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_KERNEL); 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 = kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count * 119 sizeof(struct f2fs_acl_entry), GFP_KERNEL); 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 = 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 if (!IS_ERR(acl)) 194 set_cached_acl(inode, type, acl); 195 196 return acl; 197 } 198 199 struct posix_acl *f2fs_get_acl(struct inode *inode, int type) 200 { 201 return __f2fs_get_acl(inode, type, NULL); 202 } 203 204 static int __f2fs_set_acl(struct inode *inode, int type, 205 struct posix_acl *acl, struct page *ipage) 206 { 207 struct f2fs_inode_info *fi = F2FS_I(inode); 208 int name_index; 209 void *value = NULL; 210 size_t size = 0; 211 int error; 212 213 switch (type) { 214 case ACL_TYPE_ACCESS: 215 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS; 216 if (acl) { 217 error = posix_acl_equiv_mode(acl, &inode->i_mode); 218 if (error < 0) 219 return error; 220 set_acl_inode(fi, inode->i_mode); 221 if (error == 0) 222 acl = NULL; 223 } 224 break; 225 226 case ACL_TYPE_DEFAULT: 227 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT; 228 if (!S_ISDIR(inode->i_mode)) 229 return acl ? -EACCES : 0; 230 break; 231 232 default: 233 return -EINVAL; 234 } 235 236 if (acl) { 237 value = f2fs_acl_to_disk(acl, &size); 238 if (IS_ERR(value)) { 239 clear_inode_flag(fi, FI_ACL_MODE); 240 return (int)PTR_ERR(value); 241 } 242 } 243 244 error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0); 245 246 kfree(value); 247 if (!error) 248 set_cached_acl(inode, type, acl); 249 250 clear_inode_flag(fi, FI_ACL_MODE); 251 return error; 252 } 253 254 int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 255 { 256 return __f2fs_set_acl(inode, type, acl, NULL); 257 } 258 259 /* 260 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create 261 * are copied from posix_acl.c 262 */ 263 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl, 264 gfp_t flags) 265 { 266 struct posix_acl *clone = NULL; 267 268 if (acl) { 269 int size = sizeof(struct posix_acl) + acl->a_count * 270 sizeof(struct posix_acl_entry); 271 clone = kmemdup(acl, size, flags); 272 if (clone) 273 atomic_set(&clone->a_refcount, 1); 274 } 275 return clone; 276 } 277 278 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) 279 { 280 struct posix_acl_entry *pa, *pe; 281 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; 282 umode_t mode = *mode_p; 283 int not_equiv = 0; 284 285 /* assert(atomic_read(acl->a_refcount) == 1); */ 286 287 FOREACH_ACL_ENTRY(pa, acl, pe) { 288 switch(pa->e_tag) { 289 case ACL_USER_OBJ: 290 pa->e_perm &= (mode >> 6) | ~S_IRWXO; 291 mode &= (pa->e_perm << 6) | ~S_IRWXU; 292 break; 293 294 case ACL_USER: 295 case ACL_GROUP: 296 not_equiv = 1; 297 break; 298 299 case ACL_GROUP_OBJ: 300 group_obj = pa; 301 break; 302 303 case ACL_OTHER: 304 pa->e_perm &= mode | ~S_IRWXO; 305 mode &= pa->e_perm | ~S_IRWXO; 306 break; 307 308 case ACL_MASK: 309 mask_obj = pa; 310 not_equiv = 1; 311 break; 312 313 default: 314 return -EIO; 315 } 316 } 317 318 if (mask_obj) { 319 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 320 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; 321 } else { 322 if (!group_obj) 323 return -EIO; 324 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 325 mode &= (group_obj->e_perm << 3) | ~S_IRWXG; 326 } 327 328 *mode_p = (*mode_p & ~S_IRWXUGO) | mode; 329 return not_equiv; 330 } 331 332 static int f2fs_acl_create(struct inode *dir, umode_t *mode, 333 struct posix_acl **default_acl, struct posix_acl **acl, 334 struct page *dpage) 335 { 336 struct posix_acl *p; 337 int ret; 338 339 if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) 340 goto no_acl; 341 342 p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage); 343 if (IS_ERR(p)) { 344 if (p == ERR_PTR(-EOPNOTSUPP)) 345 goto apply_umask; 346 return PTR_ERR(p); 347 } 348 349 if (!p) 350 goto apply_umask; 351 352 *acl = f2fs_acl_clone(p, GFP_NOFS); 353 if (!*acl) 354 return -ENOMEM; 355 356 ret = f2fs_acl_create_masq(*acl, mode); 357 if (ret < 0) { 358 posix_acl_release(*acl); 359 return -ENOMEM; 360 } 361 362 if (ret == 0) { 363 posix_acl_release(*acl); 364 *acl = NULL; 365 } 366 367 if (!S_ISDIR(*mode)) { 368 posix_acl_release(p); 369 *default_acl = NULL; 370 } else { 371 *default_acl = p; 372 } 373 return 0; 374 375 apply_umask: 376 *mode &= ~current_umask(); 377 no_acl: 378 *default_acl = NULL; 379 *acl = NULL; 380 return 0; 381 } 382 383 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage, 384 struct page *dpage) 385 { 386 struct posix_acl *default_acl = NULL, *acl = NULL; 387 int error = 0; 388 389 error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage); 390 if (error) 391 return error; 392 393 if (default_acl) { 394 error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl, 395 ipage); 396 posix_acl_release(default_acl); 397 } 398 if (acl) { 399 if (error) 400 error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl, 401 ipage); 402 posix_acl_release(acl); 403 } 404 405 return error; 406 } 407