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 xprefix, struct posix_acl *acl)
 232 {
 233         char *value = NULL;
 234         size_t size = 0;
 235         int rc;
 236
 237         if (acl) {
 238                 value = jffs2_acl_to_medium(acl, &size);
 239                 if (IS_ERR(value))
 240                         return PTR_ERR(value);
 241         }
 242         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
 243         if (!value && rc == -ENODATA)
 244                 rc = 0;
 245         kfree(value);
 246
 247         return rc;
 248 }
 249
 250 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 251 {
 252         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 253         int rc, xprefix;
 254
 255         if (S_ISLNK(inode->i_mode))
 256                 return -EOPNOTSUPP;
 257
 258         switch (type) {
 259         case ACL_TYPE_ACCESS:
 260                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
 261                 if (acl) {
 262                         mode_t mode = inode->i_mode;
 263                         rc = posix_acl_equiv_mode(acl, &mode);
 264                         if (rc < 0)
 265                                 return rc;
 266                         if (inode->i_mode != mode) {
 267                                 struct iattr attr;
 268
 269                                 attr.ia_valid = ATTR_MODE;
 270                                 attr.ia_mode = mode;
 271                                 rc = jffs2_do_setattr(inode, &attr);
 272                                 if (rc < 0)
 273                                         return rc;
 274                         }
 275                         if (rc == 0)
 276                                 acl = NULL;
 277                 }
 278                 break;
 279         case ACL_TYPE_DEFAULT:
 280                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
 281                 if (!S_ISDIR(inode->i_mode))
 282                         return acl ? -EACCES : 0;
 283                 break;
 284         default:
 285                 return -EINVAL;
 286         }
 287         rc = __jffs2_set_acl(inode, xprefix, acl);
 288         if (!rc) {
 289                 switch(type) {
 290                 case ACL_TYPE_ACCESS:
 291                         jffs2_iset_acl(inode, &f->i_acl_access, acl);
 292                         break;
 293                 case ACL_TYPE_DEFAULT:
 294                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 295                         break;
 296                 }
 297         }
 298         return rc;
 299 }
 300
 301 static int jffs2_check_acl(struct inode *inode, int mask)
 302 {
 303         struct posix_acl *acl;
 304         int rc;
 305
 306         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 307         if (IS_ERR(acl))
 308                 return PTR_ERR(acl);
 309         if (acl) {
 310                 rc = posix_acl_permission(inode, acl, mask);
 311                 posix_acl_release(acl);
 312                 return rc;
 313         }
 314         return -EAGAIN;
 315 }
 316
 317 int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
 318 {
 319         return generic_permission(inode, mask, jffs2_check_acl);
 320 }
 321
 322 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
 323 {
 324         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 325         struct posix_acl *acl, *clone;
 326         int rc;
 327
 328         f->i_acl_default = NULL;
 329         f->i_acl_access = NULL;
 330
 331         if (S_ISLNK(*i_mode))
 332                 return 0;       /* Symlink always has no-ACL */
 333
 334         acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
 335         if (IS_ERR(acl))
 336                 return PTR_ERR(acl);
 337
 338         if (!acl) {
 339                 *i_mode &= ~current->fs->umask;
 340         } else {
 341                 if (S_ISDIR(*i_mode))
 342                         jffs2_iset_acl(inode, &f->i_acl_default, acl);
 343
 344                 clone = posix_acl_clone(acl, GFP_KERNEL);
 345                 if (!clone)
 346                         return -ENOMEM;
 347                 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
 348                 if (rc < 0)
 349                         return rc;
 350                 if (rc > 0)
 351                         jffs2_iset_acl(inode, &f->i_acl_access, clone);
 352
 353                 posix_acl_release(clone);
 354         }
 355         return 0;
 356 }
 357
 358 int jffs2_init_acl_post(struct inode *inode)
 359 {
 360         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 361         int rc;
 362
 363         if (f->i_acl_default) {
 364                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, f->i_acl_default);
 365                 if (rc)
 366                         return rc;
 367         }
 368
 369         if (f->i_acl_access) {
 370                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, f->i_acl_access);
 371                 if (rc)
 372                         return rc;
 373         }
 374
 375         return 0;
 376 }
 377
 378 void jffs2_clear_acl(struct jffs2_inode_info *f)
 379 {
 380         if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
 381                 posix_acl_release(f->i_acl_access);
 382                 f->i_acl_access = JFFS2_ACL_NOT_CACHED;
 383         }
 384         if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
 385                 posix_acl_release(f->i_acl_default);
 386                 f->i_acl_default = JFFS2_ACL_NOT_CACHED;
 387         }
 388 }
 389
 390 int jffs2_acl_chmod(struct inode *inode)
 391 {
 392         struct posix_acl *acl, *clone;
 393         int rc;
 394
 395         if (S_ISLNK(inode->i_mode))
 396                 return -EOPNOTSUPP;
 397         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
 398         if (IS_ERR(acl) || !acl)
 399                 return PTR_ERR(acl);
 400         clone = posix_acl_clone(acl, GFP_KERNEL);
 401         posix_acl_release(acl);
 402         if (!clone)
 403                 return -ENOMEM;
 404         rc = posix_acl_chmod_masq(clone, inode->i_mode);
 405         if (!rc)
 406                 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
 407         posix_acl_release(clone);
 408         return rc;
 409 }
 410
 411 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
 412                                          const char *name, size_t name_len)
 413 {
 414         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
 415
 416         if (list && retlen <= list_size)
 417                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
 418         return retlen;
 419 }
 420
 421 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
 422                                           const char *name, size_t name_len)
 423 {
 424         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
 425
 426         if (list && retlen <= list_size)
 427                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
 428         return retlen;
 429 }
 430
 431 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
 432 {
 433         struct posix_acl *acl;
 434         int rc;
 435
 436         acl = jffs2_get_acl(inode, type);
 437         if (IS_ERR(acl))
 438                 return PTR_ERR(acl);
 439         if (!acl)
 440                 return -ENODATA;
 441         rc = posix_acl_to_xattr(acl, buffer, size);
 442         posix_acl_release(acl);
 443
 444         return rc;
 445 }
 446
 447 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 448 {
 449         if (name[0] != '\0')
 450                 return -EINVAL;
 451         return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 452 }
 453
 454 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
 455 {
 456         if (name[0] != '\0')
 457                 return -EINVAL;
 458         return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 459 }
 460
 461 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
 462 {
 463         struct posix_acl *acl;
 464         int rc;
 465
 466         if (!is_owner_or_cap(inode))
 467                 return -EPERM;
 468
 469         if (value) {
 470                 acl = posix_acl_from_xattr(value, size);
 471                 if (IS_ERR(acl))
 472                         return PTR_ERR(acl);
 473                 if (acl) {
 474                         rc = posix_acl_valid(acl);
 475                         if (rc)
 476                                 goto out;
 477                 }
 478         } else {
 479                 acl = NULL;
 480         }
 481         rc = jffs2_set_acl(inode, type, acl);
 482  out:
 483         posix_acl_release(acl);
 484         return rc;
 485 }
 486
 487 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
 488                                      const void *buffer, size_t size, int flags)
 489 {
 490         if (name[0] != '\0')
 491                 return -EINVAL;
 492         return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
 493 }
 494
 495 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
 496                                       const void *buffer, size_t size, int flags)
 497 {
 498         if (name[0] != '\0')
 499                 return -EINVAL;
 500         return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
 501 }
 502
 503 struct xattr_handler jffs2_acl_access_xattr_handler = {
 504         .prefix = POSIX_ACL_XATTR_ACCESS,
 505         .list   = jffs2_acl_access_listxattr,
 506         .get    = jffs2_acl_access_getxattr,
 507         .set    = jffs2_acl_access_setxattr,
 508 };
 509
 510 struct xattr_handler jffs2_acl_default_xattr_handler = {
 511         .prefix = POSIX_ACL_XATTR_DEFAULT,
 512         .list   = jffs2_acl_default_listxattr,
 513         .get    = jffs2_acl_default_getxattr,
 514         .set    = jffs2_acl_default_setxattr,
 515 };