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/* 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_H
#define OPENSSL_HEADER_BYTESTRING_H
#include <openssl/base.h>
#if defined(__cplusplus)
extern "C" {
#endif
/* Bytestrings are used for parsing and building TLS and ASN.1 messages.
*
* A "CBS" (CRYPTO ByteString) represents a string of bytes in memory and
* provides utility functions for safely parsing length-prefixed structures
* like TLS and ASN.1 from it.
*
* A "CBB" (CRYPTO ByteBuilder) is a memory buffer that grows as needed and
* provides utility functions for building length-prefixed messages. */
/* CRYPTO ByteString */
struct cbs_st {
const uint8_t *data;
size_t len;
};
/* CBS_init sets |cbs| to point to |data|. It does not take ownership of
* |data|. */
void CBS_init(CBS *cbs, const uint8_t *data, size_t len);
/* CBS_skip advances |cbs| by |len| bytes. It returns one on success and zero
* otherwise. */
int CBS_skip(CBS *cbs, size_t len);
/* CBS_data returns a pointer to the contains of |cbs|. */
const uint8_t *CBS_data(const CBS *cbs);
/* CBS_len returns the number of bytes remaining in |cbs|. */
size_t CBS_len(const CBS *cbs);
/* CBS_stow copies the current contents of |cbs| into |*out_ptr| and
* |*out_len|. If |*out_ptr| is not NULL, the contents are freed with
* OPENSSL_free. It returns one on success and zero on allocation failure. On
* success, |*out_ptr| should be freed with OPENSSL_free. If |cbs| is empty,
* |*out_ptr| will be NULL. */
int CBS_stow(const CBS *cbs, uint8_t **out_ptr, size_t *out_len);
/* CBS_get_u8 sets |*out| to the next uint8_t from |cbs| and advances |cbs|. It
* returns one on success and zero on error. */
int CBS_get_u8(CBS *cbs, uint8_t *out);
/* CBS_get_u16 sets |*out| to the next, big-endian uint16_t from |cbs| and
* advances |cbs|. It returns one on success and zero on error. */
int CBS_get_u16(CBS *cbs, uint16_t *out);
/* CBS_get_u24 sets |*out| to the next, big-endian 24-bit value from |cbs| and
* advances |cbs|. It returns one on success and zero on error. */
int CBS_get_u24(CBS *cbs, uint32_t *out);
/* CBS_get_u32 sets |*out| to the next, big-endian uint32_t value from |cbs|
* and advances |cbs|. It returns one on success and zero on error. */
int CBS_get_u32(CBS *cbs, uint32_t *out);
/* CBS_get_bytes sets |*out| to the next |len| bytes from |cbs| and advances
* |cbs|. It returns one on success and zero on error. */
int CBS_get_bytes(CBS *cbs, CBS *out, size_t len);
/* CBS_get_u8_length_prefixed sets |*out| to the contents of an 8-bit,
* length-prefixed value from |cbs| and advances |cbs| over it. It returns one
* on success and zero on error. */
int CBS_get_u8_length_prefixed(CBS *cbs, CBS *out);
/* CBS_get_u16_length_prefixed sets |*out| to the contents of a 16-bit,
* big-endian, length-prefixed value from |cbs| and advances |cbs| over it. It
* returns one on success and zero on error. */
int CBS_get_u16_length_prefixed(CBS *cbs, CBS *out);
/* CBS_get_u24_length_prefixed sets |*out| to the contents of a 24-bit,
* big-endian, length-prefixed value from |cbs| and advances |cbs| over it. It
* returns one on success and zero on error. */
int CBS_get_u24_length_prefixed(CBS *cbs, CBS *out);
/* Parsing ASN.1 */
#define CBS_ASN1_BOOLEAN 0x1
#define CBS_ASN1_INTEGER 0x2
#define CBS_ASN1_BITSTRING 0x3
#define CBS_ASN1_OCTETSTRING 0x4
#define CBS_ASN1_OBJECT 0x6
#define CBS_ASN1_SEQUENCE (0x10 | CBS_ASN1_CONSTRUCTED)
#define CBS_ASN1_SET (0x11 | CBS_ASN1_CONSTRUCTED)
#define CBS_ASN1_CONSTRUCTED 0x20
#define CBS_ASN1_CONTEXT_SPECIFIC 0x80
#define CBS_ASN1_ANY 0x10000
/* CBS_get_asn1 sets |*out| to the contents of DER-encoded, ASN.1 element (not
* including tag and length bytes) and advances |cbs| over it. The ASN.1
* element must match |tag_value|. It returns one on success and zero
* on error.
*
* Tag numbers greater than 31 are not supported. */
int CBS_get_asn1(CBS *cbs, CBS *out, unsigned tag_value);
/* CBS_get_asn1_ber sets |*out| to the contents of BER-encoded, ASN.1 element
* (not including tag and length bytes) and advances |cbs| over it. The ASN.1
* element must match |tag_value|. It returns one on success and zero on error.
*
* The major difference between this function and |CBS_get_asn1| is that
* indefinite-length elements may be processed by this function.
*
* Tag numbers greater than 31 are not supported. */
int CBS_get_asn1_ber(CBS *cbs, CBS *out, unsigned tag_value);
/* CBS_get_asn1_element acts like |CBS_get_asn1| but |out| will include the
* ASN.1 header bytes too. */
int CBS_get_asn1_element(CBS *cbs, CBS *out, unsigned tag_value);
/* CRYPTO ByteBuilder.
*
* |CBB| objects allow one to build length-prefixed serialisations. A |CBB|
* object is associated with a buffer and new buffers are created with
* |CBB_init|. Several |CBB| objects can point at the same buffer when a
* length-prefix is pending, however only a single |CBB| can be 'current' at
* any one time. For example, if one calls |CBB_add_u8_length_prefixed| then
* the new |CBB| points at the same buffer as the original. But if the original
* |CBB| is used then the length prefix is written out and the new |CBB| must
* not be used again.
*
* If one needs to force a length prefix to be written out because a |CBB| is
* going out of scope, use |CBB_flush|. */
struct cbb_buffer_st {
uint8_t *buf;
size_t len; /* The number of valid bytes. */
size_t cap; /* The size of buf. */
char can_resize; /* One iff |buf| is owned by this object. If not then |buf|
cannot be resized. */
};
struct cbb_st {
struct cbb_buffer_st *base;
/* offset is the offset from the start of |base->buf| to the position of any
* pending length-prefix. */
size_t offset;
/* child points to a child CBB if a length-prefix is pending. */
struct cbb_st *child;
/* pending_len_len contains the number of bytes in a pending length-prefix,
* or zero if no length-prefix is pending. */
uint8_t pending_len_len;
char pending_is_asn1;
/* is_top_level is true iff this is a top-level |CBB| (as opposed to a child
* |CBB|). Top-level objects are valid arguments for |CBB_finish|. */
char is_top_level;
};
/* CBB_init initialises |cbb| with |initial_capacity|. Since a |CBB| grows as
* needed, the |initial_capacity| is just a hint. It returns one on success or
* zero on error. */
int CBB_init(CBB *cbb, size_t initial_capacity);
/* CBB_init_fixed initialises |cbb| to write to |len| bytes at |buf|. Since
* |buf| cannot grow, trying to write more than |len| bytes will cause CBB
* functions to fail. It returns one on success or zero on error. */
int CBB_init_fixed(CBB *cbb, uint8_t *buf, size_t len);
/* CBB_cleanup frees all resources owned by |cbb| and other |CBB| objects
* writing to the same buffer. This should be used in an error case where a
* serialisation is abandoned. */
void CBB_cleanup(CBB *cbb);
/* CBB_finish completes any pending length prefix and sets |*out_data| to a
* malloced buffer and |*out_len| to the length of that buffer. The caller
* takes ownership of the buffer and, unless the buffer was fixed with
* |CBB_init_fixed|, must call |OPENSSL_free| when done.
*
* It can only be called on a "top level" |CBB|, i.e. one initialised with
* |CBB_init| or |CBB_init_fixed|. It returns one on success and zero on
* error. */
int CBB_finish(CBB *cbb, uint8_t **out_data, size_t *out_len);
/* CBB_flush causes any pending length prefixes to be written out and any child
* |CBB| objects of |cbb| to be invalidated. It returns one on success or zero
* on error. */
int CBB_flush(CBB *cbb);
/* CBB_add_u8_length_prefixed sets |*out_contents| to a new child of |cbb|. The
* data written to |*out_contents| will be prefixed in |cbb| with an 8-bit
* length. It returns one on success or zero on error. */
int CBB_add_u8_length_prefixed(CBB *cbb, CBB *out_contents);
/* CBB_add_u16_length_prefixed sets |*out_contents| to a new child of |cbb|.
* The data written to |*out_contents| will be prefixed in |cbb| with a 16-bit,
* big-endian length. It returns one on success or zero on error. */
int CBB_add_u16_length_prefixed(CBB *cbb, CBB *out_contents);
/* CBB_add_u24_length_prefixed sets |*out_contents| to a new child of |cbb|.
* The data written to |*out_contents| will be prefixed in |cbb| with a 24-bit,
* big-endian length. It returns one on success or zero on error. */
int CBB_add_u24_length_prefixed(CBB *cbb, CBB *out_contents);
/* CBB_add_asn sets |*out_contents| to a |CBB| into which the contents of an
* ASN.1 object can be written. The |tag| argument will be used as the tag for
* the object. It returns one on success or zero on error. */
int CBB_add_asn1(CBB *cbb, CBB *out_contents, uint8_t tag);
/* CBB_add_bytes appends |len| bytes from |data| to |cbb|. It returns one on
* success and zero otherwise. */
int CBB_add_bytes(CBB *cbb, const uint8_t *data, size_t len);
/* CBB_add_u8 appends an 8-bit number from |value| to |cbb|. It returns one on
* success and zero otherwise. */
int CBB_add_u8(CBB *cbb, uint8_t value);
/* CBB_add_u8 appends a 16-bit, big-endian number from |value| to |cbb|. It
* returns one on success and zero otherwise. */
int CBB_add_u16(CBB *cbb, uint16_t value);
/* CBB_add_u24 appends a 24-bit, big-endian number from |value| to |cbb|. It
* returns one on success and zero otherwise. */
int CBB_add_u24(CBB *cbb, uint32_t value);
#if defined(__cplusplus)
} /* extern C */
#endif
#endif /* OPENSSL_HEADER_BYTESTRING_H */