// 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.

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

#include <openssl/asn1.h>
#include <openssl/conf.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/x509.h>

#include "internal.h"


static void *v2i_subject_alt(const X509V3_EXT_METHOD *method,
                             const X509V3_CTX *ctx,
                             const STACK_OF(CONF_VALUE) *nval);
static void *v2i_issuer_alt(const X509V3_EXT_METHOD *method,
                            const X509V3_CTX *ctx,
                            const STACK_OF(CONF_VALUE) *nval);
static int copy_email(const X509V3_CTX *ctx, GENERAL_NAMES *gens, int move_p);
static int copy_issuer(const X509V3_CTX *ctx, GENERAL_NAMES *gens);
static int do_othername(GENERAL_NAME *gen, const char *value,
                        const X509V3_CTX *ctx);
static int do_dirname(GENERAL_NAME *gen, const char *value,
                      const X509V3_CTX *ctx);

static STACK_OF(CONF_VALUE) *i2v_GENERAL_NAMES_cb(
    const X509V3_EXT_METHOD *method, void *ext, STACK_OF(CONF_VALUE) *ret) {
  return i2v_GENERAL_NAMES(method, reinterpret_cast<GENERAL_NAMES *>(ext), ret);
}

const X509V3_EXT_METHOD v3_subject_alt_name = {
    NID_subject_alt_name,
    0,
    ASN1_ITEM_ref(GENERAL_NAMES),
    0,
    0,
    0,
    0,
    0,
    0,
    i2v_GENERAL_NAMES_cb,
    v2i_subject_alt,
    nullptr,
    nullptr,
    nullptr,
};

const X509V3_EXT_METHOD v3_issuer_alt_name = {
    NID_issuer_alt_name,
    0,
    ASN1_ITEM_ref(GENERAL_NAMES),
    0,
    0,
    0,
    0,
    0,
    0,
    i2v_GENERAL_NAMES_cb,
    v2i_issuer_alt,
    nullptr,
    nullptr,
    nullptr,
};

const X509V3_EXT_METHOD v3_certificate_issuer = {
    NID_certificate_issuer,
    0,
    ASN1_ITEM_ref(GENERAL_NAMES),
    0,
    0,
    0,
    0,
    0,
    0,
    i2v_GENERAL_NAMES_cb,
    NULL,
    NULL,
    NULL,
    NULL,
};

STACK_OF(CONF_VALUE) *i2v_GENERAL_NAMES(const X509V3_EXT_METHOD *method,
                                        const GENERAL_NAMES *gens,
                                        STACK_OF(CONF_VALUE) *ret) {
  int ret_was_null = ret == NULL;
  for (size_t i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
    const GENERAL_NAME *gen = sk_GENERAL_NAME_value(gens, i);
    STACK_OF(CONF_VALUE) *tmp = i2v_GENERAL_NAME(method, gen, ret);
    if (tmp == NULL) {
      if (ret_was_null) {
        sk_CONF_VALUE_pop_free(ret, X509V3_conf_free);
      }
      return NULL;
    }
    ret = tmp;
  }
  if (!ret) {
    return sk_CONF_VALUE_new_null();
  }
  return ret;
}

STACK_OF(CONF_VALUE) *i2v_GENERAL_NAME(const X509V3_EXT_METHOD *method,
                                       const GENERAL_NAME *gen,
                                       STACK_OF(CONF_VALUE) *ret) {
  // Note the error-handling for this function relies on there being at most
  // one |X509V3_add_value| call. If there were two and the second failed, we
  // would need to sometimes free the first call's result.
  unsigned char *p;
  char oline[256], htmp[5];
  int i;
  switch (gen->type) {
    case GEN_OTHERNAME:
      if (!X509V3_add_value("othername", "<unsupported>", &ret)) {
        return NULL;
      }
      break;

    case GEN_X400:
      if (!X509V3_add_value("X400Name", "<unsupported>", &ret)) {
        return NULL;
      }
      break;

    case GEN_EDIPARTY:
      if (!X509V3_add_value("EdiPartyName", "<unsupported>", &ret)) {
        return NULL;
      }
      break;

    case GEN_EMAIL:
      if (!x509V3_add_value_asn1_string("email", gen->d.ia5, &ret)) {
        return NULL;
      }
      break;

    case GEN_DNS:
      if (!x509V3_add_value_asn1_string("DNS", gen->d.ia5, &ret)) {
        return NULL;
      }
      break;

    case GEN_URI:
      if (!x509V3_add_value_asn1_string("URI", gen->d.ia5, &ret)) {
        return NULL;
      }
      break;

    case GEN_DIRNAME:
      if (X509_NAME_oneline(gen->d.dirn, oline, 256) == NULL ||
          !X509V3_add_value("DirName", oline, &ret)) {
        return NULL;
      }
      break;

    case GEN_IPADD:
      p = gen->d.ip->data;
      if (gen->d.ip->length == 4) {
        snprintf(oline, sizeof(oline), "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
      } else if (gen->d.ip->length == 16) {
        oline[0] = 0;
        for (i = 0; i < 8; i++) {
          uint16_t v = ((uint16_t)p[0] << 8) | p[1];
          snprintf(htmp, sizeof(htmp), "%X", v);
          p += 2;
          OPENSSL_strlcat(oline, htmp, sizeof(oline));
          if (i != 7) {
            OPENSSL_strlcat(oline, ":", sizeof(oline));
          }
        }
      } else {
        if (!X509V3_add_value("IP Address", "<invalid>", &ret)) {
          return NULL;
        }
        break;
      }
      if (!X509V3_add_value("IP Address", oline, &ret)) {
        return NULL;
      }
      break;

    case GEN_RID:
      i2t_ASN1_OBJECT(oline, 256, gen->d.rid);
      if (!X509V3_add_value("Registered ID", oline, &ret)) {
        return NULL;
      }
      break;
  }
  return ret;
}

int GENERAL_NAME_print(BIO *out, const GENERAL_NAME *gen) {
  switch (gen->type) {
    case GEN_OTHERNAME:
      BIO_printf(out, "othername:<unsupported>");
      break;

    case GEN_X400:
      BIO_printf(out, "X400Name:<unsupported>");
      break;

    case GEN_EDIPARTY:
      // Maybe fix this: it is supported now
      BIO_printf(out, "EdiPartyName:<unsupported>");
      break;

    case GEN_EMAIL:
      BIO_printf(out, "email:");
      ASN1_STRING_print(out, gen->d.ia5);
      break;

    case GEN_DNS:
      BIO_printf(out, "DNS:");
      ASN1_STRING_print(out, gen->d.ia5);
      break;

    case GEN_URI:
      BIO_printf(out, "URI:");
      ASN1_STRING_print(out, gen->d.ia5);
      break;

    case GEN_DIRNAME:
      BIO_printf(out, "DirName: ");
      X509_NAME_print_ex(out, gen->d.dirn, 0, XN_FLAG_ONELINE);
      break;

    case GEN_IPADD: {
      const unsigned char *p = gen->d.ip->data;
      if (gen->d.ip->length == 4) {
        BIO_printf(out, "IP Address:%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
      } else if (gen->d.ip->length == 16) {
        BIO_printf(out, "IP Address");
        for (int i = 0; i < 8; i++) {
          uint16_t v = ((uint16_t)p[0] << 8) | p[1];
          BIO_printf(out, ":%X", v);
          p += 2;
        }
        BIO_puts(out, "\n");
      } else {
        BIO_printf(out, "IP Address:<invalid>");
        break;
      }
      break;
    }

    case GEN_RID:
      BIO_printf(out, "Registered ID");
      i2a_ASN1_OBJECT(out, gen->d.rid);
      break;
  }
  return 1;
}

static void *v2i_issuer_alt(const X509V3_EXT_METHOD *method,
                            const X509V3_CTX *ctx,
                            const STACK_OF(CONF_VALUE) *nval) {
  GENERAL_NAMES *gens = sk_GENERAL_NAME_new_null();
  if (gens == NULL) {
    return NULL;
  }
  for (size_t i = 0; i < sk_CONF_VALUE_num(nval); i++) {
    const CONF_VALUE *cnf = sk_CONF_VALUE_value(nval, i);
    if (x509v3_conf_name_matches(cnf->name, "issuer") && cnf->value &&
        !strcmp(cnf->value, "copy")) {
      if (!copy_issuer(ctx, gens)) {
        goto err;
      }
    } else {
      GENERAL_NAME *gen = v2i_GENERAL_NAME(method, ctx, cnf);
      if (gen == NULL || !sk_GENERAL_NAME_push(gens, gen)) {
        GENERAL_NAME_free(gen);
        goto err;
      }
    }
  }
  return gens;
err:
  sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
  return NULL;
}

// Append subject altname of issuer to issuer alt name of subject

static int copy_issuer(const X509V3_CTX *ctx, GENERAL_NAMES *gens) {
  if (ctx && (ctx->flags == X509V3_CTX_TEST)) {
    return 1;
  }
  if (!ctx || !ctx->issuer_cert) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_NO_ISSUER_DETAILS);
    return 0;
  }
  int i = X509_get_ext_by_NID(ctx->issuer_cert, NID_subject_alt_name, -1);
  if (i < 0) {
    return 1;
  }

  int ret = 0;
  GENERAL_NAMES *ialt = NULL;
  X509_EXTENSION *ext;
  if (!(ext = X509_get_ext(ctx->issuer_cert, i)) ||
      !(ialt = reinterpret_cast<GENERAL_NAMES *>(X509V3_EXT_d2i(ext)))) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_ISSUER_DECODE_ERROR);
    goto err;
  }

  for (size_t j = 0; j < sk_GENERAL_NAME_num(ialt); j++) {
    GENERAL_NAME *gen = sk_GENERAL_NAME_value(ialt, j);
    if (!sk_GENERAL_NAME_push(gens, gen)) {
      goto err;
    }
    // Ownership of |gen| has moved from |ialt| to |gens|.
    sk_GENERAL_NAME_set(ialt, j, NULL);
  }

  ret = 1;

err:
  GENERAL_NAMES_free(ialt);
  return ret;
}

static void *v2i_subject_alt(const X509V3_EXT_METHOD *method,
                             const X509V3_CTX *ctx,
                             const STACK_OF(CONF_VALUE) *nval) {
  GENERAL_NAMES *gens = sk_GENERAL_NAME_new_null();
  if (gens == NULL) {
    return NULL;
  }
  for (size_t i = 0; i < sk_CONF_VALUE_num(nval); i++) {
    const CONF_VALUE *cnf = sk_CONF_VALUE_value(nval, i);
    if (x509v3_conf_name_matches(cnf->name, "email") && cnf->value &&
        !strcmp(cnf->value, "copy")) {
      if (!copy_email(ctx, gens, 0)) {
        goto err;
      }
    } else if (x509v3_conf_name_matches(cnf->name, "email") && cnf->value &&
               !strcmp(cnf->value, "move")) {
      if (!copy_email(ctx, gens, 1)) {
        goto err;
      }
    } else {
      GENERAL_NAME *gen = v2i_GENERAL_NAME(method, ctx, cnf);
      if (gen == NULL || !sk_GENERAL_NAME_push(gens, gen)) {
        GENERAL_NAME_free(gen);
        goto err;
      }
    }
  }
  return gens;
err:
  sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
  return NULL;
}

// Copy any email addresses in a certificate or request to GENERAL_NAMES

static int copy_email(const X509V3_CTX *ctx, GENERAL_NAMES *gens, int move_p) {
  X509_NAME *nm;
  ASN1_IA5STRING *email = NULL;
  X509_NAME_ENTRY *ne;
  GENERAL_NAME *gen = NULL;
  int i;
  if (ctx != NULL && ctx->flags == X509V3_CTX_TEST) {
    return 1;
  }
  if (!ctx || (!ctx->subject_cert && !ctx->subject_req)) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_NO_SUBJECT_DETAILS);
    goto err;
  }
  // Find the subject name
  if (ctx->subject_cert) {
    nm = X509_get_subject_name(ctx->subject_cert);
  } else {
    nm = X509_REQ_get_subject_name(ctx->subject_req);
  }

  // Now add any email address(es) to STACK
  i = -1;
  while ((i = X509_NAME_get_index_by_NID(nm, NID_pkcs9_emailAddress, i)) >= 0) {
    ne = X509_NAME_get_entry(nm, i);
    email = ASN1_STRING_dup(X509_NAME_ENTRY_get_data(ne));
    if (move_p) {
      X509_NAME_delete_entry(nm, i);
      X509_NAME_ENTRY_free(ne);
      i--;
    }
    if (!email || !(gen = GENERAL_NAME_new())) {
      goto err;
    }
    gen->d.ia5 = email;
    email = NULL;
    gen->type = GEN_EMAIL;
    if (!sk_GENERAL_NAME_push(gens, gen)) {
      goto err;
    }
    gen = NULL;
  }

  return 1;

err:
  GENERAL_NAME_free(gen);
  ASN1_IA5STRING_free(email);
  return 0;
}

GENERAL_NAMES *v2i_GENERAL_NAMES(const X509V3_EXT_METHOD *method,
                                 const X509V3_CTX *ctx,
                                 const STACK_OF(CONF_VALUE) *nval) {
  GENERAL_NAMES *gens = sk_GENERAL_NAME_new_null();
  if (gens == NULL) {
    return NULL;
  }
  for (size_t i = 0; i < sk_CONF_VALUE_num(nval); i++) {
    const CONF_VALUE *cnf = sk_CONF_VALUE_value(nval, i);
    GENERAL_NAME *gen = v2i_GENERAL_NAME(method, ctx, cnf);
    if (gen == NULL || !sk_GENERAL_NAME_push(gens, gen)) {
      GENERAL_NAME_free(gen);
      goto err;
    }
  }
  return gens;
err:
  sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
  return NULL;
}

GENERAL_NAME *v2i_GENERAL_NAME(const X509V3_EXT_METHOD *method,
                               const X509V3_CTX *ctx, const CONF_VALUE *cnf) {
  return v2i_GENERAL_NAME_ex(NULL, method, ctx, cnf, 0);
}

static GENERAL_NAME *a2i_GENERAL_NAME(GENERAL_NAME *out,
                                      const X509V3_EXT_METHOD *method,
                                      const X509V3_CTX *ctx, int gen_type,
                                      const char *value, int is_nc) {
  if (!value) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_MISSING_VALUE);
    return NULL;
  }

  GENERAL_NAME *gen = NULL;
  if (out) {
    gen = out;
  } else {
    gen = GENERAL_NAME_new();
    if (gen == NULL) {
      return NULL;
    }
  }

  switch (gen_type) {
    case GEN_URI:
    case GEN_EMAIL:
    case GEN_DNS: {
      ASN1_IA5STRING *str = ASN1_IA5STRING_new();
      if (str == NULL || !ASN1_STRING_set(str, value, strlen(value))) {
        ASN1_STRING_free(str);
        goto err;
      }
      gen->type = gen_type;
      gen->d.ia5 = str;
      break;
    }

    case GEN_RID: {
      ASN1_OBJECT *obj;
      if (!(obj = OBJ_txt2obj(value, 0))) {
        OPENSSL_PUT_ERROR(X509V3, X509V3_R_BAD_OBJECT);
        ERR_add_error_data(2, "value=", value);
        goto err;
      }
      gen->type = GEN_RID;
      gen->d.rid = obj;
      break;
    }

    case GEN_IPADD:
      gen->type = GEN_IPADD;
      if (is_nc) {
        gen->d.ip = a2i_IPADDRESS_NC(value);
      } else {
        gen->d.ip = a2i_IPADDRESS(value);
      }
      if (gen->d.ip == NULL) {
        OPENSSL_PUT_ERROR(X509V3, X509V3_R_BAD_IP_ADDRESS);
        ERR_add_error_data(2, "value=", value);
        goto err;
      }
      break;

    case GEN_DIRNAME:
      if (!do_dirname(gen, value, ctx)) {
        OPENSSL_PUT_ERROR(X509V3, X509V3_R_DIRNAME_ERROR);
        goto err;
      }
      break;

    case GEN_OTHERNAME:
      if (!do_othername(gen, value, ctx)) {
        OPENSSL_PUT_ERROR(X509V3, X509V3_R_OTHERNAME_ERROR);
        goto err;
      }
      break;
    default:
      OPENSSL_PUT_ERROR(X509V3, X509V3_R_UNSUPPORTED_TYPE);
      goto err;
  }

  return gen;

err:
  if (!out) {
    GENERAL_NAME_free(gen);
  }
  return NULL;
}

GENERAL_NAME *v2i_GENERAL_NAME_ex(GENERAL_NAME *out,
                                  const X509V3_EXT_METHOD *method,
                                  const X509V3_CTX *ctx, const CONF_VALUE *cnf,
                                  int is_nc) {
  const char *name = cnf->name;
  const char *value = cnf->value;
  if (!value) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_MISSING_VALUE);
    return NULL;
  }

  int type;
  if (x509v3_conf_name_matches(name, "email")) {
    type = GEN_EMAIL;
  } else if (x509v3_conf_name_matches(name, "URI")) {
    type = GEN_URI;
  } else if (x509v3_conf_name_matches(name, "DNS")) {
    type = GEN_DNS;
  } else if (x509v3_conf_name_matches(name, "RID")) {
    type = GEN_RID;
  } else if (x509v3_conf_name_matches(name, "IP")) {
    type = GEN_IPADD;
  } else if (x509v3_conf_name_matches(name, "dirName")) {
    type = GEN_DIRNAME;
  } else if (x509v3_conf_name_matches(name, "otherName")) {
    type = GEN_OTHERNAME;
  } else {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_UNSUPPORTED_OPTION);
    ERR_add_error_data(2, "name=", name);
    return NULL;
  }

  return a2i_GENERAL_NAME(out, method, ctx, type, value, is_nc);
}

static int do_othername(GENERAL_NAME *gen, const char *value,
                        const X509V3_CTX *ctx) {
  const char *semicolon = strchr(value, ';');
  if (semicolon == NULL) {
    return 0;
  }

  OTHERNAME *name = OTHERNAME_new();
  if (name == NULL) {
    return 0;
  }

  char *objtmp = OPENSSL_strndup(value, semicolon - value);
  if (objtmp == NULL) {
    goto err;
  }
  ASN1_OBJECT_free(name->type_id);
  name->type_id = OBJ_txt2obj(objtmp, /*dont_search_names=*/0);
  OPENSSL_free(objtmp);
  if (name->type_id == NULL) {
    goto err;
  }

  ASN1_TYPE_free(name->value);
  name->value = ASN1_generate_v3(semicolon + 1, ctx);
  if (name->value == NULL) {
    goto err;
  }

  gen->type = GEN_OTHERNAME;
  gen->d.otherName = name;
  return 1;

err:
  OTHERNAME_free(name);
  return 0;
}

static int do_dirname(GENERAL_NAME *gen, const char *value,
                      const X509V3_CTX *ctx) {
  int ret = 0;
  const STACK_OF(CONF_VALUE) *sk = X509V3_get_section(ctx, value);
  X509_NAME *nm = X509_NAME_new();
  if (nm == NULL) {
    goto err;
  }
  if (sk == NULL) {
    OPENSSL_PUT_ERROR(X509V3, X509V3_R_SECTION_NOT_FOUND);
    ERR_add_error_data(2, "section=", value);
    goto err;
  }
  // FIXME: should allow other character types...
  if (!X509V3_NAME_from_section(nm, sk, MBSTRING_ASC)) {
    goto err;
  }
  gen->type = GEN_DIRNAME;
  gen->d.dirn = nm;
  ret = 1;

err:
  if (!ret) {
    X509_NAME_free(nm);
  }
  return ret;
}