bufaux.c revision 99063
1153761Swollman/* 2192886Sedwin * Author: Tatu Ylonen <ylo@cs.hut.fi> 3192886Sedwin * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4192886Sedwin * All rights reserved 564499Swollman * Auxiliary functions for storing and retrieving various data types to/from 62742Swollman * Buffers. 72742Swollman * 82742Swollman * As far as I am concerned, the code I have written for this software 92742Swollman * can be used freely for any purpose. Any derived versions of this 10158421Swollman * software must be clearly marked as such, and if the derived work is 112742Swollman * incompatible with the protocol description in the RFC file, it must be 12158421Swollman * called by a name other than "ssh" or "Secure Shell". 13158421Swollman * 142742Swollman * 1586222Swollman * SSH2 packet format added by Markus Friedl 1620094Swollman * Copyright (c) 2000 Markus Friedl. All rights reserved. 1720094Swollman * 1820094Swollman * Redistribution and use in source and binary forms, with or without 1920094Swollman * modification, are permitted provided that the following conditions 2020094Swollman * are met: 21158421Swollman * 1. Redistributions of source code must retain the above copyright 22158421Swollman * notice, this list of conditions and the following disclaimer. 2320094Swollman * 2. Redistributions in binary form must reproduce the above copyright 2419878Swollman * notice, this list of conditions and the following disclaimer in the 2519878Swollman * documentation and/or other materials provided with the distribution. 2619878Swollman * 2719878Swollman * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 2819878Swollman * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 2919878Swollman * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 3019878Swollman * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 3119878Swollman * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 3258787Sru * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 3358787Sru * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 3458787Sru * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 3558787Sru * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 3658787Sru * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 3758787Sru */ 3858787Sru 3958787Sru#include "includes.h" 4058787SruRCSID("$OpenBSD: bufaux.c,v 1.27 2002/06/26 08:53:12 markus Exp $"); 4158787SruRCSID("$FreeBSD: head/crypto/openssh/bufaux.c 99063 2002-06-29 11:48:59Z des $"); 4258787Sru 4358787Sru#include <openssl/bn.h> 4458787Sru#include "bufaux.h" 4558787Sru#include "xmalloc.h" 4658787Sru#include "getput.h" 4758787Sru#include "log.h" 4858787Sru 4958787Sru/* 502742Swollman * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed 512742Swollman * by (bits+7)/8 bytes of binary data, msb first. 522742Swollman */ 532742Swollmanvoid 542742Swollmanbuffer_put_bignum(Buffer *buffer, BIGNUM *value) 552742Swollman{ 562742Swollman int bits = BN_num_bits(value); 5719878Swollman int bin_size = (bits + 7) / 8; 582742Swollman u_char *buf = xmalloc(bin_size); 592742Swollman int oi; 602742Swollman char msg[2]; 6119878Swollman 622742Swollman /* Get the value of in binary */ 632742Swollman oi = BN_bn2bin(value, buf); 64149514Swollman if (oi != bin_size) 6521217Swollman fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", 669908Swollman oi, bin_size); 679908Swollman 682742Swollman /* Store the number of bits in the buffer in two bytes, msb first. */ 6919878Swollman PUT_16BIT(msg, bits); 7019878Swollman buffer_append(buffer, msg, 2); 7119878Swollman /* Store the binary data. */ 7219878Swollman buffer_append(buffer, (char *)buf, oi); 7319878Swollman 7419878Swollman memset(buf, 0, bin_size); 7519878Swollman xfree(buf); 7619878Swollman} 7719878Swollman 7819878Swollman/* 7919878Swollman * Retrieves an BIGNUM from the buffer. 8019878Swollman */ 8119878Swollmanvoid 8219878Swollmanbuffer_get_bignum(Buffer *buffer, BIGNUM *value) 8319878Swollman{ 8419878Swollman int bits, bytes; 8593799Swollman u_char buf[2], *bin; 8658787Sru 8758787Sru /* Get the number for bits. */ 8819878Swollman buffer_get(buffer, (char *) buf, 2); 8919878Swollman bits = GET_16BIT(buf); 9019878Swollman /* Compute the number of binary bytes that follow. */ 919908Swollman bytes = (bits + 7) / 8; 92149514Swollman if (bytes > 8 * 1024) 939908Swollman fatal("buffer_get_bignum: cannot handle BN of size %d", bytes); 949908Swollman if (buffer_len(buffer) < bytes) 959908Swollman fatal("buffer_get_bignum: input buffer too small"); 9621217Swollman bin = buffer_ptr(buffer); 9719878Swollman BN_bin2bn(bin, bytes, value); 9819878Swollman buffer_consume(buffer, bytes); 999908Swollman} 100149514Swollman 1019908Swollman/* 1029908Swollman * Stores an BIGNUM in the buffer in SSH2 format. 1039908Swollman */ 1049908Swollmanvoid 10558787Srubuffer_put_bignum2(Buffer *buffer, BIGNUM *value) 10658787Sru{ 10758787Sru int bytes = BN_num_bytes(value) + 1; 10864499Swollman u_char *buf = xmalloc(bytes); 10964499Swollman int oi; 110175034Sedwin int hasnohigh = 0; 111175034Sedwin 112175034Sedwin buf[0] = '\0'; 113175034Sedwin /* Get the value of in binary */ 114175034Sedwin oi = BN_bn2bin(value, buf+1); 11558787Sru if (oi != bytes-1) 11658787Sru fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", 11767578Swollman oi, bytes); 11858787Sru hasnohigh = (buf[1] & 0x80) ? 0 : 1; 11958787Sru if (value->neg) { 12058787Sru /**XXX should be two's-complement */ 121149514Swollman int i, carry; 12264499Swollman u_char *uc = buf; 12364499Swollman log("negativ!"); 12464499Swollman for (i = bytes-1, carry = 1; i>=0; i--) { 12564499Swollman uc[i] ^= 0xff; 12686222Swollman if (carry) 12786222Swollman carry = !++uc[i]; 12886222Swollman } 12986222Swollman } 13086222Swollman buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); 13186222Swollman memset(buf, 0, bytes); 13286222Swollman xfree(buf); 13386222Swollman} 13486222Swollman 13586222Swollman/* XXX does not handle negative BNs */ 13686222Swollmanvoid 13786222Swollmanbuffer_get_bignum2(Buffer *buffer, BIGNUM *value) 13886222Swollman{ 13986222Swollman u_int len; 14086222Swollman u_char *bin = buffer_get_string(buffer, &len); 14186222Swollman 14286222Swollman if (len > 8 * 1024) 14386222Swollman fatal("buffer_get_bignum2: cannot handle BN of size %d", len); 14486222Swollman BN_bin2bn(bin, len, value); 14586222Swollman xfree(bin); 14686222Swollman} 14786222Swollman/* 14886222Swollman * Returns integers from the buffer (msb first). 149175034Sedwin */ 150175034Sedwin 151175034Sedwinu_short 152175034Sedwinbuffer_get_short(Buffer *buffer) 153175034Sedwin{ 154175034Sedwin u_char buf[2]; 155175034Sedwin 156175034Sedwin buffer_get(buffer, (char *) buf, 2); 157175034Sedwin return GET_16BIT(buf); 158175034Sedwin} 159175034Sedwin 160175034Sedwinu_int 161175034Sedwinbuffer_get_int(Buffer *buffer) 162175034Sedwin{ 163175034Sedwin u_char buf[4]; 164175034Sedwin 165175034Sedwin buffer_get(buffer, (char *) buf, 4); 166175034Sedwin return GET_32BIT(buf); 167175034Sedwin} 168175034Sedwin 169183066Sedwin#ifdef HAVE_U_INT64_T 170183066Sedwinu_int64_t 171183066Sedwinbuffer_get_int64(Buffer *buffer) 172183066Sedwin{ 173183066Sedwin u_char buf[8]; 174183066Sedwin 175183066Sedwin buffer_get(buffer, (char *) buf, 8); 176183066Sedwin return GET_64BIT(buf); 177183066Sedwin} 178183066Sedwin#endif 179183066Sedwin 180183066Sedwin/* 181183066Sedwin * Stores integers in the buffer, msb first. 182183864Sedwin */ 183183864Sedwinvoid 184183864Sedwinbuffer_put_short(Buffer *buffer, u_short value) 185183864Sedwin{ 186183864Sedwin char buf[2]; 187183864Sedwin 188183864Sedwin PUT_16BIT(buf, value); 189183864Sedwin buffer_append(buffer, buf, 2); 190183864Sedwin} 191183864Sedwin 192183864Sedwinvoid 193183864Sedwinbuffer_put_int(Buffer *buffer, u_int value) 194183864Sedwin{ 195183864Sedwin char buf[4]; 196183864Sedwin 197183864Sedwin PUT_32BIT(buf, value); 198184406Sedwin buffer_append(buffer, buf, 4); 199184406Sedwin} 200184406Sedwin 201184406Sedwin#ifdef HAVE_U_INT64_T 202184406Sedwinvoid 203184406Sedwinbuffer_put_int64(Buffer *buffer, u_int64_t value) 204184406Sedwin{ 205184406Sedwin char buf[8]; 206184406Sedwin 207184406Sedwin PUT_64BIT(buf, value); 208184406Sedwin buffer_append(buffer, buf, 8); 209184406Sedwin} 210184406Sedwin#endif 211184406Sedwin 212184406Sedwin/* 213184406Sedwin * Returns an arbitrary binary string from the buffer. The string cannot 214184406Sedwin * be longer than 256k. The returned value points to memory allocated 215184406Sedwin * with xmalloc; it is the responsibility of the calling function to free 216184406Sedwin * the data. If length_ptr is non-NULL, the length of the returned data 217184406Sedwin * will be stored there. A null character will be automatically appended 218175034Sedwin * to the returned string, and is not counted in length. 219175034Sedwin */ 220183066Sedwinvoid * 221175034Sedwinbuffer_get_string(Buffer *buffer, u_int *length_ptr) 222136638Swollman{ 223136638Swollman u_char *value; 224136638Swollman u_int len; 225136638Swollman 226136638Swollman /* Get the length. */ 227136638Swollman len = buffer_get_int(buffer); 228136638Swollman if (len > 256 * 1024) 22993799Swollman fatal("buffer_get_string: bad string length %d", len); 230158421Swollman /* Allocate space for the string. Add one byte for a null character. */ 23193799Swollman value = xmalloc(len + 1); 232158421Swollman /* Get the string. */ 23393799Swollman buffer_get(buffer, value, len); 23493799Swollman /* Append a null character to make processing easier. */ 235158421Swollman value[len] = 0; 236136638Swollman /* Optionally return the length of the string. */ 237136638Swollman if (length_ptr) 238136638Swollman *length_ptr = len; 239136638Swollman return value; 240136638Swollman} 241136638Swollman 242136638Swollman/* 243136638Swollman * Stores and arbitrary binary string in the buffer. 244136638Swollman */ 245136638Swollmanvoid 246136638Swollmanbuffer_put_string(Buffer *buffer, const void *buf, u_int len) 247136638Swollman{ 248136638Swollman buffer_put_int(buffer, len); 249136638Swollman buffer_append(buffer, buf, len); 250136638Swollman} 251136638Swollmanvoid 252136638Swollmanbuffer_put_cstring(Buffer *buffer, const char *s) 253136638Swollman{ 254136638Swollman if (s == NULL) 255136638Swollman fatal("buffer_put_cstring: s == NULL"); 256136638Swollman buffer_put_string(buffer, s, strlen(s)); 257136638Swollman} 258136638Swollman 259136638Swollman/* 260136638Swollman * Returns a character from the buffer (0 - 255). 261136638Swollman */ 262136638Swollmanint 263136638Swollmanbuffer_get_char(Buffer *buffer) 264136638Swollman{ 265136638Swollman char ch; 266136638Swollman 267136638Swollman buffer_get(buffer, &ch, 1); 268136638Swollman return (u_char) ch; 269136638Swollman} 270136638Swollman 271136638Swollman/* 272136638Swollman * Stores a character in the buffer. 273136638Swollman */ 274136638Swollmanvoid 275136638Swollmanbuffer_put_char(Buffer *buffer, int value) 276136638Swollman{ 277136638Swollman char ch = value; 278136638Swollman 279136638Swollman buffer_append(buffer, &ch, 1); 280136638Swollman} 28193799Swollman