ec_pmeth.c revision 296341 
1/*
2 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
3 * 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 <stdio.h>
60#include "cryptlib.h"
61#include <openssl/asn1t.h>
62#include <openssl/x509.h>
63#include <openssl/ec.h>
64#include <openssl/ecdsa.h>
65#include <openssl/evp.h>
66#include "evp_locl.h"
67
68/* EC pkey context structure */
69
70typedef struct {
71    /* Key and paramgen group */
72    EC_GROUP *gen_group;
73    /* message digest */
74    const EVP_MD *md;
75} EC_PKEY_CTX;
76
77static int pkey_ec_init(EVP_PKEY_CTX *ctx)
78{
79    EC_PKEY_CTX *dctx;
80    dctx = OPENSSL_malloc(sizeof(EC_PKEY_CTX));
81    if (!dctx)
82        return 0;
83    dctx->gen_group = NULL;
84    dctx->md = NULL;
85
86    ctx->data = dctx;
87
88    return 1;
89}
90
91static int pkey_ec_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
92{
93    EC_PKEY_CTX *dctx, *sctx;
94    if (!pkey_ec_init(dst))
95        return 0;
96    sctx = src->data;
97    dctx = dst->data;
98    if (sctx->gen_group) {
99        dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
100        if (!dctx->gen_group)
101            return 0;
102    }
103    dctx->md = sctx->md;
104    return 1;
105}
106
107static void pkey_ec_cleanup(EVP_PKEY_CTX *ctx)
108{
109    EC_PKEY_CTX *dctx = ctx->data;
110    if (dctx) {
111        if (dctx->gen_group)
112            EC_GROUP_free(dctx->gen_group);
113        OPENSSL_free(dctx);
114    }
115}
116
117static int pkey_ec_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
118                        const unsigned char *tbs, size_t tbslen)
119{
120    int ret, type;
121    unsigned int sltmp;
122    EC_PKEY_CTX *dctx = ctx->data;
123    EC_KEY *ec = ctx->pkey->pkey.ec;
124
125    if (!sig) {
126        *siglen = ECDSA_size(ec);
127        return 1;
128    } else if (*siglen < (size_t)ECDSA_size(ec)) {
129        ECerr(EC_F_PKEY_EC_SIGN, EC_R_BUFFER_TOO_SMALL);
130        return 0;
131    }
132
133    if (dctx->md)
134        type = EVP_MD_type(dctx->md);
135    else
136        type = NID_sha1;
137
138    ret = ECDSA_sign(type, tbs, tbslen, sig, &sltmp, ec);
139
140    if (ret <= 0)
141        return ret;
142    *siglen = (size_t)sltmp;
143    return 1;
144}
145
146static int pkey_ec_verify(EVP_PKEY_CTX *ctx,
147                          const unsigned char *sig, size_t siglen,
148                          const unsigned char *tbs, size_t tbslen)
149{
150    int ret, type;
151    EC_PKEY_CTX *dctx = ctx->data;
152    EC_KEY *ec = ctx->pkey->pkey.ec;
153
154    if (dctx->md)
155        type = EVP_MD_type(dctx->md);
156    else
157        type = NID_sha1;
158
159    ret = ECDSA_verify(type, tbs, tbslen, sig, siglen, ec);
160
161    return ret;
162}
163
164#ifndef OPENSSL_NO_ECDH
165static int pkey_ec_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
166                          size_t *keylen)
167{
168    int ret;
169    size_t outlen;
170    const EC_POINT *pubkey = NULL;
171    if (!ctx->pkey || !ctx->peerkey) {
172        ECerr(EC_F_PKEY_EC_DERIVE, EC_R_KEYS_NOT_SET);
173        return 0;
174    }
175
176    if (!key) {
177        const EC_GROUP *group;
178        group = EC_KEY_get0_group(ctx->pkey->pkey.ec);
179        *keylen = (EC_GROUP_get_degree(group) + 7) / 8;
180        return 1;
181    }
182
183    pubkey = EC_KEY_get0_public_key(ctx->peerkey->pkey.ec);
184
185    /*
186     * NB: unlike PKCS#3 DH, if *outlen is less than maximum size this is not
187     * an error, the result is truncated.
188     */
189
190    outlen = *keylen;
191
192    ret = ECDH_compute_key(key, outlen, pubkey, ctx->pkey->pkey.ec, 0);
193    if (ret < 0)
194        return ret;
195    *keylen = ret;
196    return 1;
197}
198#endif
199
200static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
201{
202    EC_PKEY_CTX *dctx = ctx->data;
203    EC_GROUP *group;
204    switch (type) {
205    case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
206        group = EC_GROUP_new_by_curve_name(p1);
207        if (group == NULL) {
208            ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_CURVE);
209            return 0;
210        }
211        if (dctx->gen_group)
212            EC_GROUP_free(dctx->gen_group);
213        dctx->gen_group = group;
214        return 1;
215
216    case EVP_PKEY_CTRL_MD:
217        if (EVP_MD_type((const EVP_MD *)p2) != NID_sha1 &&
218            EVP_MD_type((const EVP_MD *)p2) != NID_ecdsa_with_SHA1 &&
219            EVP_MD_type((const EVP_MD *)p2) != NID_sha224 &&
220            EVP_MD_type((const EVP_MD *)p2) != NID_sha256 &&
221            EVP_MD_type((const EVP_MD *)p2) != NID_sha384 &&
222            EVP_MD_type((const EVP_MD *)p2) != NID_sha512) {
223            ECerr(EC_F_PKEY_EC_CTRL, EC_R_INVALID_DIGEST_TYPE);
224            return 0;
225        }
226        dctx->md = p2;
227        return 1;
228
229    case EVP_PKEY_CTRL_PEER_KEY:
230        /* Default behaviour is OK */
231    case EVP_PKEY_CTRL_DIGESTINIT:
232    case EVP_PKEY_CTRL_PKCS7_SIGN:
233    case EVP_PKEY_CTRL_CMS_SIGN:
234        return 1;
235
236    default:
237        return -2;
238
239    }
240}
241
242static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
243                            const char *type, const char *value)
244{
245    if (!strcmp(type, "ec_paramgen_curve")) {
246        int nid;
247        nid = OBJ_sn2nid(value);
248        if (nid == NID_undef)
249            nid = OBJ_ln2nid(value);
250        if (nid == NID_undef) {
251            ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_CURVE);
252            return 0;
253        }
254        return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
255    }
256    return -2;
257}
258
259static int pkey_ec_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
260{
261    EC_KEY *ec = NULL;
262    EC_PKEY_CTX *dctx = ctx->data;
263    int ret = 0;
264    if (dctx->gen_group == NULL) {
265        ECerr(EC_F_PKEY_EC_PARAMGEN, EC_R_NO_PARAMETERS_SET);
266        return 0;
267    }
268    ec = EC_KEY_new();
269    if (!ec)
270        return 0;
271    ret = EC_KEY_set_group(ec, dctx->gen_group);
272    if (ret)
273        EVP_PKEY_assign_EC_KEY(pkey, ec);
274    else
275        EC_KEY_free(ec);
276    return ret;
277}
278
279static int pkey_ec_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
280{
281    EC_KEY *ec = NULL;
282    if (ctx->pkey == NULL) {
283        ECerr(EC_F_PKEY_EC_KEYGEN, EC_R_NO_PARAMETERS_SET);
284        return 0;
285    }
286    ec = EC_KEY_new();
287    if (!ec)
288        return 0;
289    EVP_PKEY_assign_EC_KEY(pkey, ec);
290    /* Note: if error return, pkey is freed by parent routine */
291    if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))
292        return 0;
293    return EC_KEY_generate_key(pkey->pkey.ec);
294}
295
296const EVP_PKEY_METHOD ec_pkey_meth = {
297    EVP_PKEY_EC,
298    0,
299    pkey_ec_init,
300    pkey_ec_copy,
301    pkey_ec_cleanup,
302
303    0,
304    pkey_ec_paramgen,
305
306    0,
307    pkey_ec_keygen,
308
309    0,
310    pkey_ec_sign,
311
312    0,
313    pkey_ec_verify,
314
315    0, 0,
316
317    0, 0, 0, 0,
318
319    0, 0,
320
321    0, 0,
322
323    0,
324#ifndef OPENSSL_NO_ECDH
325    pkey_ec_derive,
326#else
327    0,
328#endif
329
330    pkey_ec_ctrl,
331    pkey_ec_ctrl_str
332};
333