fs/f2fs/acl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * fs/f2fs/acl.c
   4  *
   5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   6  *             http://www.samsung.com/
   7  *
   8  * Portions of this code from linux/fs/ext2/acl.c
   9  *
  10  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
  11  */
  12 #include <linux/f2fs_fs.h>
  13 #include "f2fs.h"
  14 #include "xattr.h"
  15 #include "acl.h"
  16
  17 static inline size_t f2fs_acl_size(int count)
  18 {
  19         if (count <= 4) {
  20                 return sizeof(struct f2fs_acl_header) +
  21                         count * sizeof(struct f2fs_acl_entry_short);
  22         } else {
  23                 return sizeof(struct f2fs_acl_header) +
  24                         4 * sizeof(struct f2fs_acl_entry_short) +
  25                         (count - 4) * sizeof(struct f2fs_acl_entry);
  26         }
  27 }
  28
  29 static inline int f2fs_acl_count(size_t size)
  30 {
  31         ssize_t s;
  32
  33         size -= sizeof(struct f2fs_acl_header);
  34         s = size - 4 * sizeof(struct f2fs_acl_entry_short);
  35         if (s < 0) {
  36                 if (size % sizeof(struct f2fs_acl_entry_short))
  37                         return -1;
  38                 return size / sizeof(struct f2fs_acl_entry_short);
  39         } else {
  40                 if (s % sizeof(struct f2fs_acl_entry))
  41                         return -1;
  42                 return s / sizeof(struct f2fs_acl_entry) + 4;
  43         }
  44 }
  45
  46 static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
  47 {
  48         int i, count;
  49         struct posix_acl *acl;
  50         struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
  51         struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
  52         const char *end = value + size;
  53
  54         if (size < sizeof(struct f2fs_acl_header))
  55                 return ERR_PTR(-EINVAL);
  56
  57         if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
  58                 return ERR_PTR(-EINVAL);
  59
  60         count = f2fs_acl_count(size);
  61         if (count < 0)
  62                 return ERR_PTR(-EINVAL);
  63         if (count == 0)
  64                 return NULL;
  65
  66         acl = posix_acl_alloc(count, GFP_NOFS);
  67         if (!acl)
  68                 return ERR_PTR(-ENOMEM);
  69
  70         for (i = 0; i < count; i++) {
  71
  72                 if ((char *)entry > end)
  73                         goto fail;
  74
  75                 acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
  76                 acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
  77
  78                 switch (acl->a_entries[i].e_tag) {
  79                 case ACL_USER_OBJ:
  80                 case ACL_GROUP_OBJ:
  81                 case ACL_MASK:
  82                 case ACL_OTHER:
  83                         entry = (struct f2fs_acl_entry *)((char *)entry +
  84                                         sizeof(struct f2fs_acl_entry_short));
  85                         break;
  86
  87                 case ACL_USER:
  88                         acl->a_entries[i].e_uid =
  89                                 make_kuid(&init_user_ns,
  90                                                 le32_to_cpu(entry->e_id));
  91                         entry = (struct f2fs_acl_entry *)((char *)entry +
  92                                         sizeof(struct f2fs_acl_entry));
  93                         break;
  94                 case ACL_GROUP:
  95                         acl->a_entries[i].e_gid =
  96                                 make_kgid(&init_user_ns,
  97                                                 le32_to_cpu(entry->e_id));
  98                         entry = (struct f2fs_acl_entry *)((char *)entry +
  99                                         sizeof(struct f2fs_acl_entry));
 100                         break;
 101                 default:
 102                         goto fail;
 103                 }
 104         }
 105         if ((char *)entry != end)
 106                 goto fail;
 107         return acl;
 108 fail:
 109         posix_acl_release(acl);
 110         return ERR_PTR(-EINVAL);
 111 }
 112
 113 static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
 114                                 const struct posix_acl *acl, size_t *size)
 115 {
 116         struct f2fs_acl_header *f2fs_acl;
 117         struct f2fs_acl_entry *entry;
 118         int i;
 119
 120         f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
 121                         acl->a_count * sizeof(struct f2fs_acl_entry),
 122                         GFP_NOFS);
 123         if (!f2fs_acl)
 124                 return ERR_PTR(-ENOMEM);
 125
 126         f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
 127         entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
 128
 129         for (i = 0; i < acl->a_count; i++) {
 130
 131                 entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
 132                 entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
 133
 134                 switch (acl->a_entries[i].e_tag) {
 135                 case ACL_USER:
 136                         entry->e_id = cpu_to_le32(
 137                                         from_kuid(&init_user_ns,
 138                                                 acl->a_entries[i].e_uid));
 139                         entry = (struct f2fs_acl_entry *)((char *)entry +
 140                                         sizeof(struct f2fs_acl_entry));
 141                         break;
 142                 case ACL_GROUP:
 143                         entry->e_id = cpu_to_le32(
 144                                         from_kgid(&init_user_ns,
 145                                                 acl->a_entries[i].e_gid));
 146                         entry = (struct f2fs_acl_entry *)((char *)entry +
 147                                         sizeof(struct f2fs_acl_entry));
 148                         break;
 149                 case ACL_USER_OBJ:
 150                 case ACL_GROUP_OBJ:
 151                 case ACL_MASK:
 152                 case ACL_OTHER:
 153                         entry = (struct f2fs_acl_entry *)((char *)entry +
 154                                         sizeof(struct f2fs_acl_entry_short));
 155                         break;
 156                 default:
 157                         goto fail;
 158                 }
 159         }
 160         *size = f2fs_acl_size(acl->a_count);
 161         return (void *)f2fs_acl;
 162
 163 fail:
 164         kfree(f2fs_acl);
 165         return ERR_PTR(-EINVAL);
 166 }
 167
 168 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
 169                                                 struct page *dpage)
 170 {
 171         int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 172         void *value = NULL;
 173         struct posix_acl *acl;
 174         int retval;
 175
 176         if (type == ACL_TYPE_ACCESS)
 177                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 178
 179         retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
 180         if (retval > 0) {
 181                 value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
 182                 if (!value)
 183                         return ERR_PTR(-ENOMEM);
 184                 retval = f2fs_getxattr(inode, name_index, "", value,
 185                                                         retval, dpage);
 186         }
 187
 188         if (retval > 0)
 189                 acl = f2fs_acl_from_disk(value, retval);
 190         else if (retval == -ENODATA)
 191                 acl = NULL;
 192         else
 193                 acl = ERR_PTR(retval);
 194         kfree(value);
 195
 196         return acl;
 197 }
 198
 199 struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
 200 {
 201         if (rcu)
 202                 return ERR_PTR(-ECHILD);
 203
 204         return __f2fs_get_acl(inode, type, NULL);
 205 }
 206
 207 static int f2fs_acl_update_mode(struct user_namespace *mnt_userns,
 208                                 struct inode *inode, umode_t *mode_p,
 209                                 struct posix_acl **acl)
 210 {
 211         umode_t mode = inode->i_mode;
 212         int error;
 213
 214         if (is_inode_flag_set(inode, FI_ACL_MODE))
 215                 mode = F2FS_I(inode)->i_acl_mode;
 216
 217         error = posix_acl_equiv_mode(*acl, &mode);
 218         if (error < 0)
 219                 return error;
 220         if (error == 0)
 221                 *acl = NULL;
 222         if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) &&
 223             !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
 224                 mode &= ~S_ISGID;
 225         *mode_p = mode;
 226         return 0;
 227 }
 228
 229 static int __f2fs_set_acl(struct user_namespace *mnt_userns,
 230                         struct inode *inode, int type,
 231                         struct posix_acl *acl, struct page *ipage)
 232 {
 233         int name_index;
 234         void *value = NULL;
 235         size_t size = 0;
 236         int error;
 237         umode_t mode = inode->i_mode;
 238
 239         switch (type) {
 240         case ACL_TYPE_ACCESS:
 241                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 242                 if (acl && !ipage) {
 243                         error = f2fs_acl_update_mode(mnt_userns, inode,
 244                                                                 &mode, &acl);
 245                         if (error)
 246                                 return error;
 247                         set_acl_inode(inode, mode);
 248                 }
 249                 break;
 250
 251         case ACL_TYPE_DEFAULT:
 252                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 253                 if (!S_ISDIR(inode->i_mode))
 254                         return acl ? -EACCES : 0;
 255                 break;
 256
 257         default:
 258                 return -EINVAL;
 259         }
 260
 261         if (acl) {
 262                 value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
 263                 if (IS_ERR(value)) {
 264                         clear_inode_flag(inode, FI_ACL_MODE);
 265                         return PTR_ERR(value);
 266                 }
 267         }
 268
 269         error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
 270
 271         kfree(value);
 272         if (!error)
 273                 set_cached_acl(inode, type, acl);
 274
 275         clear_inode_flag(inode, FI_ACL_MODE);
 276         return error;
 277 }
 278
 279 int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 280                  struct posix_acl *acl, int type)
 281 {
 282         struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
 283         struct inode *inode = d_inode(dentry);
 284
 285         if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
 286                 return -EIO;
 287
 288         return __f2fs_set_acl(mnt_userns, inode, type, acl, NULL);
 289 }
 290
 291 /*
 292  * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
 293  * are copied from posix_acl.c
 294  */
 295 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
 296                                                         gfp_t flags)
 297 {
 298         struct posix_acl *clone = NULL;
 299
 300         if (acl) {
 301                 int size = sizeof(struct posix_acl) + acl->a_count *
 302                                 sizeof(struct posix_acl_entry);
 303                 clone = kmemdup(acl, size, flags);
 304                 if (clone)
 305                         refcount_set(&clone->a_refcount, 1);
 306         }
 307         return clone;
 308 }
 309
 310 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
 311 {
 312         struct posix_acl_entry *pa, *pe;
 313         struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
 314         umode_t mode = *mode_p;
 315         int not_equiv = 0;
 316
 317         /* assert(atomic_read(acl->a_refcount) == 1); */
 318
 319         FOREACH_ACL_ENTRY(pa, acl, pe) {
 320                 switch (pa->e_tag) {
 321                 case ACL_USER_OBJ:
 322                         pa->e_perm &= (mode >> 6) | ~S_IRWXO;
 323                         mode &= (pa->e_perm << 6) | ~S_IRWXU;
 324                         break;
 325
 326                 case ACL_USER:
 327                 case ACL_GROUP:
 328                         not_equiv = 1;
 329                         break;
 330
 331                 case ACL_GROUP_OBJ:
 332                         group_obj = pa;
 333                         break;
 334
 335                 case ACL_OTHER:
 336                         pa->e_perm &= mode | ~S_IRWXO;
 337                         mode &= pa->e_perm | ~S_IRWXO;
 338                         break;
 339
 340                 case ACL_MASK:
 341                         mask_obj = pa;
 342                         not_equiv = 1;
 343                         break;
 344
 345                 default:
 346                         return -EIO;
 347                 }
 348         }
 349
 350         if (mask_obj) {
 351                 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 352                 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
 353         } else {
 354                 if (!group_obj)
 355                         return -EIO;
 356                 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 357                 mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
 358         }
 359
 360         *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
 361         return not_equiv;
 362 }
 363
 364 static int f2fs_acl_create(struct inode *dir, umode_t *mode,
 365                 struct posix_acl **default_acl, struct posix_acl **acl,
 366                 struct page *dpage)
 367 {
 368         struct posix_acl *p;
 369         struct posix_acl *clone;
 370         int ret;
 371
 372         *acl = NULL;
 373         *default_acl = NULL;
 374
 375         if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
 376                 return 0;
 377
 378         p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
 379         if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
 380                 *mode &= ~current_umask();
 381                 return 0;
 382         }
 383         if (IS_ERR(p))
 384                 return PTR_ERR(p);
 385
 386         clone = f2fs_acl_clone(p, GFP_NOFS);
 387         if (!clone) {
 388                 ret = -ENOMEM;
 389                 goto release_acl;
 390         }
 391
 392         ret = f2fs_acl_create_masq(clone, mode);
 393         if (ret < 0)
 394                 goto release_clone;
 395
 396         if (ret == 0)
 397                 posix_acl_release(clone);
 398         else
 399                 *acl = clone;
 400
 401         if (!S_ISDIR(*mode))
 402                 posix_acl_release(p);
 403         else
 404                 *default_acl = p;
 405
 406         return 0;
 407
 408 release_clone:
 409         posix_acl_release(clone);
 410 release_acl:
 411         posix_acl_release(p);
 412         return ret;
 413 }
 414
 415 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
 416                                                         struct page *dpage)
 417 {
 418         struct posix_acl *default_acl = NULL, *acl = NULL;
 419         int error;
 420
 421         error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
 422         if (error)
 423                 return error;
 424
 425         f2fs_mark_inode_dirty_sync(inode, true);
 426
 427         if (default_acl) {
 428                 error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
 429                                        ipage);
 430                 posix_acl_release(default_acl);
 431         } else {
 432                 inode->i_default_acl = NULL;
 433         }
 434         if (acl) {
 435                 if (!error)
 436                         error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
 437                                                ipage);
 438                 posix_acl_release(acl);
 439         } else {
 440                 inode->i_acl = NULL;
 441         }
 442
 443         return error;
 444 }