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(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_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 = 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_update_mode(inode, &inode->i_mode, &acl);
 218                         if (error)
 219                                 return error;
 220                         set_acl_inode(fi, inode->i_mode);
 221                 }
 222                 break;
 223
 224         case ACL_TYPE_DEFAULT:
 225                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 226                 if (!S_ISDIR(inode->i_mode))
 227                         return acl ? -EACCES : 0;
 228                 break;
 229
 230         default:
 231                 return -EINVAL;
 232         }
 233
 234         if (acl) {
 235                 value = f2fs_acl_to_disk(acl, &size);
 236                 if (IS_ERR(value)) {
 237                         clear_inode_flag(fi, FI_ACL_MODE);
 238                         return (int)PTR_ERR(value);
 239                 }
 240         }
 241
 242         error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
 243
 244         kfree(value);
 245         if (!error)
 246                 set_cached_acl(inode, type, acl);
 247
 248         clear_inode_flag(fi, FI_ACL_MODE);
 249         return error;
 250 }
 251
 252 int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 253 {
 254         return __f2fs_set_acl(inode, type, acl, NULL);
 255 }
 256
 257 /*
 258  * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
 259  * are copied from posix_acl.c
 260  */
 261 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
 262                                                         gfp_t flags)
 263 {
 264         struct posix_acl *clone = NULL;
 265
 266         if (acl) {
 267                 int size = sizeof(struct posix_acl) + acl->a_count *
 268                                 sizeof(struct posix_acl_entry);
 269                 clone = kmemdup(acl, size, flags);
 270                 if (clone)
 271                         atomic_set(&clone->a_refcount, 1);
 272         }
 273         return clone;
 274 }
 275
 276 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
 277 {
 278         struct posix_acl_entry *pa, *pe;
 279         struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
 280         umode_t mode = *mode_p;
 281         int not_equiv = 0;
 282
 283         /* assert(atomic_read(acl->a_refcount) == 1); */
 284
 285         FOREACH_ACL_ENTRY(pa, acl, pe) {
 286                 switch(pa->e_tag) {
 287                 case ACL_USER_OBJ:
 288                         pa->e_perm &= (mode >> 6) | ~S_IRWXO;
 289                         mode &= (pa->e_perm << 6) | ~S_IRWXU;
 290                         break;
 291
 292                 case ACL_USER:
 293                 case ACL_GROUP:
 294                         not_equiv = 1;
 295                         break;
 296
 297                 case ACL_GROUP_OBJ:
 298                         group_obj = pa;
 299                         break;
 300
 301                 case ACL_OTHER:
 302                         pa->e_perm &= mode | ~S_IRWXO;
 303                         mode &= pa->e_perm | ~S_IRWXO;
 304                         break;
 305
 306                 case ACL_MASK:
 307                         mask_obj = pa;
 308                         not_equiv = 1;
 309                         break;
 310
 311                 default:
 312                         return -EIO;
 313                 }
 314         }
 315
 316         if (mask_obj) {
 317                 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 318                 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
 319         } else {
 320                 if (!group_obj)
 321                         return -EIO;
 322                 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 323                 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
 324         }
 325
 326         *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
 327         return not_equiv;
 328 }
 329
 330 static int f2fs_acl_create(struct inode *dir, umode_t *mode,
 331                 struct posix_acl **default_acl, struct posix_acl **acl,
 332                 struct page *dpage)
 333 {
 334         struct posix_acl *p;
 335         int ret;
 336
 337         if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
 338                 goto no_acl;
 339
 340         p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
 341         if (IS_ERR(p)) {
 342                 if (p == ERR_PTR(-EOPNOTSUPP))
 343                         goto apply_umask;
 344                 return PTR_ERR(p);
 345         }
 346
 347         if (!p)
 348                 goto apply_umask;
 349
 350         *acl = f2fs_acl_clone(p, GFP_NOFS);
 351         if (!*acl)
 352                 goto no_mem;
 353
 354         ret = f2fs_acl_create_masq(*acl, mode);
 355         if (ret < 0)
 356                 goto no_mem_clone;
 357
 358         if (ret == 0) {
 359                 posix_acl_release(*acl);
 360                 *acl = NULL;
 361         }
 362
 363         if (!S_ISDIR(*mode)) {
 364                 posix_acl_release(p);
 365                 *default_acl = NULL;
 366         } else {
 367                 *default_acl = p;
 368         }
 369         return 0;
 370
 371 apply_umask:
 372         *mode &= ~current_umask();
 373 no_acl:
 374         *default_acl = NULL;
 375         *acl = NULL;
 376         return 0;
 377
 378 no_mem_clone:
 379         posix_acl_release(*acl);
 380 no_mem:
 381         posix_acl_release(p);
 382         return -ENOMEM;
 383 }
 384
 385 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
 386                                                         struct page *dpage)
 387 {
 388         struct posix_acl *default_acl = NULL, *acl = NULL;
 389         int error = 0;
 390
 391         error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
 392         if (error)
 393                 return error;
 394
 395         if (default_acl) {
 396                 error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
 397                                        ipage);
 398                 posix_acl_release(default_acl);
 399         }
 400         if (acl) {
 401                 if (!error)
 402                         error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
 403                                                ipage);
 404                 posix_acl_release(acl);
 405         }
 406
 407         return error;
 408 }