1/*
2 * Copyright 2002-2018 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 <openssl/crypto.h>
11#include <openssl/err.h>
12#include "ec_local.h"
13
14BIGNUM *EC_POINT_point2bn(const EC_GROUP *group,
15                          const EC_POINT *point,
16                          point_conversion_form_t form,
17                          BIGNUM *ret, BN_CTX *ctx)
18{
19    size_t buf_len = 0;
20    unsigned char *buf;
21
22    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);
23
24    if (buf_len == 0)
25        return NULL;
26
27    ret = BN_bin2bn(buf, buf_len, ret);
28
29    OPENSSL_free(buf);
30
31    return ret;
32}
33
34EC_POINT *EC_POINT_bn2point(const EC_GROUP *group,
35                            const BIGNUM *bn, EC_POINT *point, BN_CTX *ctx)
36{
37    size_t buf_len = 0;
38    unsigned char *buf;
39    EC_POINT *ret;
40
41    if ((buf_len = BN_num_bytes(bn)) == 0)
42        buf_len = 1;
43    if ((buf = OPENSSL_malloc(buf_len)) == NULL) {
44        ECerr(EC_F_EC_POINT_BN2POINT, ERR_R_MALLOC_FAILURE);
45        return NULL;
46    }
47
48    if (!BN_bn2binpad(bn, buf, buf_len)) {
49        OPENSSL_free(buf);
50        return NULL;
51    }
52
53    if (point == NULL) {
54        if ((ret = EC_POINT_new(group)) == NULL) {
55            OPENSSL_free(buf);
56            return NULL;
57        }
58    } else
59        ret = point;
60
61    if (!EC_POINT_oct2point(group, ret, buf, buf_len, ctx)) {
62        if (ret != point)
63            EC_POINT_clear_free(ret);
64        OPENSSL_free(buf);
65        return NULL;
66    }
67
68    OPENSSL_free(buf);
69    return ret;
70}
71
72static const char *HEX_DIGITS = "0123456789ABCDEF";
73
74/* the return value must be freed (using OPENSSL_free()) */
75char *EC_POINT_point2hex(const EC_GROUP *group,
76                         const EC_POINT *point,
77                         point_conversion_form_t form, BN_CTX *ctx)
78{
79    char *ret, *p;
80    size_t buf_len = 0, i;
81    unsigned char *buf = NULL, *pbuf;
82
83    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);
84
85    if (buf_len == 0)
86        return NULL;
87
88    ret = OPENSSL_malloc(buf_len * 2 + 2);
89    if (ret == NULL) {
90        OPENSSL_free(buf);
91        return NULL;
92    }
93    p = ret;
94    pbuf = buf;
95    for (i = buf_len; i > 0; i--) {
96        int v = (int)*(pbuf++);
97        *(p++) = HEX_DIGITS[v >> 4];
98        *(p++) = HEX_DIGITS[v & 0x0F];
99    }
100    *p = '\0';
101
102    OPENSSL_free(buf);
103
104    return ret;
105}
106
107EC_POINT *EC_POINT_hex2point(const EC_GROUP *group,
108                             const char *buf, EC_POINT *point, BN_CTX *ctx)
109{
110    EC_POINT *ret = NULL;
111    BIGNUM *tmp_bn = NULL;
112
113    if (!BN_hex2bn(&tmp_bn, buf))
114        return NULL;
115
116    ret = EC_POINT_bn2point(group, tmp_bn, point, ctx);
117
118    BN_clear_free(tmp_bn);
119
120    return ret;
121}
122