fs/reiserfs/xattr_security.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "reiserfs.h"
   3 #include <linux/errno.h>
   4 #include <linux/fs.h>
   5 #include <linux/pagemap.h>
   6 #include <linux/xattr.h>
   7 #include <linux/slab.h>
   8 #include "xattr.h"
   9 #include <linux/security.h>
  10 #include <linux/uaccess.h>
  11
  12 static int
  13 security_get(const struct xattr_handler *handler, struct dentry *unused,
  14              struct inode *inode, const char *name, void *buffer, size_t size)
  15 {
  16         if (IS_PRIVATE(inode))
  17                 return -EPERM;
  18
  19         return reiserfs_xattr_get(inode, xattr_full_name(handler, name),
  20                                   buffer, size);
  21 }
  22
  23 static int
  24 security_set(const struct xattr_handler *handler,
  25              struct mnt_idmap *idmap, struct dentry *unused,
  26              struct inode *inode, const char *name, const void *buffer,
  27              size_t size, int flags)
  28 {
  29         if (IS_PRIVATE(inode))
  30                 return -EPERM;
  31
  32         return reiserfs_xattr_set(inode,
  33                                   xattr_full_name(handler, name),
  34                                   buffer, size, flags);
  35 }
  36
  37 static bool security_list(struct dentry *dentry)
  38 {
  39         return !IS_PRIVATE(d_inode(dentry));
  40 }
  41
  42 static int
  43 reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
  44                     void *fs_info)
  45 {
  46         struct reiserfs_security_handle *sec = fs_info;
  47
  48         sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
  49                              GFP_KERNEL);
  50         if (!sec->value)
  51                 return -ENOMEM;
  52
  53         sec->name = xattr_array->name;
  54         sec->length = xattr_array->value_len;
  55         return 0;
  56 }
  57
  58 /* Initializes the security context for a new inode and returns the number
  59  * of blocks needed for the transaction. If successful, reiserfs_security
  60  * must be released using reiserfs_security_free when the caller is done. */
  61 int reiserfs_security_init(struct inode *dir, struct inode *inode,
  62                            const struct qstr *qstr,
  63                            struct reiserfs_security_handle *sec)
  64 {
  65         int blocks = 0;
  66         int error;
  67
  68         sec->name = NULL;
  69         sec->value = NULL;
  70         sec->length = 0;
  71
  72         /* Don't add selinux attributes on xattrs - they'll never get used */
  73         if (IS_PRIVATE(dir))
  74                 return 0;
  75
  76         error = security_inode_init_security(inode, dir, qstr,
  77                                              &reiserfs_initxattrs, sec);
  78         if (error) {
  79                 sec->name = NULL;
  80                 sec->value = NULL;
  81                 sec->length = 0;
  82                 return error;
  83         }
  84
  85         if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
  86                 blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  87                          reiserfs_xattr_nblocks(inode, sec->length);
  88                 /* We don't want to count the directories twice if we have
  89                  * a default ACL. */
  90                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
  91         }
  92         return blocks;
  93 }
  94
  95 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
  96                             struct inode *inode,
  97                             struct reiserfs_security_handle *sec)
  98 {
  99         char xattr_name[XATTR_NAME_MAX + 1] = XATTR_SECURITY_PREFIX;
 100         int error;
 101
 102         if (XATTR_SECURITY_PREFIX_LEN + strlen(sec->name) > XATTR_NAME_MAX)
 103                 return -EINVAL;
 104
 105         strlcat(xattr_name, sec->name, sizeof(xattr_name));
 106
 107         error = reiserfs_xattr_set_handle(th, inode, xattr_name, sec->value,
 108                                           sec->length, XATTR_CREATE);
 109         if (error == -ENODATA || error == -EOPNOTSUPP)
 110                 error = 0;
 111
 112         return error;
 113 }
 114
 115 void reiserfs_security_free(struct reiserfs_security_handle *sec)
 116 {
 117         kfree(sec->value);
 118         sec->name = NULL;
 119         sec->value = NULL;
 120 }
 121
 122 const struct xattr_handler reiserfs_xattr_security_handler = {
 123         .prefix = XATTR_SECURITY_PREFIX,
 124         .get = security_get,
 125         .set = security_set,
 126         .list = security_list,
 127 };