text: /*
   * Copyright 1999-2021 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <stdio.h>
  #include "internal/cryptlib.h"
  #include <openssl/x509v3.h>
  #include "crypto/x509.h"
  #include "ext_dat.h"
  
  static ASN1_OCTET_STRING *s2i_skey_id(X509V3_EXT_METHOD *method,
                                        X509V3_CTX *ctx, char *str);
  const X509V3_EXT_METHOD v3_skey_id = {
      NID_subject_key_identifier, 0, ASN1_ITEM_ref(ASN1_OCTET_STRING),
      0, 0, 0, 0,
      (X509V3_EXT_I2S)i2s_ASN1_OCTET_STRING,
      (X509V3_EXT_S2I)s2i_skey_id,
      0, 0, 0, 0,
      NULL
  };
  
  char *i2s_ASN1_OCTET_STRING(X509V3_EXT_METHOD *method,
                              const ASN1_OCTET_STRING *oct)
  {
      return OPENSSL_buf2hexstr(oct->data, oct->length);
  }
  
  ASN1_OCTET_STRING *s2i_ASN1_OCTET_STRING(X509V3_EXT_METHOD *method,
                                           X509V3_CTX *ctx, const char *str)
  {
      ASN1_OCTET_STRING *oct;
      long length;
  
      if ((oct = ASN1_OCTET_STRING_new()) == NULL) {
          ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
          return NULL;
      }
  
      if ((oct->data = OPENSSL_hexstr2buf(str, &length)) == NULL) {
          ASN1_OCTET_STRING_free(oct);
          return NULL;
      }
  
      oct->length = length;
  
      return oct;
  
  }
  
  ASN1_OCTET_STRING *x509_pubkey_hash(X509_PUBKEY *pubkey)
  {
      ASN1_OCTET_STRING *oct;
      const unsigned char *pk;
      int pklen;
      unsigned char pkey_dig[EVP_MAX_MD_SIZE];
      unsigned int diglen;
  
      if (pubkey == NULL) {
          ERR_raise(ERR_LIB_X509V3, X509V3_R_NO_PUBLIC_KEY);
          return NULL;
      }
      if ((oct = ASN1_OCTET_STRING_new()) == NULL)
          return NULL;
  
      X509_PUBKEY_get0_param(NULL, &pk, &pklen, NULL, pubkey);
      /* TODO(3.0) - explicitly fetch the digest */
      if (EVP_Digest(pk, pklen, pkey_dig, &diglen, EVP_sha1(), NULL)
              && ASN1_OCTET_STRING_set(oct, pkey_dig, diglen))
          return oct;
  
      ASN1_OCTET_STRING_free(oct);
      return NULL;
  }
  
  static ASN1_OCTET_STRING *s2i_skey_id(X509V3_EXT_METHOD *method,
                                        X509V3_CTX *ctx, char *str)
  {
      if (strcmp(str, "none") == 0)
          return ASN1_OCTET_STRING_new(); /* dummy */
  
      if (strcmp(str, "hash") != 0)
          return s2i_ASN1_OCTET_STRING(method, ctx /* not used */, str);
  
      if (ctx != NULL && (ctx->flags & X509V3_CTX_TEST) != 0)
          return ASN1_OCTET_STRING_new();
      if (ctx == NULL
          || (ctx->subject_cert == NULL && ctx->subject_req == NULL)) {
          ERR_raise(ERR_LIB_X509V3, X509V3_R_NO_SUBJECT_DETAILS);
          return NULL;
      }
  
      return x509_pubkey_hash(ctx->subject_req != NULL ?
                              ctx->subject_req->req_info.pubkey :
                              ctx->subject_cert->cert_info.key);
  }
  