root/crypto/asymmetric_keys/pkcs7_key_type.c

DEFINITIONS

1. pkcs7_view_content
2. pkcs7_preparse
3. pkcs7_key_init
4. pkcs7_key_cleanup

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Testing module to load key from trusted PKCS#7 message
   3  *
   4  * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7 
   8 #define pr_fmt(fmt) "PKCS7key: "fmt
   9 #include <linux/key.h>
  10 #include <linux/err.h>
  11 #include <linux/module.h>
  12 #include <linux/verification.h>
  13 #include <linux/key-type.h>
  14 #include <keys/user-type.h>
  15 
  16 MODULE_LICENSE("GPL");
  17 MODULE_DESCRIPTION("PKCS#7 testing key type");
  18 MODULE_AUTHOR("Red Hat, Inc.");
  19 
  20 static unsigned pkcs7_usage;
  21 module_param_named(usage, pkcs7_usage, uint, S_IWUSR | S_IRUGO);
  22 MODULE_PARM_DESC(pkcs7_usage,
  23                  "Usage to specify when verifying the PKCS#7 message");
  24 
  25 /*
  26  * Retrieve the PKCS#7 message content.
  27  */
  28 static int pkcs7_view_content(void *ctx, const void *data, size_t len,
  29                               size_t asn1hdrlen)
  30 {
  31         struct key_preparsed_payload *prep = ctx;
  32         const void *saved_prep_data;
  33         size_t saved_prep_datalen;
  34         int ret;
  35 
  36         saved_prep_data = prep->data;
  37         saved_prep_datalen = prep->datalen;
  38         prep->data = data;
  39         prep->datalen = len;
  40 
  41         ret = user_preparse(prep);
  42 
  43         prep->data = saved_prep_data;
  44         prep->datalen = saved_prep_datalen;
  45         return ret;
  46 }
  47 
  48 /*
  49  * Preparse a PKCS#7 wrapped and validated data blob.
  50  */
  51 static int pkcs7_preparse(struct key_preparsed_payload *prep)
  52 {
  53         enum key_being_used_for usage = pkcs7_usage;
  54 
  55         if (usage >= NR__KEY_BEING_USED_FOR) {
  56                 pr_err("Invalid usage type %d\n", usage);
  57                 return -EINVAL;
  58         }
  59 
  60         return verify_pkcs7_signature(NULL, 0,
  61                                       prep->data, prep->datalen,
  62                                       VERIFY_USE_SECONDARY_KEYRING, usage,
  63                                       pkcs7_view_content, prep);
  64 }
  65 
  66 /*
  67  * user defined keys take an arbitrary string as the description and an
  68  * arbitrary blob of data as the payload
  69  */
  70 static struct key_type key_type_pkcs7 = {
  71         .name                   = "pkcs7_test",
  72         .preparse               = pkcs7_preparse,
  73         .free_preparse          = user_free_preparse,
  74         .instantiate            = generic_key_instantiate,
  75         .revoke                 = user_revoke,
  76         .destroy                = user_destroy,
  77         .describe               = user_describe,
  78         .read                   = user_read,
  79 };
  80 
  81 /*
  82  * Module stuff
  83  */
  84 static int __init pkcs7_key_init(void)
  85 {
  86         return register_key_type(&key_type_pkcs7);
  87 }
  88 
  89 static void __exit pkcs7_key_cleanup(void)
  90 {
  91         unregister_key_type(&key_type_pkcs7);
  92 }
  93 
  94 module_init(pkcs7_key_init);
  95 module_exit(pkcs7_key_cleanup);