/* $NetBSD: bufaux.c,v 1.1.1.4 2001/04/10 07:13:51 itojun Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , 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 1.17 2001/01/21 19:05:45 markus Exp $"); #include #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. */ void buffer_put_bignum(Buffer *buffer, 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) fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", oi, bin_size); /* 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); } /* * Retrieves an BIGNUM from the buffer. */ int buffer_get_bignum(Buffer *buffer, BIGNUM *value) { int bits, bytes; u_char buf[2], *bin; /* Get the number for bits. */ buffer_get(buffer, (char *) buf, 2); bits = GET_16BIT(buf); /* Compute the number of binary bytes that follow. */ bytes = (bits + 7) / 8; if (buffer_len(buffer) < bytes) fatal("buffer_get_bignum: input buffer too small"); bin = (u_char *) buffer_ptr(buffer); BN_bin2bn(bin, bytes, value); buffer_consume(buffer, bytes); return 2 + bytes; } /* * Stores an BIGNUM in the buffer in SSH2 format. */ void buffer_put_bignum2(Buffer *buffer, BIGNUM *value) { int bytes = BN_num_bytes(value) + 1; u_char *buf = xmalloc(bytes); int oi; int hasnohigh = 0; buf[0] = '\0'; /* Get the value of in binary */ oi = BN_bn2bin(value, buf+1); if (oi != bytes-1) fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", oi, bytes); hasnohigh = (buf[1] & 0x80) ? 0 : 1; if (value->neg) { /**XXX should be two's-complement */ int i, carry; u_char *uc = buf; log("negativ!"); for(i = bytes-1, carry = 1; i>=0; i--) { uc[i] ^= 0xff; if(carry) carry = !++uc[i]; } } buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); memset(buf, 0, bytes); xfree(buf); } int buffer_get_bignum2(Buffer *buffer, BIGNUM *value) { /**XXX should be two's-complement */ int len; u_char *bin = (u_char *)buffer_get_string(buffer, (u_int *)&len); BN_bin2bn(bin, len, value); xfree(bin); return len; } /* * Returns an integer from the buffer (4 bytes, msb first). */ u_int buffer_get_int(Buffer *buffer) { u_char buf[4]; buffer_get(buffer, (char *) buf, 4); return GET_32BIT(buf); } u_int64_t buffer_get_int64(Buffer *buffer) { u_char buf[8]; buffer_get(buffer, (char *) buf, 8); return GET_64BIT(buf); } /* * Stores an integer in the buffer in 4 bytes, msb first. */ 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. */ char * buffer_get_string(Buffer *buffer, u_int *length_ptr) { u_int len; char *value; /* Get the length. */ len = buffer_get_int(buffer); if (len > 256 * 1024) fatal("Received packet with bad string length %d", len); /* Allocate space for the string. Add one byte for a null character. */ value = xmalloc(len + 1); /* Get the string. */ buffer_get(buffer, value, len); /* 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; } /* * 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) { buffer_put_string(buffer, s, strlen(s)); } /* * Returns a character from the buffer (0 - 255). */ int buffer_get_char(Buffer *buffer) { char ch; buffer_get(buffer, &ch, 1); 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); }