1 /* 2 * Copyright 1995-2024 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 /* 11 * DSA low level APIs are deprecated for public use, but still ok for 12 * internal use. 13 */ 14 #include "internal/deprecated.h" 15 16 #include <stdio.h> 17 #include "internal/cryptlib.h" 18 #include <openssl/bn.h> 19 #include "dsa_local.h" 20 #include "crypto/dsa.h" 21 22 static int dsa_precheck_params(const DSA *dsa, int *ret) 23 { 24 if (dsa->params.p == NULL || dsa->params.q == NULL) { 25 ERR_raise(ERR_LIB_DSA, DSA_R_BAD_FFC_PARAMETERS); 26 *ret = FFC_CHECK_INVALID_PQ; 27 return 0; 28 } 29 30 if (BN_num_bits(dsa->params.p) > OPENSSL_DSA_MAX_MODULUS_BITS) { 31 ERR_raise(ERR_LIB_DSA, DSA_R_MODULUS_TOO_LARGE); 32 *ret = FFC_CHECK_INVALID_PQ; 33 return 0; 34 } 35 36 if (BN_num_bits(dsa->params.q) >= BN_num_bits(dsa->params.p)) { 37 ERR_raise(ERR_LIB_DSA, DSA_R_BAD_Q_VALUE); 38 *ret = FFC_CHECK_INVALID_PQ; 39 return 0; 40 } 41 42 return 1; 43 } 44 45 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret) 46 { 47 if (!dsa_precheck_params(dsa, ret)) 48 return 0; 49 50 if (checktype == OSSL_KEYMGMT_VALIDATE_QUICK_CHECK) 51 return ossl_ffc_params_simple_validate(dsa->libctx, &dsa->params, 52 FFC_PARAM_TYPE_DSA, ret); 53 else 54 /* 55 * Do full FFC domain params validation according to FIPS-186-4 56 * - always in FIPS_MODULE 57 * - only if possible (i.e., seed is set) in default provider 58 */ 59 return ossl_ffc_params_full_validate(dsa->libctx, &dsa->params, 60 FFC_PARAM_TYPE_DSA, ret); 61 } 62 63 /* 64 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation. 65 */ 66 int ossl_dsa_check_pub_key(const DSA *dsa, const BIGNUM *pub_key, int *ret) 67 { 68 if (!dsa_precheck_params(dsa, ret)) 69 return 0; 70 71 return ossl_ffc_validate_public_key(&dsa->params, pub_key, ret) 72 && *ret == 0; 73 } 74 75 /* 76 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation. 77 * To only be used with ephemeral FFC public keys generated using the approved 78 * safe-prime groups. 79 */ 80 int ossl_dsa_check_pub_key_partial(const DSA *dsa, const BIGNUM *pub_key, int *ret) 81 { 82 if (!dsa_precheck_params(dsa, ret)) 83 return 0; 84 85 return ossl_ffc_validate_public_key_partial(&dsa->params, pub_key, ret) 86 && *ret == 0; 87 } 88 89 int ossl_dsa_check_priv_key(const DSA *dsa, const BIGNUM *priv_key, int *ret) 90 { 91 *ret = 0; 92 93 if (!dsa_precheck_params(dsa, ret)) 94 return 0; 95 96 return ossl_ffc_validate_private_key(dsa->params.q, priv_key, ret); 97 } 98 99 /* 100 * FFC pairwise check from SP800-56A R3. 101 * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency 102 */ 103 int ossl_dsa_check_pairwise(const DSA *dsa) 104 { 105 int ret = 0; 106 BN_CTX *ctx = NULL; 107 BIGNUM *pub_key = NULL; 108 109 if (!dsa_precheck_params(dsa, &ret)) 110 return 0; 111 112 if (dsa->params.g == NULL 113 || dsa->priv_key == NULL 114 || dsa->pub_key == NULL) 115 return 0; 116 117 ctx = BN_CTX_new_ex(dsa->libctx); 118 if (ctx == NULL) 119 goto err; 120 pub_key = BN_new(); 121 if (pub_key == NULL) 122 goto err; 123 124 /* recalculate the public key = (g ^ priv) mod p */ 125 if (!ossl_dsa_generate_public_key(ctx, dsa, dsa->priv_key, pub_key)) 126 goto err; 127 /* check it matches the existing pubic_key */ 128 ret = BN_cmp(pub_key, dsa->pub_key) == 0; 129 err: 130 BN_free(pub_key); 131 BN_CTX_free(ctx); 132 return ret; 133 } 134