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_KERNEL);
  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_KERNEL);
 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 struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
 166 {
 167         int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 168         void *value = NULL;
 169         struct posix_acl *acl;
 170         int retval;
 171
 172         if (type == ACL_TYPE_ACCESS)
 173                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 174
 175         retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
 176         if (retval > 0) {
 177                 value = kmalloc(retval, GFP_F2FS_ZERO);
 178                 if (!value)
 179                         return ERR_PTR(-ENOMEM);
 180                 retval = f2fs_getxattr(inode, name_index, "", value, retval);
 181         }
 182
 183         if (retval > 0)
 184                 acl = f2fs_acl_from_disk(value, retval);
 185         else if (retval == -ENODATA)
 186                 acl = NULL;
 187         else
 188                 acl = ERR_PTR(retval);
 189         kfree(value);
 190
 191         if (!IS_ERR(acl))
 192                 set_cached_acl(inode, type, acl);
 193
 194         return acl;
 195 }
 196
 197 static int __f2fs_set_acl(struct inode *inode, int type,
 198                         struct posix_acl *acl, struct page *ipage)
 199 {
 200         struct f2fs_inode_info *fi = F2FS_I(inode);
 201         int name_index;
 202         void *value = NULL;
 203         size_t size = 0;
 204         int error;
 205
 206         if (acl) {
 207                 error = posix_acl_valid(acl);
 208                 if (error < 0)
 209                         return error;
 210         }
 211
 212         switch (type) {
 213         case ACL_TYPE_ACCESS:
 214                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 215                 if (acl) {
 216                         error = posix_acl_equiv_mode(acl, &inode->i_mode);
 217                         if (error < 0)
 218                                 return error;
 219                         set_acl_inode(fi, inode->i_mode);
 220                         if (error == 0)
 221                                 acl = NULL;
 222                 }
 223                 break;
 224
 225         case ACL_TYPE_DEFAULT:
 226                 name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 227                 if (!S_ISDIR(inode->i_mode))
 228                         return acl ? -EACCES : 0;
 229                 break;
 230
 231         default:
 232                 return -EINVAL;
 233         }
 234
 235         if (acl) {
 236                 value = f2fs_acl_to_disk(acl, &size);
 237                 if (IS_ERR(value)) {
 238                         cond_clear_inode_flag(fi, FI_ACL_MODE);
 239                         return (int)PTR_ERR(value);
 240                 }
 241         }
 242
 243         error = f2fs_setxattr(inode, name_index, "", value, size, ipage);
 244
 245         kfree(value);
 246         if (!error)
 247                 set_cached_acl(inode, type, acl);
 248
 249         cond_clear_inode_flag(fi, FI_ACL_MODE);
 250         return error;
 251 }
 252
 253 int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 254 {
 255         return __f2fs_set_acl(inode, type, acl, NULL);
 256 }
 257
 258 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage)
 259 {
 260         struct posix_acl *default_acl, *acl;
 261         int error = 0;
 262
 263         error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 264         if (error)
 265                 return error;
 266
 267         if (default_acl) {
 268                 error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
 269                                        ipage);
 270                 posix_acl_release(default_acl);
 271         }
 272         if (acl) {
 273                 if (error)
 274                         error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
 275                                                ipage);
 276                 posix_acl_release(acl);
 277         }
 278
 279         return error;
 280 }