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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Auxiliary functions for storing and retrieving various data types to/from
6 * Buffers.
7 *
Damien Millere4340be2000-09-16 13:29:08 +11008 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
Damien Millerb38eff82000-04-01 11:09:21 +100013 *
Damien Millere4340be2000-09-16 13:29:08 +110014 *
15 * SSH2 packet format added by Markus Friedl
16 * Copyright (c) 2000 Markus Friedl. All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110037 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100038
39#include "includes.h"
Damien Millerd5580922003-05-14 13:40:06 +100040RCSID("$OpenBSD: bufaux.c,v 1.29 2003/04/08 20:21:28 itojun Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100041
Damien Millerd4a8b7e1999-10-27 13:42:43 +100042#include <openssl/bn.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100043#include "bufaux.h"
44#include "xmalloc.h"
45#include "getput.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000046#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100047
Damien Miller95def091999-11-25 00:26:21 +110048/*
49 * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
50 * by (bits+7)/8 bytes of binary data, msb first.
51 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100052void
53buffer_put_bignum(Buffer *buffer, BIGNUM *value)
54{
Damien Miller95def091999-11-25 00:26:21 +110055 int bits = BN_num_bits(value);
56 int bin_size = (bits + 7) / 8;
Ben Lindstrom46c16222000-12-22 01:43:59 +000057 u_char *buf = xmalloc(bin_size);
Damien Miller95def091999-11-25 00:26:21 +110058 int oi;
59 char msg[2];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100060
Damien Miller95def091999-11-25 00:26:21 +110061 /* Get the value of in binary */
62 oi = BN_bn2bin(value, buf);
63 if (oi != bin_size)
64 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
Damien Miller9f0f5c62001-12-21 14:45:46 +110065 oi, bin_size);
Damien Miller95def091999-11-25 00:26:21 +110066
67 /* Store the number of bits in the buffer in two bytes, msb first. */
68 PUT_16BIT(msg, bits);
69 buffer_append(buffer, msg, 2);
70 /* Store the binary data. */
Damien Miller7684ee12000-03-17 23:40:15 +110071 buffer_append(buffer, (char *)buf, oi);
Damien Miller5428f641999-11-25 11:54:57 +110072
Damien Miller95def091999-11-25 00:26:21 +110073 memset(buf, 0, bin_size);
74 xfree(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100075}
76
Damien Miller95def091999-11-25 00:26:21 +110077/*
78 * Retrieves an BIGNUM from the buffer.
79 */
Damien Miller76e1e362002-01-22 23:15:57 +110080void
Damien Millerd4a8b7e1999-10-27 13:42:43 +100081buffer_get_bignum(Buffer *buffer, BIGNUM *value)
82{
Damien Miller95def091999-11-25 00:26:21 +110083 int bits, bytes;
Ben Lindstrom46c16222000-12-22 01:43:59 +000084 u_char buf[2], *bin;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100085
Damien Miller95def091999-11-25 00:26:21 +110086 /* Get the number for bits. */
87 buffer_get(buffer, (char *) buf, 2);
88 bits = GET_16BIT(buf);
89 /* Compute the number of binary bytes that follow. */
90 bytes = (bits + 7) / 8;
Damien Milleraa151372002-06-26 19:14:08 +100091 if (bytes > 8 * 1024)
92 fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
Damien Miller95def091999-11-25 00:26:21 +110093 if (buffer_len(buffer) < bytes)
94 fatal("buffer_get_bignum: input buffer too small");
Damien Miller4a8ed542002-01-22 23:33:31 +110095 bin = buffer_ptr(buffer);
Damien Miller95def091999-11-25 00:26:21 +110096 BN_bin2bn(bin, bytes, value);
97 buffer_consume(buffer, bytes);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100098}
99
Damien Miller95def091999-11-25 00:26:21 +1100100/*
Damien Millerb38eff82000-04-01 11:09:21 +1000101 * Stores an BIGNUM in the buffer in SSH2 format.
102 */
103void
104buffer_put_bignum2(Buffer *buffer, BIGNUM *value)
105{
106 int bytes = BN_num_bytes(value) + 1;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000107 u_char *buf = xmalloc(bytes);
Damien Millerb38eff82000-04-01 11:09:21 +1000108 int oi;
109 int hasnohigh = 0;
Ben Lindstrome1353632002-06-23 21:29:23 +0000110
Damien Millerb38eff82000-04-01 11:09:21 +1000111 buf[0] = '\0';
112 /* Get the value of in binary */
113 oi = BN_bn2bin(value, buf+1);
114 if (oi != bytes-1)
115 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100116 oi, bytes);
Damien Millerb38eff82000-04-01 11:09:21 +1000117 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
118 if (value->neg) {
119 /**XXX should be two's-complement */
120 int i, carry;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000121 u_char *uc = buf;
Damien Miller996acd22003-04-09 20:59:48 +1000122 logit("negativ!");
Damien Miller9f0f5c62001-12-21 14:45:46 +1100123 for (i = bytes-1, carry = 1; i>=0; i--) {
Damien Millerb38eff82000-04-01 11:09:21 +1000124 uc[i] ^= 0xff;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000125 if (carry)
Damien Millerb38eff82000-04-01 11:09:21 +1000126 carry = !++uc[i];
127 }
128 }
129 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
130 memset(buf, 0, bytes);
131 xfree(buf);
132}
133
Damien Milleraa151372002-06-26 19:14:08 +1000134/* XXX does not handle negative BNs */
Damien Miller76e1e362002-01-22 23:15:57 +1100135void
Damien Millerb38eff82000-04-01 11:09:21 +1000136buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
137{
Damien Milleraa151372002-06-26 19:14:08 +1000138 u_int len;
139 u_char *bin = buffer_get_string(buffer, &len);
Ben Lindstrome1353632002-06-23 21:29:23 +0000140
Damien Milleraa151372002-06-26 19:14:08 +1000141 if (len > 8 * 1024)
142 fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
Damien Millerb38eff82000-04-01 11:09:21 +1000143 BN_bin2bn(bin, len, value);
144 xfree(bin);
Damien Millerb38eff82000-04-01 11:09:21 +1000145}
Damien Millerb38eff82000-04-01 11:09:21 +1000146/*
Damien Miller3b235662002-04-23 20:42:36 +1000147 * Returns integers from the buffer (msb first).
Damien Miller95def091999-11-25 00:26:21 +1100148 */
Damien Miller3b235662002-04-23 20:42:36 +1000149
150u_short
151buffer_get_short(Buffer *buffer)
152{
153 u_char buf[2];
Ben Lindstrome1353632002-06-23 21:29:23 +0000154
Damien Miller3b235662002-04-23 20:42:36 +1000155 buffer_get(buffer, (char *) buf, 2);
156 return GET_16BIT(buf);
157}
158
Ben Lindstrom46c16222000-12-22 01:43:59 +0000159u_int
Damien Miller95def091999-11-25 00:26:21 +1100160buffer_get_int(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000161{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000162 u_char buf[4];
Ben Lindstrome1353632002-06-23 21:29:23 +0000163
Damien Miller95def091999-11-25 00:26:21 +1100164 buffer_get(buffer, (char *) buf, 4);
165 return GET_32BIT(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000166}
167
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000168u_int64_t
169buffer_get_int64(Buffer *buffer)
170{
171 u_char buf[8];
Ben Lindstrome1353632002-06-23 21:29:23 +0000172
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000173 buffer_get(buffer, (char *) buf, 8);
174 return GET_64BIT(buf);
175}
176
Damien Miller95def091999-11-25 00:26:21 +1100177/*
Damien Miller3b235662002-04-23 20:42:36 +1000178 * Stores integers in the buffer, msb first.
Damien Miller95def091999-11-25 00:26:21 +1100179 */
Damien Miller5f056372000-04-16 12:31:48 +1000180void
Damien Miller3b235662002-04-23 20:42:36 +1000181buffer_put_short(Buffer *buffer, u_short value)
182{
183 char buf[2];
Ben Lindstrome1353632002-06-23 21:29:23 +0000184
Damien Miller3b235662002-04-23 20:42:36 +1000185 PUT_16BIT(buf, value);
186 buffer_append(buffer, buf, 2);
187}
188
189void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000190buffer_put_int(Buffer *buffer, u_int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000191{
Damien Miller95def091999-11-25 00:26:21 +1100192 char buf[4];
Ben Lindstrome1353632002-06-23 21:29:23 +0000193
Damien Miller95def091999-11-25 00:26:21 +1100194 PUT_32BIT(buf, value);
195 buffer_append(buffer, buf, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000196}
197
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000198void
199buffer_put_int64(Buffer *buffer, u_int64_t value)
200{
201 char buf[8];
Ben Lindstrome1353632002-06-23 21:29:23 +0000202
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000203 PUT_64BIT(buf, value);
204 buffer_append(buffer, buf, 8);
205}
206
Damien Miller95def091999-11-25 00:26:21 +1100207/*
208 * Returns an arbitrary binary string from the buffer. The string cannot
209 * be longer than 256k. The returned value points to memory allocated
210 * with xmalloc; it is the responsibility of the calling function to free
211 * the data. If length_ptr is non-NULL, the length of the returned data
212 * will be stored there. A null character will be automatically appended
213 * to the returned string, and is not counted in length.
214 */
Damien Miller5a6b4fe2001-12-21 14:56:54 +1100215void *
Ben Lindstrom46c16222000-12-22 01:43:59 +0000216buffer_get_string(Buffer *buffer, u_int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000217{
Damien Miller5a6b4fe2001-12-21 14:56:54 +1100218 u_char *value;
Ben Lindstrome1353632002-06-23 21:29:23 +0000219 u_int len;
220
Damien Miller95def091999-11-25 00:26:21 +1100221 /* Get the length. */
222 len = buffer_get_int(buffer);
223 if (len > 256 * 1024)
Ben Lindstromee844912002-11-09 15:43:23 +0000224 fatal("buffer_get_string: bad string length %u", len);
Damien Miller95def091999-11-25 00:26:21 +1100225 /* Allocate space for the string. Add one byte for a null character. */
226 value = xmalloc(len + 1);
227 /* Get the string. */
228 buffer_get(buffer, value, len);
229 /* Append a null character to make processing easier. */
230 value[len] = 0;
231 /* Optionally return the length of the string. */
232 if (length_ptr)
233 *length_ptr = len;
234 return value;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000235}
236
Damien Miller95def091999-11-25 00:26:21 +1100237/*
238 * Stores and arbitrary binary string in the buffer.
239 */
Damien Miller5f056372000-04-16 12:31:48 +1000240void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000241buffer_put_string(Buffer *buffer, const void *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000242{
Damien Miller95def091999-11-25 00:26:21 +1100243 buffer_put_int(buffer, len);
244 buffer_append(buffer, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000245}
Damien Miller5f056372000-04-16 12:31:48 +1000246void
Damien Millerb38eff82000-04-01 11:09:21 +1000247buffer_put_cstring(Buffer *buffer, const char *s)
248{
Ben Lindstrom88aa1b42002-03-22 01:47:52 +0000249 if (s == NULL)
250 fatal("buffer_put_cstring: s == NULL");
Damien Millerb38eff82000-04-01 11:09:21 +1000251 buffer_put_string(buffer, s, strlen(s));
252}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000253
Damien Miller95def091999-11-25 00:26:21 +1100254/*
255 * Returns a character from the buffer (0 - 255).
256 */
Damien Miller5f056372000-04-16 12:31:48 +1000257int
Damien Miller95def091999-11-25 00:26:21 +1100258buffer_get_char(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000259{
Damien Miller95def091999-11-25 00:26:21 +1100260 char ch;
Ben Lindstrome1353632002-06-23 21:29:23 +0000261
Damien Miller95def091999-11-25 00:26:21 +1100262 buffer_get(buffer, &ch, 1);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000263 return (u_char) ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000264}
265
Damien Miller95def091999-11-25 00:26:21 +1100266/*
267 * Stores a character in the buffer.
268 */
Damien Miller5f056372000-04-16 12:31:48 +1000269void
Damien Miller95def091999-11-25 00:26:21 +1100270buffer_put_char(Buffer *buffer, int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000271{
Damien Miller95def091999-11-25 00:26:21 +1100272 char ch = value;
Ben Lindstrome1353632002-06-23 21:29:23 +0000273
Damien Miller95def091999-11-25 00:26:21 +1100274 buffer_append(buffer, &ch, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000275}