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 */
pkcs7_view_content(void * ctx,const void * data,size_t len,size_t asn1hdrlen)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 */
pkcs7_preparse(struct key_preparsed_payload * prep)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 */
pkcs7_key_init(void)84 static int __init pkcs7_key_init(void)
85 {
86 return register_key_type(&key_type_pkcs7);
87 }
88
pkcs7_key_cleanup(void)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);
96