fs/f2fs/acl.c

   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(struct f2fs_sb_info *sbi,
 113                                 const struct posix_acl *acl, size_t *size)
 114 {
 115         struct f2fs_acl_header *f2fs_acl;
 116         struct f2fs_acl_entry *entry;
 117         int i;
 118
 119         f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
 120                         acl->a_count * sizeof(struct f2fs_acl_entry),
 121                         GFP_NOFS);
 122         if (!f2fs_acl)
 123                 return ERR_PTR(-ENOMEM);
 124
 125         f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
 126         entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
 127
 128         for (i = 0; i < acl->a_count; i++) {
 129
 130                 entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
 131                 entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
 132
 133                 switch (acl->a_entries[i].e_tag) {
 134                 case ACL_USER:
 135                         entry->e_id = cpu_to_le32(
 136                                         from_kuid(&init_user_ns,
 137                                                 acl->a_entries[i].e_uid));
 138                         entry = (struct f2fs_acl_entry *)((char *)entry +
 139                                         sizeof(struct f2fs_acl_entry));
 140                         break;
 141                 case ACL_GROUP:
 142                         entry->e_id = cpu_to_le32(
 143                                         from_kgid(&init_user_ns,
 144                                                 acl->a_entries[i].e_gid));
 145                         entry = (struct f2fs_acl_entry *)((char *)entry +
 146                                         sizeof(struct f2fs_acl_entry));
 147                         break;
 148                 case ACL_USER_OBJ:
 149                 case ACL_GROUP_OBJ:
 150                 case ACL_MASK:
 151                 case ACL_OTHER:
 152                         entry = (struct f2fs_acl_entry *)((char *)entry +
 153                                         sizeof(struct f2fs_acl_entry_short));
 154                         break;
 155                 default:
 156                         goto fail;
 157                 }
 158         }
 159         *size = f2fs_acl_size(acl->a_count);
 160         return (void *)f2fs_acl;
 161
 162 fail:
 163         kfree(f2fs_acl);
 164         return ERR_PTR(-EINVAL);
 165 }
 166
 167 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
 168                                                 struct page *dpage)
 169 {
 170         int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 171         void *value = NULL;
 172         struct posix_acl *acl;
 173         int retval;
 174
 175         if (type == ACL_TYPE_ACCESS)
 176                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 177
 178         retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
 179         if (retval > 0) {
 180                 value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
 181                 if (!value)
 182                         return ERR_PTR(-ENOMEM);
 183                 retval = f2fs_getxattr(inode, name_index, "", value,
 184                                                         retval, dpage);
 185         }
 186
 187         if (retval > 0)
 188                 acl = f2fs_acl_from_disk(value, retval);
 189         else if (retval == -ENODATA)
 190                 acl = NULL;
 191         else
 192                 acl = ERR_PTR(retval);
 193         kfree(value);
 194
 195         return acl;
 196 }
 197
 198 struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
 199 {
 200         return __f2fs_get_acl(inode, type, NULL);
 201 }
 202
 203 static int __f2fs_set_acl(struct inode *inode, int type,
 204                         struct posix_acl *acl, struct page *ipage)
 205 {
 206         int name_index;
 207         void *value = NULL;
 208         size_t size = 0;
 209         int error;
 210
 211         switch (type) {
 212         case ACL_TYPE_ACCESS:
 213                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 214                 if (acl) {
 215                         error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
 216                         if (error)
 217                                 return error;
 218                         set_acl_inode(inode, inode->i_mode);
 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(F2FS_I_SB(inode), acl, &size);
 234                 if (IS_ERR(value)) {
 235                         clear_inode_flag(inode, FI_ACL_MODE);
 236                         return 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, true);
 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 }