1/* 2 * Copyright 2002-2020 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 <string.h> /* strlen */ 11#include <openssl/crypto.h> 12#include "ec_local.h" 13 14static const char *HEX_DIGITS = "0123456789ABCDEF"; 15 16/* the return value must be freed (using OPENSSL_free()) */ 17char *EC_POINT_point2hex(const EC_GROUP *group, 18 const EC_POINT *point, 19 point_conversion_form_t form, BN_CTX *ctx) 20{ 21 char *ret, *p; 22 size_t buf_len = 0, i; 23 unsigned char *buf = NULL, *pbuf; 24 25 buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx); 26 27 if (buf_len == 0) 28 return NULL; 29 30 ret = OPENSSL_malloc(buf_len * 2 + 2); 31 if (ret == NULL) { 32 OPENSSL_free(buf); 33 return NULL; 34 } 35 p = ret; 36 pbuf = buf; 37 for (i = buf_len; i > 0; i--) { 38 int v = (int)*(pbuf++); 39 *(p++) = HEX_DIGITS[v >> 4]; 40 *(p++) = HEX_DIGITS[v & 0x0F]; 41 } 42 *p = '\0'; 43 44 OPENSSL_free(buf); 45 46 return ret; 47} 48 49EC_POINT *EC_POINT_hex2point(const EC_GROUP *group, 50 const char *hex, EC_POINT *point, BN_CTX *ctx) 51{ 52 int ok = 0; 53 unsigned char *oct_buf = NULL; 54 size_t len, oct_buf_len = 0; 55 EC_POINT *pt = NULL; 56 57 if (group == NULL || hex == NULL) 58 return NULL; 59 60 if (point == NULL) { 61 pt = EC_POINT_new(group); 62 if (pt == NULL) 63 goto err; 64 } else { 65 pt = point; 66 } 67 68 len = strlen(hex) / 2; 69 oct_buf = OPENSSL_malloc(len); 70 if (oct_buf == NULL) 71 goto err; 72 73 if (!OPENSSL_hexstr2buf_ex(oct_buf, len, &oct_buf_len, hex, '\0') 74 || !EC_POINT_oct2point(group, pt, oct_buf, oct_buf_len, ctx)) 75 goto err; 76 ok = 1; 77err: 78 OPENSSL_clear_free(oct_buf, oct_buf_len); 79 if (!ok) { 80 if (pt != point) 81 EC_POINT_clear_free(pt); 82 pt = NULL; 83 } 84 return pt; 85} 86