xref: /linux/crypto/rsa_helper.c (revision 9a379e77033f02c4a071891afdf0f0a01eff8ccb)
1 /*
2  * RSA key extract helper
3  *
4  * Copyright (c) 2015, Intel Corporation
5  * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  *
12  */
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <linux/err.h>
16 #include <linux/fips.h>
17 #include <crypto/internal/rsa.h>
18 #include "rsapubkey-asn1.h"
19 #include "rsaprivkey-asn1.h"
20 
21 int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
22 	      const void *value, size_t vlen)
23 {
24 	struct rsa_key *key = context;
25 	const u8 *ptr = value;
26 	size_t n_sz = vlen;
27 
28 	/* invalid key provided */
29 	if (!value || !vlen)
30 		return -EINVAL;
31 
32 	if (fips_enabled) {
33 		while (n_sz && !*ptr) {
34 			ptr++;
35 			n_sz--;
36 		}
37 
38 		/* In FIPS mode only allow key size 2K and higher */
39 		if (n_sz < 256) {
40 			pr_err("RSA: key size not allowed in FIPS mode\n");
41 			return -EINVAL;
42 		}
43 	}
44 
45 	key->n = value;
46 	key->n_sz = vlen;
47 
48 	return 0;
49 }
50 
51 int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
52 	      const void *value, size_t vlen)
53 {
54 	struct rsa_key *key = context;
55 
56 	/* invalid key provided */
57 	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
58 		return -EINVAL;
59 
60 	key->e = value;
61 	key->e_sz = vlen;
62 
63 	return 0;
64 }
65 
66 int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
67 	      const void *value, size_t vlen)
68 {
69 	struct rsa_key *key = context;
70 
71 	/* invalid key provided */
72 	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
73 		return -EINVAL;
74 
75 	key->d = value;
76 	key->d_sz = vlen;
77 
78 	return 0;
79 }
80 
81 int rsa_get_p(void *context, size_t hdrlen, unsigned char tag,
82 	      const void *value, size_t vlen)
83 {
84 	struct rsa_key *key = context;
85 
86 	/* invalid key provided */
87 	if (!value || !vlen || vlen > key->n_sz)
88 		return -EINVAL;
89 
90 	key->p = value;
91 	key->p_sz = vlen;
92 
93 	return 0;
94 }
95 
96 int rsa_get_q(void *context, size_t hdrlen, unsigned char tag,
97 	      const void *value, size_t vlen)
98 {
99 	struct rsa_key *key = context;
100 
101 	/* invalid key provided */
102 	if (!value || !vlen || vlen > key->n_sz)
103 		return -EINVAL;
104 
105 	key->q = value;
106 	key->q_sz = vlen;
107 
108 	return 0;
109 }
110 
111 int rsa_get_dp(void *context, size_t hdrlen, unsigned char tag,
112 	       const void *value, size_t vlen)
113 {
114 	struct rsa_key *key = context;
115 
116 	/* invalid key provided */
117 	if (!value || !vlen || vlen > key->n_sz)
118 		return -EINVAL;
119 
120 	key->dp = value;
121 	key->dp_sz = vlen;
122 
123 	return 0;
124 }
125 
126 int rsa_get_dq(void *context, size_t hdrlen, unsigned char tag,
127 	       const void *value, size_t vlen)
128 {
129 	struct rsa_key *key = context;
130 
131 	/* invalid key provided */
132 	if (!value || !vlen || vlen > key->n_sz)
133 		return -EINVAL;
134 
135 	key->dq = value;
136 	key->dq_sz = vlen;
137 
138 	return 0;
139 }
140 
141 int rsa_get_qinv(void *context, size_t hdrlen, unsigned char tag,
142 		 const void *value, size_t vlen)
143 {
144 	struct rsa_key *key = context;
145 
146 	/* invalid key provided */
147 	if (!value || !vlen || vlen > key->n_sz)
148 		return -EINVAL;
149 
150 	key->qinv = value;
151 	key->qinv_sz = vlen;
152 
153 	return 0;
154 }
155 
156 /**
157  * rsa_parse_pub_key() - decodes the BER encoded buffer and stores in the
158  *                       provided struct rsa_key, pointers to the raw key as is,
159  *                       so that the caller can copy it or MPI parse it, etc.
160  *
161  * @rsa_key:	struct rsa_key key representation
162  * @key:	key in BER format
163  * @key_len:	length of key
164  *
165  * Return:	0 on success or error code in case of error
166  */
167 int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
168 		      unsigned int key_len)
169 {
170 	return asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
171 }
172 EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
173 
174 /**
175  * rsa_parse_priv_key() - decodes the BER encoded buffer and stores in the
176  *                        provided struct rsa_key, pointers to the raw key
177  *                        as is, so that the caller can copy it or MPI parse it,
178  *                        etc.
179  *
180  * @rsa_key:	struct rsa_key key representation
181  * @key:	key in BER format
182  * @key_len:	length of key
183  *
184  * Return:	0 on success or error code in case of error
185  */
186 int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
187 		       unsigned int key_len)
188 {
189 	return asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
190 }
191 EXPORT_SYMBOL_GPL(rsa_parse_priv_key);
192