// Copyright 1995-2016 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 <openssl/asn1.h>

#include <limits.h>

#include <string.h>

#include <openssl/bytestring.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "../internal.h"

#include "../mem_internal.h"

#include "internal.h"

using namespace bssl;

// Cross-module errors from crypto/x509/i2d_pr.c.

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNSUPPORTED_PUBLIC_KEY_TYPE)

// Cross-module errors from crypto/x509/algorithm.c.

OPENSSL_DECLARE_ERROR_REASON(ASN1, CONTEXT_NOT_INITIALISED)

OPENSSL_DECLARE_ERROR_REASON(ASN1, DIGEST_AND_KEY_TYPE_NOT_SUPPORTED)

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNKNOWN_MESSAGE_DIGEST_ALGORITHM)

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNKNOWN_SIGNATURE_ALGORITHM)

OPENSSL_DECLARE_ERROR_REASON(ASN1, WRONG_PUBLIC_KEY_TYPE)

// Cross-module errors from crypto/x509/asn1_gen.c. TODO(davidben): Remove

// these once asn1_gen.c is gone.

OPENSSL_DECLARE_ERROR_REASON(ASN1, DEPTH_EXCEEDED)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_BITSTRING_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_BOOLEAN)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_HEX)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_IMPLICIT_TAG)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_INTEGER)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_NESTED_TAGGING)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_NULL_VALUE)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_OBJECT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, ILLEGAL_TIME_VALUE)

OPENSSL_DECLARE_ERROR_REASON(ASN1, INTEGER_NOT_ASCII_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, INVALID_MODIFIER)

OPENSSL_DECLARE_ERROR_REASON(ASN1, INVALID_NUMBER)

OPENSSL_DECLARE_ERROR_REASON(ASN1, LIST_ERROR)

OPENSSL_DECLARE_ERROR_REASON(ASN1, MISSING_VALUE)

OPENSSL_DECLARE_ERROR_REASON(ASN1, NOT_ASCII_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, OBJECT_NOT_ASCII_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, SEQUENCE_OR_SET_NEEDS_CONFIG)

OPENSSL_DECLARE_ERROR_REASON(ASN1, TIME_NOT_ASCII_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNKNOWN_FORMAT)

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNKNOWN_TAG)

OPENSSL_DECLARE_ERROR_REASON(ASN1, UNSUPPORTED_TYPE)

// Limit |ASN1_STRING|s to 64 MiB of data. Most of this module, as well as

// downstream code, does not correctly handle overflow. We cap string fields

// more tightly than strictly necessary to fit in |int|. This is not expected to

// impact real world uses of this field.

//

// In particular, this limit is small enough that the bit count of a BIT STRING

// comfortably fits in an |int|, with room for arithmetic.

#define ASN1_STRING_MAX (64 * 1024 * 1024)

static void asn1_put_length(unsigned char **pp, int length);

int ASN1_get_object(const unsigned char **inp, long *out_len, int *out_tag,

                    int *out_class, long in_len) {

  if (in_len < 0) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_HEADER_TOO_LONG);

    return 0x80;

  }

  CBS_ASN1_TAG tag;

  CBS cbs, body;

  CBS_init(&cbs, *inp, (size_t)in_len);

  if (!CBS_get_any_asn1(&cbs, &body, &tag) ||

      // Bound the length to comfortably fit in an int. Lengths in this

      // module often switch between int and long without overflow checks.

      CBS_len(&body) > INT_MAX / 2) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_HEADER_TOO_LONG);

    return 0x80;

  }

  // Convert between tag representations.

  int tag_class = (tag & CBS_ASN1_CLASS_MASK) >> CBS_ASN1_TAG_SHIFT;

  int constructed = (tag & CBS_ASN1_CONSTRUCTED) >> CBS_ASN1_TAG_SHIFT;

  int tag_number = tag & CBS_ASN1_TAG_NUMBER_MASK;

  // To avoid ambiguity with V_ASN1_NEG, impose a limit on universal tags.

  if (tag_class == V_ASN1_UNIVERSAL && tag_number > V_ASN1_MAX_UNIVERSAL) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_HEADER_TOO_LONG);

    return 0x80;

  }

  *inp = CBS_data(&body);

  *out_len = CBS_len(&body);

  *out_tag = tag_number;

  *out_class = tag_class;

  return constructed;

}

// class 0 is constructed constructed == 2 for indefinite length constructed

void ASN1_put_object(unsigned char **pp, int constructed, int length, int tag,

                     int xclass) {

  unsigned char *p = *pp;

  int i, ttag;

  i = (constructed) ? V_ASN1_CONSTRUCTED : 0;

  i |= (xclass & V_ASN1_PRIVATE);

  if (tag < 31) {

    *(p++) = i | (tag & V_ASN1_PRIMITIVE_TAG);

  } else {

    *(p++) = i | V_ASN1_PRIMITIVE_TAG;

    for (i = 0, ttag = tag; ttag > 0; i++) {

      ttag >>= 7;

    }

    ttag = i;

    while (i-- > 0) {

      p[i] = tag & 0x7f;

      if (i != (ttag - 1)) {

        p[i] |= 0x80;

      }

      tag >>= 7;

    }

    p += ttag;

  }

  if (constructed == 2) {

    *(p++) = 0x80;

  } else {

    asn1_put_length(&p, length);

  }

  *pp = p;

}

int ASN1_put_eoc(unsigned char **pp) {

  // This function is no longer used in the library, but some external code

  // uses it.

  unsigned char *p = *pp;

  *p++ = 0;

  *p++ = 0;

  *pp = p;

  return 2;

}

static void asn1_put_length(unsigned char **pp, int length) {

  unsigned char *p = *pp;

  int i, l;

  if (length <= 127) {

    *(p++) = (unsigned char)length;

  } else {

    l = length;

    for (i = 0; l > 0; i++) {

      l >>= 8;

    }

    *(p++) = i | 0x80;

    l = i;

    while (i-- > 0) {

      p[i] = length & 0xff;

      length >>= 8;

    }

    p += l;

  }

  *pp = p;

}

int ASN1_object_size(int constructed, int length, int tag) {

  int ret = 1;

  if (length < 0) {

    return -1;

  }

  if (tag >= 31) {

    while (tag > 0) {

      tag >>= 7;

      ret++;

    }

  }

  if (constructed == 2) {

    ret += 3;

  } else {

    ret++;

    if (length > 127) {

      int tmplen = length;

      while (tmplen > 0) {

        tmplen >>= 8;

        ret++;

      }

    }

  }

  if (ret >= INT_MAX - length) {

    return -1;

  }

  return ret + length;

}

int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str) {

  if (str == nullptr) {

    return 0;

  }

  if (dst == str) {

    return 1;

  }

  if (!ASN1_STRING_set(dst, str->data, str->length)) {

    return 0;

  }

  dst->type = str->type;

  dst->flags = str->flags;

  return 1;

}

ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *str) {

  ASN1_STRING *ret;

  if (!str) {

    return nullptr;

  }

  ret = ASN1_STRING_new();

  if (!ret) {

    return nullptr;

  }

  if (!ASN1_STRING_copy(ret, str)) {

    ASN1_STRING_free(ret);

    return nullptr;

  }

  return ret;

}

int ASN1_STRING_set(ASN1_STRING *str, const void *_data, ossl_ssize_t len_s) {

  const char *data = reinterpret_cast<const char *>(_data);

  size_t len;

  if (len_s < 0) {

    if (data == nullptr) {

      return 0;

    }

    len = strlen(data);

  } else {

    len = (size_t)len_s;

  }

  static_assert(ASN1_STRING_MAX < INT_MAX, "len will not overflow int");

  if (len > ASN1_STRING_MAX) {

    OPENSSL_PUT_ERROR(ASN1, ERR_R_OVERFLOW);

    return 0;

  }

  if (str->length <= (int)len || str->data == nullptr) {

    unsigned char *c = str->data;

    if (c == nullptr) {

      str->data = reinterpret_cast<uint8_t *>(OPENSSL_malloc(len + 1));

    } else {

      str->data = reinterpret_cast<uint8_t *>(OPENSSL_realloc(c, len + 1));

    }

    if (str->data == nullptr) {

      str->data = c;

      return 0;

    }

  }

  str->length = (int)len;

  if (data != nullptr) {

    OPENSSL_memcpy(str->data, data, len);

    // Historically, OpenSSL would NUL-terminate most (but not all)

    // |ASN1_STRING|s, in case anyone accidentally passed |str->data| into a

    // function expecting a C string. We retain this behavior for compatibility,

    // but code must not rely on this. See CVE-2021-3712.

    str->data[len] = '\0';

  }

  return 1;

}

void ASN1_STRING_set0(ASN1_STRING *str, void *data, int len) {

  OPENSSL_free(str->data);

  str->data = reinterpret_cast<uint8_t *>(data);

  str->length = len;

}

ASN1_STRING *ASN1_STRING_new() {

  return (ASN1_STRING_type_new(V_ASN1_OCTET_STRING));

}

ASN1_STRING *ASN1_STRING_type_new(int type) {

  ASN1_STRING *ret = New<ASN1_STRING>();

  if (ret == nullptr) {

    return nullptr;

  }

  ret->length = 0;

  ret->type = type;

  ret->data = nullptr;

  ret->flags = 0;

  return ret;

}

void bssl::asn1_string_init(ASN1_STRING *str, int type) {

  OPENSSL_memset(str, 0, sizeof(ASN1_STRING));

  str->type = type;

}

void bssl::asn1_string_cleanup(ASN1_STRING *str) {

  OPENSSL_free(str->data);

  str->data = nullptr;

}

void ASN1_STRING_free(ASN1_STRING *str) {

  if (str == nullptr) {

    return;

  }

  asn1_string_cleanup(str);

  Delete(str);

}

int ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b) {

  // Capture padding bits and implicit truncation in BIT STRINGs.

  int a_length = a->length, b_length = b->length;

  uint8_t a_padding = 0, b_padding = 0;

  if (a->type == V_ASN1_BIT_STRING) {

    a_length = asn1_bit_string_length(a, &a_padding);

  }

  if (b->type == V_ASN1_BIT_STRING) {

    b_length = asn1_bit_string_length(b, &b_padding);

  }

  if (a_length < b_length) {

    return -1;

  }

  if (a_length > b_length) {

    return 1;

  }

  // In a BIT STRING, the number of bits is 8 * length - padding. Invert this

  // comparison so we compare by lengths.

  if (a_padding > b_padding) {

    return -1;

  }

  if (a_padding < b_padding) {

    return 1;

  }

  int ret = OPENSSL_memcmp(a->data, b->data, a_length);

  if (ret != 0) {

    return ret;

  }

  // Comparing the type first is more natural, but this matches OpenSSL.

  if (a->type < b->type) {

    return -1;

  }

  if (a->type > b->type) {

    return 1;

  }

  return 0;

}

int ASN1_STRING_length(const ASN1_STRING *str) { return str->length; }

int ASN1_STRING_type(const ASN1_STRING *str) { return str->type; }

unsigned char *ASN1_STRING_data(ASN1_STRING *str) { return str->data; }

const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *str) {

  return str->data;

}

int bssl::asn1_parse_octet_string(CBS *cbs, ASN1_STRING *out,

                                  CBS_ASN1_TAG tag) {

  tag = tag == 0 ? CBS_ASN1_OCTETSTRING : tag;

  CBS child;

  if (!CBS_get_asn1(cbs, &child, tag)) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);

    return 0;

  }

  if (!ASN1_STRING_set(out, CBS_data(&child), CBS_len(&child))) {

    return 0;

  }

  out->type = V_ASN1_OCTET_STRING;

  return 1;

}

int bssl::asn1_marshal_octet_string(CBB *out, const ASN1_STRING *in,

                                    CBS_ASN1_TAG tag) {

  tag = tag == 0 ? CBS_ASN1_OCTETSTRING : tag;

  return CBB_add_asn1_element(out, tag, ASN1_STRING_get0_data(in),

                              ASN1_STRING_length(in));

}

static int asn1_parse_character_string(CBS *cbs, ASN1_STRING *out,

                                       CBS_ASN1_TAG tag, int str_type,

                                       int (*get_char)(CBS *cbs, uint32_t *),

                                       int bad_char_err) {

  CBS child;

  if (!CBS_get_asn1(cbs, &child, tag)) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);

    return 0;

  }

  CBS copy = child;

  while (CBS_len(&copy) != 0) {

    uint32_t c;

    if (!get_char(&copy, &c)) {

      OPENSSL_PUT_ERROR(ASN1, bad_char_err);

      return 0;

    }

  }

  if (!ASN1_STRING_set(out, CBS_data(&child), CBS_len(&child))) {

    return 0;

  }

  out->type = str_type;

  return 1;

}

int bssl::asn1_parse_bmp_string(CBS *cbs, ASN1_BMPSTRING *out,

                                CBS_ASN1_TAG tag) {

  tag = tag == 0 ? CBS_ASN1_BMPSTRING : tag;

  return asn1_parse_character_string(cbs, out, tag, V_ASN1_BMPSTRING,

                                     &CBS_get_ucs2_be,

                                     ASN1_R_INVALID_BMPSTRING);

}

int bssl::asn1_parse_universal_string(CBS *cbs, ASN1_UNIVERSALSTRING *out,

                                      CBS_ASN1_TAG tag) {

  tag = tag == 0 ? CBS_ASN1_UNIVERSALSTRING : tag;

  return asn1_parse_character_string(cbs, out, tag, V_ASN1_UNIVERSALSTRING,

                                     &CBS_get_utf32_be,

                                     ASN1_R_INVALID_UNIVERSALSTRING);

}

int bssl::asn1_parse_utf8_string(CBS *cbs, ASN1_UNIVERSALSTRING *out,

                                 CBS_ASN1_TAG tag) {

  tag = tag == 0 ? CBS_ASN1_UTF8STRING : tag;

  return asn1_parse_character_string(cbs, out, tag, V_ASN1_UTF8STRING,

                                     &CBS_get_utf8, ASN1_R_INVALID_UTF8STRING);

}