1 /* 2 * fs/f2fs/acl.c 3 * 4 * Copyright (c) 2012 Samsung Electronics Co., Ltd. 5 * http://www.samsung.com/ 6 * 7 * Portions of this code from linux/fs/ext2/acl.c 8 * 9 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 #include <linux/f2fs_fs.h> 16 #include "f2fs.h" 17 #include "xattr.h" 18 #include "acl.h" 19 20 static inline size_t f2fs_acl_size(int count) 21 { 22 if (count <= 4) { 23 return sizeof(struct f2fs_acl_header) + 24 count * sizeof(struct f2fs_acl_entry_short); 25 } else { 26 return sizeof(struct f2fs_acl_header) + 27 4 * sizeof(struct f2fs_acl_entry_short) + 28 (count - 4) * sizeof(struct f2fs_acl_entry); 29 } 30 } 31 32 static inline int f2fs_acl_count(size_t size) 33 { 34 ssize_t s; 35 size -= sizeof(struct f2fs_acl_header); 36 s = size - 4 * sizeof(struct f2fs_acl_entry_short); 37 if (s < 0) { 38 if (size % sizeof(struct f2fs_acl_entry_short)) 39 return -1; 40 return size / sizeof(struct f2fs_acl_entry_short); 41 } else { 42 if (s % sizeof(struct f2fs_acl_entry)) 43 return -1; 44 return s / sizeof(struct f2fs_acl_entry) + 4; 45 } 46 } 47 48 static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) 49 { 50 int i, count; 51 struct posix_acl *acl; 52 struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value; 53 struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1); 54 const char *end = value + size; 55 56 if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION)) 57 return ERR_PTR(-EINVAL); 58 59 count = f2fs_acl_count(size); 60 if (count < 0) 61 return ERR_PTR(-EINVAL); 62 if (count == 0) 63 return NULL; 64 65 acl = posix_acl_alloc(count, GFP_NOFS); 66 if (!acl) 67 return ERR_PTR(-ENOMEM); 68 69 for (i = 0; i < count; i++) { 70 71 if ((char *)entry > end) 72 goto fail; 73 74 acl->a_entries[i].e_tag = le16_to_cpu(entry->e_tag); 75 acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm); 76 77 switch (acl->a_entries[i].e_tag) { 78 case ACL_USER_OBJ: 79 case ACL_GROUP_OBJ: 80 case ACL_MASK: 81 case ACL_OTHER: 82 entry = (struct f2fs_acl_entry *)((char *)entry + 83 sizeof(struct f2fs_acl_entry_short)); 84 break; 85 86 case ACL_USER: 87 acl->a_entries[i].e_uid = 88 make_kuid(&init_user_ns, 89 le32_to_cpu(entry->e_id)); 90 entry = (struct f2fs_acl_entry *)((char *)entry + 91 sizeof(struct f2fs_acl_entry)); 92 break; 93 case ACL_GROUP: 94 acl->a_entries[i].e_gid = 95 make_kgid(&init_user_ns, 96 le32_to_cpu(entry->e_id)); 97 entry = (struct f2fs_acl_entry *)((char *)entry + 98 sizeof(struct f2fs_acl_entry)); 99 break; 100 default: 101 goto fail; 102 } 103 } 104 if ((char *)entry != end) 105 goto fail; 106 return acl; 107 fail: 108 posix_acl_release(acl); 109 return ERR_PTR(-EINVAL); 110 } 111 112 static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size) 113 { 114 struct f2fs_acl_header *f2fs_acl; 115 struct f2fs_acl_entry *entry; 116 int i; 117 118 f2fs_acl = f2fs_kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count * 119 sizeof(struct f2fs_acl_entry), GFP_NOFS); 120 if (!f2fs_acl) 121 return ERR_PTR(-ENOMEM); 122 123 f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION); 124 entry = (struct f2fs_acl_entry *)(f2fs_acl + 1); 125 126 for (i = 0; i < acl->a_count; i++) { 127 128 entry->e_tag = cpu_to_le16(acl->a_entries[i].e_tag); 129 entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm); 130 131 switch (acl->a_entries[i].e_tag) { 132 case ACL_USER: 133 entry->e_id = cpu_to_le32( 134 from_kuid(&init_user_ns, 135 acl->a_entries[i].e_uid)); 136 entry = (struct f2fs_acl_entry *)((char *)entry + 137 sizeof(struct f2fs_acl_entry)); 138 break; 139 case ACL_GROUP: 140 entry->e_id = cpu_to_le32( 141 from_kgid(&init_user_ns, 142 acl->a_entries[i].e_gid)); 143 entry = (struct f2fs_acl_entry *)((char *)entry + 144 sizeof(struct f2fs_acl_entry)); 145 break; 146 case ACL_USER_OBJ: 147 case ACL_GROUP_OBJ: 148 case ACL_MASK: 149 case ACL_OTHER: 150 entry = (struct f2fs_acl_entry *)((char *)entry + 151 sizeof(struct f2fs_acl_entry_short)); 152 break; 153 default: 154 goto fail; 155 } 156 } 157 *size = f2fs_acl_size(acl->a_count); 158 return (void *)f2fs_acl; 159 160 fail: 161 kfree(f2fs_acl); 162 return ERR_PTR(-EINVAL); 163 } 164 165 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type, 166 struct page *dpage) 167 { 168 int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT; 169 void *value = NULL; 170 struct posix_acl *acl; 171 int retval; 172 173 if (type == ACL_TYPE_ACCESS) 174 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS; 175 176 retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage); 177 if (retval > 0) { 178 value = f2fs_kmalloc(retval, GFP_F2FS_ZERO); 179 if (!value) 180 return ERR_PTR(-ENOMEM); 181 retval = f2fs_getxattr(inode, name_index, "", value, 182 retval, dpage); 183 } 184 185 if (retval > 0) 186 acl = f2fs_acl_from_disk(value, retval); 187 else if (retval == -ENODATA) 188 acl = NULL; 189 else 190 acl = ERR_PTR(retval); 191 kfree(value); 192 193 return acl; 194 } 195 196 struct posix_acl *f2fs_get_acl(struct inode *inode, int type) 197 { 198 return __f2fs_get_acl(inode, type, NULL); 199 } 200 201 static int __f2fs_set_acl(struct inode *inode, int type, 202 struct posix_acl *acl, struct page *ipage) 203 { 204 int name_index; 205 void *value = NULL; 206 size_t size = 0; 207 int error; 208 209 switch (type) { 210 case ACL_TYPE_ACCESS: 211 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS; 212 if (acl) { 213 error = posix_acl_equiv_mode(acl, &inode->i_mode); 214 if (error < 0) 215 return error; 216 set_acl_inode(inode, inode->i_mode); 217 if (error == 0) 218 acl = NULL; 219 } 220 break; 221 222 case ACL_TYPE_DEFAULT: 223 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT; 224 if (!S_ISDIR(inode->i_mode)) 225 return acl ? -EACCES : 0; 226 break; 227 228 default: 229 return -EINVAL; 230 } 231 232 if (acl) { 233 value = f2fs_acl_to_disk(acl, &size); 234 if (IS_ERR(value)) { 235 clear_inode_flag(inode, FI_ACL_MODE); 236 return (int)PTR_ERR(value); 237 } 238 } 239 240 error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0); 241 242 kfree(value); 243 if (!error) 244 set_cached_acl(inode, type, acl); 245 246 clear_inode_flag(inode, FI_ACL_MODE); 247 return error; 248 } 249 250 int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 251 { 252 return __f2fs_set_acl(inode, type, acl, NULL); 253 } 254 255 /* 256 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create 257 * are copied from posix_acl.c 258 */ 259 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl, 260 gfp_t flags) 261 { 262 struct posix_acl *clone = NULL; 263 264 if (acl) { 265 int size = sizeof(struct posix_acl) + acl->a_count * 266 sizeof(struct posix_acl_entry); 267 clone = kmemdup(acl, size, flags); 268 if (clone) 269 atomic_set(&clone->a_refcount, 1); 270 } 271 return clone; 272 } 273 274 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) 275 { 276 struct posix_acl_entry *pa, *pe; 277 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; 278 umode_t mode = *mode_p; 279 int not_equiv = 0; 280 281 /* assert(atomic_read(acl->a_refcount) == 1); */ 282 283 FOREACH_ACL_ENTRY(pa, acl, pe) { 284 switch(pa->e_tag) { 285 case ACL_USER_OBJ: 286 pa->e_perm &= (mode >> 6) | ~S_IRWXO; 287 mode &= (pa->e_perm << 6) | ~S_IRWXU; 288 break; 289 290 case ACL_USER: 291 case ACL_GROUP: 292 not_equiv = 1; 293 break; 294 295 case ACL_GROUP_OBJ: 296 group_obj = pa; 297 break; 298 299 case ACL_OTHER: 300 pa->e_perm &= mode | ~S_IRWXO; 301 mode &= pa->e_perm | ~S_IRWXO; 302 break; 303 304 case ACL_MASK: 305 mask_obj = pa; 306 not_equiv = 1; 307 break; 308 309 default: 310 return -EIO; 311 } 312 } 313 314 if (mask_obj) { 315 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 316 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; 317 } else { 318 if (!group_obj) 319 return -EIO; 320 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 321 mode &= (group_obj->e_perm << 3) | ~S_IRWXG; 322 } 323 324 *mode_p = (*mode_p & ~S_IRWXUGO) | mode; 325 return not_equiv; 326 } 327 328 static int f2fs_acl_create(struct inode *dir, umode_t *mode, 329 struct posix_acl **default_acl, struct posix_acl **acl, 330 struct page *dpage) 331 { 332 struct posix_acl *p; 333 struct posix_acl *clone; 334 int ret; 335 336 *acl = NULL; 337 *default_acl = NULL; 338 339 if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) 340 return 0; 341 342 p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage); 343 if (!p || p == ERR_PTR(-EOPNOTSUPP)) { 344 *mode &= ~current_umask(); 345 return 0; 346 } 347 if (IS_ERR(p)) 348 return PTR_ERR(p); 349 350 clone = f2fs_acl_clone(p, GFP_NOFS); 351 if (!clone) 352 goto no_mem; 353 354 ret = f2fs_acl_create_masq(clone, mode); 355 if (ret < 0) 356 goto no_mem_clone; 357 358 if (ret == 0) 359 posix_acl_release(clone); 360 else 361 *acl = clone; 362 363 if (!S_ISDIR(*mode)) 364 posix_acl_release(p); 365 else 366 *default_acl = p; 367 368 return 0; 369 370 no_mem_clone: 371 posix_acl_release(clone); 372 no_mem: 373 posix_acl_release(p); 374 return -ENOMEM; 375 } 376 377 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage, 378 struct page *dpage) 379 { 380 struct posix_acl *default_acl = NULL, *acl = NULL; 381 int error = 0; 382 383 error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage); 384 if (error) 385 return error; 386 387 f2fs_mark_inode_dirty_sync(inode); 388 389 if (default_acl) { 390 error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl, 391 ipage); 392 posix_acl_release(default_acl); 393 } 394 if (acl) { 395 if (!error) 396 error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl, 397 ipage); 398 posix_acl_release(acl); 399 } 400 401 return error; 402 } 403