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/module.h>
  16#include <linux/verification.h>
  17#include <linux/key-type.h>
  18#include <keys/user-type.h>
  19
  20MODULE_LICENSE("GPL");
  21MODULE_DESCRIPTION("PKCS#7 testing key type");
  22MODULE_AUTHOR("Red Hat, Inc.");
  23
  24static unsigned pkcs7_usage;
  25module_param_named(usage, pkcs7_usage, uint, S_IWUSR | S_IRUGO);
  26MODULE_PARM_DESC(pkcs7_usage,
  27                 "Usage to specify when verifying the PKCS#7 message");
  28
  29/*
  30 * Retrieve the PKCS#7 message content.
  31 */
  32static int pkcs7_view_content(void *ctx, const void *data, size_t len,
  33                              size_t asn1hdrlen)
  34{
  35        struct key_preparsed_payload *prep = ctx;
  36        const void *saved_prep_data;
  37        size_t saved_prep_datalen;
  38        int ret;
  39
  40        saved_prep_data = prep->data;
  41        saved_prep_datalen = prep->datalen;
  42        prep->data = data;
  43        prep->datalen = len;
  44
  45        ret = user_preparse(prep);
  46
  47        prep->data = saved_prep_data;
  48        prep->datalen = saved_prep_datalen;
  49        return ret;
  50}
  51
  52/*
  53 * Preparse a PKCS#7 wrapped and validated data blob.
  54 */
  55static int pkcs7_preparse(struct key_preparsed_payload *prep)
  56{
  57        enum key_being_used_for usage = pkcs7_usage;
  58
  59        if (usage >= NR__KEY_BEING_USED_FOR) {
  60                pr_err("Invalid usage type %d\n", usage);
  61                return -EINVAL;
  62        }
  63
  64        return verify_pkcs7_signature(NULL, 0,
  65                                      prep->data, prep->datalen,
  66                                      (void *)1UL, usage,
  67                                      pkcs7_view_content, prep);
  68}
  69
  70/*
  71 * user defined keys take an arbitrary string as the description and an
  72 * arbitrary blob of data as the payload
  73 */
  74static struct key_type key_type_pkcs7 = {
  75        .name                   = "pkcs7_test",
  76        .preparse               = pkcs7_preparse,
  77        .free_preparse          = user_free_preparse,
  78        .instantiate            = generic_key_instantiate,
  79        .revoke                 = user_revoke,
  80        .destroy                = user_destroy,
  81        .describe               = user_describe,
  82        .read                   = user_read,
  83};
  84
  85/*
  86 * Module stuff
  87 */
  88static int __init pkcs7_key_init(void)
  89{
  90        return register_key_type(&key_type_pkcs7);
  91}
  92
  93static void __exit pkcs7_key_cleanup(void)
  94{
  95        unregister_key_type(&key_type_pkcs7);
  96}
  97
  98module_init(pkcs7_key_init);
  99module_exit(pkcs7_key_cleanup);
 100