crypto/asn1/internal.h - boringssl - Git at Google

 // Copyright 2005-2016 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.

 #ifndef OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H
 #define OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H

 #include <time.h>

 #include <openssl/asn1.h>
 #include <openssl/asn1t.h>
 #include <openssl/span.h>

 #include "../internal.h"


 BSSL_NAMESPACE_BEGIN

 // Wrapper functions for time functions.

 // OPENSSL_gmtime converts a time_t value in `time` which must be in the range
 // of year 0000 to 9999 to a broken out time value in `tm`. On success `tm` is
 // returned. On failure NULL is returned.
 OPENSSL_EXPORT struct tm *OPENSSL_gmtime(const time_t *time, struct tm *result);

 // OPENSSL_gmtime_adj returns one on success, and updates `tm` by adding
 // `offset_day` days and `offset_sec` seconds. It returns zero on failure. `tm`
 // must be in the range of year 0000 to 9999 both before and after the update or
 // a failure will be returned.
 OPENSSL_EXPORT int OPENSSL_gmtime_adj(struct tm *tm, int offset_day,
                                       int64_t offset_sec);

 // OPENSSL_gmtime_diff calculates the difference between `from` and `to`. It
 // returns one, and outputs the difference as a number of days and seconds in
 // `*out_days` and `*out_secs` on success. It returns zero on failure.  Both
 // `from` and `to` must be in the range of year 0000 to 9999 or a failure will
 // be returned.
 OPENSSL_EXPORT int OPENSSL_gmtime_diff(int *out_days, int *out_secs,
                                        const struct tm *from,
                                        const struct tm *to);


 // Object identifiers.

 // These are used internally in the ASN1_OBJECT to keep track of
 // whether the names and data need to be free()ed
 #define ASN1_OBJECT_FLAG_DYNAMIC 0x01          // internal use
 #define ASN1_OBJECT_FLAG_DYNAMIC_STRINGS 0x04  // internal use
 #define ASN1_OBJECT_FLAG_DYNAMIC_DATA 0x08     // internal use

 BSSL_NAMESPACE_END

 // An asn1_object_st (aka `ASN1_OBJECT`) represents an ASN.1 OBJECT IDENTIFIER.
 // Note: Mutating an `ASN1_OBJECT` is only permitted when initializing it. The
 // library maintains a table of static `ASN1_OBJECT`s, which may be referenced
 // by non-const `ASN1_OBJECT` pointers. Code which receives an `ASN1_OBJECT`
 // pointer externally must assume it is immutable, even if the pointer is not
 // const.
 struct asn1_object_st {
   const char *sn, *ln;
   int nid;
   int length;
   const unsigned char *data;  // data remains const after init
   int flags;                  // Should we free this one
 };

 BSSL_NAMESPACE_BEGIN

 ASN1_OBJECT *ASN1_OBJECT_new();

 // asn1_parse_object parses a DER-encoded ASN.1 OBJECT IDENTIFIER from `cbs` and
 // write the result to `out`. If `tag` is non-zero, the value is implicitly
 // tagged with `tag`. On success, it returns a newly-allocated `ASN1_OBJECT`
 // with the result and advances `cbs` past the parsed element.
 //
 // TODO(crbug.com/boringssl/414361735): This should return a bssl::UniquePtr,
 // but cannot until it is made C++ linkage.
 ASN1_OBJECT *asn1_parse_object(CBS *cbs, CBS_ASN1_TAG tag);

 // asn1_marshal_object marshals `in` as a DER-encoded, ASN.1 OBJECT IDENTIFIER
 // and writes the result to `out`. It returns one on success and zero on error.
 // If `tag` is non-zero, the tag is replaced with `tag`.
 int asn1_marshal_object(CBB *out, const ASN1_OBJECT *in, CBS_ASN1_TAG tag);


 // Strings.

 // asn1_is_printable returns one if `value` is a valid Unicode codepoint for an
 // ASN.1 PrintableString, and zero otherwise.
 int asn1_is_printable(uint32_t value);

 // asn1_string_init initializes `str`, which may be uninitialized, with type
 // `type`.
 void asn1_string_init(ASN1_STRING *str, int type);

 // asn1_string_cleanup releases memory associated with `str`'s value, without
 // freeing `str` itself.
 void asn1_string_cleanup(ASN1_STRING *str);

 // asn1_parse_string_unchecked parses a DER-encoded string of type `str_type`,
 // tagged with `tag`. It does not check the contents.
 int asn1_parse_string_unchecked(CBS *cbs, ASN1_STRING *out, int str_type,
                                 CBS_ASN1_TAG tag);

 // The following functions parse a DER-encoded ASN.1 value of the specified
 // type from `cbs` and write the result to `*out`. If `tag` is non-zero, the
 // value is implicitly tagged with `tag`. On success, they return one and
 // advance `cbs` past the parsed element. On entry, `*out` must contain an
 // `ASN1_STRING` in some valid state.
 int asn1_parse_bit_string(CBS *cbs, ASN1_BIT_STRING *out, CBS_ASN1_TAG tag);
 int asn1_parse_integer(CBS *cbs, ASN1_INTEGER *out, CBS_ASN1_TAG tag);
 int asn1_parse_enumerated(CBS *cbs, ASN1_ENUMERATED *out, CBS_ASN1_TAG tag);
 int asn1_parse_octet_string(CBS *cbs, ASN1_STRING *out, CBS_ASN1_TAG tag);
 int asn1_parse_t61_string(CBS *cbs, ASN1_STRING *out, CBS_ASN1_TAG tag);
 int asn1_parse_bmp_string(CBS *cbs, ASN1_BMPSTRING *out, CBS_ASN1_TAG tag);
 int asn1_parse_universal_string(CBS *cbs, ASN1_UNIVERSALSTRING *out,
                                 CBS_ASN1_TAG tag);
 int asn1_parse_utf8_string(CBS *cbs, ASN1_UNIVERSALSTRING *out,
                            CBS_ASN1_TAG tag);
 int asn1_parse_generalized_time(CBS *cbs, ASN1_GENERALIZEDTIME *out,
                                 CBS_ASN1_TAG tag);
 int asn1_parse_utc_time(CBS *cbs, ASN1_UTCTIME *out, CBS_ASN1_TAG tag,
                         int allow_timezone_offset);

 // asn1_parse_bit_string_with_bad_length behaves like `asn1_parse_bit_string`
 // but tolerates BER non-minimal, definite lengths.
 int asn1_parse_bit_string_with_bad_length(CBS *cbs, ASN1_BIT_STRING *out);

 // asn1_marshal_bit_string marshals `in` as a DER-encoded, ASN.1 BIT STRING and
 // writes the result to `out`. It returns one on success and zero on error. If
 // `tag` is non-zero, the tag is replaced with `tag`.
 int asn1_marshal_bit_string(CBB *out, const ASN1_BIT_STRING *in,
                             CBS_ASN1_TAG tag);

 // asn1_marshal_integer marshals `in` as a DER-encoded, ASN.1 INTEGER and writes
 // the result to `out`. It returns one on success and zero on error. If `tag` is
 // non-zero, the tag is replaced with `tag`. This can also be used to marshal an
 // ASN.1 ENUMERATED value by overriding the tag.
 int asn1_marshal_integer(CBB *out, const ASN1_INTEGER *in, CBS_ASN1_TAG tag);

 // asn1_marshal_octet_string marshals `in` as a DER-encoded, ASN.1 OCTET STRING
 // and writes the result to `out`. It returns one on success and zero on error.
 // If `tag` is non-zero, the tag is replaced with `tag`.
 //
 // This function may be used to marshal other string-based universal types whose
 // encoding is that of an implicitly-tagged OCTET STRING, e.g. UTF8String.
 int asn1_marshal_octet_string(CBB *out, const ASN1_STRING *in,
                               CBS_ASN1_TAG tag);

 OPENSSL_EXPORT int asn1_utctime_to_tm(struct tm *tm, const ASN1_UTCTIME *d,
                                       int allow_timezone_offset);
 OPENSSL_EXPORT int asn1_generalizedtime_to_tm(struct tm *tm,
                                               const ASN1_GENERALIZEDTIME *d);

 int asn1_parse_time(CBS *cbs, ASN1_TIME *out, int allow_utc_timezone_offset);
 int asn1_marshal_time(CBB *cbb, const ASN1_TIME *in);


 // The ASN.1 ANY type.

 // asn1_type_value_as_pointer returns `a`'s value in pointer form. This is
 // usually the value object but, for BOOLEAN values, is 0 or 0xff cast to
 // a pointer.
 const void *asn1_type_value_as_pointer(const ASN1_TYPE *a);

 // asn1_type_set0_string sets `a`'s value to the object represented by `str` and
 // takes ownership of `str`.
 void asn1_type_set0_string(ASN1_TYPE *a, ASN1_STRING *str);

 // asn1_parse_any parses a DER-encoded ASN.1 value of any type from `cbs` and
 // writes the result to `*out`. On success, it advances `cbs` past the parsed
 // element and returns one. On entry, `*out` must contain an `ASN1_TYPE` in some
 // valid state.
 int asn1_parse_any(CBS *cbs, ASN1_TYPE *out);

 // asn1_parse_any_as_string behaves like `asn1_parse_any` but represents the
 // value as an `ASN1_STRING`. Types which are not represented with
 // `ASN1_STRING`, such as `ASN1_OBJECT`, are represented with type
 // `V_ASN1_OTHER`.
 int asn1_parse_any_as_string(CBS *cbs, ASN1_STRING *out);

 // asn1_marshal_any marshals `in` as a DER-encoded ASN.1 value and writes the
 // result to `out`. It returns one on success and zero on error.
 int asn1_marshal_any(CBB *out, const ASN1_TYPE *in);

 // asn1_marshal_any_string marshals `in` as a DER-encoded ASN.1 value and writes
 // the result to `out`. It returns one on success and zero on error.
 int asn1_marshal_any_string(CBB *out, const ASN1_STRING *in);


 // Support structures for the template-based encoder.

 // ASN1_ENCODING is used to save the received encoding of an ASN.1 type. This
 // avoids problems with invalid encodings that break signatures.
 typedef struct ASN1_ENCODING_st {
   // enc is the saved DER encoding. Its ownership is determined by `buf`.
   uint8_t *enc;
   // len is the length of `enc`. If zero, there is no saved encoding.
   size_t len;
 } ASN1_ENCODING;

 int ASN1_item_ex_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
 void ASN1_item_ex_free(ASN1_VALUE **pval, const ASN1_ITEM *it);

 void ASN1_template_free(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt);

 void ASN1_primitive_free(ASN1_VALUE **pval, const ASN1_ITEM *it);

 // asn1_load_ptr returns `*pval`, but without asserting `*pval`'s underlying
 // type for strict aliasing. This helper must be used when the field's
 // underlying type is not known statically. It must not be used for
 // `ASN1_BOOLEAN` fields, which are not a pointers.
 inline ASN1_VALUE *asn1_load_ptr(ASN1_VALUE **pval) {
   ASN1_VALUE *ret;
   OPENSSL_memcpy(&ret, pval, sizeof(ASN1_VALUE *));
   return ret;
 }

 // asn1_load_ptr_as behaves like `asn1_load_ptr`, but casts the result to `T*`.
 template <typename T>
 inline T *asn1_load_ptr_as(ASN1_VALUE **pval) {
   return reinterpret_cast<T *>(asn1_load_ptr(pval));
 }

 // asn1_store_ptr sets `*pval` to `v`, but without asserting `*pval`'s
 // underlying type for strict aliasing. This helper must be used when the
 // field's underlying type is not known statically. It must not be used for
 // `ASN1_BOOLEAN` fields, which are not a pointers.
 inline void asn1_store_ptr(ASN1_VALUE **pval, const void *v) {
   OPENSSL_memcpy(pval, &v, sizeof(v));
 }

 // asn1_get_choice_selector returns the CHOICE selector value for `*pval`, which
 // must of type `it`.
 int asn1_get_choice_selector(ASN1_VALUE **pval, const ASN1_ITEM *it);

 int asn1_set_choice_selector(ASN1_VALUE **pval, int value, const ASN1_ITEM *it);

 // asn1_get_field_ptr returns a pointer to the field in `*pval` corresponding to
 // `tt`.
 ASN1_VALUE **asn1_get_field_ptr(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt);

 // asn1_do_adb returns the `ASN1_TEMPLATE` for the ANY DEFINED BY field `tt`,
 // based on the selector INTEGER or OID in `*pval`. If `tt` is not an ADB field,
 // it returns `tt`. If the selector does not match any value, it returns NULL.
 // If `nullerr` is non-zero, it will additionally push an error to the error
 // queue when there is no match.
 const ASN1_TEMPLATE *asn1_do_adb(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt,
                                  int nullerr);

 void asn1_refcount_set_one(ASN1_VALUE **pval, const ASN1_ITEM *it);
 int asn1_refcount_dec_and_test_zero(ASN1_VALUE **pval, const ASN1_ITEM *it);

 void asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it);
 void asn1_enc_free(ASN1_VALUE **pval, const ASN1_ITEM *it);

 // asn1_enc_restore, if `*pval` has a saved encoding, sets `*out` to it, and
 // returns one. If it has no saved encoding, it returns zero.
 int asn1_enc_restore(Span<const uint8_t> *out, ASN1_VALUE **pval,
                      const ASN1_ITEM *it);

 // asn1_enc_save saves `inlen` bytes from `in` as `*pval`'s saved encoding. It
 // returns one on success and zero on error. If `buf` is non-NULL, `in` must
 // point into `buf`.
 int asn1_enc_save(ASN1_VALUE **pval, const uint8_t *in, size_t inlen,
                   const ASN1_ITEM *it);

 // asn1_encoding_clear clears the cached encoding in `enc`.
 void asn1_encoding_clear(ASN1_ENCODING *enc);

 // asn1_tag_to_cbs converts a tag from this library's representation (the
 // `V_ASN1_*` constants) to that of `CBS` and `CBB`. It returns the tag on
 // success and zero if the input could not be represented. (Zero would be
 // [UNIVERSAL 0], which is a reserved tag value.)
 //
 // The resulting tag will not have the constructed bit set. The caller must OR
 // the result with `CBS_ASN1_CONSTRUCTED` if necessary, before passing to
 // `CBS` and `CBB` functions.
 CBS_ASN1_TAG asn1_tag_to_cbs(int aclass, int tag);

 typedef struct {
   int nid;
   long minsize;
   long maxsize;
   unsigned long mask;
   unsigned long flags;
 } ASN1_STRING_TABLE;

 // asn1_get_string_table_for_testing sets `*out_ptr` and `*out_len` to the table
 // of built-in `ASN1_STRING_TABLE` values. It is exported for testing.
 OPENSSL_EXPORT void asn1_get_string_table_for_testing(
     const ASN1_STRING_TABLE **out_ptr, size_t *out_len);

 typedef ASN1_VALUE *ASN1_new_func();
 typedef void ASN1_free_func(ASN1_VALUE *a);
 typedef ASN1_VALUE *ASN1_d2i_func(ASN1_VALUE **a, const unsigned char **in,
                                   long length);
 typedef int ASN1_i2d_func(ASN1_VALUE *a, unsigned char **in);

 // An ASN1_ex_parse function should parse a value from `cbs` and set `*pval` to
 // the result. It should return one on success and zero on failure. If `opt` is
 // non-zero, the field may be optional. If an optional element is missing, the
 // function should return one and consume zero bytes from `cbs`.
 //
 // If `opt` is non-zero, the function can assume that `*pval` is nullptr on
 // entry. Otherwise, `*pval` may either be nullptr, or the result of
 // `ASN1_ex_new_func`. The function may either write into the existing object,
 // if any, or unconditionally make a new one. (The existing object comes from
 // tasn_new.cc recursively filling in objects before parsing into them.)
 typedef int ASN1_ex_parse(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it,
                           int opt);

 // An ASN1_ex_marshal function should marshal `*pval`, a value of type `it`, to
 // `cbb` and return one on success or zero on error.
 typedef int ASN1_ex_marshal(CBB *cbb, ASN1_VALUE **pval, const ASN1_ITEM *it);

 typedef int ASN1_ex_new_func(ASN1_VALUE **pval, const ASN1_ITEM *it);
 typedef void ASN1_ex_free_func(ASN1_VALUE **pval, const ASN1_ITEM *it);

 typedef struct ASN1_EXTERN_FUNCS_st {
   ASN1_ex_new_func *asn1_ex_new;
   ASN1_ex_free_func *asn1_ex_free;
   ASN1_ex_parse *asn1_ex_parse;
   ASN1_ex_marshal *asn1_ex_marshal;
 } ASN1_EXTERN_FUNCS;

 // IMPLEMENT_EXTERN_ASN1_PARSE_NEW implements an `ASN1_ITEM` for a type whose
 // parse function returns a new object.
 #define IMPLEMENT_EXTERN_ASN1_PARSE_NEW(name, new_func, free_func, tag,        \
                                         parse_func, marshal_func)              \
   static int name##_new_cb(ASN1_VALUE **pval, const ASN1_ITEM *it) {           \
     name *obj = new_func();                                                    \
     if (obj == nullptr) {                                                      \
       return 0;                                                                \
     }                                                                          \
     asn1_store_ptr(pval, obj);                                                 \
     return 1;                                                                  \
   }                                                                            \
                                                                                \
   static void name##_free_cb(ASN1_VALUE **pval, const ASN1_ITEM *it) {         \
     free_func(asn1_load_ptr_as<name>(pval));                                   \
     asn1_store_ptr(pval, nullptr);                                             \
   }                                                                            \
                                                                                \
   static int name##_parse_cb(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it, \
                              int opt) {                                        \
     if (opt && !CBS_peek_asn1_tag(cbs, (tag))) {                               \
       return 1;                                                                \
     }                                                                          \
                                                                                \
     bssl::UniquePtr<name> ret = parse_func(cbs);                               \
     if (ret == nullptr) {                                                      \
       return 0;                                                                \
     }                                                                          \
     name##_free_cb(pval, it);                                                  \
     asn1_store_ptr(pval, ret.release());                                       \
     return 1;                                                                  \
   }                                                                            \
                                                                                \
   static int name##_marshal_cb(CBB *cbb, ASN1_VALUE **pval,                    \
                                const ASN1_ITEM *it) {                          \
     return marshal_func(cbb, asn1_load_ptr_as<name>(pval));                    \
   }                                                                            \
                                                                                \
   static const ASN1_EXTERN_FUNCS name##_extern_funcs = {                       \
       name##_new_cb, name##_free_cb, name##_parse_cb, name##_marshal_cb};      \
                                                                                \
   IMPLEMENT_EXTERN_ASN1(name, name##_extern_funcs)

 // IMPLEMENT_EXTERN_ASN1_PARSE_INTO implements an `ASN1_ITEM` for a type whose
 // parse function writes into an existing object.
 #define IMPLEMENT_EXTERN_ASN1_PARSE_INTO(name, new_func, free_func, tag, \
                                          parse_func, marshal_func)       \
                                                                          \
   static bssl::UniquePtr<name> name##_parse_new(CBS *cbs) {              \
     bssl::UniquePtr<name> ret(new_func());                               \
     if (ret == nullptr || !parse_func(cbs, ret.get())) {                 \
       return 0;                                                          \
     }                                                                    \
     return ret;                                                          \
   }                                                                      \
                                                                          \
   IMPLEMENT_EXTERN_ASN1_PARSE_NEW(name, new_func, free_func, tag,        \
                                   name##_parse_new, marshal_func)

 // ASN1_TIME is an `ASN1_ITEM` whose ASN.1 type is X.509 Time (RFC 5280) and C
 // type is `ASN1_TIME*`.
 DECLARE_ASN1_ITEM(ASN1_TIME)

 // DIRECTORYSTRING is an `ASN1_ITEM` whose ASN.1 type is X.509 DirectoryString
 // (RFC 5280) and C type is `ASN1_STRING*`.
 DECLARE_ASN1_ITEM(DIRECTORYSTRING)

 // DISPLAYTEXT is an `ASN1_ITEM` whose ASN.1 type is X.509 DisplayText (RFC
 // 5280) and C type is `ASN1_STRING*`.
 DECLARE_ASN1_ITEM(DISPLAYTEXT)

 BSSL_NAMESPACE_END

 #endif  // OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H
	// Copyright 2005-2016 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.

	#ifndef OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H
	#define OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H

	#include <time.h>

	#include <openssl/asn1.h>
	#include <openssl/asn1t.h>
	#include <openssl/span.h>

	#include "../internal.h"


	BSSL_NAMESPACE_BEGIN

	// Wrapper functions for time functions.

	// OPENSSL_gmtime converts a time_t value in `time` which must be in the range
	// of year 0000 to 9999 to a broken out time value in `tm`. On success `tm` is
	// returned. On failure NULL is returned.
	OPENSSL_EXPORT struct tm OPENSSL_gmtime(const time_t time, struct tm *result);

	// OPENSSL_gmtime_adj returns one on success, and updates `tm` by adding
	// `offset_day` days and `offset_sec` seconds. It returns zero on failure. `tm`
	// must be in the range of year 0000 to 9999 both before and after the update or
	// a failure will be returned.
	OPENSSL_EXPORT int OPENSSL_gmtime_adj(struct tm *tm, int offset_day,
	int64_t offset_sec);

	// OPENSSL_gmtime_diff calculates the difference between `from` and `to`. It
	// returns one, and outputs the difference as a number of days and seconds in
	// `out_days` and `out_secs` on success. It returns zero on failure. Both
	// `from` and `to` must be in the range of year 0000 to 9999 or a failure will
	// be returned.
	OPENSSL_EXPORT int OPENSSL_gmtime_diff(int out_days, int out_secs,
	const struct tm *from,
	const struct tm *to);


	// Object identifiers.

	// These are used internally in the ASN1_OBJECT to keep track of
	// whether the names and data need to be free()ed
	#define ASN1_OBJECT_FLAG_DYNAMIC 0x01 // internal use
	#define ASN1_OBJECT_FLAG_DYNAMIC_STRINGS 0x04 // internal use
	#define ASN1_OBJECT_FLAG_DYNAMIC_DATA 0x08 // internal use

	BSSL_NAMESPACE_END

	// An asn1_object_st (aka `ASN1_OBJECT`) represents an ASN.1 OBJECT IDENTIFIER.
	// Note: Mutating an `ASN1_OBJECT` is only permitted when initializing it. The
	// library maintains a table of static `ASN1_OBJECT`s, which may be referenced
	// by non-const `ASN1_OBJECT` pointers. Code which receives an `ASN1_OBJECT`
	// pointer externally must assume it is immutable, even if the pointer is not
	// const.
	struct asn1_object_st {
	const char sn, ln;
	int nid;
	int length;
	const unsigned char *data; // data remains const after init
	int flags; // Should we free this one
	};

	BSSL_NAMESPACE_BEGIN

	ASN1_OBJECT *ASN1_OBJECT_new();

	// asn1_parse_object parses a DER-encoded ASN.1 OBJECT IDENTIFIER from `cbs` and
	// write the result to `out`. If `tag` is non-zero, the value is implicitly
	// tagged with `tag`. On success, it returns a newly-allocated `ASN1_OBJECT`
	// with the result and advances `cbs` past the parsed element.
	//
	// TODO(crbug.com/boringssl/414361735): This should return a bssl::UniquePtr,
	// but cannot until it is made C++ linkage.
	ASN1_OBJECT asn1_parse_object(CBS cbs, CBS_ASN1_TAG tag);

	// asn1_marshal_object marshals `in` as a DER-encoded, ASN.1 OBJECT IDENTIFIER
	// and writes the result to `out`. It returns one on success and zero on error.
	// If `tag` is non-zero, the tag is replaced with `tag`.
	int asn1_marshal_object(CBB out, const ASN1_OBJECT in, CBS_ASN1_TAG tag);


	// Strings.

	// asn1_is_printable returns one if `value` is a valid Unicode codepoint for an
	// ASN.1 PrintableString, and zero otherwise.
	int asn1_is_printable(uint32_t value);

	// asn1_string_init initializes `str`, which may be uninitialized, with type
	// `type`.
	void asn1_string_init(ASN1_STRING *str, int type);

	// asn1_string_cleanup releases memory associated with `str`'s value, without
	// freeing `str` itself.
	void asn1_string_cleanup(ASN1_STRING *str);

	// asn1_parse_string_unchecked parses a DER-encoded string of type `str_type`,
	// tagged with `tag`. It does not check the contents.
	int asn1_parse_string_unchecked(CBS cbs, ASN1_STRING out, int str_type,
	CBS_ASN1_TAG tag);

	// The following functions parse a DER-encoded ASN.1 value of the specified
	// type from `cbs` and write the result to `*out`. If `tag` is non-zero, the
	// value is implicitly tagged with `tag`. On success, they return one and
	// advance `cbs` past the parsed element. On entry, `*out` must contain an
	// `ASN1_STRING` in some valid state.
	int asn1_parse_bit_string(CBS cbs, ASN1_BIT_STRING out, CBS_ASN1_TAG tag);
	int asn1_parse_integer(CBS cbs, ASN1_INTEGER out, CBS_ASN1_TAG tag);
	int asn1_parse_enumerated(CBS cbs, ASN1_ENUMERATED out, CBS_ASN1_TAG tag);
	int asn1_parse_octet_string(CBS cbs, ASN1_STRING out, CBS_ASN1_TAG tag);
	int asn1_parse_t61_string(CBS cbs, ASN1_STRING out, CBS_ASN1_TAG tag);
	int asn1_parse_bmp_string(CBS cbs, ASN1_BMPSTRING out, CBS_ASN1_TAG tag);
	int asn1_parse_universal_string(CBS cbs, ASN1_UNIVERSALSTRING out,
	CBS_ASN1_TAG tag);
	int asn1_parse_utf8_string(CBS cbs, ASN1_UNIVERSALSTRING out,
	CBS_ASN1_TAG tag);
	int asn1_parse_generalized_time(CBS cbs, ASN1_GENERALIZEDTIME out,
	CBS_ASN1_TAG tag);
	int asn1_parse_utc_time(CBS cbs, ASN1_UTCTIME out, CBS_ASN1_TAG tag,
	int allow_timezone_offset);

	// asn1_parse_bit_string_with_bad_length behaves like `asn1_parse_bit_string`
	// but tolerates BER non-minimal, definite lengths.
	int asn1_parse_bit_string_with_bad_length(CBS cbs, ASN1_BIT_STRING out);

	// asn1_marshal_bit_string marshals `in` as a DER-encoded, ASN.1 BIT STRING and
	// writes the result to `out`. It returns one on success and zero on error. If
	// `tag` is non-zero, the tag is replaced with `tag`.
	int asn1_marshal_bit_string(CBB out, const ASN1_BIT_STRING in,
	CBS_ASN1_TAG tag);

	// asn1_marshal_integer marshals `in` as a DER-encoded, ASN.1 INTEGER and writes
	// the result to `out`. It returns one on success and zero on error. If `tag` is
	// non-zero, the tag is replaced with `tag`. This can also be used to marshal an
	// ASN.1 ENUMERATED value by overriding the tag.
	int asn1_marshal_integer(CBB out, const ASN1_INTEGER in, CBS_ASN1_TAG tag);

	// asn1_marshal_octet_string marshals `in` as a DER-encoded, ASN.1 OCTET STRING
	// and writes the result to `out`. It returns one on success and zero on error.
	// If `tag` is non-zero, the tag is replaced with `tag`.
	//
	// This function may be used to marshal other string-based universal types whose
	// encoding is that of an implicitly-tagged OCTET STRING, e.g. UTF8String.
	int asn1_marshal_octet_string(CBB out, const ASN1_STRING in,
	CBS_ASN1_TAG tag);

	OPENSSL_EXPORT int asn1_utctime_to_tm(struct tm tm, const ASN1_UTCTIME d,
	int allow_timezone_offset);
	OPENSSL_EXPORT int asn1_generalizedtime_to_tm(struct tm *tm,
	const ASN1_GENERALIZEDTIME *d);

	int asn1_parse_time(CBS cbs, ASN1_TIME out, int allow_utc_timezone_offset);
	int asn1_marshal_time(CBB cbb, const ASN1_TIME in);


	// The ASN.1 ANY type.

	// asn1_type_value_as_pointer returns `a`'s value in pointer form. This is
	// usually the value object but, for BOOLEAN values, is 0 or 0xff cast to
	// a pointer.
	const void asn1_type_value_as_pointer(const ASN1_TYPE a);

	// asn1_type_set0_string sets `a`'s value to the object represented by `str` and
	// takes ownership of `str`.
	void asn1_type_set0_string(ASN1_TYPE a, ASN1_STRING str);

	// asn1_parse_any parses a DER-encoded ASN.1 value of any type from `cbs` and
	// writes the result to `*out`. On success, it advances `cbs` past the parsed
	// element and returns one. On entry, `*out` must contain an `ASN1_TYPE` in some
	// valid state.
	int asn1_parse_any(CBS cbs, ASN1_TYPE out);

	// asn1_parse_any_as_string behaves like `asn1_parse_any` but represents the
	// value as an `ASN1_STRING`. Types which are not represented with
	// `ASN1_STRING`, such as `ASN1_OBJECT`, are represented with type
	// `V_ASN1_OTHER`.
	int asn1_parse_any_as_string(CBS cbs, ASN1_STRING out);

	// asn1_marshal_any marshals `in` as a DER-encoded ASN.1 value and writes the
	// result to `out`. It returns one on success and zero on error.
	int asn1_marshal_any(CBB out, const ASN1_TYPE in);

	// asn1_marshal_any_string marshals `in` as a DER-encoded ASN.1 value and writes
	// the result to `out`. It returns one on success and zero on error.
	int asn1_marshal_any_string(CBB out, const ASN1_STRING in);


	// Support structures for the template-based encoder.

	// ASN1_ENCODING is used to save the received encoding of an ASN.1 type. This
	// avoids problems with invalid encodings that break signatures.
	typedef struct ASN1_ENCODING_st {
	// enc is the saved DER encoding. Its ownership is determined by `buf`.
	uint8_t *enc;
	// len is the length of `enc`. If zero, there is no saved encoding.
	size_t len;
	} ASN1_ENCODING;

	int ASN1_item_ex_new(ASN1_VALUE *pval, const ASN1_ITEM it);
	void ASN1_item_ex_free(ASN1_VALUE *pval, const ASN1_ITEM it);

	void ASN1_template_free(ASN1_VALUE *pval, const ASN1_TEMPLATE tt);

	void ASN1_primitive_free(ASN1_VALUE *pval, const ASN1_ITEM it);

	// asn1_load_ptr returns `pval`, but without asserting `pval`'s underlying
	// type for strict aliasing. This helper must be used when the field's
	// underlying type is not known statically. It must not be used for
	// `ASN1_BOOLEAN` fields, which are not a pointers.
	inline ASN1_VALUE asn1_load_ptr(ASN1_VALUE *pval) {
	ASN1_VALUE *ret;
	OPENSSL_memcpy(&ret, pval, sizeof(ASN1_VALUE *));
	return ret;
	}

	// asn1_load_ptr_as behaves like `asn1_load_ptr`, but casts the result to `T*`.
	template <typename T>
	inline T asn1_load_ptr_as(ASN1_VALUE *pval) {
	return reinterpret_cast<T *>(asn1_load_ptr(pval));
	}

	// asn1_store_ptr sets `pval` to `v`, but without asserting `pval`'s
	// underlying type for strict aliasing. This helper must be used when the
	// field's underlying type is not known statically. It must not be used for
	// `ASN1_BOOLEAN` fields, which are not a pointers.
	inline void asn1_store_ptr(ASN1_VALUE *pval, const void v) {
	OPENSSL_memcpy(pval, &v, sizeof(v));
	}

	// asn1_get_choice_selector returns the CHOICE selector value for `*pval`, which
	// must of type `it`.
	int asn1_get_choice_selector(ASN1_VALUE *pval, const ASN1_ITEM it);

	int asn1_set_choice_selector(ASN1_VALUE *pval, int value, const ASN1_ITEM it);

	// asn1_get_field_ptr returns a pointer to the field in `*pval` corresponding to
	// `tt`.
	ASN1_VALUE asn1_get_field_ptr(ASN1_VALUE pval, const ASN1_TEMPLATE *tt);

	// asn1_do_adb returns the `ASN1_TEMPLATE` for the ANY DEFINED BY field `tt`,
	// based on the selector INTEGER or OID in `*pval`. If `tt` is not an ADB field,
	// it returns `tt`. If the selector does not match any value, it returns NULL.
	// If `nullerr` is non-zero, it will additionally push an error to the error
	// queue when there is no match.
	const ASN1_TEMPLATE asn1_do_adb(ASN1_VALUE pval, const ASN1_TEMPLATE tt,
	int nullerr);

	void asn1_refcount_set_one(ASN1_VALUE *pval, const ASN1_ITEM it);
	int asn1_refcount_dec_and_test_zero(ASN1_VALUE *pval, const ASN1_ITEM it);

	void asn1_enc_init(ASN1_VALUE *pval, const ASN1_ITEM it);
	void asn1_enc_free(ASN1_VALUE *pval, const ASN1_ITEM it);

	// asn1_enc_restore, if `pval` has a saved encoding, sets `out` to it, and
	// returns one. If it has no saved encoding, it returns zero.
	int asn1_enc_restore(Span<const uint8_t> out, ASN1_VALUE *pval,
	const ASN1_ITEM *it);

	// asn1_enc_save saves `inlen` bytes from `in` as `*pval`'s saved encoding. It
	// returns one on success and zero on error. If `buf` is non-NULL, `in` must
	// point into `buf`.
	int asn1_enc_save(ASN1_VALUE *pval, const uint8_t in, size_t inlen,
	const ASN1_ITEM *it);

	// asn1_encoding_clear clears the cached encoding in `enc`.
	void asn1_encoding_clear(ASN1_ENCODING *enc);

	// asn1_tag_to_cbs converts a tag from this library's representation (the
	// `V_ASN1_*` constants) to that of `CBS` and `CBB`. It returns the tag on
	// success and zero if the input could not be represented. (Zero would be
	// [UNIVERSAL 0], which is a reserved tag value.)
	//
	// The resulting tag will not have the constructed bit set. The caller must OR
	// the result with `CBS_ASN1_CONSTRUCTED` if necessary, before passing to
	// `CBS` and `CBB` functions.
	CBS_ASN1_TAG asn1_tag_to_cbs(int aclass, int tag);

	typedef struct {
	int nid;
	long minsize;
	long maxsize;
	unsigned long mask;
	unsigned long flags;
	} ASN1_STRING_TABLE;

	// asn1_get_string_table_for_testing sets `out_ptr` and `out_len` to the table
	// of built-in `ASN1_STRING_TABLE` values. It is exported for testing.
	OPENSSL_EXPORT void asn1_get_string_table_for_testing(
	const ASN1_STRING_TABLE *out_ptr, size_t out_len);

	typedef ASN1_VALUE *ASN1_new_func();
	typedef void ASN1_free_func(ASN1_VALUE *a);
	typedef ASN1_VALUE ASN1_d2i_func(ASN1_VALUE a, const unsigned char *in,
	long length);
	typedef int ASN1_i2d_func(ASN1_VALUE a, unsigned char *in);

	// An ASN1_ex_parse function should parse a value from `cbs` and set `*pval` to
	// the result. It should return one on success and zero on failure. If `opt` is
	// non-zero, the field may be optional. If an optional element is missing, the
	// function should return one and consume zero bytes from `cbs`.
	//
	// If `opt` is non-zero, the function can assume that `*pval` is nullptr on
	// entry. Otherwise, `*pval` may either be nullptr, or the result of
	// `ASN1_ex_new_func`. The function may either write into the existing object,
	// if any, or unconditionally make a new one. (The existing object comes from
	// tasn_new.cc recursively filling in objects before parsing into them.)
	typedef int ASN1_ex_parse(ASN1_VALUE *pval, CBS cbs, const ASN1_ITEM *it,
	int opt);

	// An ASN1_ex_marshal function should marshal `*pval`, a value of type `it`, to
	// `cbb` and return one on success or zero on error.
	typedef int ASN1_ex_marshal(CBB cbb, ASN1_VALUE pval, const ASN1_ITEM it);

	typedef int ASN1_ex_new_func(ASN1_VALUE *pval, const ASN1_ITEM it);
	typedef void ASN1_ex_free_func(ASN1_VALUE *pval, const ASN1_ITEM it);

	typedef struct ASN1_EXTERN_FUNCS_st {
	ASN1_ex_new_func *asn1_ex_new;
	ASN1_ex_free_func *asn1_ex_free;
	ASN1_ex_parse *asn1_ex_parse;
	ASN1_ex_marshal *asn1_ex_marshal;
	} ASN1_EXTERN_FUNCS;

	// IMPLEMENT_EXTERN_ASN1_PARSE_NEW implements an `ASN1_ITEM` for a type whose
	// parse function returns a new object.
	#define IMPLEMENT_EXTERN_ASN1_PARSE_NEW(name, new_func, free_func, tag, \
	parse_func, marshal_func) \
	static int name##_new_cb(ASN1_VALUE *pval, const ASN1_ITEM it) { \
	name *obj = new_func(); \
	if (obj == nullptr) { \
	return 0; \
	} \
	asn1_store_ptr(pval, obj); \
	return 1; \
	} \
	\
	static void name##_free_cb(ASN1_VALUE *pval, const ASN1_ITEM it) { \
	free_func(asn1_load_ptr_as<name>(pval)); \
	asn1_store_ptr(pval, nullptr); \
	} \
	\
	static int name##_parse_cb(ASN1_VALUE *pval, CBS cbs, const ASN1_ITEM *it, \
	int opt) { \
	if (opt && !CBS_peek_asn1_tag(cbs, (tag))) { \
	return 1; \
	} \
	\
	bssl::UniquePtr<name> ret = parse_func(cbs); \
	if (ret == nullptr) { \
	return 0; \
	} \
	name##_free_cb(pval, it); \
	asn1_store_ptr(pval, ret.release()); \
	return 1; \
	} \
	\
	static int name##_marshal_cb(CBB cbb, ASN1_VALUE *pval, \
	const ASN1_ITEM *it) { \
	return marshal_func(cbb, asn1_load_ptr_as<name>(pval)); \
	} \
	\
	static const ASN1_EXTERN_FUNCS name##_extern_funcs = { \
	name##_new_cb, name##_free_cb, name##_parse_cb, name##_marshal_cb}; \
	\
	IMPLEMENT_EXTERN_ASN1(name, name##_extern_funcs)

	// IMPLEMENT_EXTERN_ASN1_PARSE_INTO implements an `ASN1_ITEM` for a type whose
	// parse function writes into an existing object.
	#define IMPLEMENT_EXTERN_ASN1_PARSE_INTO(name, new_func, free_func, tag, \
	parse_func, marshal_func) \
	\
	static bssl::UniquePtr<name> name##_parse_new(CBS *cbs) { \
	bssl::UniquePtr<name> ret(new_func()); \
	if (ret == nullptr \|\| !parse_func(cbs, ret.get())) { \
	return 0; \
	} \
	return ret; \
	} \
	\
	IMPLEMENT_EXTERN_ASN1_PARSE_NEW(name, new_func, free_func, tag, \
	name##_parse_new, marshal_func)

	// ASN1_TIME is an `ASN1_ITEM` whose ASN.1 type is X.509 Time (RFC 5280) and C
	// type is `ASN1_TIME*`.
	DECLARE_ASN1_ITEM(ASN1_TIME)

	// DIRECTORYSTRING is an `ASN1_ITEM` whose ASN.1 type is X.509 DirectoryString
	// (RFC 5280) and C type is `ASN1_STRING*`.
	DECLARE_ASN1_ITEM(DIRECTORYSTRING)

	// DISPLAYTEXT is an `ASN1_ITEM` whose ASN.1 type is X.509 DisplayText (RFC
	// 5280) and C type is `ASN1_STRING*`.
	DECLARE_ASN1_ITEM(DISPLAYTEXT)

	BSSL_NAMESPACE_END

	#endif // OPENSSL_HEADER_CRYPTO_ASN1_INTERNAL_H