+
+#ifdef OPENSSL_FIPS
+#undef fips_dsa_builtin_paramgen2
+extern int fips_dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
+ const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
+ int idx, unsigned char *seed_out,
+ int *counter_ret, unsigned long *h_ret, BN_GENCB *cb);
+#endif
+
+/* This is a parameter generation algorithm for the DSA2 algorithm as
+ * described in FIPS 186-3.
+ */
+
+int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
+ const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
+ int idx, unsigned char *seed_out,
+ int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
+ {
+ int ok=-1;
+ unsigned char *seed = NULL, *seed_tmp = NULL;
+ unsigned char md[EVP_MAX_MD_SIZE];
+ int mdsize;
+ BIGNUM *r0,*W,*X,*c,*test;
+ BIGNUM *g=NULL,*q=NULL,*p=NULL;
+ BN_MONT_CTX *mont=NULL;
+ int i, k, n=0, m=0, qsize = N >> 3;
+ int counter=0;
+ int r=0;
+ BN_CTX *ctx=NULL;
+ EVP_MD_CTX mctx;
+ unsigned int h=2;
+
+#ifdef OPENSSL_FIPS
+
+ if (FIPS_mode())
+ return fips_dsa_builtin_paramgen2(ret, L, N, evpmd,
+ seed_in, seed_len, idx,
+ seed_out, counter_ret,
+ h_ret, cb);
+#endif
+
+ EVP_MD_CTX_init(&mctx);
+
+ if (evpmd == NULL)
+ {
+ if (N == 160)
+ evpmd = EVP_sha1();
+ else if (N == 224)
+ evpmd = EVP_sha224();
+ else
+ evpmd = EVP_sha256();
+ }
+
+ mdsize = EVP_MD_size(evpmd);
+ /* If unverificable g generation only don't need seed */
+ if (!ret->p || !ret->q || idx >= 0)
+ {
+ if (seed_len == 0)
+ seed_len = mdsize;
+
+ seed = OPENSSL_malloc(seed_len);
+
+ if (seed_out)
+ seed_tmp = seed_out;
+ else
+ seed_tmp = OPENSSL_malloc(seed_len);
+
+ if (!seed || !seed_tmp)
+ goto err;
+
+ if (seed_in)
+ memcpy(seed, seed_in, seed_len);
+
+ }
+
+ if ((ctx=BN_CTX_new()) == NULL)
+ goto err;
+
+ if ((mont=BN_MONT_CTX_new()) == NULL)
+ goto err;
+
+ BN_CTX_start(ctx);
+ r0 = BN_CTX_get(ctx);
+ g = BN_CTX_get(ctx);
+ W = BN_CTX_get(ctx);
+ X = BN_CTX_get(ctx);
+ c = BN_CTX_get(ctx);
+ test = BN_CTX_get(ctx);
+
+ /* if p, q already supplied generate g only */
+ if (ret->p && ret->q)
+ {
+ p = ret->p;
+ q = ret->q;
+ if (idx >= 0)
+ memcpy(seed_tmp, seed, seed_len);
+ goto g_only;
+ }
+ else
+ {
+ p = BN_CTX_get(ctx);
+ q = BN_CTX_get(ctx);
+ }
+
+ if (!BN_lshift(test,BN_value_one(),L-1))
+ goto err;
+ for (;;)
+ {
+ for (;;) /* find q */
+ {
+ unsigned char *pmd;
+ /* step 1 */
+ if(!BN_GENCB_call(cb, 0, m++))
+ goto err;
+
+ if (!seed_in)
+ {
+ if (RAND_pseudo_bytes(seed, seed_len) < 0)
+ goto err;
+ }
+ /* step 2 */
+ if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
+ goto err;
+ /* Take least significant bits of md */
+ if (mdsize > qsize)
+ pmd = md + mdsize - qsize;
+ else
+ pmd = md;
+
+ if (mdsize < qsize)
+ memset(md + mdsize, 0, qsize - mdsize);
+
+ /* step 3 */
+ pmd[0] |= 0x80;
+ pmd[qsize-1] |= 0x01;
+ if (!BN_bin2bn(pmd, qsize, q))
+ goto err;
+
+ /* step 4 */
+ r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
+ seed_in ? 1 : 0, cb);
+ if (r > 0)
+ break;
+ if (r != 0)
+ goto err;
+ /* Provided seed didn't produce a prime: error */
+ if (seed_in)
+ {
+ ok = 0;
+ DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
+ goto err;
+ }
+
+ /* do a callback call */
+ /* step 5 */
+ }
+ /* Copy seed to seed_out before we mess with it */
+ if (seed_out)
+ memcpy(seed_out, seed, seed_len);
+
+ if(!BN_GENCB_call(cb, 2, 0)) goto err;
+ if(!BN_GENCB_call(cb, 3, 0)) goto err;
+
+ /* step 6 */
+ counter=0;
+ /* "offset = 1" */
+
+ n=(L-1)/(mdsize << 3);
+
+ for (;;)
+ {
+ if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
+ goto err;
+
+ /* step 7 */
+ BN_zero(W);
+ /* now 'buf' contains "SEED + offset - 1" */
+ for (k=0; k<=n; k++)
+ {
+ /* obtain "SEED + offset + k" by incrementing: */
+ for (i = seed_len-1; i >= 0; i--)
+ {
+ seed[i]++;
+ if (seed[i] != 0)
+ break;
+ }
+
+ if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
+ NULL))
+ goto err;
+
+ /* step 8 */
+ if (!BN_bin2bn(md, mdsize, r0))
+ goto err;
+ if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
+ if (!BN_add(W,W,r0)) goto err;
+ }
+
+ /* more of step 8 */
+ if (!BN_mask_bits(W,L-1)) goto err;
+ if (!BN_copy(X,W)) goto err;
+ if (!BN_add(X,X,test)) goto err;
+
+ /* step 9 */
+ if (!BN_lshift1(r0,q)) goto err;
+ if (!BN_mod(c,X,r0,ctx)) goto err;
+ if (!BN_sub(r0,c,BN_value_one())) goto err;
+ if (!BN_sub(p,X,r0)) goto err;
+
+ /* step 10 */
+ if (BN_cmp(p,test) >= 0)
+ {
+ /* step 11 */
+ r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
+ ctx, 1, cb);
+ if (r > 0)
+ goto end; /* found it */
+ if (r != 0)
+ goto err;
+ }
+
+ /* step 13 */
+ counter++;
+ /* "offset = offset + n + 1" */
+
+ /* step 14 */
+ if (counter >= (int)(4 * L)) break;
+ }
+ if (seed_in)
+ {
+ ok = 0;
+ DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS);
+ goto err;
+ }
+ }
+end:
+ if(!BN_GENCB_call(cb, 2, 1))
+ goto err;
+
+ g_only:
+
+ /* We now need to generate g */
+ /* Set r0=(p-1)/q */
+ if (!BN_sub(test,p,BN_value_one())) goto err;
+ if (!BN_div(r0,NULL,test,q,ctx)) goto err;
+
+ if (idx < 0)
+ {
+ if (!BN_set_word(test,h))
+ goto err;
+ }
+ else
+ h = 1;
+ if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
+
+ for (;;)
+ {
+ static const unsigned char ggen[4] = {0x67,0x67,0x65,0x6e};
+ if (idx >= 0)
+ {
+ md[0] = idx & 0xff;
+ md[1] = (h >> 8) & 0xff;
+ md[2] = h & 0xff;
+ if (!EVP_DigestInit_ex(&mctx, evpmd, NULL))
+ goto err;
+ if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len))
+ goto err;
+ if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen)))
+ goto err;
+ if (!EVP_DigestUpdate(&mctx, md, 3))
+ goto err;
+ if (!EVP_DigestFinal_ex(&mctx, md, NULL))
+ goto err;
+ if (!BN_bin2bn(md, mdsize, test))
+ goto err;
+ }
+ /* g=test^r0%p */
+ if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
+ if (!BN_is_one(g)) break;
+ if (idx < 0 && !BN_add(test,test,BN_value_one())) goto err;
+ h++;
+ if ( idx >= 0 && h > 0xffff)
+ goto err;
+ }
+
+ if(!BN_GENCB_call(cb, 3, 1))
+ goto err;
+
+ ok=1;
+err:
+ if (ok == 1)
+ {
+ if (p != ret->p)
+ {
+ if(ret->p) BN_free(ret->p);
+ ret->p=BN_dup(p);
+ }
+ if (q != ret->q)
+ {
+ if(ret->q) BN_free(ret->q);
+ ret->q=BN_dup(q);
+ }
+ if(ret->g) BN_free(ret->g);
+ ret->g=BN_dup(g);
+ if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
+ {
+ ok=-1;
+ goto err;
+ }
+ if (counter_ret != NULL) *counter_ret=counter;
+ if (h_ret != NULL) *h_ret=h;
+ }
+ if (seed)
+ OPENSSL_free(seed);
+ if (seed_out != seed_tmp)
+ OPENSSL_free(seed_tmp);
+ if(ctx)
+ {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+ if (mont != NULL) BN_MONT_CTX_free(mont);
+ EVP_MD_CTX_cleanup(&mctx);
+ return ok;
+ }
+
+int dsa_paramgen_check_g(DSA *dsa)
+ {
+ BN_CTX *ctx;
+ BIGNUM *tmp;
+ BN_MONT_CTX *mont = NULL;
+ int rv = -1;
+ ctx = BN_CTX_new();
+ if (!ctx)
+ return -1;
+ BN_CTX_start(ctx);
+ if (BN_cmp(dsa->g, BN_value_one()) <= 0)
+ return 0;
+ if (BN_cmp(dsa->g, dsa->p) >= 0)
+ return 0;
+ tmp = BN_CTX_get(ctx);
+ if (!tmp)
+ goto err;
+ if ((mont=BN_MONT_CTX_new()) == NULL)
+ goto err;
+ if (!BN_MONT_CTX_set(mont,dsa->p,ctx))
+ goto err;
+ /* Work out g^q mod p */
+ if (!BN_mod_exp_mont(tmp,dsa->g,dsa->q, dsa->p, ctx, mont))
+ goto err;
+ if (!BN_cmp(tmp, BN_value_one()))
+ rv = 1;
+ else
+ rv = 0;
+ err:
+ BN_CTX_end(ctx);
+ if (mont)
+ BN_MONT_CTX_free(mont);
+ BN_CTX_free(ctx);
+ return rv;
+
+ }
projects / openssl.git / commitdiff