_acl_access_listxattr,
 477         .get    = jffs2_acl_access_getxattr,
 478         .set    = jffs2_acl_access_setxattr,
 479 };
 480
 481 struct xattr_handler jffs2_acl_default_xattr_handler = {
 482         .prefix = POSIX_ACL_XATTR_DEFAULT,
 483         .list   = jffs2_acl_default_listxattr,
 484         .get    = jffs2_acl_default_getxattr,
 485         .set    = jffs2_acl_default_setxattr,
 486 };