X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_prime.c;h=bbb124fb61281186ab8732ea30a46f5622386eb1;hp=c4fb58ef9ae62ddf4ba3208dcaf31355dde1055d;hb=120a9e1a825bd0407639bedb1e8e15823cf7a545;hpb=31b8d8684441e6cd5138832bb1b2ddb10acd6ba6 diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c index c4fb58ef9a..bbb124fb61 100644 --- a/crypto/bn/bn_prime.c +++ b/crypto/bn/bn_prime.c @@ -1,481 +1,484 @@ -/* crypto/bn/bn_prime.c */ -/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) - * All rights reserved. +/* + * WARNING: do not edit! + * Generated by crypto/bn/bn_prime.pl + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. * - * This package is an SSL implementation written - * by Eric Young (eay@cryptsoft.com). - * The implementation was written so as to conform with Netscapes SSL. - * - * This library is free for commercial and non-commercial use as long as - * the following conditions are aheared to. The following conditions - * apply to all code found in this distribution, be it the RC4, RSA, - * lhash, DES, etc., code; not just the SSL code. The SSL documentation - * included with this distribution is covered by the same copyright terms - * except that the holder is Tim Hudson (tjh@cryptsoft.com). - * - * Copyright remains Eric Young's, and as such any Copyright notices in - * the code are not to be removed. - * If this package is used in a product, Eric Young should be given attribution - * as the author of the parts of the library used. - * This can be in the form of a textual message at program startup or - * in documentation (online or textual) provided with the package. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * "This product includes cryptographic software written by - * Eric Young (eay@cryptsoft.com)" - * The word 'cryptographic' can be left out if the rouines from the library - * being used are not cryptographic related :-). - * 4. If you include any Windows specific code (or a derivative thereof) from - * the apps directory (application code) you must include an acknowledgement: - * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" - * - * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * The licence and distribution terms for any publically available version or - * derivative of this code cannot be changed. i.e. this code cannot simply be - * copied and put under another distribution licence - * [including the GNU Public Licence.] + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html */ #include #include -#include "cryptlib.h" +#include "internal/cryptlib.h" #include "bn_lcl.h" -#include "rand.h" -/* The quick seive algorithm approach to weeding out primes is - * Philip Zimmermann's, as implemented in PGP. I have had a read of - * his comments and implemented my own version. +/* + * The quick sieve algorithm approach to weeding out primes is Philip + * Zimmermann's, as implemented in PGP. I have had a read of his comments + * and implemented my own version. */ #include "bn_prime.h" -#ifndef NOPROTO -static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx,BN_CTX *ctx2, - BN_MONT_CTX *mont); -static int probable_prime(BIGNUM *rnd, int bits); -static int probable_prime_dh(BIGNUM *rnd, int bits, - BIGNUM *add, BIGNUM *rem, BN_CTX *ctx); -static int probable_prime_dh_strong(BIGNUM *rnd, int bits, - BIGNUM *add, BIGNUM *rem, BN_CTX *ctx); -#else -static int witness(); -static int probable_prime(); -static int probable_prime_dh(); -static int probable_prime_dh_strong(); -#endif - -BIGNUM *BN_generate_prime(ret,bits,strong,add,rem,callback,cb_arg) -BIGNUM *ret; -int bits; -int strong; -BIGNUM *add; -BIGNUM *rem; -void (*callback)(P_I_I_P); -char *cb_arg; - { - BIGNUM *rnd=NULL; - BIGNUM t; - int i,j,c1=0; - BN_CTX *ctx; - - ctx=BN_CTX_new(); - if (ctx == NULL) goto err; - if (ret == NULL) - { - if ((rnd=BN_new()) == NULL) goto err; - } - else - rnd=ret; - BN_init(&t); -loop: - /* make a random number and set the top and bottom bits */ - if (add == NULL) - { - if (!probable_prime(rnd,bits)) goto err; - } - else - { - if (strong) - { - if (!probable_prime_dh_strong(rnd,bits,add,rem,ctx)) - goto err; - } - else - { - if (!probable_prime_dh(rnd,bits,add,rem,ctx)) - goto err; - } - } - /* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */ - if (callback != NULL) callback(0,c1++,cb_arg); - - if (!strong) - { - i=BN_is_prime(rnd,BN_prime_checks,callback,ctx,cb_arg); - if (i == -1) goto err; - if (i == 0) goto loop; - } - else - { - /* for a strong prime generation, - * check that (p-1)/2 is prime. - * Since a prime is odd, We just - * need to divide by 2 */ - if (!BN_rshift1(&t,rnd)) goto err; - - for (i=0; ibn[ctx->tos++]); - - /* Setup the montgomery structure */ - if (!BN_MONT_CTX_set(mont,a,ctx2)) goto err; - - for (i=0; itos--; - if ((ctx_passed == NULL) && (ctx != NULL)) - BN_CTX_free(ctx); - if (ctx2 != NULL) - BN_CTX_free(ctx2); - if (mont != NULL) BN_MONT_CTX_free(mont); - - return(ret); - } - -#define RECP_MUL_MOD - -static int witness(a,n,ctx,ctx2,mont) -BIGNUM *a; -BIGNUM *n; -BN_CTX *ctx,*ctx2; -BN_MONT_CTX *mont; - { - int k,i,ret= -1,good; - BIGNUM *d,*dd,*tmp,*d1,*d2,*n1; - BIGNUM *mont_one,*mont_n1,*mont_a; - - d1= &(ctx->bn[ctx->tos]); - d2= &(ctx->bn[ctx->tos+1]); - n1= &(ctx->bn[ctx->tos+2]); - ctx->tos+=3; - - mont_one= &(ctx2->bn[ctx2->tos]); - mont_n1= &(ctx2->bn[ctx2->tos+1]); - mont_a= &(ctx2->bn[ctx2->tos+2]); - ctx2->tos+=3; - - d=d1; - dd=d2; - if (!BN_one(d)) goto err; - if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */ - k=BN_num_bits(n1); - - if (!BN_to_montgomery(mont_one,BN_value_one(),mont,ctx2)) goto err; - if (!BN_to_montgomery(mont_n1,n1,mont,ctx2)) goto err; - if (!BN_to_montgomery(mont_a,a,mont,ctx2)) goto err; - - BN_copy(d,mont_one); - for (i=k-1; i>=0; i--) - { - if ( (BN_cmp(d,mont_one) != 0) && - (BN_cmp(d,mont_n1) != 0)) - good=1; - else - good=0; - - BN_mod_mul_montgomery(dd,d,d,mont,ctx2); - - if (good && (BN_cmp(dd,mont_one) == 0)) - { - ret=1; - goto err; - } - if (BN_is_bit_set(n1,i)) - { - BN_mod_mul_montgomery(d,dd,mont_a,mont,ctx2); - } - else - { - tmp=d; - d=dd; - dd=tmp; - } - } - if (BN_cmp(d,mont_one) == 0) - i=0; - else i=1; - ret=i; -err: - ctx->tos-=3; - ctx2->tos-=3; - return(ret); - } - -static int probable_prime(rnd, bits) -BIGNUM *rnd; -int bits; - { - int i; - MS_STATIC BN_ULONG mods[NUMPRIMES]; - BN_ULONG delta,d; - -again: - if (!BN_rand(rnd,bits,1,1)) return(0); - /* we now have a random number 'rand' to test. */ - for (i=1; ibn[ctx->tos++]); - - if (!BN_rand(rnd,bits,0,1)) goto err; - - /* we need ((rnd-rem) % add) == 0 */ - - if (!BN_mod(t1,rnd,add,ctx)) goto err; - if (!BN_sub(rnd,rnd,t1)) goto err; - if (rem == NULL) - { if (!BN_add_word(rnd,1)) goto err; } - else - { if (!BN_add(rnd,rnd,rem)) goto err; } - - /* we now have a random number 'rand' to test. */ - - loop: for (i=1; itos--; - return(ret); - } - -static int probable_prime_dh_strong(p, bits, padd, rem,ctx) -BIGNUM *p; -int bits; -BIGNUM *padd; -BIGNUM *rem; -BN_CTX *ctx; - { - int i,ret=0; - BIGNUM *t1,*qadd=NULL,*q=NULL; - - bits--; - t1= &(ctx->bn[ctx->tos++]); - q= &(ctx->bn[ctx->tos++]); - qadd= &(ctx->bn[ctx->tos++]); - - if (!BN_rshift1(qadd,padd)) goto err; - - if (!BN_rand(q,bits,0,1)) goto err; - - /* we need ((rnd-rem) % add) == 0 */ - if (!BN_mod(t1,q,qadd,ctx)) goto err; - if (!BN_sub(q,q,t1)) goto err; - if (rem == NULL) - { if (!BN_add_word(q,1)) goto err; } - else - { - if (!BN_rshift1(t1,rem)) goto err; - if (!BN_add(q,q,t1)) goto err; - } - - /* we now have a random number 'rand' to test. */ - if (!BN_lshift1(p,q)) goto err; - if (!BN_add_word(p,1)) goto err; - - loop: for (i=1; itos-=3; - return(ret); - } - -#if 0 -static int witness(a, n,ctx) -BIGNUM *a; -BIGNUM *n; -BN_CTX *ctx; - { - int k,i,nb,ret= -1; - BIGNUM *d,*dd,*tmp; - BIGNUM *d1,*d2,*x,*n1,*inv; - - d1= &(ctx->bn[ctx->tos]); - d2= &(ctx->bn[ctx->tos+1]); - x= &(ctx->bn[ctx->tos+2]); - n1= &(ctx->bn[ctx->tos+3]); - inv=&(ctx->bn[ctx->tos+4]); - ctx->tos+=5; - - d=d1; - dd=d2; - if (!BN_one(d)) goto err; - if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */ - k=BN_num_bits(n1); - - /* i=BN_num_bits(n); */ -#ifdef RECP_MUL_MOD - nb=BN_reciprocal(inv,n,ctx); /**/ - if (nb == -1) goto err; -#endif - - for (i=k-1; i>=0; i--) - { - if (BN_copy(x,d) == NULL) goto err; -#ifndef RECP_MUL_MOD - if (!BN_mod_mul(dd,d,d,n,ctx)) goto err; -#else - if (!BN_mod_mul_reciprocal(dd,d,d,n,inv,nb,ctx)) goto err; -#endif - if ( BN_is_one(dd) && - !BN_is_one(x) && - (BN_cmp(x,n1) != 0)) - { - ret=1; - goto err; - } - if (BN_is_bit_set(n1,i)) - { -#ifndef RECP_MUL_MOD - if (!BN_mod_mul(d,dd,a,n,ctx)) goto err; -#else - if (!BN_mod_mul_reciprocal(d,dd,a,n,inv,nb,ctx)) goto err; -#endif - } - else - { - tmp=d; - d=dd; - dd=tmp; - } - } - if (BN_is_one(d)) - i=0; - else i=1; - ret=i; -err: - ctx->tos-=5; - return(ret); - } -#endif +static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, + const BIGNUM *a1_odd, int k, BN_CTX *ctx, + BN_MONT_CTX *mont); +static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods); +static int probable_prime_dh_safe(BIGNUM *rnd, int bits, + const BIGNUM *add, const BIGNUM *rem, + BN_CTX *ctx); + +int BN_GENCB_call(BN_GENCB *cb, int a, int b) +{ + /* No callback means continue */ + if (!cb) + return 1; + switch (cb->ver) { + case 1: + /* Deprecated-style callbacks */ + if (!cb->cb.cb_1) + return 1; + cb->cb.cb_1(a, b, cb->arg); + return 1; + case 2: + /* New-style callbacks */ + return cb->cb.cb_2(a, b, cb); + default: + break; + } + /* Unrecognised callback type */ + return 0; +} + +int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, + const BIGNUM *add, const BIGNUM *rem, BN_GENCB *cb) +{ + BIGNUM *t; + int found = 0; + int i, j, c1 = 0; + BN_CTX *ctx = NULL; + prime_t *mods = NULL; + int checks = BN_prime_checks_for_size(bits); + + if (bits < 2) { + /* There are no prime numbers this small. */ + BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL); + return 0; + } else if (bits == 2 && safe) { + /* The smallest safe prime (7) is three bits. */ + BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL); + return 0; + } + + mods = OPENSSL_zalloc(sizeof(*mods) * NUMPRIMES); + if (mods == NULL) + goto err; + + ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + BN_CTX_start(ctx); + t = BN_CTX_get(ctx); + if (!t) + goto err; + loop: + /* make a random number and set the top and bottom bits */ + if (add == NULL) { + if (!probable_prime(ret, bits, mods)) + goto err; + } else { + if (safe) { + if (!probable_prime_dh_safe(ret, bits, add, rem, ctx)) + goto err; + } else { + if (!bn_probable_prime_dh(ret, bits, add, rem, ctx)) + goto err; + } + } + + if (!BN_GENCB_call(cb, 0, c1++)) + /* aborted */ + goto err; + + if (!safe) { + i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb); + if (i == -1) + goto err; + if (i == 0) + goto loop; + } else { + /* + * for "safe prime" generation, check that (p-1)/2 is prime. Since a + * prime is odd, We just need to divide by 2 + */ + if (!BN_rshift1(t, ret)) + goto err; + + for (i = 0; i < checks; i++) { + j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, cb); + if (j == -1) + goto err; + if (j == 0) + goto loop; + + j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, cb); + if (j == -1) + goto err; + if (j == 0) + goto loop; + + if (!BN_GENCB_call(cb, 2, c1 - 1)) + goto err; + /* We have a safe prime test pass */ + } + } + /* we have a prime :-) */ + found = 1; + err: + OPENSSL_free(mods); + if (ctx != NULL) + BN_CTX_end(ctx); + BN_CTX_free(ctx); + bn_check_top(ret); + return found; +} + +int BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, + BN_GENCB *cb) +{ + return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb); +} + +int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed, + int do_trial_division, BN_GENCB *cb) +{ + int i, j, ret = -1; + int k; + BN_CTX *ctx = NULL; + BIGNUM *A1, *A1_odd, *check; /* taken from ctx */ + BN_MONT_CTX *mont = NULL; + const BIGNUM *A = NULL; + + if (BN_cmp(a, BN_value_one()) <= 0) + return 0; + + if (checks == BN_prime_checks) + checks = BN_prime_checks_for_size(BN_num_bits(a)); + + /* first look for small factors */ + if (!BN_is_odd(a)) + /* a is even => a is prime if and only if a == 2 */ + return BN_is_word(a, 2); + if (do_trial_division) { + for (i = 1; i < NUMPRIMES; i++) { + BN_ULONG mod = BN_mod_word(a, primes[i]); + if (mod == (BN_ULONG)-1) + goto err; + if (mod == 0) + return 0; + } + if (!BN_GENCB_call(cb, 1, -1)) + goto err; + } + + if (ctx_passed != NULL) + ctx = ctx_passed; + else if ((ctx = BN_CTX_new()) == NULL) + goto err; + BN_CTX_start(ctx); + + /* A := abs(a) */ + if (a->neg) { + BIGNUM *t; + if ((t = BN_CTX_get(ctx)) == NULL) + goto err; + if (BN_copy(t, a) == NULL) + goto err; + t->neg = 0; + A = t; + } else + A = a; + A1 = BN_CTX_get(ctx); + A1_odd = BN_CTX_get(ctx); + check = BN_CTX_get(ctx); + if (check == NULL) + goto err; + + /* compute A1 := A - 1 */ + if (!BN_copy(A1, A)) + goto err; + if (!BN_sub_word(A1, 1)) + goto err; + if (BN_is_zero(A1)) { + ret = 0; + goto err; + } + + /* write A1 as A1_odd * 2^k */ + k = 1; + while (!BN_is_bit_set(A1, k)) + k++; + if (!BN_rshift(A1_odd, A1, k)) + goto err; + + /* Montgomery setup for computations mod A */ + mont = BN_MONT_CTX_new(); + if (mont == NULL) + goto err; + if (!BN_MONT_CTX_set(mont, A, ctx)) + goto err; + + for (i = 0; i < checks; i++) { + if (!BN_pseudo_rand_range(check, A1)) + goto err; + if (!BN_add_word(check, 1)) + goto err; + /* now 1 <= check < A */ + + j = witness(check, A, A1, A1_odd, k, ctx, mont); + if (j == -1) + goto err; + if (j) { + ret = 0; + goto err; + } + if (!BN_GENCB_call(cb, 1, i)) + goto err; + } + ret = 1; + err: + if (ctx != NULL) { + BN_CTX_end(ctx); + if (ctx_passed == NULL) + BN_CTX_free(ctx); + } + BN_MONT_CTX_free(mont); + + return (ret); +} + +static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1, + const BIGNUM *a1_odd, int k, BN_CTX *ctx, + BN_MONT_CTX *mont) +{ + if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */ + return -1; + if (BN_is_one(w)) + return 0; /* probably prime */ + if (BN_cmp(w, a1) == 0) + return 0; /* w == -1 (mod a), 'a' is probably prime */ + while (--k) { + if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */ + return -1; + if (BN_is_one(w)) + return 1; /* 'a' is composite, otherwise a previous 'w' + * would have been == -1 (mod 'a') */ + if (BN_cmp(w, a1) == 0) + return 0; /* w == -1 (mod a), 'a' is probably prime */ + } + /* + * If we get here, 'w' is the (a-1)/2-th power of the original 'w', and + * it is neither -1 nor +1 -- so 'a' cannot be prime + */ + bn_check_top(w); + return 1; +} + +static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods) +{ + int i; + BN_ULONG delta; + BN_ULONG maxdelta = BN_MASK2 - primes[NUMPRIMES - 1]; + char is_single_word = bits <= BN_BITS2; + + again: + if (!BN_rand(rnd, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ODD)) + return (0); + /* we now have a random number 'rnd' to test. */ + for (i = 1; i < NUMPRIMES; i++) { + BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]); + if (mod == (BN_ULONG)-1) + return 0; + mods[i] = (prime_t) mod; + } + /* + * If bits is so small that it fits into a single word then we + * additionally don't want to exceed that many bits. + */ + if (is_single_word) { + BN_ULONG size_limit; + + if (bits == BN_BITS2) { + /* + * Shifting by this much has undefined behaviour so we do it a + * different way + */ + size_limit = ~((BN_ULONG)0) - BN_get_word(rnd); + } else { + size_limit = (((BN_ULONG)1) << bits) - BN_get_word(rnd) - 1; + } + if (size_limit < maxdelta) + maxdelta = size_limit; + } + delta = 0; + loop: + if (is_single_word) { + BN_ULONG rnd_word = BN_get_word(rnd); + + /*- + * In the case that the candidate prime is a single word then + * we check that: + * 1) It's greater than primes[i] because we shouldn't reject + * 3 as being a prime number because it's a multiple of + * three. + * 2) That it's not a multiple of a known prime. We don't + * check that rnd-1 is also coprime to all the known + * primes because there aren't many small primes where + * that's true. + */ + for (i = 1; i < NUMPRIMES && primes[i] < rnd_word; i++) { + if ((mods[i] + delta) % primes[i] == 0) { + delta += 2; + if (delta > maxdelta) + goto again; + goto loop; + } + } + } else { + for (i = 1; i < NUMPRIMES; i++) { + /* + * check that rnd is not a prime and also that gcd(rnd-1,primes) + * == 1 (except for 2) + */ + if (((mods[i] + delta) % primes[i]) <= 1) { + delta += 2; + if (delta > maxdelta) + goto again; + goto loop; + } + } + } + if (!BN_add_word(rnd, delta)) + return (0); + if (BN_num_bits(rnd) != bits) + goto again; + bn_check_top(rnd); + return (1); +} + +int bn_probable_prime_dh(BIGNUM *rnd, int bits, + const BIGNUM *add, const BIGNUM *rem, BN_CTX *ctx) +{ + int i, ret = 0; + BIGNUM *t1; + + BN_CTX_start(ctx); + if ((t1 = BN_CTX_get(ctx)) == NULL) + goto err; + + if (!BN_rand(rnd, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD)) + goto err; + + /* we need ((rnd-rem) % add) == 0 */ + + if (!BN_mod(t1, rnd, add, ctx)) + goto err; + if (!BN_sub(rnd, rnd, t1)) + goto err; + if (rem == NULL) { + if (!BN_add_word(rnd, 1)) + goto err; + } else { + if (!BN_add(rnd, rnd, rem)) + goto err; + } + + /* we now have a random number 'rand' to test. */ + + loop: + for (i = 1; i < NUMPRIMES; i++) { + /* check that rnd is a prime */ + BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]); + if (mod == (BN_ULONG)-1) + goto err; + if (mod <= 1) { + if (!BN_add(rnd, rnd, add)) + goto err; + goto loop; + } + } + ret = 1; + + err: + BN_CTX_end(ctx); + bn_check_top(rnd); + return (ret); +} + +static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd, + const BIGNUM *rem, BN_CTX *ctx) +{ + int i, ret = 0; + BIGNUM *t1, *qadd, *q; + + bits--; + BN_CTX_start(ctx); + t1 = BN_CTX_get(ctx); + q = BN_CTX_get(ctx); + qadd = BN_CTX_get(ctx); + if (qadd == NULL) + goto err; + + if (!BN_rshift1(qadd, padd)) + goto err; + + if (!BN_rand(q, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD)) + goto err; + + /* we need ((rnd-rem) % add) == 0 */ + if (!BN_mod(t1, q, qadd, ctx)) + goto err; + if (!BN_sub(q, q, t1)) + goto err; + if (rem == NULL) { + if (!BN_add_word(q, 1)) + goto err; + } else { + if (!BN_rshift1(t1, rem)) + goto err; + if (!BN_add(q, q, t1)) + goto err; + } + + /* we now have a random number 'rand' to test. */ + if (!BN_lshift1(p, q)) + goto err; + if (!BN_add_word(p, 1)) + goto err; + + loop: + for (i = 1; i < NUMPRIMES; i++) { + /* check that p and q are prime */ + /* + * check that for p and q gcd(p-1,primes) == 1 (except for 2) + */ + BN_ULONG pmod = BN_mod_word(p, (BN_ULONG)primes[i]); + BN_ULONG qmod = BN_mod_word(q, (BN_ULONG)primes[i]); + if (pmod == (BN_ULONG)-1 || qmod == (BN_ULONG)-1) + goto err; + if (pmod == 0 || qmod == 0) { + if (!BN_add(p, p, padd)) + goto err; + if (!BN_add(q, q, qadd)) + goto err; + goto loop; + } + } + ret = 1; + + err: + BN_CTX_end(ctx); + bn_check_top(p); + return (ret); +}