bufaux.c - security/openssh-library - Rivoreo Source Code Repositories

 /* $OpenBSD: bufaux.c,v 1.57 2014/04/16 23:22:45 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  * Auxiliary functions for storing and retrieving various data types to/from
  * Buffers.
  *
  * As far as I am concerned, the code I have written for this software
  * can be used freely for any purpose.  Any derived versions of this
  * software must be clearly marked as such, and if the derived work is
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  *
  *
  * SSH2 packet format added by Markus Friedl
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "includes.h"

 #include <sys/types.h>

 #include <openssl/bn.h>

 #include <string.h>
 #include <stdarg.h>
 #include <stdlib.h>

 #include "xmalloc.h"
 #include "buffer.h"
 #include "log.h"
 #include "misc.h"

 /*
  * Returns integers from the buffer (msb first).
  */

 int
 buffer_get_short_ret(u_short *ret, Buffer *buffer)
 {
 	u_char buf[2];

 	if (buffer_get_ret(buffer, (char *) buf, 2) == -1)
 		return (-1);
 	*ret = get_u16(buf);
 	return (0);
 }

 u_short
 buffer_get_short(Buffer *buffer)
 {
 	u_short ret;

 	if (buffer_get_short_ret(&ret, buffer) == -1)
 		fatal("buffer_get_short: buffer error");

 	return (ret);
 }

 int
 buffer_get_int_ret(u_int *ret, Buffer *buffer)
 {
 	u_char buf[4];

 	if (buffer_get_ret(buffer, (char *) buf, 4) == -1)
 		return (-1);
 	if (ret != NULL)
 		*ret = get_u32(buf);
 	return (0);
 }

 u_int
 buffer_get_int(Buffer *buffer)
 {
 	u_int ret;

 	if (buffer_get_int_ret(&ret, buffer) == -1)
 		fatal("buffer_get_int: buffer error");

 	return (ret);
 }

 int
 buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer)
 {
 	u_char buf[8];

 	if (buffer_get_ret(buffer, (char *) buf, 8) == -1)
 		return (-1);
 	if (ret != NULL)
 		*ret = get_u64(buf);
 	return (0);
 }

 u_int64_t
 buffer_get_int64(Buffer *buffer)
 {
 	u_int64_t ret;

 	if (buffer_get_int64_ret(&ret, buffer) == -1)
 		fatal("buffer_get_int: buffer error");

 	return (ret);
 }

 /*
  * Stores integers in the buffer, msb first.
  */
 void
 buffer_put_short(Buffer *buffer, u_short value)
 {
 	char buf[2];

 	put_u16(buf, value);
 	buffer_append(buffer, buf, 2);
 }

 void
 buffer_put_int(Buffer *buffer, u_int value)
 {
 	char buf[4];

 	put_u32(buf, value);
 	buffer_append(buffer, buf, 4);
 }

 void
 buffer_put_int64(Buffer *buffer, u_int64_t value)
 {
 	char buf[8];

 	put_u64(buf, value);
 	buffer_append(buffer, buf, 8);
 }

 /*
  * Returns an arbitrary binary string from the buffer.  The string cannot
  * be longer than 256k.  The returned value points to memory allocated
  * with xmalloc; it is the responsibility of the calling function to free
  * the data.  If length_ptr is non-NULL, the length of the returned data
  * will be stored there.  A null character will be automatically appended
  * to the returned string, and is not counted in length.
  */
 void *
 buffer_get_string_ret(Buffer *buffer, u_int *length_ptr)
 {
 	u_char *value;
 	u_int len;

 	/* Get the length. */
 	if (buffer_get_int_ret(&len, buffer) != 0) {
 		error("buffer_get_string_ret: cannot extract length");
 		return (NULL);
 	}
 	if (len > 256 * 1024) {
 		error("buffer_get_string_ret: bad string length %u", len);
 		return (NULL);
 	}
 	/* Allocate space for the string.  Add one byte for a null character. */
 	value = xmalloc(len + 1);
 	/* Get the string. */
 	if (buffer_get_ret(buffer, value, len) == -1) {
 		error("buffer_get_string_ret: buffer_get failed");
 		free(value);
 		return (NULL);
 	}
 	/* Append a null character to make processing easier. */
 	value[len] = '\0';
 	/* Optionally return the length of the string. */
 	if (length_ptr)
 		*length_ptr = len;
 	return (value);
 }

 void *
 buffer_get_string(Buffer *buffer, u_int *length_ptr)
 {
 	void *ret;

 	if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
 		fatal("buffer_get_string: buffer error");
 	return (ret);
 }

 char *
 buffer_get_cstring_ret(Buffer *buffer, u_int *length_ptr)
 {
 	u_int length;
 	char *cp, *ret = buffer_get_string_ret(buffer, &length);

 	if (ret == NULL)
 		return NULL;
 	if ((cp = memchr(ret, '\0', length)) != NULL) {
 		/* XXX allow \0 at end-of-string for a while, remove later */
 		if (cp == ret + length - 1)
 			error("buffer_get_cstring_ret: string contains \\0");
 		else {
 			explicit_bzero(ret, length);
 			free(ret);
 			return NULL;
 		}
 	}
 	if (length_ptr != NULL)
 		*length_ptr = length;
 	return ret;
 }

 char *
 buffer_get_cstring(Buffer *buffer, u_int *length_ptr)
 {
 	char *ret;

 	if ((ret = buffer_get_cstring_ret(buffer, length_ptr)) == NULL)
 		fatal("buffer_get_cstring: buffer error");
 	return ret;
 }

 void *
 buffer_get_string_ptr_ret(Buffer *buffer, u_int *length_ptr)
 {
 	void *ptr;
 	u_int len;

 	if (buffer_get_int_ret(&len, buffer) != 0)
 		return NULL;
 	if (len > 256 * 1024) {
 		error("buffer_get_string_ptr: bad string length %u", len);
 		return NULL;
 	}
 	ptr = buffer_ptr(buffer);
 	buffer_consume(buffer, len);
 	if (length_ptr)
 		*length_ptr = len;
 	return (ptr);
 }

 void *
 buffer_get_string_ptr(Buffer *buffer, u_int *length_ptr)
 {
 	void *ret;

 	if ((ret = buffer_get_string_ptr_ret(buffer, length_ptr)) == NULL)
 		fatal("buffer_get_string_ptr: buffer error");
 	return (ret);
 }

 /*
  * Stores and arbitrary binary string in the buffer.
  */
 void
 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
 {
 	buffer_put_int(buffer, len);
 	buffer_append(buffer, buf, len);
 }
 void
 buffer_put_cstring(Buffer *buffer, const char *s)
 {
 	if (s == NULL)
 		fatal("buffer_put_cstring: s == NULL");
 	buffer_put_string(buffer, s, strlen(s));
 }

 /*
  * Returns a character from the buffer (0 - 255).
  */
 int
 buffer_get_char_ret(u_char *ret, Buffer *buffer)
 {
 	if (buffer_get_ret(buffer, ret, 1) == -1) {
 		error("buffer_get_char_ret: buffer_get_ret failed");
 		return (-1);
 	}
 	return (0);
 }

 int
 buffer_get_char(Buffer *buffer)
 {
 	u_char ch;

 	if (buffer_get_char_ret(&ch, buffer) == -1)
 		fatal("buffer_get_char: buffer error");
 	return ch;
 }

 /*
  * Stores a character in the buffer.
  */
 void
 buffer_put_char(Buffer *buffer, int value)
 {
 	char ch = value;

 	buffer_append(buffer, &ch, 1);
 }

 /* Pseudo bignum functions */

 void *
 buffer_get_bignum2_as_string_ret(Buffer *buffer, u_int *length_ptr)
 {
 	u_int len;
 	u_char *bin, *p, *ret;

 	if ((p = bin = buffer_get_string_ret(buffer, &len)) == NULL) {
 		error("%s: invalid bignum", __func__);
 		return NULL;
 	}

 	if (len > 0 && (bin[0] & 0x80)) {
 		error("%s: negative numbers not supported", __func__);
 		free(bin);
 		return NULL;
 	}
 	if (len > 8 * 1024) {
 		error("%s: cannot handle BN of size %d", __func__, len);
 		free(bin);
 		return NULL;
 	}
 	/* Skip zero prefix on numbers with the MSB set */
 	if (len > 1 && bin[0] == 0x00 && (bin[1] & 0x80) != 0) {
 		p++;
 		len--;
 	}
 	ret = xmalloc(len);
 	memcpy(ret, p, len);
 	explicit_bzero(p, len);
 	free(bin);
 	return ret;
 }

 void *
 buffer_get_bignum2_as_string(Buffer *buffer, u_int *l)
 {
 	void *ret = buffer_get_bignum2_as_string_ret(buffer, l);

 	if (ret == NULL)
 		fatal("%s: buffer error", __func__);
 	return ret;
 }

 /*
  * Stores a string using the bignum encoding rules (\0 pad if MSB set).
  */
 void
 buffer_put_bignum2_from_string(Buffer *buffer, const u_char *s, u_int l)
 {
 	u_char *buf, *p;
 	int pad = 0;

 	if (l > 8 * 1024)
 		fatal("%s: length %u too long", __func__, l);
 	/* Skip leading zero bytes */
 	for (; l > 0 && *s == 0; l--, s++)
 		;
 	p = buf = xmalloc(l + 1);
 	/*
 	 * If most significant bit is set then prepend a zero byte to
 	 * avoid interpretation as a negative number.
 	 */
 	if (l > 0 && (s[0] & 0x80) != 0) {
 		*p++ = '\0';
 		pad = 1;
 	}
 	memcpy(p, s, l);
 	buffer_put_string(buffer, buf, l + pad);
 	explicit_bzero(buf, l + pad);
 	free(buf);
 }
	/* $OpenBSD: bufaux.c,v 1.57 2014/04/16 23:22:45 djm Exp $ */
	/*
	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	* All rights reserved
	* Auxiliary functions for storing and retrieving various data types to/from
	* Buffers.
	*
	* As far as I am concerned, the code I have written for this software
	* can be used freely for any purpose. Any derived versions of this
	* software must be clearly marked as such, and if the derived work is
	* incompatible with the protocol description in the RFC file, it must be
	* called by a name other than "ssh" or "Secure Shell".
	*
	*
	* SSH2 packet format added by Markus Friedl
	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "includes.h"

	#include <sys/types.h>

	#include <openssl/bn.h>

	#include <string.h>
	#include <stdarg.h>
	#include <stdlib.h>

	#include "xmalloc.h"
	#include "buffer.h"
	#include "log.h"
	#include "misc.h"

	/*
	* Returns integers from the buffer (msb first).
	*/

	int
	buffer_get_short_ret(u_short ret, Buffer buffer)
	{
	u_char buf[2];

	if (buffer_get_ret(buffer, (char *) buf, 2) == -1)
	return (-1);
	*ret = get_u16(buf);
	return (0);
	}

	u_short
	buffer_get_short(Buffer *buffer)
	{
	u_short ret;

	if (buffer_get_short_ret(&ret, buffer) == -1)
	fatal("buffer_get_short: buffer error");

	return (ret);
	}

	int
	buffer_get_int_ret(u_int ret, Buffer buffer)
	{
	u_char buf[4];

	if (buffer_get_ret(buffer, (char *) buf, 4) == -1)
	return (-1);
	if (ret != NULL)
	*ret = get_u32(buf);
	return (0);
	}

	u_int
	buffer_get_int(Buffer *buffer)
	{
	u_int ret;

	if (buffer_get_int_ret(&ret, buffer) == -1)
	fatal("buffer_get_int: buffer error");

	return (ret);
	}

	int
	buffer_get_int64_ret(u_int64_t ret, Buffer buffer)
	{
	u_char buf[8];

	if (buffer_get_ret(buffer, (char *) buf, 8) == -1)
	return (-1);
	if (ret != NULL)
	*ret = get_u64(buf);
	return (0);
	}

	u_int64_t
	buffer_get_int64(Buffer *buffer)
	{
	u_int64_t ret;

	if (buffer_get_int64_ret(&ret, buffer) == -1)
	fatal("buffer_get_int: buffer error");

	return (ret);
	}

	/*
	* Stores integers in the buffer, msb first.
	*/
	void
	buffer_put_short(Buffer *buffer, u_short value)
	{
	char buf[2];

	put_u16(buf, value);
	buffer_append(buffer, buf, 2);
	}

	void
	buffer_put_int(Buffer *buffer, u_int value)
	{
	char buf[4];

	put_u32(buf, value);
	buffer_append(buffer, buf, 4);
	}

	void
	buffer_put_int64(Buffer *buffer, u_int64_t value)
	{
	char buf[8];

	put_u64(buf, value);
	buffer_append(buffer, buf, 8);
	}

	/*
	* Returns an arbitrary binary string from the buffer. The string cannot
	* be longer than 256k. The returned value points to memory allocated
	* with xmalloc; it is the responsibility of the calling function to free
	* the data. If length_ptr is non-NULL, the length of the returned data
	* will be stored there. A null character will be automatically appended
	* to the returned string, and is not counted in length.
	*/
	void *
	buffer_get_string_ret(Buffer buffer, u_int length_ptr)
	{
	u_char *value;
	u_int len;

	/* Get the length. */
	if (buffer_get_int_ret(&len, buffer) != 0) {
	error("buffer_get_string_ret: cannot extract length");
	return (NULL);
	}
	if (len > 256 * 1024) {
	error("buffer_get_string_ret: bad string length %u", len);
	return (NULL);
	}
	/* Allocate space for the string. Add one byte for a null character. */
	value = xmalloc(len + 1);
	/* Get the string. */
	if (buffer_get_ret(buffer, value, len) == -1) {
	error("buffer_get_string_ret: buffer_get failed");
	free(value);
	return (NULL);
	}
	/* Append a null character to make processing easier. */
	value[len] = '\0';
	/* Optionally return the length of the string. */
	if (length_ptr)
	*length_ptr = len;
	return (value);
	}

	void *
	buffer_get_string(Buffer buffer, u_int length_ptr)
	{
	void *ret;

	if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
	fatal("buffer_get_string: buffer error");
	return (ret);
	}

	char *
	buffer_get_cstring_ret(Buffer buffer, u_int length_ptr)
	{
	u_int length;
	char cp, ret = buffer_get_string_ret(buffer, &length);

	if (ret == NULL)
	return NULL;
	if ((cp = memchr(ret, '\0', length)) != NULL) {
	/* XXX allow \0 at end-of-string for a while, remove later */
	if (cp == ret + length - 1)
	error("buffer_get_cstring_ret: string contains \\0");
	else {
	explicit_bzero(ret, length);
	free(ret);
	return NULL;
	}
	}
	if (length_ptr != NULL)
	*length_ptr = length;
	return ret;
	}

	char *
	buffer_get_cstring(Buffer buffer, u_int length_ptr)
	{
	char *ret;

	if ((ret = buffer_get_cstring_ret(buffer, length_ptr)) == NULL)
	fatal("buffer_get_cstring: buffer error");
	return ret;
	}

	void *
	buffer_get_string_ptr_ret(Buffer buffer, u_int length_ptr)
	{
	void *ptr;
	u_int len;

	if (buffer_get_int_ret(&len, buffer) != 0)
	return NULL;
	if (len > 256 * 1024) {
	error("buffer_get_string_ptr: bad string length %u", len);
	return NULL;
	}
	ptr = buffer_ptr(buffer);
	buffer_consume(buffer, len);
	if (length_ptr)
	*length_ptr = len;
	return (ptr);
	}

	void *
	buffer_get_string_ptr(Buffer buffer, u_int length_ptr)
	{
	void *ret;

	if ((ret = buffer_get_string_ptr_ret(buffer, length_ptr)) == NULL)
	fatal("buffer_get_string_ptr: buffer error");
	return (ret);
	}

	/*
	* Stores and arbitrary binary string in the buffer.
	*/
	void
	buffer_put_string(Buffer buffer, const void buf, u_int len)
	{
	buffer_put_int(buffer, len);
	buffer_append(buffer, buf, len);
	}
	void
	buffer_put_cstring(Buffer buffer, const char s)
	{
	if (s == NULL)
	fatal("buffer_put_cstring: s == NULL");
	buffer_put_string(buffer, s, strlen(s));
	}

	/*
	* Returns a character from the buffer (0 - 255).
	*/
	int
	buffer_get_char_ret(u_char ret, Buffer buffer)
	{
	if (buffer_get_ret(buffer, ret, 1) == -1) {
	error("buffer_get_char_ret: buffer_get_ret failed");
	return (-1);
	}
	return (0);
	}

	int
	buffer_get_char(Buffer *buffer)
	{
	u_char ch;

	if (buffer_get_char_ret(&ch, buffer) == -1)
	fatal("buffer_get_char: buffer error");
	return ch;
	}

	/*
	* Stores a character in the buffer.
	*/
	void
	buffer_put_char(Buffer *buffer, int value)
	{
	char ch = value;

	buffer_append(buffer, &ch, 1);
	}

	/* Pseudo bignum functions */

	void *
	buffer_get_bignum2_as_string_ret(Buffer buffer, u_int length_ptr)
	{
	u_int len;
	u_char bin, p, *ret;

	if ((p = bin = buffer_get_string_ret(buffer, &len)) == NULL) {
	error("%s: invalid bignum", __func__);
	return NULL;
	}

	if (len > 0 && (bin[0] & 0x80)) {
	error("%s: negative numbers not supported", __func__);
	free(bin);
	return NULL;
	}
	if (len > 8 * 1024) {
	error("%s: cannot handle BN of size %d", __func__, len);
	free(bin);
	return NULL;
	}
	/* Skip zero prefix on numbers with the MSB set */
	if (len > 1 && bin[0] == 0x00 && (bin[1] & 0x80) != 0) {
	p++;
	len--;
	}
	ret = xmalloc(len);
	memcpy(ret, p, len);
	explicit_bzero(p, len);
	free(bin);
	return ret;
	}

	void *
	buffer_get_bignum2_as_string(Buffer buffer, u_int l)
	{
	void *ret = buffer_get_bignum2_as_string_ret(buffer, l);

	if (ret == NULL)
	fatal("%s: buffer error", __func__);
	return ret;
	}

	/*
	* Stores a string using the bignum encoding rules (\0 pad if MSB set).
	*/
	void
	buffer_put_bignum2_from_string(Buffer buffer, const u_char s, u_int l)
	{
	u_char buf, p;
	int pad = 0;

	if (l > 8 * 1024)
	fatal("%s: length %u too long", __func__, l);
	/* Skip leading zero bytes */
	for (; l > 0 && *s == 0; l--, s++)
	;
	p = buf = xmalloc(l + 1);
	/*
	* If most significant bit is set then prepend a zero byte to
	* avoid interpretation as a negative number.
	*/
	if (l > 0 && (s[0] & 0x80) != 0) {
	*p++ = '\0';
	pad = 1;
	}
	memcpy(p, s, l);
	buffer_put_string(buffer, buf, l + pad);
	explicit_bzero(buf, l + pad);
	free(buf);
	}