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
20 MODULE_LICENSE("GPL");
21 MODULE_DESCRIPTION("PKCS#7 testing key type");
22 MODULE_AUTHOR("Red Hat, Inc.");
23
24 static unsigned pkcs7_usage;
25 module_param_named(usage, pkcs7_usage, uint, S_IWUSR | S_IRUGO);
26 MODULE_PARM_DESC(pkcs7_usage,
27 "Usage to specify when verifying the PKCS#7 message");
28
29 /*
30 * Retrieve the PKCS#7 message content.
31 */
pkcs7_view_content(void * ctx,const void * data,size_t len,size_t asn1hdrlen)32 static 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 */
pkcs7_preparse(struct key_preparsed_payload * prep)55 static 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 VERIFY_USE_SECONDARY_KEYRING, 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 */
74 static 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 */
pkcs7_key_init(void)88 static int __init pkcs7_key_init(void)
89 {
90 return register_key_type(&key_type_pkcs7);
91 }
92
pkcs7_key_cleanup(void)93 static void __exit pkcs7_key_cleanup(void)
94 {
95 unregister_key_type(&key_type_pkcs7);
96 }
97
98 module_init(pkcs7_key_init);
99 module_exit(pkcs7_key_cleanup);
100