boringssl/crypto/bytestring/internal.h
David Benjamin 8803c0589d Properly advance the CBS when parsing BER structures.
CBS_asn1_ber_to_der was a little cumbersome to use. While it, in theory,
allowed callers to consistently advance past the element, no caller
actually did so consistently. Instead they would advance if conversion
happened, and not if it was already DER. For the PKCS7_* functions, this
was even caller-exposed.

Change-Id: I658d265df899bace9ba6616cb465f19c9e6c3534
Reviewed-on: https://boringssl-review.googlesource.com/29304
Reviewed-by: Adam Langley <agl@google.com>
2018-06-26 07:23:10 +00:00

97 lines
4.3 KiB
C

/* Copyright (c) 2014, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#ifndef OPENSSL_HEADER_BYTESTRING_INTERNAL_H
#define OPENSSL_HEADER_BYTESTRING_INTERNAL_H
#include <openssl/base.h>
#if defined(__cplusplus)
extern "C" {
#endif
// CBS_asn1_ber_to_der reads a BER element from |in|. If it finds
// indefinite-length elements or constructed strings then it converts the BER
// data to DER, sets |out| to the converted contents and |*out_storage| to a
// buffer which the caller must release with |OPENSSL_free|. Otherwise, it sets
// |out| to the original BER element in |in| and |*out_storage| to NULL.
// Additionally, |*in| will be advanced over the BER element.
//
// This function should successfully process any valid BER input, however it
// will not convert all of BER's deviations from DER. BER is ambiguous between
// implicitly-tagged SEQUENCEs of strings and implicitly-tagged constructed
// strings. Implicitly-tagged strings must be parsed with
// |CBS_get_ber_implicitly_tagged_string| instead of |CBS_get_asn1|. The caller
// must also account for BER variations in the contents of a primitive.
//
// It returns one on success and zero otherwise.
OPENSSL_EXPORT int CBS_asn1_ber_to_der(CBS *in, CBS *out,
uint8_t **out_storage);
// CBS_get_asn1_implicit_string parses a BER string of primitive type
// |inner_tag| implicitly-tagged with |outer_tag|. It sets |out| to the
// contents. If concatenation was needed, it sets |*out_storage| to a buffer
// which the caller must release with |OPENSSL_free|. Otherwise, it sets
// |*out_storage| to NULL.
//
// This function does not parse all of BER. It requires the string be
// definite-length. Constructed strings are allowed, but all children of the
// outermost element must be primitive. The caller should use
// |CBS_asn1_ber_to_der| before running this function.
//
// It returns one on success and zero otherwise.
OPENSSL_EXPORT int CBS_get_asn1_implicit_string(CBS *in, CBS *out,
uint8_t **out_storage,
unsigned outer_tag,
unsigned inner_tag);
// CBB_finish_i2d calls |CBB_finish| on |cbb| which must have been initialized
// with |CBB_init|. If |outp| is not NULL then the result is written to |*outp|
// and |*outp| is advanced just past the output. It returns the number of bytes
// in the result, whether written or not, or a negative value on error. On
// error, it calls |CBB_cleanup| on |cbb|.
//
// This function may be used to help implement legacy i2d ASN.1 functions.
int CBB_finish_i2d(CBB *cbb, uint8_t **outp);
// Unicode utilities.
// The following functions read one Unicode code point from |cbs| with the
// corresponding encoding and store it in |*out|. They return one on success and
// zero on error.
OPENSSL_EXPORT int cbs_get_utf8(CBS *cbs, uint32_t *out);
OPENSSL_EXPORT int cbs_get_latin1(CBS *cbs, uint32_t *out);
OPENSSL_EXPORT int cbs_get_ucs2_be(CBS *cbs, uint32_t *out);
OPENSSL_EXPORT int cbs_get_utf32_be(CBS *cbs, uint32_t *out);
// cbb_get_utf8_len returns the number of bytes needed to represent |u| in
// UTF-8.
OPENSSL_EXPORT size_t cbb_get_utf8_len(uint32_t u);
// The following functions encode |u| to |cbb| with the corresponding
// encoding. They return one on success and zero on error.
OPENSSL_EXPORT int cbb_add_utf8(CBB *cbb, uint32_t u);
OPENSSL_EXPORT int cbb_add_latin1(CBB *cbb, uint32_t u);
OPENSSL_EXPORT int cbb_add_ucs2_be(CBB *cbb, uint32_t u);
OPENSSL_EXPORT int cbb_add_utf32_be(CBB *cbb, uint32_t u);
#if defined(__cplusplus)
} // extern C
#endif
#endif // OPENSSL_HEADER_BYTESTRING_INTERNAL_H