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 user_namespace *mnt_userns, 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 /* Initializes the security context for a new inode and returns the number
  43  * of blocks needed for the transaction. If successful, reiserfs_security
  44  * must be released using reiserfs_security_free when the caller is done. */
  45 int reiserfs_security_init(struct inode *dir, struct inode *inode,
  46                            const struct qstr *qstr,
  47                            struct reiserfs_security_handle *sec)
  48 {
  49         int blocks = 0;
  50         int error;
  51
  52         sec->name = NULL;
  53         sec->value = NULL;
  54
  55         /* Don't add selinux attributes on xattrs - they'll never get used */
  56         if (IS_PRIVATE(dir))
  57                 return 0;
  58
  59         error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
  60                                                  &sec->value, &sec->length);
  61         if (error) {
  62                 if (error == -EOPNOTSUPP)
  63                         error = 0;
  64
  65                 sec->name = NULL;
  66                 sec->value = NULL;
  67                 sec->length = 0;
  68                 return error;
  69         }
  70
  71         if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
  72                 blocks = reiserfs_xattr_jcreate_nblocks(inode) +
  73                          reiserfs_xattr_nblocks(inode, sec->length);
  74                 /* We don't want to count the directories twice if we have
  75                  * a default ACL. */
  76                 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
  77         }
  78         return blocks;
  79 }
  80
  81 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
  82                             struct inode *inode,
  83                             struct reiserfs_security_handle *sec)
  84 {
  85         char xattr_name[XATTR_NAME_MAX + 1] = XATTR_SECURITY_PREFIX;
  86         int error;
  87
  88         if (XATTR_SECURITY_PREFIX_LEN + strlen(sec->name) > XATTR_NAME_MAX)
  89                 return -EINVAL;
  90
  91         strlcat(xattr_name, sec->name, sizeof(xattr_name));
  92
  93         error = reiserfs_xattr_set_handle(th, inode, xattr_name, sec->value,
  94                                           sec->length, XATTR_CREATE);
  95         if (error == -ENODATA || error == -EOPNOTSUPP)
  96                 error = 0;
  97
  98         return error;
  99 }
 100
 101 void reiserfs_security_free(struct reiserfs_security_handle *sec)
 102 {
 103         kfree(sec->value);
 104         sec->name = NULL;
 105         sec->value = NULL;
 106 }
 107
 108 const struct xattr_handler reiserfs_xattr_security_handler = {
 109         .prefix = XATTR_SECURITY_PREFIX,
 110         .get = security_get,
 111         .set = security_set,
 112         .list = security_list,
 113 };