bufaux.c

   1 /* $OpenBSD: bufaux.c,v 1.48 2010/02/02 22:49:34 djm 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
  58 int
  59 buffer_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
  69 u_short
  70 buffer_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
  80 int
  81 buffer_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
  91 u_int
  92 buffer_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
 102 int
 103 buffer_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
 113 u_int64_t
 114 buffer_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  */
 127 void
 128 buffer_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
 136 void
 137 buffer_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
 145 void
 146 buffer_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  */
 162 void *
 163 buffer_get_string_ret(Buffer *buffer, u_int *length_ptr)
 164 {
 165         u_char *value;
 166         u_int len;
 167
 168         /* Get the length. */
 169         if (buffer_get_int_ret(&len, buffer) != 0) {
 170                 error("buffer_get_string_ret: cannot extract length");
 171                 return (NULL);
 172         }
 173         if (len > 256 * 1024) {
 174                 error("buffer_get_string_ret: bad string length %u", len);
 175                 return (NULL);
 176         }
 177         /* Allocate space for the string.  Add one byte for a null character. */
 178         value = xmalloc(len + 1);
 179         /* Get the string. */
 180         if (buffer_get_ret(buffer, value, len) == -1) {
 181                 error("buffer_get_string_ret: buffer_get failed");
 182                 xfree(value);
 183                 return (NULL);
 184         }
 185         /* Append a null character to make processing easier. */
 186         value[len] = '\0';
 187         /* Optionally return the length of the string. */
 188         if (length_ptr)
 189                 *length_ptr = len;
 190         return (value);
 191 }
 192
 193 void *
 194 buffer_get_string(Buffer *buffer, u_int *length_ptr)
 195 {
 196         void *ret;
 197
 198         if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
 199                 fatal("buffer_get_string: buffer error");
 200         return (ret);
 201 }
 202
 203 void *
 204 buffer_get_string_ptr_ret(Buffer *buffer, u_int *length_ptr)
 205 {
 206         void *ptr;
 207         u_int len;
 208
 209         if (buffer_get_int_ret(&len, buffer) != 0)
 210                 return NULL;
 211         if (len > 256 * 1024) {
 212                 error("buffer_get_string_ptr: bad string length %u", len);
 213                 return NULL;
 214         }
 215         ptr = buffer_ptr(buffer);
 216         buffer_consume(buffer, len);
 217         if (length_ptr)
 218                 *length_ptr = len;
 219         return (ptr);
 220 }
 221
 222 void *
 223 buffer_get_string_ptr(Buffer *buffer, u_int *length_ptr)
 224 {
 225         void *ret;
 226
 227         if ((ret = buffer_get_string_ptr_ret(buffer, length_ptr)) == NULL)
 228                 fatal("buffer_get_string_ptr: buffer error");
 229         return (ret);
 230 }
 231
 232 /*
 233  * Stores and arbitrary binary string in the buffer.
 234  */
 235 void
 236 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
 237 {
 238         buffer_put_int(buffer, len);
 239         buffer_append(buffer, buf, len);
 240 }
 241 void
 242 buffer_put_cstring(Buffer *buffer, const char *s)
 243 {
 244         if (s == NULL)
 245                 fatal("buffer_put_cstring: s == NULL");
 246         buffer_put_string(buffer, s, strlen(s));
 247 }
 248
 249 /*
 250  * Returns a character from the buffer (0 - 255).
 251  */
 252 int
 253 buffer_get_char_ret(char *ret, Buffer *buffer)
 254 {
 255         if (buffer_get_ret(buffer, ret, 1) == -1) {
 256                 error("buffer_get_char_ret: buffer_get_ret failed");
 257                 return (-1);
 258         }
 259         return (0);
 260 }
 261
 262 int
 263 buffer_get_char(Buffer *buffer)
 264 {
 265         char ch;
 266
 267         if (buffer_get_char_ret(&ch, buffer) == -1)
 268                 fatal("buffer_get_char: buffer error");
 269         return (u_char) ch;
 270 }
 271
 272 /*
 273  * Stores a character in the buffer.
 274  */
 275 void
 276 buffer_put_char(Buffer *buffer, int value)
 277 {
 278         char ch = value;
 279
 280         buffer_append(buffer, &ch, 1);
 281 }