LXR linux/crypto/asymmetric_keys/pkcs7_key

   1/* Testing module to load key from trusted PKCS#7 message
   2 *
   3 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public Licence
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the Licence, or (at your option) any later version.
  10 */
  11
  12#define pr_fmt(fmt) "PKCS7key: "fmt
  13#include <linux/key.h>
  14#include <linux/err.h>
  15#include <linux/key-type.h>
  16#include <crypto/pkcs7.h>
  17#include <keys/user-type.h>
  18#include <keys/system_keyring.h>
  19#include "pkcs7_parser.h"
  20
  21/*
  22 * Preparse a PKCS#7 wrapped and validated data blob.
  23 */
  24static int pkcs7_preparse(struct key_preparsed_payload *prep)
  25{
  26        struct pkcs7_message *pkcs7;
  27        const void *data, *saved_prep_data;
  28        size_t datalen, saved_prep_datalen;
  29        bool trusted;
  30        int ret;
  31
  32        kenter("");
  33
  34        saved_prep_data = prep->data;
  35        saved_prep_datalen = prep->datalen;
  36        pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen);
  37        if (IS_ERR(pkcs7)) {
  38                ret = PTR_ERR(pkcs7);
  39                goto error;
  40        }
  41
  42        ret = pkcs7_verify(pkcs7);
  43        if (ret < 0)
  44                goto error_free;
  45
  46        ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
  47        if (ret < 0)
  48                goto error_free;
  49        if (!trusted)
  50                pr_warn("PKCS#7 message doesn't chain back to a trusted key\n");
  51
  52        ret = pkcs7_get_content_data(pkcs7, &data, &datalen, false);
  53        if (ret < 0)
  54                goto error_free;
  55
  56        prep->data = data;
  57        prep->datalen = datalen;
  58        ret = user_preparse(prep);
  59        prep->data = saved_prep_data;
  60        prep->datalen = saved_prep_datalen;
  61
  62error_free:
  63        pkcs7_free_message(pkcs7);
  64error:
  65        kleave(" = %d", ret);
  66        return ret;
  67}
  68
  69/*
  70 * user defined keys take an arbitrary string as the description and an
  71 * arbitrary blob of data as the payload
  72 */
  73static struct key_type key_type_pkcs7 = {
  74        .name                   = "pkcs7_test",
  75        .preparse               = pkcs7_preparse,
  76        .free_preparse          = user_free_preparse,
  77        .instantiate            = generic_key_instantiate,
  78        .revoke                 = user_revoke,
  79        .destroy                = user_destroy,
  80        .describe               = user_describe,
  81        .read                   = user_read,
  82};
  83
  84/*
  85 * Module stuff
  86 */
  87static int __init pkcs7_key_init(void)
  88{
  89        return register_key_type(&key_type_pkcs7);
  90}
  91
  92static void __exit pkcs7_key_cleanup(void)
  93{
  94        unregister_key_type(&key_type_pkcs7);
  95}
  96
  97module_init(pkcs7_key_init);
  98module_exit(pkcs7_key_cleanup);
  99