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                 return ERR_PTR(-EINVAL);
  34         }
  35
  36         size = btrfs_getxattr(inode, name, NULL, 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 == -ENODATA || size == 0)
  46                 acl = NULL;
  47         else
  48                 acl = ERR_PTR(size);
  49         kfree(value);
  50
  51         return acl;
  52 }
  53
  54 static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
  55                          struct inode *inode, struct posix_acl *acl, int type)
  56 {
  57         int ret, size = 0;
  58         const char *name;
  59         char *value = NULL;
  60
  61         switch (type) {
  62         case ACL_TYPE_ACCESS:
  63                 name = XATTR_NAME_POSIX_ACL_ACCESS;
  64                 break;
  65         case ACL_TYPE_DEFAULT:
  66                 if (!S_ISDIR(inode->i_mode))
  67                         return acl ? -EINVAL : 0;
  68                 name = XATTR_NAME_POSIX_ACL_DEFAULT;
  69                 break;
  70         default:
  71                 return -EINVAL;
  72         }
  73
  74         if (acl) {
  75                 size = posix_acl_xattr_size(acl->a_count);
  76                 value = kmalloc(size, GFP_KERNEL);
  77                 if (!value) {
  78                         ret = -ENOMEM;
  79                         goto out;
  80                 }
  81
  82                 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
  83                 if (ret < 0)
  84                         goto out;
  85         }
  86
  87         ret = btrfs_setxattr(trans, inode, name, value, size, 0);
  88 out:
  89         kfree(value);
  90
  91         if (!ret)
  92                 set_cached_acl(inode, type, acl);
  93
  94         return ret;
  95 }
  96
  97 int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
  98 {
  99         int ret;
 100         umode_t old_mode = inode->i_mode;
 101
 102         if (type == ACL_TYPE_ACCESS && acl) {
 103                 ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
 104                 if (ret)
 105                         return ret;
 106         }
 107         ret = __btrfs_set_acl(NULL, inode, acl, type);
 108         if (ret)
 109                 inode->i_mode = old_mode;
 110         return ret;
 111 }
 112
 113 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 114                    struct inode *inode, struct inode *dir)
 115 {
 116         struct posix_acl *default_acl, *acl;
 117         int ret = 0;
 118
 119         /* this happens with subvols */
 120         if (!dir)
 121                 return 0;
 122
 123         ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
 124         if (ret)
 125                 return ret;
 126
 127         if (default_acl) {
 128                 ret = __btrfs_set_acl(trans, inode, default_acl,
 129                                       ACL_TYPE_DEFAULT);
 130                 posix_acl_release(default_acl);
 131         }
 132
 133         if (acl) {
 134                 if (!ret)
 135                         ret = __btrfs_set_acl(trans, inode, acl,
 136                                               ACL_TYPE_ACCESS);
 137                 posix_acl_release(acl);
 138         }
 139
 140         if (!default_acl && !acl)
 141                 cache_no_acl(inode);
 142         return ret;
 143 }