fs/btrfs/acl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Red Hat.  All rights reserved.
   4  */
   5
   6 #include <linux/fs.h>
   7 #include <linux/string.h>
   8 #include <linux/xattr.h>
   9 #include <linux/posix_acl_xattr.h>
  10 #include <linux/posix_acl.h>
  11 #include <linux/sched.h>
  12 #include <linux/slab.h>
  13
  14 #include "ctree.h"
  15 #include "btrfs_inode.h"
  16 #include "xattr.h"
  17
  18 struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
  19 {
  20         int size;
  21         const char *name;
  22         char *value = NULL;
  23         struct posix_acl *acl;
  24
  25         switch (type) {
  26         case ACL_TYPE_ACCESS:
  27                 name = XATTR_NAME_POSIX_ACL_ACCESS;
  28                 break;
  29         case ACL_TYPE_DEFAULT:
  30                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
  31                 break;
  32         default:
  33                 BUG();
  34         }
  35
  36         size = btrfs_getxattr(inode, name, "", 0);
  37         if (size > 0) {
  38                 value = kzalloc(size, GFP_KERNEL);
  39                 if (!value)
  40                         return ERR_PTR(-ENOMEM);
  41                 size = btrfs_getxattr(inode, name, value, size);
  42         }
  43         if (size > 0) {
  44                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
  45         } else if (size == -ERANGE || size == -ENODATA || size == 0) {
  46                 acl = NULL;
  47         } else {
  48                 acl = ERR_PTR(-EIO);
  49         }
  50         kfree(value);
  51
  52         return acl;
  53 }
  54
  55 static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
  56                          struct inode *inode, struct posix_acl *acl, int type)
  57 {
  58         int ret, size = 0;
  59         const char *name;
  60         char *value = NULL;
  61
  62         switch (type) {
  63         case ACL_TYPE_ACCESS:
  64                 name = XATTR_NAME_POSIX_ACL_ACCESS;
  65                 break;
  66         case ACL_TYPE_DEFAULT:
  67                 if (!S_ISDIR(inode->i_mode))
  68                         return acl ? -EINVAL : 0;
  69                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
  70                 break;
  71         default:
  72                 return -EINVAL;
  73         }
  74
  75         if (acl) {
  76                 size = posix_acl_xattr_size(acl->a_count);
  77                 value = kmalloc(size, GFP_KERNEL);
  78                 if (!value) {
  79                         ret = -ENOMEM;
  80                         goto out;
  81                 }
  82
  83                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
  84                 if (ret < 0)
  85                         goto out;
  86         }
  87
  88         ret = btrfs_setxattr(trans, inode, name, value, size, 0);
  89 out:
  90         kfree(value);
  91
  92         if (!ret)
  93                 set_cached_acl(inode, type, acl);
  94
  95         return ret;
  96 }
  97
  98 int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  99 {
 100         int ret;
 101         umode_t old_mode = inode->i_mode;
 102
 103         if (type == ACL_TYPE_ACCESS && acl) {
 104                 ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
 105                 if (ret)
 106                         return ret;
 107         }
 108         ret = __btrfs_set_acl(NULL, inode, acl, type);
 109         if (ret)
 110                 inode->i_mode = old_mode;
 111         return ret;
 112 }
 113
 114 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 115                    struct inode *inode, struct inode *dir)
 116 {
 117         struct posix_acl *default_acl, *acl;
 118         int ret = 0;
 119
 120         /* this happens with subvols */
 121         if (!dir)
 122                 return 0;
 123
 124         ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 125         if (ret)
 126                 return ret;
 127
 128         if (default_acl) {
 129                 ret = __btrfs_set_acl(trans, inode, default_acl,
 130                                       ACL_TYPE_DEFAULT);
 131                 posix_acl_release(default_acl);
 132         }
 133
 134         if (acl) {
 135                 if (!ret)
 136                         ret = __btrfs_set_acl(trans, inode, acl,
 137                                               ACL_TYPE_ACCESS);
 138                 posix_acl_release(acl);
 139         }
 140
 141         if (!default_acl && !acl)
 142                 cache_no_acl(inode);
 143         return ret;
 144 }