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 if (size < 4 * sizeof(struct jffs2_acl_entry_short)) { 42 if (size % sizeof(struct jffs2_acl_entry_short)) 43 return -1; 44 return size / sizeof(struct jffs2_acl_entry_short); 45 } else { 46 s = size - 4 * sizeof(struct jffs2_acl_entry_short); 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_get_acl(struct inode *inode, int type) 160 { 161 struct posix_acl *acl; 162 char *value = NULL; 163 int rc, xprefix; 164 165 acl = get_cached_acl(inode, type); 166 if (acl != ACL_NOT_CACHED) 167 return acl; 168 169 switch (type) { 170 case ACL_TYPE_ACCESS: 171 xprefix = JFFS2_XPREFIX_ACL_ACCESS; 172 break; 173 case ACL_TYPE_DEFAULT: 174 xprefix = JFFS2_XPREFIX_ACL_DEFAULT; 175 break; 176 default: 177 BUG(); 178 } 179 rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0); 180 if (rc > 0) { 181 value = kmalloc(rc, GFP_KERNEL); 182 if (!value) 183 return ERR_PTR(-ENOMEM); 184 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc); 185 } 186 if (rc > 0) { 187 acl = jffs2_acl_from_medium(value, rc); 188 } else if (rc == -ENODATA || rc == -ENOSYS) { 189 acl = NULL; 190 } else { 191 acl = ERR_PTR(rc); 192 } 193 if (value) 194 kfree(value); 195 if (!IS_ERR(acl)) 196 set_cached_acl(inode, type, acl); 197 return acl; 198 } 199 200 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl) 201 { 202 char *value = NULL; 203 size_t size = 0; 204 int rc; 205 206 if (acl) { 207 value = jffs2_acl_to_medium(acl, &size); 208 if (IS_ERR(value)) 209 return PTR_ERR(value); 210 } 211 rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0); 212 if (!value && rc == -ENODATA) 213 rc = 0; 214 kfree(value); 215 216 return rc; 217 } 218 219 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl) 220 { 221 int rc, xprefix; 222 223 if (S_ISLNK(inode->i_mode)) 224 return -EOPNOTSUPP; 225 226 switch (type) { 227 case ACL_TYPE_ACCESS: 228 xprefix = JFFS2_XPREFIX_ACL_ACCESS; 229 if (acl) { 230 mode_t mode = inode->i_mode; 231 rc = posix_acl_equiv_mode(acl, &mode); 232 if (rc < 0) 233 return rc; 234 if (inode->i_mode != mode) { 235 struct iattr attr; 236 237 attr.ia_valid = ATTR_MODE | ATTR_CTIME; 238 attr.ia_mode = mode; 239 attr.ia_ctime = CURRENT_TIME_SEC; 240 rc = jffs2_do_setattr(inode, &attr); 241 if (rc < 0) 242 return rc; 243 } 244 if (rc == 0) 245 acl = NULL; 246 } 247 break; 248 case ACL_TYPE_DEFAULT: 249 xprefix = JFFS2_XPREFIX_ACL_DEFAULT; 250 if (!S_ISDIR(inode->i_mode)) 251 return acl ? -EACCES : 0; 252 break; 253 default: 254 return -EINVAL; 255 } 256 rc = __jffs2_set_acl(inode, xprefix, acl); 257 if (!rc) 258 set_cached_acl(inode, type, acl); 259 return rc; 260 } 261 262 int jffs2_check_acl(struct inode *inode, int mask) 263 { 264 struct posix_acl *acl; 265 int rc; 266 267 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS); 268 if (IS_ERR(acl)) 269 return PTR_ERR(acl); 270 if (acl) { 271 rc = posix_acl_permission(inode, acl, mask); 272 posix_acl_release(acl); 273 return rc; 274 } 275 return -EAGAIN; 276 } 277 278 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, mode_t *i_mode) 279 { 280 struct posix_acl *acl; 281 int rc; 282 283 cache_no_acl(inode); 284 285 if (S_ISLNK(*i_mode)) 286 return 0; /* Symlink always has no-ACL */ 287 288 acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT); 289 if (IS_ERR(acl)) 290 return PTR_ERR(acl); 291 292 if (!acl) { 293 *i_mode &= ~current_umask(); 294 } else { 295 if (S_ISDIR(*i_mode)) 296 set_cached_acl(inode, ACL_TYPE_DEFAULT, acl); 297 298 rc = posix_acl_create(&acl, GFP_KERNEL, i_mode); 299 if (rc < 0) 300 return rc; 301 if (rc > 0) 302 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 303 304 posix_acl_release(acl); 305 } 306 return 0; 307 } 308 309 int jffs2_init_acl_post(struct inode *inode) 310 { 311 int rc; 312 313 if (inode->i_default_acl) { 314 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl); 315 if (rc) 316 return rc; 317 } 318 319 if (inode->i_acl) { 320 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl); 321 if (rc) 322 return rc; 323 } 324 325 return 0; 326 } 327 328 int jffs2_acl_chmod(struct inode *inode) 329 { 330 struct posix_acl *acl; 331 int rc; 332 333 if (S_ISLNK(inode->i_mode)) 334 return -EOPNOTSUPP; 335 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS); 336 if (IS_ERR(acl) || !acl) 337 return PTR_ERR(acl); 338 rc = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); 339 if (rc) 340 return rc; 341 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, acl); 342 posix_acl_release(acl); 343 return rc; 344 } 345 346 static size_t jffs2_acl_access_listxattr(struct dentry *dentry, char *list, 347 size_t list_size, const char *name, size_t name_len, int type) 348 { 349 const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS); 350 351 if (list && retlen <= list_size) 352 strcpy(list, POSIX_ACL_XATTR_ACCESS); 353 return retlen; 354 } 355 356 static size_t jffs2_acl_default_listxattr(struct dentry *dentry, char *list, 357 size_t list_size, const char *name, size_t name_len, int type) 358 { 359 const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT); 360 361 if (list && retlen <= list_size) 362 strcpy(list, POSIX_ACL_XATTR_DEFAULT); 363 return retlen; 364 } 365 366 static int jffs2_acl_getxattr(struct dentry *dentry, const char *name, 367 void *buffer, size_t size, int type) 368 { 369 struct posix_acl *acl; 370 int rc; 371 372 if (name[0] != '\0') 373 return -EINVAL; 374 375 acl = jffs2_get_acl(dentry->d_inode, type); 376 if (IS_ERR(acl)) 377 return PTR_ERR(acl); 378 if (!acl) 379 return -ENODATA; 380 rc = posix_acl_to_xattr(acl, buffer, size); 381 posix_acl_release(acl); 382 383 return rc; 384 } 385 386 static int jffs2_acl_setxattr(struct dentry *dentry, const char *name, 387 const void *value, size_t size, int flags, int type) 388 { 389 struct posix_acl *acl; 390 int rc; 391 392 if (name[0] != '\0') 393 return -EINVAL; 394 if (!inode_owner_or_capable(dentry->d_inode)) 395 return -EPERM; 396 397 if (value) { 398 acl = posix_acl_from_xattr(value, size); 399 if (IS_ERR(acl)) 400 return PTR_ERR(acl); 401 if (acl) { 402 rc = posix_acl_valid(acl); 403 if (rc) 404 goto out; 405 } 406 } else { 407 acl = NULL; 408 } 409 rc = jffs2_set_acl(dentry->d_inode, type, acl); 410 out: 411 posix_acl_release(acl); 412 return rc; 413 } 414 415 const struct xattr_handler jffs2_acl_access_xattr_handler = { 416 .prefix = POSIX_ACL_XATTR_ACCESS, 417 .flags = ACL_TYPE_DEFAULT, 418 .list = jffs2_acl_access_listxattr, 419 .get = jffs2_acl_getxattr, 420 .set = jffs2_acl_setxattr, 421 }; 422 423 const struct xattr_handler jffs2_acl_default_xattr_handler = { 424 .prefix = POSIX_ACL_XATTR_DEFAULT, 425 .flags = ACL_TYPE_DEFAULT, 426 .list = jffs2_acl_default_listxattr, 427 .get = jffs2_acl_getxattr, 428 .set = jffs2_acl_setxattr, 429 }; 430