]>
Commit | Line | Data |
---|---|---|
c0711f7f DSH |
1 | /* crypto/dsa/dsa_ossl.c */ |
2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
3 | * All rights reserved. | |
4 | * | |
5 | * This package is an SSL implementation written | |
6 | * by Eric Young (eay@cryptsoft.com). | |
7 | * The implementation was written so as to conform with Netscapes SSL. | |
0f113f3e | 8 | * |
c0711f7f DSH |
9 | * This library is free for commercial and non-commercial use as long as |
10 | * the following conditions are aheared to. The following conditions | |
11 | * apply to all code found in this distribution, be it the RC4, RSA, | |
12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
13 | * included with this distribution is covered by the same copyright terms | |
14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
0f113f3e | 15 | * |
c0711f7f DSH |
16 | * Copyright remains Eric Young's, and as such any Copyright notices in |
17 | * the code are not to be removed. | |
18 | * If this package is used in a product, Eric Young should be given attribution | |
19 | * as the author of the parts of the library used. | |
20 | * This can be in the form of a textual message at program startup or | |
21 | * in documentation (online or textual) provided with the package. | |
0f113f3e | 22 | * |
c0711f7f DSH |
23 | * Redistribution and use in source and binary forms, with or without |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * 3. All advertising materials mentioning features or use of this software | |
32 | * must display the following acknowledgement: | |
33 | * "This product includes cryptographic software written by | |
34 | * Eric Young (eay@cryptsoft.com)" | |
35 | * The word 'cryptographic' can be left out if the rouines from the library | |
36 | * being used are not cryptographic related :-). | |
0f113f3e | 37 | * 4. If you include any Windows specific code (or a derivative thereof) from |
c0711f7f DSH |
38 | * the apps directory (application code) you must include an acknowledgement: |
39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
0f113f3e | 40 | * |
c0711f7f DSH |
41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
51 | * SUCH DAMAGE. | |
0f113f3e | 52 | * |
c0711f7f DSH |
53 | * The licence and distribution terms for any publically available version or |
54 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
55 | * copied and put under another distribution licence | |
56 | * [including the GNU Public Licence.] | |
57 | */ | |
58 | ||
59 | /* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */ | |
60 | ||
61 | #include <stdio.h> | |
b39fc560 | 62 | #include "internal/cryptlib.h" |
c0711f7f | 63 | #include <openssl/bn.h> |
357d5de5 | 64 | #include <openssl/sha.h> |
c0711f7f DSH |
65 | #include <openssl/dsa.h> |
66 | #include <openssl/rand.h> | |
67 | #include <openssl/asn1.h> | |
68 | ||
69 | static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa); | |
0f113f3e MC |
70 | static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, |
71 | BIGNUM **rp); | |
72 | static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, | |
73 | BIGNUM **rp, const unsigned char *dgst, int dlen); | |
74 | static int dsa_do_verify(const unsigned char *dgst, int dgst_len, | |
75 | DSA_SIG *sig, DSA *dsa); | |
c0711f7f DSH |
76 | static int dsa_init(DSA *dsa); |
77 | static int dsa_finish(DSA *dsa); | |
c0711f7f DSH |
78 | |
79 | static DSA_METHOD openssl_dsa_meth = { | |
0f113f3e MC |
80 | "OpenSSL DSA method", |
81 | dsa_do_sign, | |
82 | dsa_sign_setup_no_digest, | |
83 | dsa_do_verify, | |
84 | NULL, /* dsa_mod_exp, */ | |
85 | NULL, /* dsa_bn_mod_exp, */ | |
86 | dsa_init, | |
87 | dsa_finish, | |
88 | DSA_FLAG_FIPS_METHOD, | |
89 | NULL, | |
90 | NULL, | |
91 | NULL | |
c0711f7f DSH |
92 | }; |
93 | ||
1d97c843 TH |
94 | /*- |
95 | * These macro wrappers replace attempts to use the dsa_mod_exp() and | |
879650b8 GT |
96 | * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of |
97 | * having a the macro work as an expression by bundling an "err_instr". So; | |
0f113f3e | 98 | * |
879650b8 GT |
99 | * if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, |
100 | * dsa->method_mont_p)) goto err; | |
101 | * | |
102 | * can be replaced by; | |
103 | * | |
104 | * DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, | |
105 | * dsa->method_mont_p); | |
106 | */ | |
107 | ||
108 | #define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \ | |
0f113f3e MC |
109 | do { \ |
110 | int _tmp_res53; \ | |
61986d32 | 111 | if ((dsa)->meth->dsa_mod_exp) \ |
0f113f3e MC |
112 | _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \ |
113 | (a2), (p2), (m), (ctx), (in_mont)); \ | |
114 | else \ | |
115 | _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \ | |
116 | (m), (ctx), (in_mont)); \ | |
61986d32 | 117 | if (!_tmp_res53) err_instr; \ |
0f113f3e | 118 | } while(0) |
879650b8 | 119 | #define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \ |
0f113f3e MC |
120 | do { \ |
121 | int _tmp_res53; \ | |
61986d32 | 122 | if ((dsa)->meth->bn_mod_exp) \ |
0f113f3e MC |
123 | _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \ |
124 | (m), (ctx), (m_ctx)); \ | |
125 | else \ | |
126 | _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \ | |
61986d32 | 127 | if (!_tmp_res53) err_instr; \ |
0f113f3e | 128 | } while(0) |
879650b8 | 129 | |
a4aba800 | 130 | const DSA_METHOD *DSA_OpenSSL(void) |
c0711f7f | 131 | { |
0f113f3e | 132 | return &openssl_dsa_meth; |
c0711f7f DSH |
133 | } |
134 | ||
135 | static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) | |
0f113f3e MC |
136 | { |
137 | BIGNUM *kinv = NULL, *r = NULL, *s = NULL; | |
138 | BIGNUM *m; | |
139 | BIGNUM *xr; | |
140 | BN_CTX *ctx = NULL; | |
141 | int reason = ERR_R_BN_LIB; | |
142 | DSA_SIG *ret = NULL; | |
143 | int noredo = 0; | |
144 | ||
145 | m = BN_new(); | |
146 | xr = BN_new(); | |
147 | if (!m || !xr) | |
148 | goto err; | |
149 | ||
150 | if (!dsa->p || !dsa->q || !dsa->g) { | |
151 | reason = DSA_R_MISSING_PARAMETERS; | |
152 | goto err; | |
153 | } | |
154 | ||
155 | s = BN_new(); | |
156 | if (s == NULL) | |
157 | goto err; | |
158 | ctx = BN_CTX_new(); | |
159 | if (ctx == NULL) | |
160 | goto err; | |
161 | redo: | |
162 | if ((dsa->kinv == NULL) || (dsa->r == NULL)) { | |
163 | if (!dsa_sign_setup(dsa, ctx, &kinv, &r, dgst, dlen)) | |
164 | goto err; | |
165 | } else { | |
166 | kinv = dsa->kinv; | |
167 | dsa->kinv = NULL; | |
168 | r = dsa->r; | |
169 | dsa->r = NULL; | |
170 | noredo = 1; | |
171 | } | |
172 | ||
173 | if (dlen > BN_num_bytes(dsa->q)) | |
174 | /* | |
175 | * if the digest length is greater than the size of q use the | |
176 | * BN_num_bits(dsa->q) leftmost bits of the digest, see fips 186-3, | |
177 | * 4.2 | |
178 | */ | |
179 | dlen = BN_num_bytes(dsa->q); | |
180 | if (BN_bin2bn(dgst, dlen, m) == NULL) | |
181 | goto err; | |
182 | ||
183 | /* Compute s = inv(k) (m + xr) mod q */ | |
184 | if (!BN_mod_mul(xr, dsa->priv_key, r, dsa->q, ctx)) | |
185 | goto err; /* s = xr */ | |
186 | if (!BN_add(s, xr, m)) | |
187 | goto err; /* s = m + xr */ | |
188 | if (BN_cmp(s, dsa->q) > 0) | |
189 | if (!BN_sub(s, s, dsa->q)) | |
190 | goto err; | |
191 | if (!BN_mod_mul(s, s, kinv, dsa->q, ctx)) | |
192 | goto err; | |
193 | ||
194 | ret = DSA_SIG_new(); | |
195 | if (ret == NULL) | |
196 | goto err; | |
197 | /* | |
198 | * Redo if r or s is zero as required by FIPS 186-3: this is very | |
199 | * unlikely. | |
200 | */ | |
201 | if (BN_is_zero(r) || BN_is_zero(s)) { | |
202 | if (noredo) { | |
203 | reason = DSA_R_NEED_NEW_SETUP_VALUES; | |
204 | goto err; | |
205 | } | |
206 | goto redo; | |
207 | } | |
208 | ret->r = r; | |
209 | ret->s = s; | |
210 | ||
211 | err: | |
212 | if (!ret) { | |
213 | DSAerr(DSA_F_DSA_DO_SIGN, reason); | |
214 | BN_free(r); | |
215 | BN_free(s); | |
216 | } | |
23a1d5e9 | 217 | BN_CTX_free(ctx); |
0f113f3e MC |
218 | BN_clear_free(m); |
219 | BN_clear_free(xr); | |
23a1d5e9 | 220 | BN_clear_free(kinv); |
0f113f3e MC |
221 | return (ret); |
222 | } | |
c0711f7f | 223 | |
8d6a75dc | 224 | static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in, |
0f113f3e MC |
225 | BIGNUM **kinvp, BIGNUM **rp) |
226 | { | |
227 | return dsa_sign_setup(dsa, ctx_in, kinvp, rp, NULL, 0); | |
190c615d AL |
228 | } |
229 | ||
8d6a75dc | 230 | static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, |
0f113f3e MC |
231 | BIGNUM **kinvp, BIGNUM **rp, |
232 | const unsigned char *dgst, int dlen) | |
233 | { | |
234 | BN_CTX *ctx = NULL; | |
235 | BIGNUM *k, *kq, *K, *kinv = NULL, *r = NULL; | |
236 | int ret = 0; | |
237 | ||
238 | if (!dsa->p || !dsa->q || !dsa->g) { | |
239 | DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS); | |
240 | return 0; | |
241 | } | |
242 | ||
243 | k = BN_new(); | |
244 | kq = BN_new(); | |
245 | if (!k || !kq) | |
246 | goto err; | |
247 | ||
248 | if (ctx_in == NULL) { | |
249 | if ((ctx = BN_CTX_new()) == NULL) | |
250 | goto err; | |
251 | } else | |
252 | ctx = ctx_in; | |
253 | ||
254 | if ((r = BN_new()) == NULL) | |
255 | goto err; | |
256 | ||
257 | /* Get random k */ | |
258 | do { | |
0f113f3e MC |
259 | if (dgst != NULL) { |
260 | /* | |
261 | * We calculate k from SHA512(private_key + H(message) + random). | |
262 | * This protects the private key from a weak PRNG. | |
263 | */ | |
264 | if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst, | |
265 | dlen, ctx)) | |
266 | goto err; | |
474e469b | 267 | } else if (!BN_rand_range(k, dsa->q)) |
0f113f3e MC |
268 | goto err; |
269 | } while (BN_is_zero(k)); | |
270 | ||
271 | if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) { | |
272 | BN_set_flags(k, BN_FLG_CONSTTIME); | |
273 | } | |
274 | ||
275 | if (dsa->flags & DSA_FLAG_CACHE_MONT_P) { | |
276 | if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, | |
277 | CRYPTO_LOCK_DSA, dsa->p, ctx)) | |
278 | goto err; | |
279 | } | |
280 | ||
281 | /* Compute r = (g^k mod p) mod q */ | |
282 | ||
283 | if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) { | |
284 | if (!BN_copy(kq, k)) | |
285 | goto err; | |
286 | ||
287 | /* | |
288 | * We do not want timing information to leak the length of k, so we | |
289 | * compute g^k using an equivalent exponent of fixed length. (This | |
290 | * is a kludge that we need because the BN_mod_exp_mont() does not | |
291 | * let us specify the desired timing behaviour.) | |
292 | */ | |
293 | ||
294 | if (!BN_add(kq, kq, dsa->q)) | |
295 | goto err; | |
296 | if (BN_num_bits(kq) <= BN_num_bits(dsa->q)) { | |
297 | if (!BN_add(kq, kq, dsa->q)) | |
298 | goto err; | |
299 | } | |
300 | ||
301 | K = kq; | |
302 | } else { | |
303 | K = k; | |
304 | } | |
305 | DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx, | |
306 | dsa->method_mont_p); | |
307 | if (!BN_mod(r, r, dsa->q, ctx)) | |
308 | goto err; | |
309 | ||
310 | /* Compute part of 's = inv(k) (m + xr) mod q' */ | |
311 | if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL) | |
312 | goto err; | |
313 | ||
23a1d5e9 | 314 | BN_clear_free(*kinvp); |
0f113f3e MC |
315 | *kinvp = kinv; |
316 | kinv = NULL; | |
23a1d5e9 | 317 | BN_clear_free(*rp); |
0f113f3e MC |
318 | *rp = r; |
319 | ret = 1; | |
320 | err: | |
321 | if (!ret) { | |
322 | DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB); | |
23a1d5e9 | 323 | BN_clear_free(r); |
0f113f3e | 324 | } |
23a1d5e9 | 325 | if (ctx != ctx_in) |
0f113f3e MC |
326 | BN_CTX_free(ctx); |
327 | BN_clear_free(k); | |
328 | BN_clear_free(kq); | |
329 | return (ret); | |
330 | } | |
331 | ||
332 | static int dsa_do_verify(const unsigned char *dgst, int dgst_len, | |
333 | DSA_SIG *sig, DSA *dsa) | |
334 | { | |
335 | BN_CTX *ctx; | |
336 | BIGNUM *u1, *u2, *t1; | |
337 | BN_MONT_CTX *mont = NULL; | |
338 | int ret = -1, i; | |
339 | if (!dsa->p || !dsa->q || !dsa->g) { | |
340 | DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_MISSING_PARAMETERS); | |
341 | return -1; | |
342 | } | |
343 | ||
344 | i = BN_num_bits(dsa->q); | |
345 | /* fips 186-3 allows only different sizes for q */ | |
346 | if (i != 160 && i != 224 && i != 256) { | |
347 | DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_BAD_Q_VALUE); | |
348 | return -1; | |
349 | } | |
350 | ||
351 | if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) { | |
352 | DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_MODULUS_TOO_LARGE); | |
353 | return -1; | |
354 | } | |
355 | u1 = BN_new(); | |
356 | u2 = BN_new(); | |
357 | t1 = BN_new(); | |
358 | ctx = BN_CTX_new(); | |
359 | if (!u1 || !u2 || !t1 || !ctx) | |
360 | goto err; | |
361 | ||
362 | if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || | |
363 | BN_ucmp(sig->r, dsa->q) >= 0) { | |
364 | ret = 0; | |
365 | goto err; | |
366 | } | |
367 | if (BN_is_zero(sig->s) || BN_is_negative(sig->s) || | |
368 | BN_ucmp(sig->s, dsa->q) >= 0) { | |
369 | ret = 0; | |
370 | goto err; | |
371 | } | |
372 | ||
373 | /* | |
374 | * Calculate W = inv(S) mod Q save W in u2 | |
375 | */ | |
376 | if ((BN_mod_inverse(u2, sig->s, dsa->q, ctx)) == NULL) | |
377 | goto err; | |
378 | ||
379 | /* save M in u1 */ | |
380 | if (dgst_len > (i >> 3)) | |
381 | /* | |
382 | * if the digest length is greater than the size of q use the | |
383 | * BN_num_bits(dsa->q) leftmost bits of the digest, see fips 186-3, | |
384 | * 4.2 | |
385 | */ | |
386 | dgst_len = (i >> 3); | |
387 | if (BN_bin2bn(dgst, dgst_len, u1) == NULL) | |
388 | goto err; | |
389 | ||
390 | /* u1 = M * w mod q */ | |
391 | if (!BN_mod_mul(u1, u1, u2, dsa->q, ctx)) | |
392 | goto err; | |
393 | ||
394 | /* u2 = r * w mod q */ | |
395 | if (!BN_mod_mul(u2, sig->r, u2, dsa->q, ctx)) | |
396 | goto err; | |
397 | ||
398 | if (dsa->flags & DSA_FLAG_CACHE_MONT_P) { | |
399 | mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p, | |
400 | CRYPTO_LOCK_DSA, dsa->p, ctx); | |
401 | if (!mont) | |
402 | goto err; | |
403 | } | |
404 | ||
405 | DSA_MOD_EXP(goto err, dsa, t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx, | |
406 | mont); | |
407 | /* BN_copy(&u1,&t1); */ | |
408 | /* let u1 = u1 mod q */ | |
409 | if (!BN_mod(u1, t1, dsa->q, ctx)) | |
410 | goto err; | |
411 | ||
412 | /* | |
413 | * V is now in u1. If the signature is correct, it will be equal to R. | |
414 | */ | |
415 | ret = (BN_ucmp(u1, sig->r) == 0); | |
416 | ||
417 | err: | |
418 | if (ret < 0) | |
419 | DSAerr(DSA_F_DSA_DO_VERIFY, ERR_R_BN_LIB); | |
23a1d5e9 RS |
420 | BN_CTX_free(ctx); |
421 | BN_free(u1); | |
422 | BN_free(u2); | |
423 | BN_free(t1); | |
0f113f3e MC |
424 | return (ret); |
425 | } | |
c0711f7f DSH |
426 | |
427 | static int dsa_init(DSA *dsa) | |
428 | { | |
0f113f3e MC |
429 | dsa->flags |= DSA_FLAG_CACHE_MONT_P; |
430 | return (1); | |
c0711f7f DSH |
431 | } |
432 | ||
433 | static int dsa_finish(DSA *dsa) | |
434 | { | |
23a1d5e9 | 435 | BN_MONT_CTX_free(dsa->method_mont_p); |
0f113f3e | 436 | return (1); |
c0711f7f | 437 | } |