crypto/external/bsd/openssh/dist/bufbn.c

   1 /*      $NetBSD$        */
   2 /* $OpenBSD: bufbn.c,v 1.6 2007/06/02 09:04:58 djm Exp $*/
   3 /*
   4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   6  *                    All rights reserved
   7  * Auxiliary functions for storing and retrieving various data types to/from
   8  * Buffers.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  *
  17  * SSH2 packet format added by Markus Friedl
  18  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  19  *
  20  * Redistribution and use in source and binary forms, with or without
  21  * modification, are permitted provided that the following conditions
  22  * are met:
  23  * 1. Redistributions of source code must retain the above copyright
  24  *    notice, this list of conditions and the following disclaimer.
  25  * 2. Redistributions in binary form must reproduce the above copyright
  26  *    notice, this list of conditions and the following disclaimer in the
  27  *    documentation and/or other materials provided with the distribution.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  30  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  31  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  32  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  33  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  34  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  38  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  */
  40
  41 #include "includes.h"
  42 __RCSID("$NetBSD: bufbn.c,v 1.5 2009/02/16 20:53:54 christos Exp $");
  43 #include <sys/types.h>
  44
  45 #include <openssl/bn.h>
  46
  47 #include <string.h>
  48 #include <stdarg.h>
  49 #include <time.h>
  50
  51 #include "xmalloc.h"
  52 #include "buffer.h"
  53 #include "log.h"
  54 #include "misc.h"
  55
  56 /*
  57  * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
  58  * by (bits+7)/8 bytes of binary data, msb first.
  59  */
  60 int
  61 buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value)
  62 {
  63         int bits = BN_num_bits(value);
  64         int bin_size = (bits + 7) / 8;
  65         u_char *buf = xmalloc(bin_size);
  66         int oi;
  67         char msg[2];
  68
  69         /* Get the value of in binary */
  70         oi = BN_bn2bin(value, buf);
  71         if (oi != bin_size) {
  72                 error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d",
  73                     oi, bin_size);
  74                 xfree(buf);
  75                 return (-1);
  76         }
  77
  78         /* Store the number of bits in the buffer in two bytes, msb first. */
  79         put_u16(msg, bits);
  80         buffer_append(buffer, msg, 2);
  81         /* Store the binary data. */
  82         buffer_append(buffer, buf, oi);
  83
  84         memset(buf, 0, bin_size);
  85         xfree(buf);
  86
  87         return (0);
  88 }
  89
  90 void
  91 buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
  92 {
  93         if (buffer_put_bignum_ret(buffer, value) == -1)
  94                 fatal("buffer_put_bignum: buffer error");
  95 }
  96
  97 /*
  98  * Retrieves a BIGNUM from the buffer.
  99  */
 100 int
 101 buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
 102 {
 103         u_int bits, bytes;
 104         u_char buf[2], *bin;
 105
 106         /* Get the number of bits. */
 107         if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
 108                 error("buffer_get_bignum_ret: invalid length");
 109                 return (-1);
 110         }
 111         bits = get_u16(buf);
 112         /* Compute the number of binary bytes that follow. */
 113         bytes = (bits + 7) / 8;
 114         if (bytes > 8 * 1024) {
 115                 error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
 116                 return (-1);
 117         }
 118         if (buffer_len(buffer) < bytes) {
 119                 error("buffer_get_bignum_ret: input buffer too small");
 120                 return (-1);
 121         }
 122         bin = buffer_ptr(buffer);
 123         if (BN_bin2bn(bin, bytes, value) == NULL) {
 124                 error("buffer_get_bignum_ret: BN_bin2bn failed");
 125                 return (-1);
 126         }
 127         if (buffer_consume_ret(buffer, bytes) == -1) {
 128                 error("buffer_get_bignum_ret: buffer_consume failed");
 129                 return (-1);
 130         }
 131         return (0);
 132 }
 133
 134 void
 135 buffer_get_bignum(Buffer *buffer, BIGNUM *value)
 136 {
 137         if (buffer_get_bignum_ret(buffer, value) == -1)
 138                 fatal("buffer_get_bignum: buffer error");
 139 }
 140
 141 /*
 142  * Stores a BIGNUM in the buffer in SSH2 format.
 143  */
 144 int
 145 buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value)
 146 {
 147         u_int bytes;
 148         u_char *buf;
 149         int oi;
 150         u_int hasnohigh = 0;
 151
 152         if (BN_is_zero(value)) {
 153                 buffer_put_int(buffer, 0);
 154                 return 0;
 155         }
 156         if (value->neg) {
 157                 error("buffer_put_bignum2_ret: negative numbers not supported");
 158                 return (-1);
 159         }
 160         bytes = BN_num_bytes(value) + 1; /* extra padding byte */
 161         if (bytes < 2) {
 162                 error("buffer_put_bignum2_ret: BN too small");
 163                 return (-1);
 164         }
 165         buf = xmalloc(bytes);
 166         buf[0] = 0x00;
 167         /* Get the value of in binary */
 168         oi = BN_bn2bin(value, buf+1);
 169         if (oi < 0 || (u_int)oi != bytes - 1) {
 170                 error("buffer_put_bignum2_ret: BN_bn2bin() failed: "
 171                     "oi %d != bin_size %d", oi, bytes);
 172                 xfree(buf);
 173                 return (-1);
 174         }
 175         hasnohigh = (buf[1] & 0x80) ? 0 : 1;
 176         buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
 177         memset(buf, 0, bytes);
 178         xfree(buf);
 179         return (0);
 180 }
 181
 182 void
 183 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
 184 {
 185         if (buffer_put_bignum2_ret(buffer, value) == -1)
 186                 fatal("buffer_put_bignum2: buffer error");
 187 }
 188
 189 int
 190 buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value)
 191 {
 192         u_int len;
 193         u_char *bin;
 194
 195         if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) {
 196                 error("buffer_get_bignum2_ret: invalid bignum");
 197                 return (-1);
 198         }
 199
 200         if (len > 0 && (bin[0] & 0x80)) {
 201                 error("buffer_get_bignum2_ret: negative numbers not supported");
 202                 xfree(bin);
 203                 return (-1);
 204         }
 205         if (len > 8 * 1024) {
 206                 error("buffer_get_bignum2_ret: cannot handle BN of size %d",
 207                     len);
 208                 xfree(bin);
 209                 return (-1);
 210         }
 211         if (BN_bin2bn(bin, len, value) == NULL) {
 212                 error("buffer_get_bignum2_ret: BN_bin2bn failed");
 213                 xfree(bin);
 214                 return (-1);
 215         }
 216         xfree(bin);
 217         return (0);
 218 }
 219
 220 void
 221 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
 222 {
 223         if (buffer_get_bignum2_ret(buffer, value) == -1)
 224                 fatal("buffer_get_bignum2: buffer error");
 225 }