openssl/crypto/dh/dh_gen.c
Shane Lontis 4f2271d58a Add ACVP fips module tests
For FIPS validation purposes - Automated Cryptographic Validation Protocol (ACVP) tests need to be
performed. (See https://github.com/usnistgov/ACVP). These tests are very similiar to the old CAVS tests.

This PR uses a hardwired subset of these test vectors to perform similiar operations,
to show the usage and prove that the API's are able to perform the required operations.
It may also help with communication with the lab (i.e- The lab could add a test here to show
a unworking use case - which we can then address).

The EVP layer performs these tests instead of calling lower level API's
as was done in the old FOM.
Some of these tests require access to internals that are not normally allowed/required.

The config option 'acvp_tests' (enabled by default) has been added so that this
access may be removed.

The mechanism has been implemented as additional OSSL_PARAM values that can be set and get.
A callback mechanism did not seem to add any additional benefit.
These params will not be added to the gettables lists.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11572)
2020-06-17 11:33:16 +10:00

235 lines
6.6 KiB
C

/*
* Copyright 1995-2020 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
*/
/*
* NB: These functions have been upgraded - the previous prototypes are in
* dh_depr.c as wrappers to these ones. - Geoff
*/
/*
* DH low level APIs are deprecated for public use, but still ok for
* internal use.
*
* NOTE: When generating keys for key-agreement schemes - FIPS 140-2 IG 9.9
* states that no additional pairwise tests are required (apart from the tests
* specified in SP800-56A) when generating keys. Hence DH pairwise tests are
* omitted here.
*/
#include "internal/deprecated.h"
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/sha.h>
#include "crypto/dh.h"
#include "dh_local.h"
#ifndef FIPS_MODULE
static int dh_builtin_genparams(DH *ret, int prime_len, int generator,
BN_GENCB *cb);
#endif /* FIPS_MODULE */
int dh_generate_ffc_parameters(DH *dh, int type, int pbits, int qbits,
BN_GENCB *cb)
{
int ret, res;
#ifndef FIPS_MODULE
if (type == DH_PARAMGEN_TYPE_FIPS_186_2)
ret = ffc_params_FIPS186_2_generate(dh->libctx, &dh->params,
FFC_PARAM_TYPE_DH,
pbits, qbits, &res, cb);
else
#endif
ret = ffc_params_FIPS186_4_generate(dh->libctx, &dh->params,
FFC_PARAM_TYPE_DH,
pbits, qbits, &res, cb);
if (ret > 0)
dh->dirty_cnt++;
return ret;
}
int dh_get_named_group_uid_from_size(int pbits)
{
/*
* Just choose an approved safe prime group.
* The alternative to this is to generate FIPS186-4 domain parameters i.e.
* return dh_generate_ffc_parameters(ret, prime_len, 0, NULL, cb);
* As the FIPS186-4 generated params are for backwards compatibility,
* the safe prime group should be used as the default.
*/
int nid;
switch (pbits) {
case 2048:
nid = NID_ffdhe2048;
break;
case 3072:
nid = NID_ffdhe3072;
break;
case 4096:
nid = NID_ffdhe4096;
break;
case 6144:
nid = NID_ffdhe6144;
break;
case 8192:
nid = NID_ffdhe8192;
break;
/* unsupported prime_len */
default:
return NID_undef;
}
return nid;
}
#ifdef FIPS_MODULE
static int dh_gen_named_group(OPENSSL_CTX *libctx, DH *ret, int prime_len)
{
DH *dh;
int ok = 0;
int nid = dh_get_named_group_uid_from_size(prime_len);
if (nid == NID_undef)
return 0;
dh = dh_new_by_nid_with_libctx(libctx, nid);
if (dh != NULL
&& ffc_params_copy(&ret->params, &dh->params)) {
ok = 1;
ret->dirty_cnt++;
}
DH_free(dh);
return ok;
}
#endif /* FIPS_MODULE */
int DH_generate_parameters_ex(DH *ret, int prime_len, int generator,
BN_GENCB *cb)
{
#ifdef FIPS_MODULE
if (generator != 2)
return 0;
return dh_gen_named_group(ret->libctx, ret, prime_len);
#else
if (ret->meth->generate_params)
return ret->meth->generate_params(ret, prime_len, generator, cb);
return dh_builtin_genparams(ret, prime_len, generator, cb);
#endif /* FIPS_MODULE */
}
#ifndef FIPS_MODULE
/*-
* We generate DH parameters as follows
* find a prime p which is prime_len bits long,
* where q=(p-1)/2 is also prime.
* In the following we assume that g is not 0, 1 or p-1, since it
* would generate only trivial subgroups.
* For this case, g is a generator of the order-q subgroup if
* g^q mod p == 1.
* Or in terms of the Legendre symbol: (g/p) == 1.
*
* Having said all that,
* there is another special case method for the generators 2, 3 and 5.
* Using the quadratic reciprocity law it is possible to solve
* (g/p) == 1 for the special values 2, 3, 5:
* (2/p) == 1 if p mod 8 == 1 or 7.
* (3/p) == 1 if p mod 12 == 1 or 11.
* (5/p) == 1 if p mod 5 == 1 or 4.
* See for instance: https://en.wikipedia.org/wiki/Legendre_symbol
*
* Since all safe primes > 7 must satisfy p mod 12 == 11
* and all safe primes > 11 must satisfy p mod 5 != 1
* we can further improve the condition for g = 2, 3 and 5:
* for 2, p mod 24 == 23
* for 3, p mod 12 == 11
* for 5, p mod 60 == 59
*/
static int dh_builtin_genparams(DH *ret, int prime_len, int generator,
BN_GENCB *cb)
{
BIGNUM *t1, *t2;
int g, ok = -1;
BN_CTX *ctx = NULL;
if (prime_len > OPENSSL_DH_MAX_MODULUS_BITS) {
DHerr(DH_F_DH_BUILTIN_GENPARAMS, DH_R_MODULUS_TOO_LARGE);
return 0;
}
if (prime_len < DH_MIN_MODULUS_BITS) {
DHerr(DH_F_DH_BUILTIN_GENPARAMS, DH_R_MODULUS_TOO_SMALL);
return 0;
}
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
if (t2 == NULL)
goto err;
/* Make sure 'ret' has the necessary elements */
if (ret->params.p == NULL && ((ret->params.p = BN_new()) == NULL))
goto err;
if (ret->params.g == NULL && ((ret->params.g = BN_new()) == NULL))
goto err;
if (generator <= 1) {
DHerr(DH_F_DH_BUILTIN_GENPARAMS, DH_R_BAD_GENERATOR);
goto err;
}
if (generator == DH_GENERATOR_2) {
if (!BN_set_word(t1, 24))
goto err;
if (!BN_set_word(t2, 23))
goto err;
g = 2;
} else if (generator == DH_GENERATOR_5) {
if (!BN_set_word(t1, 60))
goto err;
if (!BN_set_word(t2, 59))
goto err;
g = 5;
} else {
/*
* in the general case, don't worry if 'generator' is a generator or
* not: since we are using safe primes, it will generate either an
* order-q or an order-2q group, which both is OK
*/
if (!BN_set_word(t1, 12))
goto err;
if (!BN_set_word(t2, 11))
goto err;
g = generator;
}
if (!BN_generate_prime_ex(ret->params.p, prime_len, 1, t1, t2, cb))
goto err;
if (!BN_GENCB_call(cb, 3, 0))
goto err;
if (!BN_set_word(ret->params.g, g))
goto err;
ret->dirty_cnt++;
ok = 1;
err:
if (ok == -1) {
DHerr(DH_F_DH_BUILTIN_GENPARAMS, ERR_R_BN_LIB);
ok = 0;
}
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
#endif /* FIPS_MODULE */