LXR linux/security/keys/encrypted-keys/ecryptfs

   1/*
   2 * ecryptfs_format.c: helper functions for the encrypted key type
   3 *
   4 * Copyright (C) 2006 International Business Machines Corp.
   5 * Copyright (C) 2010 Politecnico di Torino, Italy
   6 *                    TORSEC group -- http://security.polito.it
   7 *
   8 * Authors:
   9 * Michael A. Halcrow <mahalcro@us.ibm.com>
  10 * Tyler Hicks <tyhicks@ou.edu>
  11 * Roberto Sassu <roberto.sassu@polito.it>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation, version 2 of the License.
  16 */
  17
  18#include <linux/module.h>
  19#include "ecryptfs_format.h"
  20
  21u8 *ecryptfs_get_auth_tok_key(struct ecryptfs_auth_tok *auth_tok)
  22{
  23        return auth_tok->token.password.session_key_encryption_key;
  24}
  25EXPORT_SYMBOL(ecryptfs_get_auth_tok_key);
  26
  27/*
  28 * ecryptfs_get_versions()
  29 *
  30 * Source code taken from the software 'ecryptfs-utils' version 83.
  31 *
  32 */
  33void ecryptfs_get_versions(int *major, int *minor, int *file_version)
  34{
  35        *major = ECRYPTFS_VERSION_MAJOR;
  36        *minor = ECRYPTFS_VERSION_MINOR;
  37        if (file_version)
  38                *file_version = ECRYPTFS_SUPPORTED_FILE_VERSION;
  39}
  40EXPORT_SYMBOL(ecryptfs_get_versions);
  41
  42/*
  43 * ecryptfs_fill_auth_tok - fill the ecryptfs_auth_tok structure
  44 *
  45 * Fill the ecryptfs_auth_tok structure with required ecryptfs data.
  46 * The source code is inspired to the original function generate_payload()
  47 * shipped with the software 'ecryptfs-utils' version 83.
  48 *
  49 */
  50int ecryptfs_fill_auth_tok(struct ecryptfs_auth_tok *auth_tok,
  51                           const char *key_desc)
  52{
  53        int major, minor;
  54
  55        ecryptfs_get_versions(&major, &minor, NULL);
  56        auth_tok->version = (((uint16_t)(major << 8) & 0xFF00)
  57                             | ((uint16_t)minor & 0x00FF));
  58        auth_tok->token_type = ECRYPTFS_PASSWORD;
  59        strncpy((char *)auth_tok->token.password.signature, key_desc,
  60                ECRYPTFS_PASSWORD_SIG_SIZE);
  61        auth_tok->token.password.session_key_encryption_key_bytes =
  62                ECRYPTFS_MAX_KEY_BYTES;
  63        /*
  64         * Removed auth_tok->token.password.salt and
  65         * auth_tok->token.password.session_key_encryption_key
  66         * initialization from the original code
  67         */
  68        /* TODO: Make the hash parameterizable via policy */
  69        auth_tok->token.password.flags |=
  70                ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET;
  71        /* The kernel code will encrypt the session key. */
  72        auth_tok->session_key.encrypted_key[0] = 0;
  73        auth_tok->session_key.encrypted_key_size = 0;
  74        /* Default; subject to change by kernel eCryptfs */
  75        auth_tok->token.password.hash_algo = PGP_DIGEST_ALGO_SHA512;
  76        auth_tok->token.password.flags &= ~(ECRYPTFS_PERSISTENT_PASSWORD);
  77        return 0;
  78}
  79EXPORT_SYMBOL(ecryptfs_fill_auth_tok);
  80
  81MODULE_LICENSE("GPL");
  82