/* * Copyright 1995-2023 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 */ /* * DSA low level APIs are deprecated for public use, but still ok for * internal use. */ #include "internal/deprecated.h" #include #include #include "internal/cryptlib.h" #include #include #include "prov/providercommon.h" #include "crypto/dsa.h" #include "dsa_local.h" #ifdef FIPS_MODULE # define MIN_STRENGTH 112 #else # define MIN_STRENGTH 80 #endif static int dsa_keygen(DSA *dsa); int DSA_generate_key(DSA *dsa) { #ifndef FIPS_MODULE if (dsa->meth->dsa_keygen != NULL) return dsa->meth->dsa_keygen(dsa); #endif return dsa_keygen(dsa); } int ossl_dsa_generate_public_key(BN_CTX *ctx, const DSA *dsa, const BIGNUM *priv_key, BIGNUM *pub_key) { int ret = 0; BIGNUM *prk = BN_new(); if (prk == NULL) return 0; BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME); /* pub_key = g ^ priv_key mod p */ if (!BN_mod_exp(pub_key, dsa->params.g, prk, dsa->params.p, ctx)) goto err; ret = 1; err: BN_clear_free(prk); return ret; } #ifdef FIPS_MODULE /* * Refer: FIPS 140-3 IG 10.3.A Additional Comment 1 * Perform a KAT by duplicating the public key generation. * * NOTE: This issue requires a background understanding, provided in a separate * document; the current IG 10.3.A AC1 is insufficient regarding the PCT for * the key agreement scenario. * * Currently IG 10.3.A requires PCT in the mode of use prior to use of the * key pair, citing the PCT defined in the associated standard. For key * agreement, the only PCT defined in SP 800-56A is that of Section 5.6.2.4: * the comparison of the original public key to a newly calculated public key. */ static int dsa_keygen_knownanswer_test(DSA *dsa, BN_CTX *ctx, OSSL_CALLBACK *cb, void *cbarg) { int len, ret = 0; OSSL_SELF_TEST *st = NULL; unsigned char bytes[512] = {0}; BIGNUM *pub_key2 = BN_new(); if (pub_key2 == NULL) return 0; st = OSSL_SELF_TEST_new(cb, cbarg); if (st == NULL) goto err; OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT_KAT, OSSL_SELF_TEST_DESC_PCT_DSA); if (!ossl_dsa_generate_public_key(ctx, dsa, dsa->priv_key, pub_key2)) goto err; if (BN_num_bytes(pub_key2) > (int)sizeof(bytes)) goto err; len = BN_bn2bin(pub_key2, bytes); OSSL_SELF_TEST_oncorrupt_byte(st, bytes); if (BN_bin2bn(bytes, len, pub_key2) != NULL) ret = !BN_cmp(dsa->pub_key, pub_key2); err: OSSL_SELF_TEST_onend(st, ret); OSSL_SELF_TEST_free(st); BN_free(pub_key2); return ret; } /* * FIPS 140-2 IG 9.9 AS09.33 * Perform a sign/verify operation. */ static int dsa_keygen_pairwise_test(DSA *dsa, OSSL_CALLBACK *cb, void *cbarg) { int ret = 0; unsigned char dgst[16] = {0}; unsigned int dgst_len = (unsigned int)sizeof(dgst); DSA_SIG *sig = NULL; OSSL_SELF_TEST *st = NULL; st = OSSL_SELF_TEST_new(cb, cbarg); if (st == NULL) goto err; OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT, OSSL_SELF_TEST_DESC_PCT_DSA); sig = DSA_do_sign(dgst, (int)dgst_len, dsa); if (sig == NULL) goto err; OSSL_SELF_TEST_oncorrupt_byte(st, dgst); if (DSA_do_verify(dgst, dgst_len, sig, dsa) != 1) goto err; ret = 1; err: OSSL_SELF_TEST_onend(st, ret); OSSL_SELF_TEST_free(st); DSA_SIG_free(sig); return ret; } #endif /* FIPS_MODULE */ static int dsa_keygen(DSA *dsa) { int ok = 0; BN_CTX *ctx = NULL; BIGNUM *pub_key = NULL, *priv_key = NULL; if ((ctx = BN_CTX_new_ex(dsa->libctx)) == NULL) goto err; if (dsa->priv_key == NULL) { if ((priv_key = BN_secure_new()) == NULL) goto err; } else { priv_key = dsa->priv_key; } /* Do a partial check for invalid p, q, g */ if (!ossl_ffc_params_simple_validate(dsa->libctx, &dsa->params, FFC_PARAM_TYPE_DSA, NULL)) goto err; /* * For FFC FIPS 186-4 keygen * security strength s = 112, * Max Private key size N = len(q) */ if (!ossl_ffc_generate_private_key(ctx, &dsa->params, BN_num_bits(dsa->params.q), MIN_STRENGTH, priv_key)) goto err; if (dsa->pub_key == NULL) { if ((pub_key = BN_new()) == NULL) goto err; } else { pub_key = dsa->pub_key; } if (!ossl_dsa_generate_public_key(ctx, dsa, priv_key, pub_key)) goto err; dsa->priv_key = priv_key; dsa->pub_key = pub_key; ok = 1; #ifdef FIPS_MODULE { OSSL_CALLBACK *cb = NULL; void *cbarg = NULL; OSSL_SELF_TEST_get_callback(dsa->libctx, &cb, &cbarg); ok = dsa_keygen_pairwise_test(dsa, cb, cbarg) && dsa_keygen_knownanswer_test(dsa, ctx, cb, cbarg); if (!ok) { ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT); BN_free(dsa->pub_key); BN_clear_free(dsa->priv_key); dsa->pub_key = NULL; dsa->priv_key = NULL; BN_CTX_free(ctx); return ok; } } #endif dsa->dirty_cnt++; err: if (pub_key != dsa->pub_key) BN_free(pub_key); if (priv_key != dsa->priv_key) BN_free(priv_key); BN_CTX_free(ctx); return ok; }