xref: /linux/crypto/asymmetric_keys/public_key.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /* In-software asymmetric public-key crypto subtype
2  *
3  * See Documentation/crypto/asymmetric-keys.txt
4  *
5  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
6  * Written by David Howells (dhowells@redhat.com)
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public Licence
10  * as published by the Free Software Foundation; either version
11  * 2 of the Licence, or (at your option) any later version.
12  */
13 
14 #define pr_fmt(fmt) "PKEY: "fmt
15 #include <linux/module.h>
16 #include <linux/export.h>
17 #include <linux/kernel.h>
18 #include <linux/slab.h>
19 #include <linux/seq_file.h>
20 #include <keys/asymmetric-subtype.h>
21 #include "public_key.h"
22 
23 MODULE_LICENSE("GPL");
24 
25 const char *const pkey_algo[PKEY_ALGO__LAST] = {
26 	[PKEY_ALGO_DSA]		= "DSA",
27 	[PKEY_ALGO_RSA]		= "RSA",
28 };
29 EXPORT_SYMBOL_GPL(pkey_algo);
30 
31 const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
32 	[PKEY_HASH_MD4]		= "md4",
33 	[PKEY_HASH_MD5]		= "md5",
34 	[PKEY_HASH_SHA1]	= "sha1",
35 	[PKEY_HASH_RIPE_MD_160]	= "rmd160",
36 	[PKEY_HASH_SHA256]	= "sha256",
37 	[PKEY_HASH_SHA384]	= "sha384",
38 	[PKEY_HASH_SHA512]	= "sha512",
39 	[PKEY_HASH_SHA224]	= "sha224",
40 };
41 EXPORT_SYMBOL_GPL(pkey_hash_algo);
42 
43 const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
44 	[PKEY_ID_PGP]		= "PGP",
45 	[PKEY_ID_X509]		= "X509",
46 };
47 EXPORT_SYMBOL_GPL(pkey_id_type);
48 
49 /*
50  * Provide a part of a description of the key for /proc/keys.
51  */
52 static void public_key_describe(const struct key *asymmetric_key,
53 				struct seq_file *m)
54 {
55 	struct public_key *key = asymmetric_key->payload.data;
56 
57 	if (key)
58 		seq_printf(m, "%s.%s",
59 			   pkey_id_type[key->id_type], key->algo->name);
60 }
61 
62 /*
63  * Destroy a public key algorithm key.
64  */
65 void public_key_destroy(void *payload)
66 {
67 	struct public_key *key = payload;
68 	int i;
69 
70 	if (key) {
71 		for (i = 0; i < ARRAY_SIZE(key->mpi); i++)
72 			mpi_free(key->mpi[i]);
73 		kfree(key);
74 	}
75 }
76 EXPORT_SYMBOL_GPL(public_key_destroy);
77 
78 /*
79  * Verify a signature using a public key.
80  */
81 static int public_key_verify_signature(const struct key *key,
82 				       const struct public_key_signature *sig)
83 {
84 	const struct public_key *pk = key->payload.data;
85 
86 	if (!pk->algo->verify_signature)
87 		return -ENOTSUPP;
88 
89 	if (sig->nr_mpi != pk->algo->n_sig_mpi) {
90 		pr_debug("Signature has %u MPI not %u\n",
91 			 sig->nr_mpi, pk->algo->n_sig_mpi);
92 		return -EINVAL;
93 	}
94 
95 	return pk->algo->verify_signature(pk, sig);
96 }
97 
98 /*
99  * Public key algorithm asymmetric key subtype
100  */
101 struct asymmetric_key_subtype public_key_subtype = {
102 	.owner			= THIS_MODULE,
103 	.name			= "public_key",
104 	.describe		= public_key_describe,
105 	.destroy		= public_key_destroy,
106 	.verify_signature	= public_key_verify_signature,
107 };
108 EXPORT_SYMBOL_GPL(public_key_subtype);
109