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 <openssl/bn.h> 63#include <openssl/dsa.h> 64#include <openssl/rand.h> 65#include <openssl/asn1.h> 66#ifndef OPENSSL_NO_ENGINE 67#include <openssl/engine.h> 68#endif 69#include <openssl/fips.h> 70 71#ifdef OPENSSL_FIPS 72 73static DSA_SIG *dsa_do_sign(const unsigned char *dgst, FIPS_DSA_SIZE_T dlen, DSA *dsa); 74static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp); 75static int dsa_do_verify(const unsigned char *dgst, FIPS_DSA_SIZE_T dgst_len, DSA_SIG *sig, 76 DSA *dsa); 77static int dsa_init(DSA *dsa); 78static int dsa_finish(DSA *dsa); 79static int dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, 80 BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, 81 BN_MONT_CTX *in_mont); 82static int dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p, 83 const BIGNUM *m, BN_CTX *ctx, 84 BN_MONT_CTX *m_ctx); 85 86static DSA_METHOD openssl_dsa_meth = { 87"OpenSSL FIPS DSA method", 88dsa_do_sign, 89dsa_sign_setup, 90dsa_do_verify, 91dsa_mod_exp, 92dsa_bn_mod_exp, 93dsa_init, 94dsa_finish, 950, 96NULL 97}; 98 99int FIPS_dsa_check(struct dsa_st *dsa) 100 { 101 if(dsa->meth != &openssl_dsa_meth || dsa->meth->dsa_do_sign != dsa_do_sign 102 || dsa->meth->dsa_sign_setup != dsa_sign_setup 103 || dsa->meth->dsa_mod_exp != dsa_mod_exp 104 || dsa->meth->bn_mod_exp != dsa_bn_mod_exp 105 || dsa->meth->init != dsa_init 106 || dsa->meth->finish != dsa_finish) 107 { 108 FIPSerr(FIPS_F_FIPS_DSA_CHECK,FIPS_R_NON_FIPS_METHOD); 109 return 0; 110 } 111 return 1; 112 } 113 114const DSA_METHOD *DSA_OpenSSL(void) 115{ 116 return &openssl_dsa_meth; 117} 118 119static DSA_SIG *dsa_do_sign(const unsigned char *dgst, FIPS_DSA_SIZE_T dlen, DSA *dsa) 120 { 121 BIGNUM *kinv=NULL,*r=NULL,*s=NULL; 122 BIGNUM m; 123 BIGNUM xr; 124 BN_CTX *ctx=NULL; 125 int i,reason=ERR_R_BN_LIB; 126 DSA_SIG *ret=NULL; 127 128 if(FIPS_selftest_failed()) 129 { 130 FIPSerr(FIPS_F_DSA_DO_SIGN,FIPS_R_FIPS_SELFTEST_FAILED); 131 return NULL; 132 } 133 134 BN_init(&m); 135 BN_init(&xr); 136 137 if (!dsa->p || !dsa->q || !dsa->g) 138 { 139 reason=DSA_R_MISSING_PARAMETERS; 140 goto err; 141 } 142 143 s=BN_new(); 144 if (s == NULL) goto err; 145 146 i=BN_num_bytes(dsa->q); /* should be 20 */ 147 if ((dlen > i) || (dlen > 50)) 148 { 149 reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE; 150 goto err; 151 } 152 153 ctx=BN_CTX_new(); 154 if (ctx == NULL) goto err; 155 156 if ((dsa->kinv == NULL) || (dsa->r == NULL)) 157 { 158 if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err; 159 } 160 else 161 { 162 kinv=dsa->kinv; 163 dsa->kinv=NULL; 164 r=dsa->r; 165 dsa->r=NULL; 166 } 167 168 if (BN_bin2bn(dgst,dlen,&m) == NULL) goto err; 169 170 /* Compute s = inv(k) (m + xr) mod q */ 171 if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */ 172 if (!BN_add(s, &xr, &m)) goto err; /* s = m + xr */ 173 if (BN_cmp(s,dsa->q) > 0) 174 BN_sub(s,s,dsa->q); 175 if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err; 176 177 ret=DSA_SIG_new(); 178 if (ret == NULL) goto err; 179 ret->r = r; 180 ret->s = s; 181 182err: 183 if (!ret) 184 { 185 DSAerr(DSA_F_DSA_DO_SIGN,reason); 186 BN_free(r); 187 BN_free(s); 188 } 189 if (ctx != NULL) BN_CTX_free(ctx); 190 BN_clear_free(&m); 191 BN_clear_free(&xr); 192 if (kinv != NULL) /* dsa->kinv is NULL now if we used it */ 193 BN_clear_free(kinv); 194 return(ret); 195 } 196 197static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) 198 { 199 BN_CTX *ctx; 200 BIGNUM k,*kinv=NULL,*r=NULL; 201 int ret=0; 202 203 if (!dsa->p || !dsa->q || !dsa->g) 204 { 205 DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS); 206 return 0; 207 } 208 209 BN_init(&k); 210 211 if (ctx_in == NULL) 212 { 213 if ((ctx=BN_CTX_new()) == NULL) goto err; 214 } 215 else 216 ctx=ctx_in; 217 218 if ((r=BN_new()) == NULL) goto err; 219 kinv=NULL; 220 221 /* Get random k */ 222 do 223 if (!BN_rand_range(&k, dsa->q)) goto err; 224 while (BN_is_zero(&k)); 225 226 if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P)) 227 { 228 if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) 229 if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p, 230 dsa->p,ctx)) goto err; 231 } 232 233 /* Compute r = (g^k mod p) mod q */ 234 if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, 235 (BN_MONT_CTX *)dsa->method_mont_p)) goto err; 236 if (!BN_mod(r,r,dsa->q,ctx)) goto err; 237 238 /* Compute part of 's = inv(k) (m + xr) mod q' */ 239 if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err; 240 241 if (*kinvp != NULL) BN_clear_free(*kinvp); 242 *kinvp=kinv; 243 kinv=NULL; 244 if (*rp != NULL) BN_clear_free(*rp); 245 *rp=r; 246 ret=1; 247err: 248 if (!ret) 249 { 250 DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB); 251 if (kinv != NULL) BN_clear_free(kinv); 252 if (r != NULL) BN_clear_free(r); 253 } 254 if (ctx_in == NULL) BN_CTX_free(ctx); 255 if (kinv != NULL) BN_clear_free(kinv); 256 BN_clear_free(&k); 257 return(ret); 258 } 259 260static int dsa_do_verify(const unsigned char *dgst, FIPS_DSA_SIZE_T dgst_len, DSA_SIG *sig, 261 DSA *dsa) 262 { 263 BN_CTX *ctx; 264 BIGNUM u1,u2,t1; 265 BN_MONT_CTX *mont=NULL; 266 int ret = -1; 267 268 if (!dsa->p || !dsa->q || !dsa->g) 269 { 270 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS); 271 return -1; 272 } 273 274 if(FIPS_selftest_failed()) 275 { 276 FIPSerr(FIPS_F_DSA_DO_VERIFY,FIPS_R_FIPS_SELFTEST_FAILED); 277 return -1; 278 } 279 280 BN_init(&u1); 281 BN_init(&u2); 282 BN_init(&t1); 283 284 if ((ctx=BN_CTX_new()) == NULL) goto err; 285 286 if (BN_is_zero(sig->r) || sig->r->neg || BN_ucmp(sig->r, dsa->q) >= 0) 287 { 288 ret = 0; 289 goto err; 290 } 291 if (BN_is_zero(sig->s) || sig->s->neg || BN_ucmp(sig->s, dsa->q) >= 0) 292 { 293 ret = 0; 294 goto err; 295 } 296 297 /* Calculate W = inv(S) mod Q 298 * save W in u2 */ 299 if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err; 300 301 /* save M in u1 */ 302 if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err; 303 304 /* u1 = M * w mod q */ 305 if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err; 306 307 /* u2 = r * w mod q */ 308 if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err; 309 310 if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P)) 311 { 312 if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) 313 if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p, 314 dsa->p,ctx)) goto err; 315 } 316 mont=(BN_MONT_CTX *)dsa->method_mont_p; 317 318#if 0 319 { 320 BIGNUM t2; 321 322 BN_init(&t2); 323 /* v = ( g^u1 * y^u2 mod p ) mod q */ 324 /* let t1 = g ^ u1 mod p */ 325 if (!BN_mod_exp_mont(&t1,dsa->g,&u1,dsa->p,ctx,mont)) goto err; 326 /* let t2 = y ^ u2 mod p */ 327 if (!BN_mod_exp_mont(&t2,dsa->pub_key,&u2,dsa->p,ctx,mont)) goto err; 328 /* let u1 = t1 * t2 mod p */ 329 if (!BN_mod_mul(&u1,&t1,&t2,dsa->p,ctx)) goto err_bn; 330 BN_free(&t2); 331 } 332 /* let u1 = u1 mod q */ 333 if (!BN_mod(&u1,&u1,dsa->q,ctx)) goto err; 334#else 335 { 336 if (!dsa->meth->dsa_mod_exp(dsa, &t1,dsa->g,&u1,dsa->pub_key,&u2, 337 dsa->p,ctx,mont)) goto err; 338 /* BN_copy(&u1,&t1); */ 339 /* let u1 = u1 mod q */ 340 if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err; 341 } 342#endif 343 /* V is now in u1. If the signature is correct, it will be 344 * equal to R. */ 345 ret=(BN_ucmp(&u1, sig->r) == 0); 346 347 err: 348 if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB); 349 if (ctx != NULL) BN_CTX_free(ctx); 350 BN_free(&u1); 351 BN_free(&u2); 352 BN_free(&t1); 353 return(ret); 354 } 355 356static int dsa_init(DSA *dsa) 357{ 358 dsa->flags|=DSA_FLAG_CACHE_MONT_P; 359 return(1); 360} 361 362static int dsa_finish(DSA *dsa) 363{ 364 if(dsa->method_mont_p) 365 BN_MONT_CTX_free((BN_MONT_CTX *)dsa->method_mont_p); 366 return(1); 367} 368 369static int dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, 370 BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, 371 BN_MONT_CTX *in_mont) 372{ 373 return BN_mod_exp2_mont(rr, a1, p1, a2, p2, m, ctx, in_mont); 374} 375 376static int dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p, 377 const BIGNUM *m, BN_CTX *ctx, 378 BN_MONT_CTX *m_ctx) 379{ 380 return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx); 381} 382 383#else /* ndef OPENSSL_FIPS */ 384 385static void *dummy=&dummy; 386 387#endif /* ndef OPENSSL_FIPS */ 388