fips/dsa/fips_dsa_ossl.c

   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 FIPS
  72
  73 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
  74 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp);
  75 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
  76                   DSA *dsa);
  77 static int dsa_init(DSA *dsa);
  78 static int dsa_finish(DSA *dsa);
  79 static 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);
  82 static 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
  86 static DSA_METHOD openssl_dsa_meth = {
  87 "OpenSSL FIPS DSA method",
  88 dsa_do_sign,
  89 dsa_sign_setup,
  90 dsa_do_verify,
  91 dsa_mod_exp,
  92 dsa_bn_mod_exp,
  93 dsa_init,
  94 dsa_finish,
  95 0,
  96 NULL
  97 };
  98
  99 int 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
 114 const DSA_METHOD *DSA_OpenSSL(void)
 115 {
 116         return &openssl_dsa_meth;
 117 }
 118
 119 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int 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         BN_init(&m);
 129         BN_init(&xr);
 130
 131         if (!dsa->p || !dsa->q || !dsa->g)
 132                 {
 133                 reason=DSA_R_MISSING_PARAMETERS;
 134                 goto err;
 135                 }
 136
 137         s=BN_new();
 138         if (s == NULL) goto err;
 139
 140         i=BN_num_bytes(dsa->q); /* should be 20 */
 141         if ((dlen > i) || (dlen > 50))
 142                 {
 143                 reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE;
 144                 goto err;
 145                 }
 146
 147         ctx=BN_CTX_new();
 148         if (ctx == NULL) goto err;
 149
 150         if ((dsa->kinv == NULL) || (dsa->r == NULL))
 151                 {
 152                 if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err;
 153                 }
 154         else
 155                 {
 156                 kinv=dsa->kinv;
 157                 dsa->kinv=NULL;
 158                 r=dsa->r;
 159                 dsa->r=NULL;
 160                 }
 161
 162         if (BN_bin2bn(dgst,dlen,&m) == NULL) goto err;
 163
 164         /* Compute  s = inv(k) (m + xr) mod q */
 165         if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */
 166         if (!BN_add(s, &xr, &m)) goto err;              /* s = m + xr */
 167         if (BN_cmp(s,dsa->q) > 0)
 168                 BN_sub(s,s,dsa->q);
 169         if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err;
 170
 171         ret=DSA_SIG_new();
 172         if (ret == NULL) goto err;
 173         ret->r = r;
 174         ret->s = s;
 175
 176 err:
 177         if (!ret)
 178                 {
 179                 DSAerr(DSA_F_DSA_DO_SIGN,reason);
 180                 BN_free(r);
 181                 BN_free(s);
 182                 }
 183         if (ctx != NULL) BN_CTX_free(ctx);
 184         BN_clear_free(&m);
 185         BN_clear_free(&xr);
 186         if (kinv != NULL) /* dsa->kinv is NULL now if we used it */
 187             BN_clear_free(kinv);
 188         return(ret);
 189         }
 190
 191 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
 192         {
 193         BN_CTX *ctx;
 194         BIGNUM k,*kinv=NULL,*r=NULL;
 195         int ret=0;
 196
 197         if (!dsa->p || !dsa->q || !dsa->g)
 198                 {
 199                 DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS);
 200                 return 0;
 201                 }
 202
 203         BN_init(&k);
 204
 205         if (ctx_in == NULL)
 206                 {
 207                 if ((ctx=BN_CTX_new()) == NULL) goto err;
 208                 }
 209         else
 210                 ctx=ctx_in;
 211
 212         if ((r=BN_new()) == NULL) goto err;
 213         kinv=NULL;
 214
 215         /* Get random k */
 216         do
 217                 if (!BN_rand_range(&k, dsa->q)) goto err;
 218         while (BN_is_zero(&k));
 219
 220         if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
 221                 {
 222                 if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
 223                         if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
 224                                 dsa->p,ctx)) goto err;
 225                 }
 226
 227         /* Compute r = (g^k mod p) mod q */
 228         if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx,
 229                 (BN_MONT_CTX *)dsa->method_mont_p)) goto err;
 230         if (!BN_mod(r,r,dsa->q,ctx)) goto err;
 231
 232         /* Compute  part of 's = inv(k) (m + xr) mod q' */
 233         if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err;
 234
 235         if (*kinvp != NULL) BN_clear_free(*kinvp);
 236         *kinvp=kinv;
 237         kinv=NULL;
 238         if (*rp != NULL) BN_clear_free(*rp);
 239         *rp=r;
 240         ret=1;
 241 err:
 242         if (!ret)
 243                 {
 244                 DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB);
 245                 if (kinv != NULL) BN_clear_free(kinv);
 246                 if (r != NULL) BN_clear_free(r);
 247                 }
 248         if (ctx_in == NULL) BN_CTX_free(ctx);
 249         if (kinv != NULL) BN_clear_free(kinv);
 250         BN_clear_free(&k);
 251         return(ret);
 252         }
 253
 254 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
 255                   DSA *dsa)
 256         {
 257         BN_CTX *ctx;
 258         BIGNUM u1,u2,t1;
 259         BN_MONT_CTX *mont=NULL;
 260         int ret = -1;
 261         if (!dsa->p || !dsa->q || !dsa->g)
 262                 {
 263                 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS);
 264                 return -1;
 265                 }
 266
 267         BN_init(&u1);
 268         BN_init(&u2);
 269         BN_init(&t1);
 270
 271         if ((ctx=BN_CTX_new()) == NULL) goto err;
 272
 273         if (BN_is_zero(sig->r) || sig->r->neg || BN_ucmp(sig->r, dsa->q) >= 0)
 274                 {
 275                 ret = 0;
 276                 goto err;
 277                 }
 278         if (BN_is_zero(sig->s) || sig->s->neg || BN_ucmp(sig->s, dsa->q) >= 0)
 279                 {
 280                 ret = 0;
 281                 goto err;
 282                 }
 283
 284         /* Calculate W = inv(S) mod Q
 285          * save W in u2 */
 286         if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err;
 287
 288         /* save M in u1 */
 289         if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err;
 290
 291         /* u1 = M * w mod q */
 292         if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err;
 293
 294         /* u2 = r * w mod q */
 295         if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err;
 296
 297         if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
 298                 {
 299                 if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
 300                         if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
 301                                 dsa->p,ctx)) goto err;
 302                 }
 303         mont=(BN_MONT_CTX *)dsa->method_mont_p;
 304
 305 #if 0
 306         {
 307         BIGNUM t2;
 308
 309         BN_init(&t2);
 310         /* v = ( g^u1 * y^u2 mod p ) mod q */
 311         /* let t1 = g ^ u1 mod p */
 312         if (!BN_mod_exp_mont(&t1,dsa->g,&u1,dsa->p,ctx,mont)) goto err;
 313         /* let t2 = y ^ u2 mod p */
 314         if (!BN_mod_exp_mont(&t2,dsa->pub_key,&u2,dsa->p,ctx,mont)) goto err;
 315         /* let u1 = t1 * t2 mod p */
 316         if (!BN_mod_mul(&u1,&t1,&t2,dsa->p,ctx)) goto err_bn;
 317         BN_free(&t2);
 318         }
 319         /* let u1 = u1 mod q */
 320         if (!BN_mod(&u1,&u1,dsa->q,ctx)) goto err;
 321 #else
 322         {
 323         if (!dsa->meth->dsa_mod_exp(dsa, &t1,dsa->g,&u1,dsa->pub_key,&u2,
 324                                                 dsa->p,ctx,mont)) goto err;
 325         /* BN_copy(&u1,&t1); */
 326         /* let u1 = u1 mod q */
 327         if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err;
 328         }
 329 #endif
 330         /* V is now in u1.  If the signature is correct, it will be
 331          * equal to R. */
 332         ret=(BN_ucmp(&u1, sig->r) == 0);
 333
 334         err:
 335         if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB);
 336         if (ctx != NULL) BN_CTX_free(ctx);
 337         BN_free(&u1);
 338         BN_free(&u2);
 339         BN_free(&t1);
 340         return(ret);
 341         }
 342
 343 static int dsa_init(DSA *dsa)
 344 {
 345         dsa->flags|=DSA_FLAG_CACHE_MONT_P;
 346         return(1);
 347 }
 348
 349 static int dsa_finish(DSA *dsa)
 350 {
 351         if(dsa->method_mont_p)
 352                 BN_MONT_CTX_free((BN_MONT_CTX *)dsa->method_mont_p);
 353         return(1);
 354 }
 355
 356 static int dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1, BIGNUM *p1,
 357                 BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx,
 358                 BN_MONT_CTX *in_mont)
 359 {
 360         return BN_mod_exp2_mont(rr, a1, p1, a2, p2, m, ctx, in_mont);
 361 }
 362
 363 static int dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
 364                                 const BIGNUM *m, BN_CTX *ctx,
 365                                 BN_MONT_CTX *m_ctx)
 366 {
 367         return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
 368 }
 369
 370 #else /* ndef FIPS */
 371
 372 static void *dummy=&dummy;
 373
 374 #endif /* ndef FIPS */