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 = 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         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         struct posix_acl *clone;
 338         int ret;
 339
 340         *acl = NULL;
 341         *default_acl = NULL;
 342
 343         if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
 344                 return 0;
 345
 346         p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
 347         if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
 348                 *mode &= ~current_umask();
 349                 return 0;
 350         }
 351         if (IS_ERR(p))
 352                 return PTR_ERR(p);
 353
 354         clone = f2fs_acl_clone(p, GFP_NOFS);
 355         if (!clone)
 356                 goto no_mem;
 357
 358         ret = f2fs_acl_create_masq(clone, mode);
 359         if (ret < 0)
 360                 goto no_mem_clone;
 361
 362         if (ret == 0)
 363                 posix_acl_release(clone);
 364         else
 365                 *acl = clone;
 366
 367         if (!S_ISDIR(*mode))
 368                 posix_acl_release(p);
 369         else
 370                 *default_acl = p;
 371
 372         return 0;
 373
 374 no_mem_clone:
 375         posix_acl_release(clone);
 376 no_mem:
 377         posix_acl_release(p);
 378         return -ENOMEM;
 379 }
 380
 381 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
 382                                                         struct page *dpage)
 383 {
 384         struct posix_acl *default_acl = NULL, *acl = NULL;
 385         int error = 0;
 386
 387         error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
 388         if (error)
 389                 return error;
 390
 391         if (default_acl) {
 392                 error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
 393                                        ipage);
 394                 posix_acl_release(default_acl);
 395         }
 396         if (acl) {
 397                 if (!error)
 398                         error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
 399                                                ipage);
 400                 posix_acl_release(acl);
 401         }
 402
 403         return error;
 404 }