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 #define get_inode_mode(i)       ((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \
  21                                         (F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
  22
  23 static inline size_t f2fs_acl_size(int count)
  24 {
  25         if (count <= 4) {
  26                 return sizeof(struct f2fs_acl_header) +
  27                         count * sizeof(struct f2fs_acl_entry_short);
  28         } else {
  29                 return sizeof(struct f2fs_acl_header) +
  30                         4 * sizeof(struct f2fs_acl_entry_short) +
  31                         (count - 4) * sizeof(struct f2fs_acl_entry);
  32         }
  33 }
  34
  35 static inline int f2fs_acl_count(size_t size)
  36 {
  37         ssize_t s;
  38         size -= sizeof(struct f2fs_acl_header);
  39         s = size - 4 * sizeof(struct f2fs_acl_entry_short);
  40         if (s < 0) {
  41                 if (size % sizeof(struct f2fs_acl_entry_short))
  42                         return -1;
  43                 return size / sizeof(struct f2fs_acl_entry_short);
  44         } else {
  45                 if (s % sizeof(struct f2fs_acl_entry))
  46                         return -1;
  47                 return s / sizeof(struct f2fs_acl_entry) + 4;
  48         }
  49 }
  50
  51 static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
  52 {
  53         int i, count;
  54         struct posix_acl *acl;
  55         struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
  56         struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
  57         const char *end = value + size;
  58
  59         if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
  60                 return ERR_PTR(-EINVAL);
  61
  62         count = f2fs_acl_count(size);
  63         if (count < 0)
  64                 return ERR_PTR(-EINVAL);
  65         if (count == 0)
  66                 return NULL;
  67
  68         acl = posix_acl_alloc(count, GFP_KERNEL);
  69         if (!acl)
  70                 return ERR_PTR(-ENOMEM);
  71
  72         for (i = 0; i < count; i++) {
  73
  74                 if ((char *)entry > end)
  75                         goto fail;
  76
  77                 acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
  78                 acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
  79
  80                 switch (acl->a_entries[i].e_tag) {
  81                 case ACL_USER_OBJ:
  82                 case ACL_GROUP_OBJ:
  83                 case ACL_MASK:
  84                 case ACL_OTHER:
  85                         entry = (struct f2fs_acl_entry *)((char *)entry +
  86                                         sizeof(struct f2fs_acl_entry_short));
  87                         break;
  88
  89                 case ACL_USER:
  90                         acl->a_entries[i].e_uid =
  91                                 make_kuid(&init_user_ns,
  92                                                 le32_to_cpu(entry->e_id));
  93                         entry = (struct f2fs_acl_entry *)((char *)entry +
  94                                         sizeof(struct f2fs_acl_entry));
  95                         break;
  96                 case ACL_GROUP:
  97                         acl->a_entries[i].e_gid =
  98                                 make_kgid(&init_user_ns,
  99                                                 le32_to_cpu(entry->e_id));
 100                         entry = (struct f2fs_acl_entry *)((char *)entry +
 101                                         sizeof(struct f2fs_acl_entry));
 102                         break;
 103                 default:
 104                         goto fail;
 105                 }
 106         }
 107         if ((char *)entry != end)
 108                 goto fail;
 109         return acl;
 110 fail:
 111         posix_acl_release(acl);
 112         return ERR_PTR(-EINVAL);
 113 }
 114
 115 static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size)
 116 {
 117         struct f2fs_acl_header *f2fs_acl;
 118         struct f2fs_acl_entry *entry;
 119         int i;
 120
 121         f2fs_acl = kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count *
 122                         sizeof(struct f2fs_acl_entry), GFP_KERNEL);
 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 struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
 169 {
 170         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 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 (!test_opt(sbi, POSIX_ACL))
 177                 return NULL;
 178
 179         acl = get_cached_acl(inode, type);
 180         if (acl != ACL_NOT_CACHED)
 181                 return acl;
 182
 183         if (type == ACL_TYPE_ACCESS)
 184                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 185
 186         retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
 187         if (retval > 0) {
 188                 value = kmalloc(retval, GFP_KERNEL);
 189                 if (!value)
 190                         return ERR_PTR(-ENOMEM);
 191                 retval = f2fs_getxattr(inode, name_index, "", value, retval);
 192         }
 193
 194         if (retval > 0)
 195                 acl = f2fs_acl_from_disk(value, retval);
 196         else if (retval == -ENODATA)
 197                 acl = NULL;
 198         else
 199                 acl = ERR_PTR(retval);
 200         kfree(value);
 201
 202         if (!IS_ERR(acl))
 203                 set_cached_acl(inode, type, acl);
 204
 205         return acl;
 206 }
 207
 208 static int f2fs_set_acl(struct inode *inode, int type,
 209                         struct posix_acl *acl, struct page *ipage)
 210 {
 211         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 212         struct f2fs_inode_info *fi = F2FS_I(inode);
 213         int name_index;
 214         void *value = NULL;
 215         size_t size = 0;
 216         int error;
 217
 218         if (!test_opt(sbi, POSIX_ACL))
 219                 return 0;
 220         if (S_ISLNK(inode->i_mode))
 221                 return -EOPNOTSUPP;
 222
 223         switch (type) {
 224         case ACL_TYPE_ACCESS:
 225                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 226                 if (acl) {
 227                         error = posix_acl_equiv_mode(acl, &inode->i_mode);
 228                         if (error < 0)
 229                                 return error;
 230                         set_acl_inode(fi, inode->i_mode);
 231                         if (error == 0)
 232                                 acl = NULL;
 233                 }
 234                 break;
 235
 236         case ACL_TYPE_DEFAULT:
 237                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 238                 if (!S_ISDIR(inode->i_mode))
 239                         return acl ? -EACCES : 0;
 240                 break;
 241
 242         default:
 243                 return -EINVAL;
 244         }
 245
 246         if (acl) {
 247                 value = f2fs_acl_to_disk(acl, &size);
 248                 if (IS_ERR(value)) {
 249                         cond_clear_inode_flag(fi, FI_ACL_MODE);
 250                         return (int)PTR_ERR(value);
 251                 }
 252         }
 253
 254         error = f2fs_setxattr(inode, name_index, "", value, size, ipage);
 255
 256         kfree(value);
 257         if (!error)
 258                 set_cached_acl(inode, type, acl);
 259
 260         cond_clear_inode_flag(fi, FI_ACL_MODE);
 261         return error;
 262 }
 263
 264 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage)
 265 {
 266         struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
 267         struct posix_acl *acl = NULL;
 268         int error = 0;
 269
 270         if (!S_ISLNK(inode->i_mode)) {
 271                 if (test_opt(sbi, POSIX_ACL)) {
 272                         acl = f2fs_get_acl(dir, ACL_TYPE_DEFAULT);
 273                         if (IS_ERR(acl))
 274                                 return PTR_ERR(acl);
 275                 }
 276                 if (!acl)
 277                         inode->i_mode &= ~current_umask();
 278         }
 279
 280         if (!test_opt(sbi, POSIX_ACL) || !acl)
 281                 goto cleanup;
 282
 283         if (S_ISDIR(inode->i_mode)) {
 284                 error = f2fs_set_acl(inode, ACL_TYPE_DEFAULT, acl, ipage);
 285                 if (error)
 286                         goto cleanup;
 287         }
 288         error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
 289         if (error < 0)
 290                 return error;
 291         if (error > 0)
 292                 error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl, ipage);
 293 cleanup:
 294         posix_acl_release(acl);
 295         return error;
 296 }
 297
 298 int f2fs_acl_chmod(struct inode *inode)
 299 {
 300         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 301         struct posix_acl *acl;
 302         int error;
 303         umode_t mode = get_inode_mode(inode);
 304
 305         if (!test_opt(sbi, POSIX_ACL))
 306                 return 0;
 307         if (S_ISLNK(mode))
 308                 return -EOPNOTSUPP;
 309
 310         acl = f2fs_get_acl(inode, ACL_TYPE_ACCESS);
 311         if (IS_ERR(acl) || !acl)
 312                 return PTR_ERR(acl);
 313
 314         error = posix_acl_chmod(&acl, GFP_KERNEL, mode);
 315         if (error)
 316                 return error;
 317
 318         error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl, NULL);
 319         posix_acl_release(acl);
 320         return error;
 321 }
 322
 323 static size_t f2fs_xattr_list_acl(struct dentry *dentry, char *list,
 324                 size_t list_size, const char *name, size_t name_len, int type)
 325 {
 326         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
 327         const char *xname = POSIX_ACL_XATTR_DEFAULT;
 328         size_t size;
 329
 330         if (!test_opt(sbi, POSIX_ACL))
 331                 return 0;
 332
 333         if (type == ACL_TYPE_ACCESS)
 334                 xname = POSIX_ACL_XATTR_ACCESS;
 335
 336         size = strlen(xname) + 1;
 337         if (list && size <= list_size)
 338                 memcpy(list, xname, size);
 339         return size;
 340 }
 341
 342 static int f2fs_xattr_get_acl(struct dentry *dentry, const char *name,
 343                 void *buffer, size_t size, int type)
 344 {
 345         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
 346         struct posix_acl *acl;
 347         int error;
 348
 349         if (strcmp(name, "") != 0)
 350                 return -EINVAL;
 351         if (!test_opt(sbi, POSIX_ACL))
 352                 return -EOPNOTSUPP;
 353
 354         acl = f2fs_get_acl(dentry->d_inode, type);
 355         if (IS_ERR(acl))
 356                 return PTR_ERR(acl);
 357         if (!acl)
 358                 return -ENODATA;
 359         error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
 360         posix_acl_release(acl);
 361
 362         return error;
 363 }
 364
 365 static int f2fs_xattr_set_acl(struct dentry *dentry, const char *name,
 366                 const void *value, size_t size, int flags, int type)
 367 {
 368         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
 369         struct inode *inode = dentry->d_inode;
 370         struct posix_acl *acl = NULL;
 371         int error;
 372
 373         if (strcmp(name, "") != 0)
 374                 return -EINVAL;
 375         if (!test_opt(sbi, POSIX_ACL))
 376                 return -EOPNOTSUPP;
 377         if (!inode_owner_or_capable(inode))
 378                 return -EPERM;
 379
 380         if (value) {
 381                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
 382                 if (IS_ERR(acl))
 383                         return PTR_ERR(acl);
 384                 if (acl) {
 385                         error = posix_acl_valid(acl);
 386                         if (error)
 387                                 goto release_and_out;
 388                 }
 389         } else {
 390                 acl = NULL;
 391         }
 392
 393         error = f2fs_set_acl(inode, type, acl, NULL);
 394
 395 release_and_out:
 396         posix_acl_release(acl);
 397         return error;
 398 }
 399
 400 const struct xattr_handler f2fs_xattr_acl_default_handler = {
 401         .prefix = POSIX_ACL_XATTR_DEFAULT,
 402         .flags = ACL_TYPE_DEFAULT,
 403         .list = f2fs_xattr_list_acl,
 404         .get = f2fs_xattr_get_acl,
 405         .set = f2fs_xattr_set_acl,
 406 };
 407
 408 const struct xattr_handler f2fs_xattr_acl_access_handler = {
 409         .prefix = POSIX_ACL_XATTR_ACCESS,
 410         .flags = ACL_TYPE_ACCESS,
 411         .list = f2fs_xattr_list_acl,
 412         .get = f2fs_xattr_get_acl,
 413         .set = f2fs_xattr_set_acl,
 414 };