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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_strdup copies the current contents of |cbs| into |*out_ptr| as a
- * NUL-terminated C string. 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.
- *
- * NOTE: If |cbs| contains NUL bytes, the string will be truncated. Call
- * |CBS_contains_zero_byte(cbs)| to check for NUL bytes. */
- int CBS_strdup(const CBS *cbs, char **out_ptr);
-
- /* CBS_contains_zero_byte returns one if the current contents of |cbs| contains
- * a NUL byte and zero otherwise. */
- int CBS_contains_zero_byte(const CBS *cbs);
-
- /* CBS_mem_equal compares the current contents of |cbs| with the |len| bytes
- * starting at |data|. If they're equal, it returns one, otherwise zero. If the
- * lengths match, it uses a constant-time comparison. */
- int CBS_mem_equal(const CBS *cbs, const uint8_t *data, size_t 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 */
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