1 /* $OpenBSD: dh_pmeth.c,v 1.17 2024/08/26 22:00:47 op 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 <stdlib.h>
62 #include <string.h>
63
64 #include <openssl/asn1t.h>
65 #include <openssl/bn.h>
66 #include <openssl/dh.h>
67 #include <openssl/err.h>
68 #include <openssl/evp.h>
69 #include <openssl/x509.h>
70
71 #include "bn_local.h"
72 #include "dh_local.h"
73 #include "evp_local.h"
74
75 /* DH pkey context structure */
76
77 typedef struct {
78 /* Parameter gen parameters */
79 int prime_len;
80 int generator;
81 int use_dsa;
82 /* Keygen callback info */
83 int gentmp[2];
84 /* message digest */
85 } DH_PKEY_CTX;
86
87 static int
pkey_dh_init(EVP_PKEY_CTX * ctx)88 pkey_dh_init(EVP_PKEY_CTX *ctx)
89 {
90 DH_PKEY_CTX *dctx;
91
92 dctx = malloc(sizeof(DH_PKEY_CTX));
93 if (!dctx)
94 return 0;
95 dctx->prime_len = 1024;
96 dctx->generator = 2;
97 dctx->use_dsa = 0;
98
99 ctx->data = dctx;
100 ctx->keygen_info = dctx->gentmp;
101 ctx->keygen_info_count = 2;
102
103 return 1;
104 }
105
106 static int
pkey_dh_copy(EVP_PKEY_CTX * dst,EVP_PKEY_CTX * src)107 pkey_dh_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
108 {
109 DH_PKEY_CTX *dctx, *sctx;
110
111 if (!pkey_dh_init(dst))
112 return 0;
113 sctx = src->data;
114 dctx = dst->data;
115 dctx->prime_len = sctx->prime_len;
116 dctx->generator = sctx->generator;
117 dctx->use_dsa = sctx->use_dsa;
118 return 1;
119 }
120
121 static void
pkey_dh_cleanup(EVP_PKEY_CTX * ctx)122 pkey_dh_cleanup(EVP_PKEY_CTX *ctx)
123 {
124 DH_PKEY_CTX *dctx = ctx->data;
125
126 free(dctx);
127 }
128
129 static int
pkey_dh_ctrl(EVP_PKEY_CTX * ctx,int type,int p1,void * p2)130 pkey_dh_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
131 {
132 DH_PKEY_CTX *dctx = ctx->data;
133
134 switch (type) {
135 case EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN:
136 if (p1 < 256)
137 return -2;
138 dctx->prime_len = p1;
139 return 1;
140
141 case EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR:
142 dctx->generator = p1;
143 return 1;
144
145 case EVP_PKEY_CTRL_PEER_KEY:
146 /* Default behaviour is OK */
147 return 1;
148
149 default:
150 return -2;
151 }
152 }
153
154 static int
pkey_dh_ctrl_str(EVP_PKEY_CTX * ctx,const char * type,const char * value)155 pkey_dh_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, const char *value)
156 {
157 const char *errstr;
158 int len;
159
160 if (!strcmp(type, "dh_paramgen_prime_len")) {
161 len = strtonum(value, INT_MIN, INT_MAX, &errstr);
162 if (errstr != NULL)
163 return -2;
164 return EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, len);
165 } else if (!strcmp(type, "dh_paramgen_generator")) {
166 len = strtonum(value, INT_MIN, INT_MAX, &errstr);
167 if (errstr != NULL)
168 return -2;
169 return EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, len);
170 }
171
172 return -2;
173 }
174
175 static int
pkey_dh_paramgen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)176 pkey_dh_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
177 {
178 DH *dh;
179 DH_PKEY_CTX *dctx = ctx->data;
180 BN_GENCB *pcb = NULL;
181 BN_GENCB cb = {0};
182 int ret = 0;
183
184 if ((dh = DH_new()) == NULL)
185 goto err;
186 if (ctx->pkey_gencb != NULL) {
187 pcb = &cb;
188 evp_pkey_set_cb_translate(pcb, ctx);
189 }
190 if (!DH_generate_parameters_ex(dh, dctx->prime_len, dctx->generator, pcb))
191 goto err;
192 if (!EVP_PKEY_assign_DH(pkey, dh))
193 goto err;
194 dh = NULL;
195
196 ret = 1;
197 err:
198 DH_free(dh);
199
200 return ret;
201 }
202
203 static int
pkey_dh_keygen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)204 pkey_dh_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
205 {
206 DH *dh = NULL;
207 int ret = 0;
208
209 if (ctx->pkey == NULL) {
210 DHerror(DH_R_NO_PARAMETERS_SET);
211 goto err;
212 }
213
214 if ((dh = DH_new()) == NULL)
215 goto err;
216 if (!EVP_PKEY_set1_DH(pkey, dh))
217 goto err;
218
219 if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
220 goto err;
221 if (!DH_generate_key(dh))
222 goto err;
223
224 ret = 1;
225
226 err:
227 DH_free(dh);
228
229 return ret;
230 }
231
232 static int
pkey_dh_derive(EVP_PKEY_CTX * ctx,unsigned char * key,size_t * keylen)233 pkey_dh_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)
234 {
235 int ret;
236
237 if (!ctx->pkey || !ctx->peerkey) {
238 DHerror(DH_R_KEYS_NOT_SET);
239 return 0;
240 }
241 ret = DH_compute_key(key, ctx->peerkey->pkey.dh->pub_key,
242 ctx->pkey->pkey.dh);
243 if (ret < 0)
244 return ret;
245 *keylen = ret;
246 return 1;
247 }
248
249 const EVP_PKEY_METHOD dh_pkey_meth = {
250 .pkey_id = EVP_PKEY_DH,
251 .flags = EVP_PKEY_FLAG_AUTOARGLEN,
252
253 .init = pkey_dh_init,
254 .copy = pkey_dh_copy,
255 .cleanup = pkey_dh_cleanup,
256
257 .paramgen = pkey_dh_paramgen,
258
259 .keygen = pkey_dh_keygen,
260
261 .derive = pkey_dh_derive,
262
263 .ctrl = pkey_dh_ctrl,
264 .ctrl_str = pkey_dh_ctrl_str
265 };
266