openssh-portable/bufaux.c

407 lines
9.4 KiB
C

/*
* 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"
RCSID("$OpenBSD: bufaux.c,v 1.37 2005/11/05 05:01:15 djm Exp $");
#include <openssl/bn.h>
#include "bufaux.h"
#include "xmalloc.h"
#include "getput.h"
#include "log.h"
/*
* Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
* by (bits+7)/8 bytes of binary data, msb first.
*/
int
buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value)
{
int bits = BN_num_bits(value);
int bin_size = (bits + 7) / 8;
u_char *buf = xmalloc(bin_size);
int oi;
char msg[2];
/* Get the value of in binary */
oi = BN_bn2bin(value, buf);
if (oi != bin_size) {
error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d",
oi, bin_size);
xfree(buf);
return (-1);
}
/* Store the number of bits in the buffer in two bytes, msb first. */
PUT_16BIT(msg, bits);
buffer_append(buffer, msg, 2);
/* Store the binary data. */
buffer_append(buffer, (char *)buf, oi);
memset(buf, 0, bin_size);
xfree(buf);
return (0);
}
void
buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
{
if (buffer_put_bignum_ret(buffer, value) == -1)
fatal("buffer_put_bignum: buffer error");
}
/*
* Retrieves an BIGNUM from the buffer.
*/
int
buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
{
u_int bits, bytes;
u_char buf[2], *bin;
/* Get the number for bits. */
if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
error("buffer_get_bignum_ret: invalid length");
return (-1);
}
bits = GET_16BIT(buf);
/* Compute the number of binary bytes that follow. */
bytes = (bits + 7) / 8;
if (bytes > 8 * 1024) {
error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
return (-1);
}
if (buffer_len(buffer) < bytes) {
error("buffer_get_bignum_ret: input buffer too small");
return (-1);
}
bin = buffer_ptr(buffer);
BN_bin2bn(bin, bytes, value);
if (buffer_consume_ret(buffer, bytes) == -1) {
error("buffer_get_bignum_ret: buffer_consume failed");
return (-1);
}
return (0);
}
void
buffer_get_bignum(Buffer *buffer, BIGNUM *value)
{
if (buffer_get_bignum_ret(buffer, value) == -1)
fatal("buffer_get_bignum: buffer error");
}
/*
* Stores an BIGNUM in the buffer in SSH2 format.
*/
int
buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value)
{
u_int bytes;
u_char *buf;
int oi;
u_int hasnohigh = 0;
if (BN_is_zero(value)) {
buffer_put_int(buffer, 0);
return 0;
}
if (value->neg) {
error("buffer_put_bignum2_ret: negative numbers not supported");
return (-1);
}
bytes = BN_num_bytes(value) + 1; /* extra padding byte */
if (bytes < 2) {
error("buffer_put_bignum2_ret: BN too small");
return (-1);
}
buf = xmalloc(bytes);
buf[0] = 0x00;
/* Get the value of in binary */
oi = BN_bn2bin(value, buf+1);
if (oi < 0 || (u_int)oi != bytes - 1) {
error("buffer_put_bignum2_ret: BN_bn2bin() failed: "
"oi %d != bin_size %d", oi, bytes);
xfree(buf);
return (-1);
}
hasnohigh = (buf[1] & 0x80) ? 0 : 1;
buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
memset(buf, 0, bytes);
xfree(buf);
return (0);
}
void
buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
{
if (buffer_put_bignum2_ret(buffer, value) == -1)
fatal("buffer_put_bignum2: buffer error");
}
int
buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value)
{
u_int len;
u_char *bin;
if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) {
error("buffer_get_bignum2_ret: invalid bignum");
return (-1);
}
if (len > 0 && (bin[0] & 0x80)) {
error("buffer_get_bignum2_ret: negative numbers not supported");
xfree(bin);
return (-1);
}
if (len > 8 * 1024) {
error("buffer_get_bignum2_ret: cannot handle BN of size %d", len);
xfree(bin);
return (-1);
}
BN_bin2bn(bin, len, value);
xfree(bin);
return (0);
}
void
buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
{
if (buffer_get_bignum2_ret(buffer, value) == -1)
fatal("buffer_get_bignum2: buffer error");
}
/*
* 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_16BIT(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);
*ret = GET_32BIT(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);
*ret = GET_64BIT(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_16BIT(buf, value);
buffer_append(buffer, buf, 2);
}
void
buffer_put_int(Buffer *buffer, u_int value)
{
char buf[4];
PUT_32BIT(buf, value);
buffer_append(buffer, buf, 4);
}
void
buffer_put_int64(Buffer *buffer, u_int64_t value)
{
char buf[8];
PUT_64BIT(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. */
len = buffer_get_int(buffer);
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");
xfree(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);
}
/*
* 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(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)
{
char ch;
if (buffer_get_char_ret(&ch, buffer) == -1)
fatal("buffer_get_char: buffer error");
return (u_char) ch;
}
/*
* Stores a character in the buffer.
*/
void
buffer_put_char(Buffer *buffer, int value)
{
char ch = value;
buffer_append(buffer, &ch, 1);
}