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| 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. | |
| 8 * | |
| 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). | |
| 15 * | |
| 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. | |
| 22 * | |
| 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 :-). | |
| 37 * 4. If you include any Windows specific code (or a derivative thereof) from | |
| 38 * the apps directory (application code) you must include an acknowledgement: | |
| 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
| 40 * | |
| 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. | |
| 52 * | |
| 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> | |
| 62 #include "cryptlib.h" | |
| 63 #include <openssl/bn.h> | |
| 64 #include <openssl/sha.h> | |
| 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); | |
| 70 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
; | |
| 71 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, | |
| 72 DSA *dsa); | |
| 73 static int dsa_init(DSA *dsa); | |
| 74 static int dsa_finish(DSA *dsa); | |
| 75 | |
| 76 static DSA_METHOD openssl_dsa_meth = { | |
| 77 "OpenSSL DSA method", | |
| 78 dsa_do_sign, | |
| 79 dsa_sign_setup, | |
| 80 dsa_do_verify, | |
| 81 NULL, /* dsa_mod_exp, */ | |
| 82 NULL, /* dsa_bn_mod_exp, */ | |
| 83 dsa_init, | |
| 84 dsa_finish, | |
| 85 0, | |
| 86 NULL, | |
| 87 NULL, | |
| 88 NULL | |
| 89 }; | |
| 90 | |
| 91 /* These macro wrappers replace attempts to use the dsa_mod_exp() and | |
| 92 * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of | |
| 93 * having a the macro work as an expression by bundling an "err_instr". So; | |
| 94 * | |
| 95 * if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, | |
| 96 * dsa->method_mont_p)) goto err; | |
| 97 * | |
| 98 * can be replaced by; | |
| 99 * | |
| 100 * DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, | |
| 101 * dsa->method_mont_p); | |
| 102 */ | |
| 103 | |
| 104 #define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \ | |
| 105 do { \ | |
| 106 int _tmp_res53; \ | |
| 107 if((dsa)->meth->dsa_mod_exp) \ | |
| 108 _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \ | |
| 109 (a2), (p2), (m), (ctx), (in_mont)); \ | |
| 110 else \ | |
| 111 _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \ | |
| 112 (m), (ctx), (in_mont)); \ | |
| 113 if(!_tmp_res53) err_instr; \ | |
| 114 } while(0) | |
| 115 #define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \ | |
| 116 do { \ | |
| 117 int _tmp_res53; \ | |
| 118 if((dsa)->meth->bn_mod_exp) \ | |
| 119 _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \ | |
| 120 (m), (ctx), (m_ctx)); \ | |
| 121 else \ | |
| 122 _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx))
; \ | |
| 123 if(!_tmp_res53) err_instr; \ | |
| 124 } while(0) | |
| 125 | |
| 126 const DSA_METHOD *DSA_OpenSSL(void) | |
| 127 { | |
| 128 return &openssl_dsa_meth; | |
| 129 } | |
| 130 | |
| 131 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) | |
| 132 { | |
| 133 BIGNUM *kinv=NULL,*r=NULL,*s=NULL; | |
| 134 BIGNUM m; | |
| 135 BIGNUM xr; | |
| 136 BN_CTX *ctx=NULL; | |
| 137 int reason=ERR_R_BN_LIB; | |
| 138 DSA_SIG *ret=NULL; | |
| 139 int noredo = 0; | |
| 140 | |
| 141 BN_init(&m); | |
| 142 BN_init(&xr); | |
| 143 | |
| 144 if (!dsa->p || !dsa->q || !dsa->g) | |
| 145 { | |
| 146 reason=DSA_R_MISSING_PARAMETERS; | |
| 147 goto err; | |
| 148 } | |
| 149 | |
| 150 s=BN_new(); | |
| 151 if (s == NULL) goto err; | |
| 152 ctx=BN_CTX_new(); | |
| 153 if (ctx == NULL) goto err; | |
| 154 redo: | |
| 155 if ((dsa->kinv == NULL) || (dsa->r == NULL)) | |
| 156 { | |
| 157 if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err; | |
| 158 } | |
| 159 else | |
| 160 { | |
| 161 kinv=dsa->kinv; | |
| 162 dsa->kinv=NULL; | |
| 163 r=dsa->r; | |
| 164 dsa->r=NULL; | |
| 165 noredo = 1; | |
| 166 } | |
| 167 | |
| 168 | |
| 169 if (dlen > BN_num_bytes(dsa->q)) | |
| 170 /* if the digest length is greater than the size of q use the | |
| 171 * BN_num_bits(dsa->q) leftmost bits of the digest, see | |
| 172 * fips 186-3, 4.2 */ | |
| 173 dlen = BN_num_bytes(dsa->q); | |
| 174 if (BN_bin2bn(dgst,dlen,&m) == NULL) | |
| 175 goto err; | |
| 176 | |
| 177 /* Compute s = inv(k) (m + xr) mod q */ | |
| 178 if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */ | |
| 179 if (!BN_add(s, &xr, &m)) goto err; /* s = m + xr */ | |
| 180 if (BN_cmp(s,dsa->q) > 0) | |
| 181 if (!BN_sub(s,s,dsa->q)) goto err; | |
| 182 if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err; | |
| 183 | |
| 184 ret=DSA_SIG_new(); | |
| 185 if (ret == NULL) goto err; | |
| 186 /* Redo if r or s is zero as required by FIPS 186-3: this is | |
| 187 * very unlikely. | |
| 188 */ | |
| 189 if (BN_is_zero(r) || BN_is_zero(s)) | |
| 190 { | |
| 191 if (noredo) | |
| 192 { | |
| 193 reason = DSA_R_NEED_NEW_SETUP_VALUES; | |
| 194 goto err; | |
| 195 } | |
| 196 goto redo; | |
| 197 } | |
| 198 ret->r = r; | |
| 199 ret->s = s; | |
| 200 | |
| 201 err: | |
| 202 if (!ret) | |
| 203 { | |
| 204 DSAerr(DSA_F_DSA_DO_SIGN,reason); | |
| 205 BN_free(r); | |
| 206 BN_free(s); | |
| 207 } | |
| 208 if (ctx != NULL) BN_CTX_free(ctx); | |
| 209 BN_clear_free(&m); | |
| 210 BN_clear_free(&xr); | |
| 211 if (kinv != NULL) /* dsa->kinv is NULL now if we used it */ | |
| 212 BN_clear_free(kinv); | |
| 213 return(ret); | |
| 214 } | |
| 215 | |
| 216 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) | |
| 217 { | |
| 218 BN_CTX *ctx; | |
| 219 BIGNUM k,kq,*K,*kinv=NULL,*r=NULL; | |
| 220 int ret=0; | |
| 221 | |
| 222 if (!dsa->p || !dsa->q || !dsa->g) | |
| 223 { | |
| 224 DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS); | |
| 225 return 0; | |
| 226 } | |
| 227 | |
| 228 BN_init(&k); | |
| 229 BN_init(&kq); | |
| 230 | |
| 231 if (ctx_in == NULL) | |
| 232 { | |
| 233 if ((ctx=BN_CTX_new()) == NULL) goto err; | |
| 234 } | |
| 235 else | |
| 236 ctx=ctx_in; | |
| 237 | |
| 238 if ((r=BN_new()) == NULL) goto err; | |
| 239 | |
| 240 /* Get random k */ | |
| 241 do | |
| 242 if (!BN_rand_range(&k, dsa->q)) goto err; | |
| 243 while (BN_is_zero(&k)); | |
| 244 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) | |
| 245 { | |
| 246 BN_set_flags(&k, BN_FLG_CONSTTIME); | |
| 247 } | |
| 248 | |
| 249 if (dsa->flags & DSA_FLAG_CACHE_MONT_P) | |
| 250 { | |
| 251 if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, | |
| 252 CRYPTO_LOCK_DSA, | |
| 253 dsa->p, ctx)) | |
| 254 goto err; | |
| 255 } | |
| 256 | |
| 257 /* Compute r = (g^k mod p) mod q */ | |
| 258 | |
| 259 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) | |
| 260 { | |
| 261 if (!BN_copy(&kq, &k)) goto err; | |
| 262 | |
| 263 /* We do not want timing information to leak the length of k, | |
| 264 * so we compute g^k using an equivalent exponent of fixed lengt
h. | |
| 265 * | |
| 266 * (This is a kludge that we need because the BN_mod_exp_mont() | |
| 267 * does not let us specify the desired timing behaviour.) */ | |
| 268 | |
| 269 if (!BN_add(&kq, &kq, dsa->q)) goto err; | |
| 270 if (BN_num_bits(&kq) <= BN_num_bits(dsa->q)) | |
| 271 { | |
| 272 if (!BN_add(&kq, &kq, dsa->q)) goto err; | |
| 273 } | |
| 274 | |
| 275 K = &kq; | |
| 276 } | |
| 277 else | |
| 278 { | |
| 279 K = &k; | |
| 280 } | |
| 281 DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx, | |
| 282 dsa->method_mont_p); | |
| 283 if (!BN_mod(r,r,dsa->q,ctx)) goto err; | |
| 284 | |
| 285 /* Compute part of 's = inv(k) (m + xr) mod q' */ | |
| 286 if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err; | |
| 287 | |
| 288 if (*kinvp != NULL) BN_clear_free(*kinvp); | |
| 289 *kinvp=kinv; | |
| 290 kinv=NULL; | |
| 291 if (*rp != NULL) BN_clear_free(*rp); | |
| 292 *rp=r; | |
| 293 ret=1; | |
| 294 err: | |
| 295 if (!ret) | |
| 296 { | |
| 297 DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB); | |
| 298 if (r != NULL) | |
| 299 BN_clear_free(r); | |
| 300 } | |
| 301 if (ctx_in == NULL) BN_CTX_free(ctx); | |
| 302 BN_clear_free(&k); | |
| 303 BN_clear_free(&kq); | |
| 304 return(ret); | |
| 305 } | |
| 306 | |
| 307 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, | |
| 308 DSA *dsa) | |
| 309 { | |
| 310 BN_CTX *ctx; | |
| 311 BIGNUM u1,u2,t1; | |
| 312 BN_MONT_CTX *mont=NULL; | |
| 313 int ret = -1, i; | |
| 314 if (!dsa->p || !dsa->q || !dsa->g) | |
| 315 { | |
| 316 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS); | |
| 317 return -1; | |
| 318 } | |
| 319 | |
| 320 i = BN_num_bits(dsa->q); | |
| 321 /* fips 186-3 allows only different sizes for q */ | |
| 322 if (i != 160 && i != 224 && i != 256) | |
| 323 { | |
| 324 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE); | |
| 325 return -1; | |
| 326 } | |
| 327 | |
| 328 if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) | |
| 329 { | |
| 330 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE); | |
| 331 return -1; | |
| 332 } | |
| 333 BN_init(&u1); | |
| 334 BN_init(&u2); | |
| 335 BN_init(&t1); | |
| 336 | |
| 337 if ((ctx=BN_CTX_new()) == NULL) goto err; | |
| 338 | |
| 339 if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || | |
| 340 BN_ucmp(sig->r, dsa->q) >= 0) | |
| 341 { | |
| 342 ret = 0; | |
| 343 goto err; | |
| 344 } | |
| 345 if (BN_is_zero(sig->s) || BN_is_negative(sig->s) || | |
| 346 BN_ucmp(sig->s, dsa->q) >= 0) | |
| 347 { | |
| 348 ret = 0; | |
| 349 goto err; | |
| 350 } | |
| 351 | |
| 352 /* Calculate W = inv(S) mod Q | |
| 353 * save W in u2 */ | |
| 354 if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err; | |
| 355 | |
| 356 /* save M in u1 */ | |
| 357 if (dgst_len > (i >> 3)) | |
| 358 /* if the digest length is greater than the size of q use the | |
| 359 * BN_num_bits(dsa->q) leftmost bits of the digest, see | |
| 360 * fips 186-3, 4.2 */ | |
| 361 dgst_len = (i >> 3); | |
| 362 if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err; | |
| 363 | |
| 364 /* u1 = M * w mod q */ | |
| 365 if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err; | |
| 366 | |
| 367 /* u2 = r * w mod q */ | |
| 368 if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err; | |
| 369 | |
| 370 | |
| 371 if (dsa->flags & DSA_FLAG_CACHE_MONT_P) | |
| 372 { | |
| 373 mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p, | |
| 374 CRYPTO_LOCK_DSA, dsa->p, ctx); | |
| 375 if (!mont) | |
| 376 goto err; | |
| 377 } | |
| 378 | |
| 379 | |
| 380 DSA_MOD_EXP(goto err, dsa, &t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p,
ctx, mont); | |
| 381 /* BN_copy(&u1,&t1); */ | |
| 382 /* let u1 = u1 mod q */ | |
| 383 if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err; | |
| 384 | |
| 385 /* V is now in u1. If the signature is correct, it will be | |
| 386 * equal to R. */ | |
| 387 ret=(BN_ucmp(&u1, sig->r) == 0); | |
| 388 | |
| 389 err: | |
| 390 /* XXX: surely this is wrong - if ret is 0, it just didn't verify; | |
| 391 there is no error in BN. Test should be ret == -1 (Ben) */ | |
| 392 if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB); | |
| 393 if (ctx != NULL) BN_CTX_free(ctx); | |
| 394 BN_free(&u1); | |
| 395 BN_free(&u2); | |
| 396 BN_free(&t1); | |
| 397 return(ret); | |
| 398 } | |
| 399 | |
| 400 static int dsa_init(DSA *dsa) | |
| 401 { | |
| 402 dsa->flags|=DSA_FLAG_CACHE_MONT_P; | |
| 403 return(1); | |
| 404 } | |
| 405 | |
| 406 static int dsa_finish(DSA *dsa) | |
| 407 { | |
| 408 if(dsa->method_mont_p) | |
| 409 BN_MONT_CTX_free(dsa->method_mont_p); | |
| 410 return(1); | |
| 411 } | |
| 412 | |
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Chromium Code Reviews
Issue 2072073002:
Delete bundled copy of OpenSSL and replace with README. (Closed)
Base URL: https://chromium.googlesource.com/chromium/deps/openssl@master