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, struct dentry *unused,
  25              struct inode *inode, const char *name, const void *buffer,
  26              size_t size, int flags)
  27 {
  28         if (IS_PRIVATE(inode))
  29                 return -EPERM;
  30
  31         return reiserfs_xattr_set(inode,
  32                                   xattr_full_name(handler, name),
  33                                   buffer, size, flags);
  34 }
  35
  36 static bool security_list(struct dentry *dentry)
  37 {
  38         return !IS_PRIVATE(d_inode(dentry));
  39 }
  40
  41 /* Initializes the security context for a new inode and returns the number
  42  * of blocks needed for the transaction. If successful, reiserfs_security
  43  * must be released using reiserfs_security_free when the caller is done. */
  44 int reiserfs_security_init(struct inode *dir, struct inode *inode,
  45                            const struct qstr *qstr,
  46                            struct reiserfs_security_handle *sec)
  47 {
  48         int blocks = 0;
  49         int error;
  50
  51         sec->name = NULL;
  52
  53         /* Don't add selinux attributes on xattrs - they'll never get used */
  54         if (IS_PRIVATE(dir))
  55                 return 0;
  56
  57         error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
  58                                                  &sec->value, &sec->length);
  59         if (error) {
  60                 if (error == -EOPNOTSUPP)
  61                         error = 0;
  62
  63                 sec->name = NULL;
  64                 sec->value = NULL;
  65                 sec->length = 0;
  66                 return error;
  67         }
  68
  69         if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
  70                 blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  71                          reiserfs_xattr_nblocks(inode, sec->length);
  72                 /* We don't want to count the directories twice if we have
  73                  * a default ACL. */
  74                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
  75         }
  76         return blocks;
  77 }
  78
  79 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
  80                             struct inode *inode,
  81                             struct reiserfs_security_handle *sec)
  82 {
  83         int error;
  84         if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
  85                 return -EINVAL;
  86
  87         error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
  88                                           sec->length, XATTR_CREATE);
  89         if (error == -ENODATA || error == -EOPNOTSUPP)
  90                 error = 0;
  91
  92         return error;
  93 }
  94
  95 void reiserfs_security_free(struct reiserfs_security_handle *sec)
  96 {
  97         kfree(sec->name);
  98         kfree(sec->value);
  99         sec->name = NULL;
 100         sec->value = NULL;
 101 }
 102
 103 const struct xattr_handler reiserfs_xattr_security_handler = {
 104         .prefix = XATTR_SECURITY_PREFIX,
 105         .get = security_get,
 106         .set = security_set,
 107         .list = security_list,
 108 };