crypto/ec/ec_print.c

   1 /*
   2  * Copyright 2002-2024 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 "internal/cryptlib.h"
  13 #include "ec_local.h"
  14
  15 /* the return value must be freed (using OPENSSL_free()) */
  16 char *EC_POINT_point2hex(const EC_GROUP *group,
  17                          const EC_POINT *point,
  18                          point_conversion_form_t form, BN_CTX *ctx)
  19 {
  20     char *ret, *p;
  21     size_t buf_len, i;
  22     unsigned char *buf = NULL;
  23
  24     buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);
  25
  26     if (buf_len == 0)
  27         return NULL;
  28
  29     ret = OPENSSL_malloc(buf_len * 2 + 2);
  30     if (ret == NULL)
  31         goto err;
  32
  33     p = ret;
  34     for (i = 0; i < buf_len; ++i)
  35         p += ossl_to_hex(p, buf[i]);
  36     *p = '\0';
  37
  38  err:
  39     OPENSSL_free(buf);
  40     return ret;
  41 }
  42
  43 EC_POINT *EC_POINT_hex2point(const EC_GROUP *group,
  44                              const char *hex, EC_POINT *point, BN_CTX *ctx)
  45 {
  46     int ok = 0;
  47     unsigned char *oct_buf = NULL;
  48     size_t len, oct_buf_len = 0;
  49     EC_POINT *pt = NULL;
  50
  51     if (group == NULL || hex == NULL)
  52         return NULL;
  53
  54     if (point == NULL) {
  55         pt = EC_POINT_new(group);
  56         if (pt == NULL)
  57             goto err;
  58     } else {
  59         pt = point;
  60     }
  61
  62     len = strlen(hex) / 2;
  63     oct_buf = OPENSSL_malloc(len);
  64     if (oct_buf == NULL)
  65         goto err;
  66
  67     if (!OPENSSL_hexstr2buf_ex(oct_buf, len, &oct_buf_len, hex, '\0')
  68         || !EC_POINT_oct2point(group, pt, oct_buf, oct_buf_len, ctx))
  69         goto err;
  70     ok = 1;
  71 err:
  72     OPENSSL_clear_free(oct_buf, oct_buf_len);
  73     if (!ok) {
  74         if (pt != point)
  75             EC_POINT_clear_free(pt);
  76         pt = NULL;
  77     }
  78     return pt;
  79 }