2708a81cd038ff2331aebd16714bc9a85bd344e3
[openssl.git] / crypto / dh / dh_asn1.c
1 /*
2  * Copyright 2000-2016 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 #include <stdio.h>
11 #include "internal/cryptlib.h"
12 #include <openssl/bn.h>
13 #include "dh_local.h"
14 #include <openssl/objects.h>
15 #include <openssl/asn1t.h>
16
17 /* Override the default free and new methods */
18 static int dh_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
19                  void *exarg)
20 {
21     if (operation == ASN1_OP_NEW_PRE) {
22         *pval = (ASN1_VALUE *)DH_new();
23         if (*pval != NULL)
24             return 2;
25         return 0;
26     } else if (operation == ASN1_OP_FREE_PRE) {
27         DH_free((DH *)*pval);
28         *pval = NULL;
29         return 2;
30     } else if (operation == ASN1_OP_D2I_POST) {
31         ((DH *)*pval)->dirty_cnt++;
32     }
33     return 1;
34 }
35
36 ASN1_SEQUENCE_cb(DHparams, dh_cb) = {
37         ASN1_SIMPLE(DH, p, BIGNUM),
38         ASN1_SIMPLE(DH, g, BIGNUM),
39         ASN1_OPT_EMBED(DH, length, ZINT32),
40 } ASN1_SEQUENCE_END_cb(DH, DHparams)
41
42 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(DH, DHparams, DHparams)
43
44 /*
45  * Internal only structures for handling X9.42 DH: this gets translated to or
46  * from a DH structure straight away.
47  */
48
49 typedef struct {
50     ASN1_BIT_STRING *seed;
51     BIGNUM *counter;
52 } int_dhvparams;
53
54 typedef struct {
55     BIGNUM *p;
56     BIGNUM *q;
57     BIGNUM *g;
58     BIGNUM *j;
59     int_dhvparams *vparams;
60 } int_dhx942_dh;
61
62 ASN1_SEQUENCE(DHvparams) = {
63         ASN1_SIMPLE(int_dhvparams, seed, ASN1_BIT_STRING),
64         ASN1_SIMPLE(int_dhvparams, counter, BIGNUM)
65 } static_ASN1_SEQUENCE_END_name(int_dhvparams, DHvparams)
66
67 ASN1_SEQUENCE(DHxparams) = {
68         ASN1_SIMPLE(int_dhx942_dh, p, BIGNUM),
69         ASN1_SIMPLE(int_dhx942_dh, g, BIGNUM),
70         ASN1_SIMPLE(int_dhx942_dh, q, BIGNUM),
71         ASN1_OPT(int_dhx942_dh, j, BIGNUM),
72         ASN1_OPT(int_dhx942_dh, vparams, DHvparams),
73 } static_ASN1_SEQUENCE_END_name(int_dhx942_dh, DHxparams)
74
75 int_dhx942_dh *d2i_int_dhx(int_dhx942_dh **a,
76                            const unsigned char **pp, long length);
77 int i2d_int_dhx(const int_dhx942_dh *a, unsigned char **pp);
78
79 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(int_dhx942_dh, DHxparams, int_dhx)
80
81 /* Application public function: read in X9.42 DH parameters into DH structure */
82
83 DH *d2i_DHxparams(DH **a, const unsigned char **pp, long length)
84 {
85     int_dhx942_dh *dhx = NULL;
86     DH *dh = NULL;
87     dh = DH_new();
88     if (dh == NULL)
89         return NULL;
90     dhx = d2i_int_dhx(NULL, pp, length);
91     if (dhx == NULL) {
92         DH_free(dh);
93         return NULL;
94     }
95
96     if (a) {
97         DH_free(*a);
98         *a = dh;
99     }
100
101     dh->p = dhx->p;
102     dh->q = dhx->q;
103     dh->g = dhx->g;
104     dh->j = dhx->j;
105
106     if (dhx->vparams) {
107         dh->seed = dhx->vparams->seed->data;
108         dh->seedlen = dhx->vparams->seed->length;
109         dh->counter = dhx->vparams->counter;
110         dhx->vparams->seed->data = NULL;
111         ASN1_BIT_STRING_free(dhx->vparams->seed);
112         OPENSSL_free(dhx->vparams);
113         dhx->vparams = NULL;
114     }
115
116     OPENSSL_free(dhx);
117     return dh;
118 }
119
120 int i2d_DHxparams(const DH *dh, unsigned char **pp)
121 {
122     int_dhx942_dh dhx;
123     int_dhvparams dhv;
124     ASN1_BIT_STRING bs;
125     dhx.p = dh->p;
126     dhx.g = dh->g;
127     dhx.q = dh->q;
128     dhx.j = dh->j;
129     if (dh->counter && dh->seed && dh->seedlen > 0) {
130         bs.flags = ASN1_STRING_FLAG_BITS_LEFT;
131         bs.data = dh->seed;
132         bs.length = dh->seedlen;
133         dhv.seed = &bs;
134         dhv.counter = dh->counter;
135         dhx.vparams = &dhv;
136     } else
137         dhx.vparams = NULL;
138
139     return i2d_int_dhx(&dhx, pp);
140 }