1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to.  The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 *    notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 *    notice, this list of conditions and the following disclaimer in the
29 *    documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 *    must display the following acknowledgement:
32 *    "This product includes cryptographic software written by
33 *     Eric Young (eay@cryptsoft.com)"
34 *    The word 'cryptographic' can be left out if the rouines from the library
35 *    being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 *    the apps directory (application code) you must include an acknowledgement:
38 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed.  i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.]
56 *
57 * The DSS routines are based on patches supplied by
58 * Steven Schoch <schoch@sheba.arc.nasa.gov>. */
59
60#include <openssl/dsa.h>
61
62#include <string.h>
63
64#include <openssl/asn1.h>
65#include <openssl/dh.h>
66#include <openssl/engine.h>
67#include <openssl/err.h>
68#include <openssl/ex_data.h>
69#include <openssl/mem.h>
70#include <openssl/thread.h>
71
72#include "internal.h"
73#include "../internal.h"
74
75
76extern const DSA_METHOD DSA_default_method;
77
78static CRYPTO_EX_DATA_CLASS g_ex_data_class = CRYPTO_EX_DATA_CLASS_INIT;
79
80DSA *DSA_new(void) { return DSA_new_method(NULL); }
81
82DSA *DSA_new_method(const ENGINE *engine) {
83  DSA *dsa = (DSA *)OPENSSL_malloc(sizeof(DSA));
84  if (dsa == NULL) {
85    OPENSSL_PUT_ERROR(DSA, DSA_new_method, ERR_R_MALLOC_FAILURE);
86    return NULL;
87  }
88
89  memset(dsa, 0, sizeof(DSA));
90
91  if (engine) {
92    dsa->meth = ENGINE_get_DSA_method(engine);
93  }
94
95  if (dsa->meth == NULL) {
96    dsa->meth = (DSA_METHOD*) &DSA_default_method;
97  }
98  METHOD_ref(dsa->meth);
99
100  dsa->write_params = 1;
101  dsa->references = 1;
102
103  CRYPTO_MUTEX_init(&dsa->method_mont_p_lock);
104
105  if (!CRYPTO_new_ex_data(&g_ex_data_class, dsa, &dsa->ex_data)) {
106    METHOD_unref(dsa->meth);
107    OPENSSL_free(dsa);
108    return NULL;
109  }
110
111  if (dsa->meth->init && !dsa->meth->init(dsa)) {
112    CRYPTO_free_ex_data(&g_ex_data_class, dsa, &dsa->ex_data);
113    METHOD_unref(dsa->meth);
114    OPENSSL_free(dsa);
115    return NULL;
116  }
117
118  return dsa;
119}
120
121void DSA_free(DSA *dsa) {
122  if (dsa == NULL) {
123    return;
124  }
125
126  if (!CRYPTO_refcount_dec_and_test_zero(&dsa->references)) {
127    return;
128  }
129
130  if (dsa->meth->finish) {
131    dsa->meth->finish(dsa);
132  }
133  METHOD_unref(dsa->meth);
134
135  CRYPTO_free_ex_data(&g_ex_data_class, dsa, &dsa->ex_data);
136
137  BN_clear_free(dsa->p);
138  BN_clear_free(dsa->q);
139  BN_clear_free(dsa->g);
140  BN_clear_free(dsa->pub_key);
141  BN_clear_free(dsa->priv_key);
142  BN_clear_free(dsa->kinv);
143  BN_clear_free(dsa->r);
144  CRYPTO_MUTEX_cleanup(&dsa->method_mont_p_lock);
145  OPENSSL_free(dsa);
146}
147
148int DSA_up_ref(DSA *dsa) {
149  CRYPTO_refcount_inc(&dsa->references);
150  return 1;
151}
152
153int DSA_generate_parameters_ex(DSA *dsa, unsigned bits, const uint8_t *seed_in,
154                               size_t seed_len, int *out_counter,
155                               unsigned long *out_h, BN_GENCB *cb) {
156  if (dsa->meth->generate_parameters) {
157    return dsa->meth->generate_parameters(dsa, bits, seed_in, seed_len,
158                                          out_counter, out_h, cb);
159  }
160  return DSA_default_method.generate_parameters(dsa, bits, seed_in, seed_len,
161                                                out_counter, out_h, cb);
162}
163
164int DSA_generate_key(DSA *dsa) {
165  if (dsa->meth->keygen) {
166    return dsa->meth->keygen(dsa);
167  }
168  return DSA_default_method.keygen(dsa);
169}
170
171DSA_SIG *DSA_SIG_new(void) {
172  DSA_SIG *sig;
173  sig = OPENSSL_malloc(sizeof(DSA_SIG));
174  if (!sig) {
175    return NULL;
176  }
177  sig->r = NULL;
178  sig->s = NULL;
179  return sig;
180}
181
182void DSA_SIG_free(DSA_SIG *sig) {
183  if (!sig) {
184    return;
185  }
186
187  BN_free(sig->r);
188  BN_free(sig->s);
189  OPENSSL_free(sig);
190}
191
192DSA_SIG *DSA_do_sign(const uint8_t *digest, size_t digest_len, DSA *dsa) {
193  if (dsa->meth->sign) {
194    return dsa->meth->sign(digest, digest_len, dsa);
195  }
196  return DSA_default_method.sign(digest, digest_len, dsa);
197}
198
199int DSA_do_verify(const uint8_t *digest, size_t digest_len, DSA_SIG *sig,
200                  const DSA *dsa) {
201  int valid;
202  if (!DSA_do_check_signature(&valid, digest, digest_len, sig, dsa)) {
203    return -1;
204  }
205  return valid;
206}
207
208int DSA_do_check_signature(int *out_valid, const uint8_t *digest,
209                           size_t digest_len, DSA_SIG *sig, const DSA *dsa) {
210  if (dsa->meth->verify) {
211    return dsa->meth->verify(out_valid, digest, digest_len, sig, dsa);
212  }
213
214  return DSA_default_method.verify(out_valid, digest, digest_len, sig, dsa);
215}
216
217int DSA_sign(int type, const uint8_t *digest, size_t digest_len,
218             uint8_t *out_sig, unsigned int *out_siglen, DSA *dsa) {
219  DSA_SIG *s;
220
221  s = DSA_do_sign(digest, digest_len, dsa);
222  if (s == NULL) {
223    *out_siglen = 0;
224    return 0;
225  }
226
227  *out_siglen = i2d_DSA_SIG(s, &out_sig);
228  DSA_SIG_free(s);
229  return 1;
230}
231
232int DSA_verify(int type, const uint8_t *digest, size_t digest_len,
233               const uint8_t *sig, size_t sig_len, const DSA *dsa) {
234  int valid;
235  if (!DSA_check_signature(&valid, digest, digest_len, sig, sig_len, dsa)) {
236    return -1;
237  }
238  return valid;
239}
240
241int DSA_check_signature(int *out_valid, const uint8_t *digest,
242                        size_t digest_len, const uint8_t *sig, size_t sig_len,
243                        const DSA *dsa) {
244  DSA_SIG *s = NULL;
245  int ret = 0;
246  uint8_t *der = NULL;
247
248  s = DSA_SIG_new();
249  if (s == NULL) {
250    goto err;
251  }
252
253  const uint8_t *sigp = sig;
254  if (d2i_DSA_SIG(&s, &sigp, sig_len) == NULL || sigp != sig + sig_len) {
255    goto err;
256  }
257
258  /* Ensure that the signature uses DER and doesn't have trailing garbage. */
259  int der_len = i2d_DSA_SIG(s, &der);
260  if (der_len < 0 || (size_t)der_len != sig_len || memcmp(sig, der, sig_len)) {
261    goto err;
262  }
263
264  ret = DSA_do_check_signature(out_valid, digest, digest_len, s, dsa);
265
266err:
267  OPENSSL_free(der);
268  DSA_SIG_free(s);
269  return ret;
270}
271
272int DSA_size(const DSA *dsa) {
273  int ret, i;
274  ASN1_INTEGER bs;
275  unsigned char buf[4]; /* 4 bytes looks really small.
276                           However, i2d_ASN1_INTEGER() will not look
277                           beyond the first byte, as long as the second
278                           parameter is NULL. */
279
280  i = BN_num_bits(dsa->q);
281  bs.length = (i + 7) / 8;
282  bs.data = buf;
283  bs.type = V_ASN1_INTEGER;
284  /* If the top bit is set the asn1 encoding is 1 larger. */
285  buf[0] = 0xff;
286
287  i = i2d_ASN1_INTEGER(&bs, NULL);
288  i += i; /* r and s */
289  ret = ASN1_object_size(1, i, V_ASN1_SEQUENCE);
290  return ret;
291}
292
293int DSA_sign_setup(const DSA *dsa, BN_CTX *ctx, BIGNUM **out_kinv,
294                   BIGNUM **out_r) {
295  if (dsa->meth->sign_setup) {
296    return dsa->meth->sign_setup(dsa, ctx, out_kinv, out_r, NULL, 0);
297  }
298
299  return DSA_default_method.sign_setup(dsa, ctx, out_kinv, out_r, NULL, 0);
300}
301
302int DSA_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
303                         CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func) {
304  int index;
305  if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp, new_func,
306                               dup_func, free_func)) {
307    return -1;
308  }
309  return index;
310}
311
312int DSA_set_ex_data(DSA *d, int idx, void *arg) {
313  return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
314}
315
316void *DSA_get_ex_data(const DSA *d, int idx) {
317  return CRYPTO_get_ex_data(&d->ex_data, idx);
318}
319
320DH *DSA_dup_DH(const DSA *r) {
321  DH *ret = NULL;
322
323  if (r == NULL) {
324    goto err;
325  }
326  ret = DH_new();
327  if (ret == NULL) {
328    goto err;
329  }
330  if (r->q != NULL) {
331    ret->priv_length = BN_num_bits(r->q);
332    if ((ret->q = BN_dup(r->q)) == NULL) {
333      goto err;
334    }
335  }
336  if ((r->p != NULL && (ret->p = BN_dup(r->p)) == NULL) ||
337      (r->g != NULL && (ret->g = BN_dup(r->g)) == NULL) ||
338      (r->pub_key != NULL && (ret->pub_key = BN_dup(r->pub_key)) == NULL) ||
339      (r->priv_key != NULL && (ret->priv_key = BN_dup(r->priv_key)) == NULL)) {
340      goto err;
341  }
342
343  return ret;
344
345err:
346  DH_free(ret);
347  return NULL;
348}
349