/*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
*
- * Licensed under the OpenSSL license (the "License"). You may not use
+ * 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
* 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 "dh_locl.h"
+#include <openssl/sha.h>
+#include "crypto/dh.h"
+#include "crypto/security_bits.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 ossl_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 = ossl_ffc_params_FIPS186_2_generate(dh->libctx, &dh->params,
+ FFC_PARAM_TYPE_DH,
+ pbits, qbits, &res, cb);
+ else
+#endif
+ ret = ossl_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 ossl_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(OSSL_LIB_CTX *libctx, DH *ret, int prime_len)
+{
+ DH *dh;
+ int ok = 0;
+ int nid = ossl_dh_get_named_group_uid_from_size(prime_len);
+
+ if (nid == NID_undef)
+ return 0;
+
+ dh = ossl_dh_new_by_nid_ex(libctx, nid);
+ if (dh != NULL
+ && ossl_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 q which is prime_len/2 bits long.
- * p=(2*q)+1 or (p-1)/2 = q
- * For this case, g is a generator if
- * g^((p-1)/q) mod p != 1 for values of q which are the factors of p-1.
- * Since the factors of p-1 are q and 2, we just need to check
- * g^2 mod p != 1 and g^q mod p != 1.
+ * 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.
- * for 2, p mod 24 == 11
- * for 3, p mod 12 == 5 <<<<< does not work for safe primes.
- * for 5, p mod 10 == 3 or 7
+ * 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
*
- * Thanks to Phil Karn <karn@qualcomm.com> for the pointers about the
- * special generators and for answering some of my questions.
- *
- * I've implemented the second simple method :-).
- * Since DH should be using a safe prime (both p and q are prime),
- * this generator function can take a very very long time to run.
- */
-/*
- * Actually there is no reason to insist that 'generator' be a generator.
- * It's just as OK (and in some sense better) to use a generator of the
- * order-q subgroup.
+ * 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)
int g, ok = -1;
BN_CTX *ctx = NULL;
- ctx = BN_CTX_new();
+ if (prime_len > OPENSSL_DH_MAX_MODULUS_BITS) {
+ ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
+ return 0;
+ }
+
+ if (prime_len < DH_MIN_MODULUS_BITS) {
+ ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
+ return 0;
+ }
+
+ ctx = BN_CTX_new_ex(ret->libctx);
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
- if (t1 == NULL || t2 == NULL)
+ if (t2 == NULL)
goto err;
/* Make sure 'ret' has the necessary elements */
- if (!ret->p && ((ret->p = BN_new()) == NULL))
+ if (ret->params.p == NULL && ((ret->params.p = BN_new()) == NULL))
goto err;
- if (!ret->g && ((ret->g = BN_new()) == NULL))
+ 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);
+ ERR_raise(ERR_LIB_DH, DH_R_BAD_GENERATOR);
goto err;
}
if (generator == DH_GENERATOR_2) {
if (!BN_set_word(t1, 24))
goto err;
- if (!BN_set_word(t2, 11))
+ if (!BN_set_word(t2, 23))
goto err;
g = 2;
} else if (generator == DH_GENERATOR_5) {
- if (!BN_set_word(t1, 10))
+ if (!BN_set_word(t1, 60))
goto err;
- if (!BN_set_word(t2, 3))
+ if (!BN_set_word(t2, 59))
goto err;
- /*
- * BN_set_word(t3,7); just have to miss out on these ones :-(
- */
g = 5;
} else {
/*
* 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, 2))
+ if (!BN_set_word(t1, 12))
goto err;
- if (!BN_set_word(t2, 1))
+ if (!BN_set_word(t2, 11))
goto err;
g = generator;
}
- if (!BN_generate_prime_ex(ret->p, prime_len, 1, t1, t2, cb))
+ if (!BN_generate_prime_ex2(ret->params.p, prime_len, 1, t1, t2, cb, ctx))
goto err;
if (!BN_GENCB_call(cb, 3, 0))
goto err;
- if (!BN_set_word(ret->g, g))
+ if (!BN_set_word(ret->params.g, g))
goto err;
+ /* We are using safe prime p, set key length equivalent to RFC 7919 */
+ ret->length = (2 * ossl_ifc_ffc_compute_security_bits(prime_len)
+ + 24) / 25 * 25;
+ ret->dirty_cnt++;
ok = 1;
err:
if (ok == -1) {
- DHerr(DH_F_DH_BUILTIN_GENPARAMS, ERR_R_BN_LIB);
+ ERR_raise(ERR_LIB_DH, ERR_R_BN_LIB);
ok = 0;
}
- if (ctx != NULL) {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
return ok;
}
+#endif /* FIPS_MODULE */