// Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project 1999.
// Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
// SPDX-License-Identifier: Apache-2.0

#include <limits.h>
#include <stdio.h>
#include <string.h>

#include <openssl/digest.h>
#include <openssl/err.h>
#include <openssl/obj.h>
#include <openssl/mem.h>
#include <openssl/x509.h>

#include "internal.h"


char *i2s_ASN1_OCTET_STRING(const X509V3_EXT_METHOD *method,
                            const ASN1_OCTET_STRING *oct) {
  return x509v3_bytes_to_hex(oct->data, oct->length);
}

ASN1_OCTET_STRING *s2i_ASN1_OCTET_STRING(const X509V3_EXT_METHOD *method,
                                         const X509V3_CTX *ctx,
                                         const char *str) {
  size_t len;
  uint8_t *data = x509v3_hex_to_bytes(str, &len);
  if (data == NULL) {
    return NULL;
  }
  if (len > INT_MAX) {
    OPENSSL_PUT_ERROR(X509V3, ERR_R_OVERFLOW);
    goto err;
  }

  ASN1_OCTET_STRING *oct = ASN1_OCTET_STRING_new();
  if (oct == NULL) {
    goto err;
  }
  ASN1_STRING_set0(oct, data, (int)len);
  return oct;

err:
  OPENSSL_free(data);
  return NULL;
}

static char *i2s_ASN1_OCTET_STRING_cb(const X509V3_EXT_METHOD *method,
                                      void *ext) {
  return i2s_ASN1_OCTET_STRING(method, ext);
}

static void *s2i_skey_id(const X509V3_EXT_METHOD *method, const X509V3_CTX *ctx,
                         const char *str) {
  ASN1_OCTET_STRING *oct;
  ASN1_BIT_STRING *pk;
  unsigned char pkey_dig[EVP_MAX_MD_SIZE];
  unsigned int diglen;

  if (strcmp(str, "hash")) {
    return s2i_ASN1_OCTET_STRING(method, ctx, str);
  }

  if (!(oct = ASN1_OCTET_STRING_new())) {
    return NULL;
  }

  if (ctx && (ctx->flags == X509V3_CTX_TEST)) {
    return oct;
  }

  if (!ctx || (!ctx->subject_req && !ctx->subject_cert)) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_NO_PUBLIC_KEY);
    goto err;
  }

  if (ctx->subject_req) {
    pk = ctx->subject_req->req_info->pubkey->public_key;
  } else {
    pk = ctx->subject_cert->cert_info->key->public_key;
  }

  if (!pk) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_NO_PUBLIC_KEY);
    goto err;
  }

  if (!EVP_Digest(pk->data, pk->length, pkey_dig, &diglen, EVP_sha1(), NULL)) {
    goto err;
  }

  if (!ASN1_OCTET_STRING_set(oct, pkey_dig, diglen)) {
    goto err;
  }

  return oct;

err:
  ASN1_OCTET_STRING_free(oct);
  return NULL;
}

const X509V3_EXT_METHOD v3_skey_id = {
    NID_subject_key_identifier,
    0,
    ASN1_ITEM_ref(ASN1_OCTET_STRING),
    0,
    0,
    0,
    0,
    i2s_ASN1_OCTET_STRING_cb,
    s2i_skey_id,
    0,
    0,
    0,
    0,
    NULL,
};