bufaux.c revision 181111
1/* $OpenBSD: bufaux.c,v 1.46 2008/06/10 23:21:34 dtucker Exp $ */ 2/* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Auxiliary functions for storing and retrieving various data types to/from 7 * Buffers. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * SSH2 packet format added by Markus Friedl 17 * Copyright (c) 2000 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40#include "includes.h" 41 42#include <sys/types.h> 43 44#include <openssl/bn.h> 45 46#include <string.h> 47#include <stdarg.h> 48 49#include "xmalloc.h" 50#include "buffer.h" 51#include "log.h" 52#include "misc.h" 53 54/* 55 * Returns integers from the buffer (msb first). 56 */ 57 58int 59buffer_get_short_ret(u_short *ret, Buffer *buffer) 60{ 61 u_char buf[2]; 62 63 if (buffer_get_ret(buffer, (char *) buf, 2) == -1) 64 return (-1); 65 *ret = get_u16(buf); 66 return (0); 67} 68 69u_short 70buffer_get_short(Buffer *buffer) 71{ 72 u_short ret; 73 74 if (buffer_get_short_ret(&ret, buffer) == -1) 75 fatal("buffer_get_short: buffer error"); 76 77 return (ret); 78} 79 80int 81buffer_get_int_ret(u_int *ret, Buffer *buffer) 82{ 83 u_char buf[4]; 84 85 if (buffer_get_ret(buffer, (char *) buf, 4) == -1) 86 return (-1); 87 *ret = get_u32(buf); 88 return (0); 89} 90 91u_int 92buffer_get_int(Buffer *buffer) 93{ 94 u_int ret; 95 96 if (buffer_get_int_ret(&ret, buffer) == -1) 97 fatal("buffer_get_int: buffer error"); 98 99 return (ret); 100} 101 102int 103buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer) 104{ 105 u_char buf[8]; 106 107 if (buffer_get_ret(buffer, (char *) buf, 8) == -1) 108 return (-1); 109 *ret = get_u64(buf); 110 return (0); 111} 112 113u_int64_t 114buffer_get_int64(Buffer *buffer) 115{ 116 u_int64_t ret; 117 118 if (buffer_get_int64_ret(&ret, buffer) == -1) 119 fatal("buffer_get_int: buffer error"); 120 121 return (ret); 122} 123 124/* 125 * Stores integers in the buffer, msb first. 126 */ 127void 128buffer_put_short(Buffer *buffer, u_short value) 129{ 130 char buf[2]; 131 132 put_u16(buf, value); 133 buffer_append(buffer, buf, 2); 134} 135 136void 137buffer_put_int(Buffer *buffer, u_int value) 138{ 139 char buf[4]; 140 141 put_u32(buf, value); 142 buffer_append(buffer, buf, 4); 143} 144 145void 146buffer_put_int64(Buffer *buffer, u_int64_t value) 147{ 148 char buf[8]; 149 150 put_u64(buf, value); 151 buffer_append(buffer, buf, 8); 152} 153 154/* 155 * Returns an arbitrary binary string from the buffer. The string cannot 156 * be longer than 256k. The returned value points to memory allocated 157 * with xmalloc; it is the responsibility of the calling function to free 158 * the data. If length_ptr is non-NULL, the length of the returned data 159 * will be stored there. A null character will be automatically appended 160 * to the returned string, and is not counted in length. 161 */ 162void * 163buffer_get_string_ret(Buffer *buffer, u_int *length_ptr) 164{ 165 u_char *value; 166 u_int len; 167 168 /* Get the length. */ 169 len = buffer_get_int(buffer); 170 if (len > 256 * 1024) { 171 error("buffer_get_string_ret: bad string length %u", len); 172 return (NULL); 173 } 174 /* Allocate space for the string. Add one byte for a null character. */ 175 value = xmalloc(len + 1); 176 /* Get the string. */ 177 if (buffer_get_ret(buffer, value, len) == -1) { 178 error("buffer_get_string_ret: buffer_get failed"); 179 xfree(value); 180 return (NULL); 181 } 182 /* Append a null character to make processing easier. */ 183 value[len] = '\0'; 184 /* Optionally return the length of the string. */ 185 if (length_ptr) 186 *length_ptr = len; 187 return (value); 188} 189 190void * 191buffer_get_string(Buffer *buffer, u_int *length_ptr) 192{ 193 void *ret; 194 195 if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL) 196 fatal("buffer_get_string: buffer error"); 197 return (ret); 198} 199 200void * 201buffer_get_string_ptr(Buffer *buffer, u_int *length_ptr) 202{ 203 void *ptr; 204 u_int len; 205 206 len = buffer_get_int(buffer); 207 if (len > 256 * 1024) 208 fatal("buffer_get_string_ptr: bad string length %u", len); 209 ptr = buffer_ptr(buffer); 210 buffer_consume(buffer, len); 211 if (length_ptr) 212 *length_ptr = len; 213 return (ptr); 214} 215 216/* 217 * Stores and arbitrary binary string in the buffer. 218 */ 219void 220buffer_put_string(Buffer *buffer, const void *buf, u_int len) 221{ 222 buffer_put_int(buffer, len); 223 buffer_append(buffer, buf, len); 224} 225void 226buffer_put_cstring(Buffer *buffer, const char *s) 227{ 228 if (s == NULL) 229 fatal("buffer_put_cstring: s == NULL"); 230 buffer_put_string(buffer, s, strlen(s)); 231} 232 233/* 234 * Returns a character from the buffer (0 - 255). 235 */ 236int 237buffer_get_char_ret(char *ret, Buffer *buffer) 238{ 239 if (buffer_get_ret(buffer, ret, 1) == -1) { 240 error("buffer_get_char_ret: buffer_get_ret failed"); 241 return (-1); 242 } 243 return (0); 244} 245 246int 247buffer_get_char(Buffer *buffer) 248{ 249 char ch; 250 251 if (buffer_get_char_ret(&ch, buffer) == -1) 252 fatal("buffer_get_char: buffer error"); 253 return (u_char) ch; 254} 255 256/* 257 * Stores a character in the buffer. 258 */ 259void 260buffer_put_char(Buffer *buffer, int value) 261{ 262 char ch = value; 263 264 buffer_append(buffer, &ch, 1); 265} 266