mirror of
https://github.com/openssl/openssl.git
synced 2024-12-03 05:41:46 +08:00
367ace6870
[skip ci] Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7777)
470 lines
13 KiB
C
470 lines
13 KiB
C
/*
|
|
* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
|
|
*
|
|
* Licensed under the Apache License 2.0 (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 <stdio.h>
|
|
#include <time.h>
|
|
#include "internal/cryptlib.h"
|
|
#include "bn_lcl.h"
|
|
|
|
/*
|
|
* 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"
|
|
|
|
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 == NULL)
|
|
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, *A3, *check; /* taken from ctx */
|
|
BN_MONT_CTX *mont = NULL;
|
|
|
|
/* Take care of the really small primes 2 & 3 */
|
|
if (BN_is_word(a, 2) || BN_is_word(a, 3))
|
|
return 1;
|
|
|
|
/* Check odd and bigger than 1 */
|
|
if (!BN_is_odd(a) || 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 (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 BN_is_word(a, primes[i]);
|
|
}
|
|
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);
|
|
|
|
A1 = BN_CTX_get(ctx);
|
|
A3 = 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) || !BN_sub_word(A1, 1))
|
|
goto err;
|
|
/* compute A3 := a - 3 */
|
|
if (!BN_copy(A3, a) || !BN_sub_word(A3, 3))
|
|
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++) {
|
|
/* 1 < check < a-1 */
|
|
if (!BN_priv_rand_range(check, A3) || !BN_add_word(check, 2))
|
|
goto err;
|
|
|
|
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:
|
|
/* TODO: Not all primes are private */
|
|
if (!BN_priv_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;
|
|
}
|