1 /* 2 * Copyright 2017-2022 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 /* DH parameters from RFC7919 and RFC3526 */ 11 12 /* 13 * DH low level APIs are deprecated for public use, but still ok for 14 * internal use. 15 */ 16 #include "internal/deprecated.h" 17 18 #include <stdio.h> 19 #include "internal/cryptlib.h" 20 #include "internal/ffc.h" 21 #include "dh_local.h" 22 #include <openssl/bn.h> 23 #include <openssl/objects.h> 24 #include "internal/nelem.h" 25 #include "crypto/dh.h" 26 27 static DH *dh_param_init(OSSL_LIB_CTX *libctx, const DH_NAMED_GROUP *group) 28 { 29 DH *dh = ossl_dh_new_ex(libctx); 30 31 if (dh == NULL) 32 return NULL; 33 34 ossl_ffc_named_group_set(&dh->params, group); 35 dh->params.nid = ossl_ffc_named_group_get_uid(group); 36 dh->dirty_cnt++; 37 return dh; 38 } 39 40 DH *ossl_dh_new_by_nid_ex(OSSL_LIB_CTX *libctx, int nid) 41 { 42 const DH_NAMED_GROUP *group; 43 44 if ((group = ossl_ffc_uid_to_dh_named_group(nid)) != NULL) 45 return dh_param_init(libctx, group); 46 47 ERR_raise(ERR_LIB_DH, DH_R_INVALID_PARAMETER_NID); 48 return NULL; 49 } 50 51 DH *DH_new_by_nid(int nid) 52 { 53 return ossl_dh_new_by_nid_ex(NULL, nid); 54 } 55 56 void ossl_dh_cache_named_group(DH *dh) 57 { 58 const DH_NAMED_GROUP *group; 59 60 if (dh == NULL) 61 return; 62 63 dh->params.nid = NID_undef; /* flush cached value */ 64 65 /* Exit if p or g is not set */ 66 if (dh->params.p == NULL 67 || dh->params.g == NULL) 68 return; 69 70 if ((group = ossl_ffc_numbers_to_dh_named_group(dh->params.p, 71 dh->params.q, 72 dh->params.g)) != NULL) { 73 if (dh->params.q == NULL) 74 dh->params.q = (BIGNUM *)ossl_ffc_named_group_get_q(group); 75 /* cache the nid and default key length */ 76 dh->params.nid = ossl_ffc_named_group_get_uid(group); 77 dh->params.keylength = ossl_ffc_named_group_get_keylength(group); 78 dh->dirty_cnt++; 79 } 80 } 81 82 int ossl_dh_is_named_safe_prime_group(const DH *dh) 83 { 84 int id = DH_get_nid(dh); 85 86 /* 87 * Exclude RFC5114 groups (id = 1..3) since they do not have 88 * q = (p - 1) / 2 89 */ 90 return (id > 3); 91 } 92 93 int DH_get_nid(const DH *dh) 94 { 95 if (dh == NULL) 96 return NID_undef; 97 98 return dh->params.nid; 99 } 100