// Copyright 1999-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// X509 v3 extension utilities

#include <stdio.h>

#include <openssl/bio.h>
#include <openssl/conf.h>
#include <openssl/mem.h>
#include <openssl/x509.h>

// Extension printing routines

static int unknown_ext_print(BIO *out, const X509_EXTENSION *ext,
                             unsigned long flag, int indent, int supported);

// Print out a name+value stack
static void X509V3_EXT_val_prn(BIO *out, const STACK_OF(CONF_VALUE) *val,
                               int indent, int ml) {
  if (!val) {
    return;
  }
  if (!ml || !sk_CONF_VALUE_num(val)) {
    BIO_printf(out, "%*s", indent, "");
    if (!sk_CONF_VALUE_num(val)) {
      BIO_puts(out, "<EMPTY>\n");
    }
  }
  for (size_t i = 0; i < sk_CONF_VALUE_num(val); i++) {
    if (ml) {
      BIO_printf(out, "%*s", indent, "");
    } else if (i > 0) {
      BIO_printf(out, ", ");
    }
    const CONF_VALUE *nval = sk_CONF_VALUE_value(val, i);
    if (!nval->name) {
      BIO_puts(out, nval->value);
    } else if (!nval->value) {
      BIO_puts(out, nval->name);
    } else {
      BIO_printf(out, "%s:%s", nval->name, nval->value);
    }
    if (ml) {
      BIO_puts(out, "\n");
    }
  }
}

// Main routine: print out a general extension

int X509V3_EXT_print(BIO *out, const X509_EXTENSION *ext, unsigned long flag,
                     int indent) {
  const X509V3_EXT_METHOD *method = X509V3_EXT_get(ext);
  if (method == NULL) {
    return unknown_ext_print(out, ext, flag, indent, 0);
  }
  const ASN1_STRING *ext_data = X509_EXTENSION_get_data(ext);
  const unsigned char *p = ASN1_STRING_get0_data(ext_data);
  void *ext_str = ASN1_item_d2i(NULL, &p, ASN1_STRING_length(ext_data),
                                ASN1_ITEM_ptr(method->it));
  if (!ext_str) {
    return unknown_ext_print(out, ext, flag, indent, 1);
  }

  char *value = NULL;
  STACK_OF(CONF_VALUE) *nval = NULL;
  int ok = 0;
  if (method->i2s) {
    if (!(value = method->i2s(method, ext_str))) {
      goto err;
    }
    BIO_printf(out, "%*s%s", indent, "", value);
  } else if (method->i2v) {
    if (!(nval = method->i2v(method, ext_str, NULL))) {
      goto err;
    }
    X509V3_EXT_val_prn(out, nval, indent,
                       method->ext_flags & X509V3_EXT_MULTILINE);
  } else if (method->i2r) {
    if (!method->i2r(method, ext_str, out, indent)) {
      goto err;
    }
  } else {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_OPERATION_NOT_DEFINED);
    goto err;
  }

  ok = 1;

err:
  sk_CONF_VALUE_pop_free(nval, X509V3_conf_free);
  OPENSSL_free(value);
  ASN1_item_free(reinterpret_cast<ASN1_VALUE *>(ext_str),
                 ASN1_ITEM_ptr(method->it));
  return ok;
}

int X509V3_extensions_print(BIO *bp, const char *title,
                            const STACK_OF(X509_EXTENSION) *exts,
                            unsigned long flag, int indent) {
  size_t i;
  int j;

  if (sk_X509_EXTENSION_num(exts) <= 0) {
    return 1;
  }

  if (title) {
    BIO_printf(bp, "%*s%s:\n", indent, "", title);
    indent += 4;
  }

  for (i = 0; i < sk_X509_EXTENSION_num(exts); i++) {
    const X509_EXTENSION *ex = sk_X509_EXTENSION_value(exts, i);
    if (indent && BIO_printf(bp, "%*s", indent, "") <= 0) {
      return 0;
    }
    const ASN1_OBJECT *obj = X509_EXTENSION_get_object(ex);
    i2a_ASN1_OBJECT(bp, obj);
    j = X509_EXTENSION_get_critical(ex);
    if (BIO_printf(bp, ": %s\n", j ? "critical" : "") <= 0) {
      return 0;
    }
    if (!X509V3_EXT_print(bp, ex, flag, indent + 4)) {
      BIO_printf(bp, "%*s", indent + 4, "");
      ASN1_STRING_print(bp, X509_EXTENSION_get_data(ex));
    }
    if (BIO_write(bp, "\n", 1) <= 0) {
      return 0;
    }
  }
  return 1;
}

static int unknown_ext_print(BIO *out, const X509_EXTENSION *ext,
                             unsigned long flag, int indent, int supported) {
  switch (flag & X509V3_EXT_UNKNOWN_MASK) {
    case X509V3_EXT_DEFAULT:
      return 0;

    case X509V3_EXT_ERROR_UNKNOWN:
      if (supported) {
        BIO_printf(out, "%*s<Parse Error>", indent, "");
      } else {
        BIO_printf(out, "%*s<Not Supported>", indent, "");
      }
      return 1;

    case X509V3_EXT_PARSE_UNKNOWN:
    case X509V3_EXT_DUMP_UNKNOWN: {
      const ASN1_STRING *data = X509_EXTENSION_get_data(ext);
      return BIO_hexdump(out, ASN1_STRING_get0_data(data),
                         ASN1_STRING_length(data), indent);
    }

    default:
      return 1;
  }
}

int X509V3_EXT_print_fp(FILE *fp, const X509_EXTENSION *ext, int flag,
                        int indent) {
  BIO *bio_tmp;
  int ret;
  if (!(bio_tmp = BIO_new_fp(fp, BIO_NOCLOSE))) {
    return 0;
  }
  ret = X509V3_EXT_print(bio_tmp, ext, flag, indent);
  BIO_free(bio_tmp);
  return ret;
}