1 /* $OpenBSD: dh_pmeth.c,v 1.12 2022/01/07 09:27:13 tb Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project 2006.
4 */
5 /* ====================================================================
6 * Copyright (c) 2006 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58
59 #include <limits.h>
60 #include <stdio.h>
61 #include <string.h>
62
63 #include <openssl/asn1t.h>
64 #include <openssl/bn.h>
65 #include <openssl/dh.h>
66 #include <openssl/err.h>
67 #include <openssl/evp.h>
68 #include <openssl/x509.h>
69
70 #include "bn_lcl.h"
71 #include "dh_local.h"
72 #include "evp_locl.h"
73
74 /* DH pkey context structure */
75
76 typedef struct {
77 /* Parameter gen parameters */
78 int prime_len;
79 int generator;
80 int use_dsa;
81 /* Keygen callback info */
82 int gentmp[2];
83 /* message digest */
84 } DH_PKEY_CTX;
85
86 static int
pkey_dh_init(EVP_PKEY_CTX * ctx)87 pkey_dh_init(EVP_PKEY_CTX *ctx)
88 {
89 DH_PKEY_CTX *dctx;
90
91 dctx = malloc(sizeof(DH_PKEY_CTX));
92 if (!dctx)
93 return 0;
94 dctx->prime_len = 1024;
95 dctx->generator = 2;
96 dctx->use_dsa = 0;
97
98 ctx->data = dctx;
99 ctx->keygen_info = dctx->gentmp;
100 ctx->keygen_info_count = 2;
101
102 return 1;
103 }
104
105 static int
pkey_dh_copy(EVP_PKEY_CTX * dst,EVP_PKEY_CTX * src)106 pkey_dh_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
107 {
108 DH_PKEY_CTX *dctx, *sctx;
109
110 if (!pkey_dh_init(dst))
111 return 0;
112 sctx = src->data;
113 dctx = dst->data;
114 dctx->prime_len = sctx->prime_len;
115 dctx->generator = sctx->generator;
116 dctx->use_dsa = sctx->use_dsa;
117 return 1;
118 }
119
120 static void
pkey_dh_cleanup(EVP_PKEY_CTX * ctx)121 pkey_dh_cleanup(EVP_PKEY_CTX *ctx)
122 {
123 DH_PKEY_CTX *dctx = ctx->data;
124
125 free(dctx);
126 }
127
128 static int
pkey_dh_ctrl(EVP_PKEY_CTX * ctx,int type,int p1,void * p2)129 pkey_dh_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
130 {
131 DH_PKEY_CTX *dctx = ctx->data;
132
133 switch (type) {
134 case EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN:
135 if (p1 < 256)
136 return -2;
137 dctx->prime_len = p1;
138 return 1;
139
140 case EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR:
141 dctx->generator = p1;
142 return 1;
143
144 case EVP_PKEY_CTRL_PEER_KEY:
145 /* Default behaviour is OK */
146 return 1;
147
148 default:
149 return -2;
150 }
151 }
152
153 static int
pkey_dh_ctrl_str(EVP_PKEY_CTX * ctx,const char * type,const char * value)154 pkey_dh_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, const char *value)
155 {
156 long lval;
157 char *ep;
158 int len;
159
160 if (!strcmp(type, "dh_paramgen_prime_len")) {
161 errno = 0;
162 lval = strtol(value, &ep, 10);
163 if (value[0] == '\0' || *ep != '\0')
164 goto not_a_number;
165 if ((errno == ERANGE &&
166 (lval == LONG_MAX || lval == LONG_MIN)) ||
167 (lval > INT_MAX || lval < INT_MIN))
168 goto out_of_range;
169 len = lval;
170 return EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, len);
171 } else if (!strcmp(type, "dh_paramgen_generator")) {
172 errno = 0;
173 lval = strtol(value, &ep, 10);
174 if (value[0] == '\0' || *ep != '\0')
175 goto not_a_number;
176 if ((errno == ERANGE &&
177 (lval == LONG_MAX || lval == LONG_MIN)) ||
178 (lval > INT_MAX || lval < INT_MIN))
179 goto out_of_range;
180 len = lval;
181 return EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, len);
182 }
183
184 not_a_number:
185 out_of_range:
186 return -2;
187 }
188
189 static int
pkey_dh_paramgen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)190 pkey_dh_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
191 {
192 DH *dh = NULL;
193 DH_PKEY_CTX *dctx = ctx->data;
194 BN_GENCB *pcb, cb;
195 int ret;
196
197 if (ctx->pkey_gencb) {
198 pcb = &cb;
199 evp_pkey_set_cb_translate(pcb, ctx);
200 } else
201 pcb = NULL;
202 dh = DH_new();
203 if (!dh)
204 return 0;
205 ret = DH_generate_parameters_ex(dh, dctx->prime_len, dctx->generator,
206 pcb);
207 if (ret)
208 EVP_PKEY_assign_DH(pkey, dh);
209 else
210 DH_free(dh);
211 return ret;
212 }
213
214 static int
pkey_dh_keygen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)215 pkey_dh_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
216 {
217 DH *dh = NULL;
218
219 if (ctx->pkey == NULL) {
220 DHerror(DH_R_NO_PARAMETERS_SET);
221 return 0;
222 }
223 dh = DH_new();
224 if (!dh)
225 return 0;
226 EVP_PKEY_assign_DH(pkey, dh);
227 /* Note: if error return, pkey is freed by parent routine */
228 if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
229 return 0;
230 return DH_generate_key(pkey->pkey.dh);
231 }
232
233 static int
pkey_dh_derive(EVP_PKEY_CTX * ctx,unsigned char * key,size_t * keylen)234 pkey_dh_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
235 {
236 int ret;
237
238 if (!ctx->pkey || !ctx->peerkey) {
239 DHerror(DH_R_KEYS_NOT_SET);
240 return 0;
241 }
242 ret = DH_compute_key(key, ctx->peerkey->pkey.dh->pub_key,
243 ctx->pkey->pkey.dh);
244 if (ret < 0)
245 return ret;
246 *keylen = ret;
247 return 1;
248 }
249
250 const EVP_PKEY_METHOD dh_pkey_meth = {
251 .pkey_id = EVP_PKEY_DH,
252 .flags = EVP_PKEY_FLAG_AUTOARGLEN,
253
254 .init = pkey_dh_init,
255 .copy = pkey_dh_copy,
256 .cleanup = pkey_dh_cleanup,
257
258 .paramgen = pkey_dh_paramgen,
259
260 .keygen = pkey_dh_keygen,
261
262 .derive = pkey_dh_derive,
263
264 .ctrl = pkey_dh_ctrl,
265 .ctrl_str = pkey_dh_ctrl_str
266 };
267