1 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
2  * project 2006.
3  */
4 /* ====================================================================
5  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  *
19  * 3. All advertising materials mentioning features or use of this
20  *    software must display the following acknowledgment:
21  *    "This product includes software developed by the OpenSSL Project
22  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
23  *
24  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
25  *    endorse or promote products derived from this software without
26  *    prior written permission. For written permission, please contact
27  *    licensing@OpenSSL.org.
28  *
29  * 5. Products derived from this software may not be called "OpenSSL"
30  *    nor may "OpenSSL" appear in their names without prior written
31  *    permission of the OpenSSL Project.
32  *
33  * 6. Redistributions of any form whatsoever must retain the following
34  *    acknowledgment:
35  *    "This product includes software developed by the OpenSSL Project
36  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
37  *
38  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
39  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
41  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
47  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
49  * OF THE POSSIBILITY OF SUCH DAMAGE.
50  * ====================================================================
51  *
52  * This product includes cryptographic software written by Eric Young
53  * (eay@cryptsoft.com).  This product includes software written by Tim
54  * Hudson (tjh@cryptsoft.com). */
55 
56 #include <openssl/evp.h>
57 
58 #include <string.h>
59 
60 #include <openssl/asn1.h>
61 #include <openssl/bn.h>
62 #include <openssl/buf.h>
63 #include <openssl/digest.h>
64 #include <openssl/ec.h>
65 #include <openssl/ec_key.h>
66 #include <openssl/ecdh.h>
67 #include <openssl/ecdsa.h>
68 #include <openssl/err.h>
69 #include <openssl/mem.h>
70 #include <openssl/obj.h>
71 
72 #include "internal.h"
73 #include "../ec/internal.h"
74 
75 
76 typedef struct {
77   /* Key and paramgen group */
78   EC_GROUP *gen_group;
79   /* message digest */
80   const EVP_MD *md;
81 } EC_PKEY_CTX;
82 
83 
pkey_ec_init(EVP_PKEY_CTX * ctx)84 static int pkey_ec_init(EVP_PKEY_CTX *ctx) {
85   EC_PKEY_CTX *dctx;
86   dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
87   if (!dctx) {
88     return 0;
89   }
90   memset(dctx, 0, sizeof(EC_PKEY_CTX));
91 
92   ctx->data = dctx;
93 
94   return 1;
95 }
96 
pkey_ec_copy(EVP_PKEY_CTX * dst,EVP_PKEY_CTX * src)97 static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src) {
98   EC_PKEY_CTX *dctx, *sctx;
99   if (!pkey_ec_init(dst)) {
100     return 0;
101   }
102   sctx = src->data;
103   dctx = dst->data;
104 
105   if (sctx->gen_group) {
106     dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
107     if (!dctx->gen_group) {
108       return 0;
109     }
110   }
111   dctx->md = sctx->md;
112 
113   return 1;
114 }
115 
pkey_ec_cleanup(EVP_PKEY_CTX * ctx)116 static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx) {
117   EC_PKEY_CTX *dctx = ctx->data;
118   if (!dctx) {
119     return;
120   }
121 
122   EC_GROUP_free(dctx->gen_group);
123   OPENSSL_free(dctx);
124 }
125 
pkey_ec_sign(EVP_PKEY_CTX * ctx,uint8_t * sig,size_t * siglen,const uint8_t * tbs,size_t tbslen)126 static int pkey_ec_sign(EVP_PKEY_CTX *ctx, uint8_t *sig, size_t *siglen,
127                         const uint8_t *tbs, size_t tbslen) {
128   unsigned int sltmp;
129   EC_KEY *ec = ctx->pkey->pkey.ec;
130 
131   if (!sig) {
132     *siglen = ECDSA_size(ec);
133     return 1;
134   } else if (*siglen < (size_t)ECDSA_size(ec)) {
135     OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
136     return 0;
137   }
138 
139   if (!ECDSA_sign(0, tbs, tbslen, sig, &sltmp, ec)) {
140     return 0;
141   }
142   *siglen = (size_t)sltmp;
143   return 1;
144 }
145 
pkey_ec_verify(EVP_PKEY_CTX * ctx,const uint8_t * sig,size_t siglen,const uint8_t * tbs,size_t tbslen)146 static int pkey_ec_verify(EVP_PKEY_CTX *ctx, const uint8_t *sig, size_t siglen,
147                           const uint8_t *tbs, size_t tbslen) {
148   return ECDSA_verify(0, tbs, tbslen, sig, siglen, ctx->pkey->pkey.ec);
149 }
150 
pkey_ec_derive(EVP_PKEY_CTX * ctx,uint8_t * key,size_t * keylen)151 static int pkey_ec_derive(EVP_PKEY_CTX *ctx, uint8_t *key,
152                           size_t *keylen) {
153   int ret;
154   size_t outlen;
155   const EC_POINT *pubkey = NULL;
156   EC_KEY *eckey;
157 
158   if (!ctx->pkey || !ctx->peerkey) {
159     OPENSSL_PUT_ERROR(EVP, EVP_R_KEYS_NOT_SET);
160     return 0;
161   }
162 
163   eckey = ctx->pkey->pkey.ec;
164 
165   if (!key) {
166     const EC_GROUP *group;
167     group = EC_KEY_get0_group(eckey);
168     *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
169     return 1;
170   }
171   pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
172 
173   /* NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is
174    * not an error, the result is truncated. */
175 
176   outlen = *keylen;
177 
178   ret = ECDH_compute_key(key, outlen, pubkey, eckey, 0);
179   if (ret < 0) {
180     return 0;
181   }
182   *keylen = ret;
183   return 1;
184 }
185 
pkey_ec_ctrl(EVP_PKEY_CTX * ctx,int type,int p1,void * p2)186 static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) {
187   EC_PKEY_CTX *dctx = ctx->data;
188   EC_GROUP *group;
189 
190   switch (type) {
191     case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
192       group = EC_GROUP_new_by_curve_name(p1);
193       if (group == NULL) {
194         OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_CURVE);
195         return 0;
196       }
197       EC_GROUP_free(dctx->gen_group);
198       dctx->gen_group = group;
199       return 1;
200 
201     case EVP_PKEY_CTRL_MD:
202       if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
203           EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
204           EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
205           EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
206           EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
207           EVP_MD_type((const EVP_MD *)p2) != NID_sha512) {
208         OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_DIGEST_TYPE);
209         return 0;
210       }
211       dctx->md = p2;
212       return 1;
213 
214     case EVP_PKEY_CTRL_GET_MD:
215       *(const EVP_MD **)p2 = dctx->md;
216       return 1;
217 
218     case EVP_PKEY_CTRL_PEER_KEY:
219       /* Default behaviour is OK */
220       return 1;
221 
222     default:
223       OPENSSL_PUT_ERROR(EVP, EVP_R_COMMAND_NOT_SUPPORTED);
224       return 0;
225   }
226 }
227 
pkey_ec_paramgen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)228 static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
229   EC_KEY *ec = NULL;
230   EC_PKEY_CTX *dctx = ctx->data;
231   int ret = 0;
232 
233   if (dctx->gen_group == NULL) {
234     OPENSSL_PUT_ERROR(EVP, EVP_R_NO_PARAMETERS_SET);
235     return 0;
236   }
237   ec = EC_KEY_new();
238   if (!ec) {
239     return 0;
240   }
241   ret = EC_KEY_set_group(ec, dctx->gen_group);
242   if (ret) {
243     EVP_PKEY_assign_EC_KEY(pkey, ec);
244   } else {
245     EC_KEY_free(ec);
246   }
247   return ret;
248 }
249 
pkey_ec_keygen(EVP_PKEY_CTX * ctx,EVP_PKEY * pkey)250 static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey) {
251   EC_KEY *ec = NULL;
252   EC_PKEY_CTX *dctx = ctx->data;
253   if (ctx->pkey == NULL && dctx->gen_group == NULL) {
254     OPENSSL_PUT_ERROR(EVP, EVP_R_NO_PARAMETERS_SET);
255     return 0;
256   }
257   ec = EC_KEY_new();
258   if (!ec) {
259     return 0;
260   }
261   EVP_PKEY_assign_EC_KEY(pkey, ec);
262   if (ctx->pkey) {
263     /* Note: if error return, pkey is freed by parent routine */
264     if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey)) {
265       return 0;
266     }
267   } else {
268     if (!EC_KEY_set_group(ec, dctx->gen_group)) {
269       return 0;
270     }
271   }
272   return EC_KEY_generate_key(pkey->pkey.ec);
273 }
274 
275 const EVP_PKEY_METHOD ec_pkey_meth = {
276     EVP_PKEY_EC,          0 /* flags */,        pkey_ec_init,
277     pkey_ec_copy,         pkey_ec_cleanup,      0 /* paramgen_init */,
278     pkey_ec_paramgen,     0 /* keygen_init */,  pkey_ec_keygen,
279     0 /* sign_init */,    pkey_ec_sign,         0 /* verify_init */,
280     pkey_ec_verify,       0 /* encrypt_init */, 0 /* encrypt */,
281     0 /* decrypt_init */, 0 /* decrypt */,      0 /* derive_init */,
282     pkey_ec_derive,       pkey_ec_ctrl,
283 };
284