400 lines
14 KiB
C
400 lines
14 KiB
C
/* $OpenBSD: sshbuf.h,v 1.28 2022/12/02 04:40:27 djm Exp $ */
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/*
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* Copyright (c) 2011 Damien Miller
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef _SSHBUF_H
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#define _SSHBUF_H
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#include <sys/types.h>
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#include <stdarg.h>
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#include <stdio.h>
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#ifdef WITH_OPENSSL
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# include <openssl/bn.h>
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# ifdef OPENSSL_HAS_ECC
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# include <openssl/ec.h>
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# endif /* OPENSSL_HAS_ECC */
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#endif /* WITH_OPENSSL */
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#define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */
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#define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */
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#define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */
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#define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */
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struct sshbuf;
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/*
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* Create a new sshbuf buffer.
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* Returns pointer to buffer on success, or NULL on allocation failure.
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*/
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struct sshbuf *sshbuf_new(void);
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/*
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* Create a new, read-only sshbuf buffer from existing data.
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* Returns pointer to buffer on success, or NULL on allocation failure.
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*/
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struct sshbuf *sshbuf_from(const void *blob, size_t len);
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/*
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* Create a new, read-only sshbuf buffer from the contents of an existing
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* buffer. The contents of "buf" must not change in the lifetime of the
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* resultant buffer.
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* Returns pointer to buffer on success, or NULL on allocation failure.
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*/
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struct sshbuf *sshbuf_fromb(struct sshbuf *buf);
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/*
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* Create a new, read-only sshbuf buffer from the contents of a string in
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* an existing buffer (the string is consumed in the process).
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* The contents of "buf" must not change in the lifetime of the resultant
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* buffer.
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* Returns pointer to buffer on success, or NULL on allocation failure.
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*/
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int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp);
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/*
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* Clear and free buf
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*/
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void sshbuf_free(struct sshbuf *buf);
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/*
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* Reset buf, clearing its contents. NB. max_size is preserved.
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*/
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void sshbuf_reset(struct sshbuf *buf);
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/*
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* Return the maximum size of buf
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*/
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size_t sshbuf_max_size(const struct sshbuf *buf);
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/*
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* Set the maximum size of buf
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* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size);
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/*
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* Returns the length of data in buf
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*/
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size_t sshbuf_len(const struct sshbuf *buf);
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/*
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* Returns number of bytes left in buffer before hitting max_size.
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*/
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size_t sshbuf_avail(const struct sshbuf *buf);
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/*
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* Returns a read-only pointer to the start of the data in buf
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*/
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const u_char *sshbuf_ptr(const struct sshbuf *buf);
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/*
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* Returns a mutable pointer to the start of the data in buf, or
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* NULL if the buffer is read-only.
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*/
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u_char *sshbuf_mutable_ptr(const struct sshbuf *buf);
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/*
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* Check whether a reservation of size len will succeed in buf
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* Safer to use than direct comparisons again sshbuf_avail as it copes
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* with unsigned overflows correctly.
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* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_check_reserve(const struct sshbuf *buf, size_t len);
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/*
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* Preallocates len additional bytes in buf.
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* Useful for cases where the caller knows how many bytes will ultimately be
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* required to avoid realloc in the buffer code.
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* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_allocate(struct sshbuf *buf, size_t len);
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/*
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* Reserve len bytes in buf.
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* Returns 0 on success and a pointer to the first reserved byte via the
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* optional dpp parameter or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp);
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/*
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* Consume len bytes from the start of buf
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* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_consume(struct sshbuf *buf, size_t len);
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/*
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* Consume len bytes from the end of buf
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* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
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*/
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int sshbuf_consume_end(struct sshbuf *buf, size_t len);
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/* Extract or deposit some bytes */
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int sshbuf_get(struct sshbuf *buf, void *v, size_t len);
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int sshbuf_put(struct sshbuf *buf, const void *v, size_t len);
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int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v);
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/* Append using a printf(3) format */
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int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
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__attribute__((format(printf, 2, 3)));
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int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap);
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/* Functions to extract or store big-endian words of various sizes */
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int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp);
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int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp);
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int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp);
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int sshbuf_get_u8(struct sshbuf *buf, u_char *valp);
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int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
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int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
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int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
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int sshbuf_put_u8(struct sshbuf *buf, u_char val);
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/* Functions to peek at the contents of a buffer without modifying it. */
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int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset,
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u_int64_t *valp);
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int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset,
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u_int32_t *valp);
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int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset,
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u_int16_t *valp);
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int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset,
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u_char *valp);
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/*
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* Functions to poke values into an existing buffer (e.g. a length header
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* to a packet). The destination bytes must already exist in the buffer.
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*/
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int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val);
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int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val);
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int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val);
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int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val);
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int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len);
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/*
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* Functions to extract or store SSH wire encoded strings (u32 len || data)
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* The "cstring" variants admit no \0 characters in the string contents.
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* Caller must free *valp.
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*/
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int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp);
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int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp);
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int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v);
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int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len);
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int sshbuf_put_cstring(struct sshbuf *buf, const char *v);
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int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v);
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/*
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* "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
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* avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
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* next sshbuf-modifying function call. Caller does not free.
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*/
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int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp,
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size_t *lenp);
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/* Skip past a string */
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#define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)
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/* Another variant: "peeks" into the buffer without modifying it */
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int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
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size_t *lenp);
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/*
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* Functions to extract or store SSH wire encoded bignums and elliptic
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* curve points.
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*/
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int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
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int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
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const u_char **valp, size_t *lenp);
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#ifdef WITH_OPENSSL
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int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp);
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int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
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# ifdef OPENSSL_HAS_ECC
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int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g);
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int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v);
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int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g);
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int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v);
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# endif /* OPENSSL_HAS_ECC */
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#endif /* WITH_OPENSSL */
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/* Dump the contents of the buffer in a human-readable format */
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void sshbuf_dump(const struct sshbuf *buf, FILE *f);
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/* Dump specified memory in a human-readable format */
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void sshbuf_dump_data(const void *s, size_t len, FILE *f);
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/* Return the hexadecimal representation of the contents of the buffer */
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char *sshbuf_dtob16(struct sshbuf *buf);
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/* Encode the contents of the buffer as base64 */
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char *sshbuf_dtob64_string(const struct sshbuf *buf, int wrap);
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int sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap);
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/* RFC4648 "base64url" encoding variant */
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int sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap);
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/* Decode base64 data and append it to the buffer */
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int sshbuf_b64tod(struct sshbuf *buf, const char *b64);
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/*
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* Tests whether the buffer contains the specified byte sequence at the
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* specified offset. Returns 0 on successful match, or a ssherr.h code
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* otherwise. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were
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* present but the buffer contents did not match those supplied. Zero-
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* length comparisons are not allowed.
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*
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* If sufficient data is present to make a comparison, then it is
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* performed with timing independent of the value of the data. If
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* insufficient data is present then the comparison is not attempted at
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* all.
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*/
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int sshbuf_cmp(const struct sshbuf *b, size_t offset,
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const void *s, size_t len);
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/*
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* Searches the buffer for the specified string. Returns 0 on success
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* and updates *offsetp with the offset of the first match, relative to
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* the start of the buffer. Otherwise sshbuf_find will return a ssherr.h
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* error code. SSH_ERR_INVALID_FORMAT indicates sufficient bytes were
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* present in the buffer for a match to be possible but none was found.
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* Searches for zero-length data are not allowed.
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*/
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int
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sshbuf_find(const struct sshbuf *b, size_t start_offset,
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const void *s, size_t len, size_t *offsetp);
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/*
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* Duplicate the contents of a buffer to a string (caller to free).
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* Returns NULL on buffer error, or if the buffer contains a premature
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* nul character.
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*/
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char *sshbuf_dup_string(struct sshbuf *buf);
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/*
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* Fill a buffer from a file descriptor or filename. Both allocate the
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* buffer for the caller.
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*/
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int sshbuf_load_fd(int, struct sshbuf **)
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__attribute__((__nonnull__ (2)));
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int sshbuf_load_file(const char *, struct sshbuf **)
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__attribute__((__nonnull__ (2)));
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/*
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* Write a buffer to a path, creating/truncating as needed (mode 0644,
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* subject to umask). The buffer contents are not modified.
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*/
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#ifdef WINDOWS
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/* umask doesn't work the same on windows. so pass the mode instead. */
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int sshbuf_write_file(const char *path, struct sshbuf *buf, mode_t mode)
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__attribute__((__nonnull__(2)));
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#else
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int sshbuf_write_file(const char *path, struct sshbuf *buf)
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__attribute__((__nonnull__ (2)));
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#endif
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/* Read up to maxlen bytes from a fd directly to a buffer */
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int sshbuf_read(int, struct sshbuf *, size_t, size_t *)
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__attribute__((__nonnull__ (2)));
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/* Macros for decoding/encoding integers */
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#define PEEK_U64(p) \
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(((u_int64_t)(((const u_char *)(p))[0]) << 56) | \
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((u_int64_t)(((const u_char *)(p))[1]) << 48) | \
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((u_int64_t)(((const u_char *)(p))[2]) << 40) | \
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((u_int64_t)(((const u_char *)(p))[3]) << 32) | \
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((u_int64_t)(((const u_char *)(p))[4]) << 24) | \
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((u_int64_t)(((const u_char *)(p))[5]) << 16) | \
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((u_int64_t)(((const u_char *)(p))[6]) << 8) | \
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(u_int64_t)(((const u_char *)(p))[7]))
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#define PEEK_U32(p) \
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(((u_int32_t)(((const u_char *)(p))[0]) << 24) | \
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((u_int32_t)(((const u_char *)(p))[1]) << 16) | \
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((u_int32_t)(((const u_char *)(p))[2]) << 8) | \
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(u_int32_t)(((const u_char *)(p))[3]))
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#define PEEK_U16(p) \
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(((u_int16_t)(((const u_char *)(p))[0]) << 8) | \
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(u_int16_t)(((const u_char *)(p))[1]))
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#define POKE_U64(p, v) \
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do { \
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const u_int64_t __v = (v); \
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((u_char *)(p))[0] = (__v >> 56) & 0xff; \
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((u_char *)(p))[1] = (__v >> 48) & 0xff; \
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((u_char *)(p))[2] = (__v >> 40) & 0xff; \
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((u_char *)(p))[3] = (__v >> 32) & 0xff; \
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((u_char *)(p))[4] = (__v >> 24) & 0xff; \
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((u_char *)(p))[5] = (__v >> 16) & 0xff; \
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((u_char *)(p))[6] = (__v >> 8) & 0xff; \
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((u_char *)(p))[7] = __v & 0xff; \
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} while (0)
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#define POKE_U32(p, v) \
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do { \
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const u_int32_t __v = (v); \
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((u_char *)(p))[0] = (__v >> 24) & 0xff; \
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((u_char *)(p))[1] = (__v >> 16) & 0xff; \
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((u_char *)(p))[2] = (__v >> 8) & 0xff; \
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((u_char *)(p))[3] = __v & 0xff; \
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} while (0)
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#define POKE_U16(p, v) \
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do { \
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const u_int16_t __v = (v); \
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((u_char *)(p))[0] = (__v >> 8) & 0xff; \
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((u_char *)(p))[1] = __v & 0xff; \
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} while (0)
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/* Internal definitions follow. Exposed for regress tests */
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#ifdef SSHBUF_INTERNAL
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/*
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* Return the allocation size of buf
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*/
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size_t sshbuf_alloc(const struct sshbuf *buf);
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/*
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* Increment the reference count of buf.
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*/
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int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent);
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/*
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* Return the parent buffer of buf, or NULL if it has no parent.
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*/
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const struct sshbuf *sshbuf_parent(const struct sshbuf *buf);
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/*
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* Return the reference count of buf
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*/
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u_int sshbuf_refcount(const struct sshbuf *buf);
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# define SSHBUF_SIZE_INIT 256 /* Initial allocation */
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# define SSHBUF_SIZE_INC 256 /* Preferred increment length */
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# define SSHBUF_PACK_MIN 8192 /* Minimum packable offset */
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/* # define SSHBUF_ABORT abort */
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/* # define SSHBUF_DEBUG */
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# ifndef SSHBUF_ABORT
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# define SSHBUF_ABORT()
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# endif
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# ifdef SSHBUF_DEBUG
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# define SSHBUF_DBG(x) do { \
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printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
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printf x; \
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printf("\n"); \
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fflush(stdout); \
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} while (0)
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# else
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# define SSHBUF_DBG(x)
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# endif
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#endif /* SSHBUF_INTERNAL */
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#endif /* _SSHBUF_H */
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