1 /*
2 * Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (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 #include <stdio.h>
11 #include "internal/cryptlib.h"
12 #include "dh_local.h"
13 #include <openssl/bn.h>
14 #include <openssl/objects.h>
15 #include "crypto/bn_dh.h"
16
dh_param_init(const BIGNUM * p,int32_t nbits)17 static DH *dh_param_init(const BIGNUM *p, int32_t nbits)
18 {
19 DH *dh = DH_new();
20 if (dh == NULL)
21 return NULL;
22 dh->p = (BIGNUM *)p;
23 dh->g = (BIGNUM *)&_bignum_const_2;
24 dh->length = nbits;
25 return dh;
26 }
27
DH_new_by_nid(int nid)28 DH *DH_new_by_nid(int nid)
29 {
30 switch (nid) {
31 case NID_ffdhe2048:
32 return dh_param_init(&_bignum_ffdhe2048_p, 225);
33 case NID_ffdhe3072:
34 return dh_param_init(&_bignum_ffdhe3072_p, 275);
35 case NID_ffdhe4096:
36 return dh_param_init(&_bignum_ffdhe4096_p, 325);
37 case NID_ffdhe6144:
38 return dh_param_init(&_bignum_ffdhe6144_p, 375);
39 case NID_ffdhe8192:
40 return dh_param_init(&_bignum_ffdhe8192_p, 400);
41 default:
42 DHerr(DH_F_DH_NEW_BY_NID, DH_R_INVALID_PARAMETER_NID);
43 return NULL;
44 }
45 }
46
DH_get_nid(const DH * dh)47 int DH_get_nid(const DH *dh)
48 {
49 int nid;
50
51 if (BN_get_word(dh->g) != 2)
52 return NID_undef;
53 if (!BN_cmp(dh->p, &_bignum_ffdhe2048_p))
54 nid = NID_ffdhe2048;
55 else if (!BN_cmp(dh->p, &_bignum_ffdhe3072_p))
56 nid = NID_ffdhe3072;
57 else if (!BN_cmp(dh->p, &_bignum_ffdhe4096_p))
58 nid = NID_ffdhe4096;
59 else if (!BN_cmp(dh->p, &_bignum_ffdhe6144_p))
60 nid = NID_ffdhe6144;
61 else if (!BN_cmp(dh->p, &_bignum_ffdhe8192_p))
62 nid = NID_ffdhe8192;
63 else
64 return NID_undef;
65 if (dh->q != NULL) {
66 BIGNUM *q = BN_dup(dh->p);
67
68 /* Check q = p * 2 + 1 we already know q is odd, so just shift right */
69 if (q == NULL || !BN_rshift1(q, q) || !BN_cmp(dh->q, q))
70 nid = NID_undef;
71 BN_free(q);
72 }
73 return nid;
74 }
75