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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"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000040RCSID("$OpenBSD: bufaux.c,v 1.17 2001/01/21 19:05:45 markus 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",
65 oi, bin_size);
66
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 Millerd4a8b7e1999-10-27 13:42:43 +100080int
81buffer_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;
91 if (buffer_len(buffer) < bytes)
92 fatal("buffer_get_bignum: input buffer too small");
Ben Lindstrombf555ba2001-01-18 02:04:35 +000093 bin = (u_char *) buffer_ptr(buffer);
Damien Miller95def091999-11-25 00:26:21 +110094 BN_bin2bn(bin, bytes, value);
95 buffer_consume(buffer, bytes);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096
Damien Miller95def091999-11-25 00:26:21 +110097 return 2 + 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;
110 buf[0] = '\0';
111 /* Get the value of in binary */
112 oi = BN_bn2bin(value, buf+1);
113 if (oi != bytes-1)
114 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
115 oi, bytes);
116 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
117 if (value->neg) {
118 /**XXX should be two's-complement */
119 int i, carry;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000120 u_char *uc = buf;
Damien Millerb38eff82000-04-01 11:09:21 +1000121 log("negativ!");
122 for(i = bytes-1, carry = 1; i>=0; i--) {
123 uc[i] ^= 0xff;
124 if(carry)
125 carry = !++uc[i];
126 }
127 }
128 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
129 memset(buf, 0, bytes);
130 xfree(buf);
131}
132
133int
134buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
135{
136 /**XXX should be two's-complement */
137 int len;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000138 u_char *bin = (u_char *)buffer_get_string(buffer, (u_int *)&len);
Damien Millerb38eff82000-04-01 11:09:21 +1000139 BN_bin2bn(bin, len, value);
140 xfree(bin);
141 return len;
142}
143
144/*
Damien Miller95def091999-11-25 00:26:21 +1100145 * Returns an integer from the buffer (4 bytes, msb first).
146 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000147u_int
Damien Miller95def091999-11-25 00:26:21 +1100148buffer_get_int(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000149{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000150 u_char buf[4];
Damien Miller95def091999-11-25 00:26:21 +1100151 buffer_get(buffer, (char *) buf, 4);
152 return GET_32BIT(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000153}
154
Ben Lindstrom16a86be2001-01-23 16:26:52 +0000155#ifdef HAVE_U_INT64_T
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000156u_int64_t
157buffer_get_int64(Buffer *buffer)
158{
159 u_char buf[8];
160 buffer_get(buffer, (char *) buf, 8);
161 return GET_64BIT(buf);
162}
Ben Lindstrom16a86be2001-01-23 16:26:52 +0000163#endif
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000164
Damien Miller95def091999-11-25 00:26:21 +1100165/*
166 * Stores an integer in the buffer in 4 bytes, msb first.
167 */
Damien Miller5f056372000-04-16 12:31:48 +1000168void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000169buffer_put_int(Buffer *buffer, u_int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000170{
Damien Miller95def091999-11-25 00:26:21 +1100171 char buf[4];
172 PUT_32BIT(buf, value);
173 buffer_append(buffer, buf, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000174}
175
Ben Lindstrom16a86be2001-01-23 16:26:52 +0000176#ifdef HAVE_U_INT64_T
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000177void
178buffer_put_int64(Buffer *buffer, u_int64_t value)
179{
180 char buf[8];
181 PUT_64BIT(buf, value);
182 buffer_append(buffer, buf, 8);
183}
Ben Lindstrom16a86be2001-01-23 16:26:52 +0000184#endif
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000185
Damien Miller95def091999-11-25 00:26:21 +1100186/*
187 * Returns an arbitrary binary string from the buffer. The string cannot
188 * be longer than 256k. The returned value points to memory allocated
189 * with xmalloc; it is the responsibility of the calling function to free
190 * the data. If length_ptr is non-NULL, the length of the returned data
191 * will be stored there. A null character will be automatically appended
192 * to the returned string, and is not counted in length.
193 */
194char *
Ben Lindstrom46c16222000-12-22 01:43:59 +0000195buffer_get_string(Buffer *buffer, u_int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000196{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000197 u_int len;
Damien Miller95def091999-11-25 00:26:21 +1100198 char *value;
199 /* Get the length. */
200 len = buffer_get_int(buffer);
201 if (len > 256 * 1024)
202 fatal("Received packet with bad string length %d", len);
203 /* Allocate space for the string. Add one byte for a null character. */
204 value = xmalloc(len + 1);
205 /* Get the string. */
206 buffer_get(buffer, value, len);
207 /* Append a null character to make processing easier. */
208 value[len] = 0;
209 /* Optionally return the length of the string. */
210 if (length_ptr)
211 *length_ptr = len;
212 return value;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000213}
214
Damien Miller95def091999-11-25 00:26:21 +1100215/*
216 * Stores and arbitrary binary string in the buffer.
217 */
Damien Miller5f056372000-04-16 12:31:48 +1000218void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000219buffer_put_string(Buffer *buffer, const void *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000220{
Damien Miller95def091999-11-25 00:26:21 +1100221 buffer_put_int(buffer, len);
222 buffer_append(buffer, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223}
Damien Miller5f056372000-04-16 12:31:48 +1000224void
Damien Millerb38eff82000-04-01 11:09:21 +1000225buffer_put_cstring(Buffer *buffer, const char *s)
226{
227 buffer_put_string(buffer, s, strlen(s));
228}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000229
Damien Miller95def091999-11-25 00:26:21 +1100230/*
231 * Returns a character from the buffer (0 - 255).
232 */
Damien Miller5f056372000-04-16 12:31:48 +1000233int
Damien Miller95def091999-11-25 00:26:21 +1100234buffer_get_char(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000235{
Damien Miller95def091999-11-25 00:26:21 +1100236 char ch;
237 buffer_get(buffer, &ch, 1);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000238 return (u_char) ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000239}
240
Damien Miller95def091999-11-25 00:26:21 +1100241/*
242 * Stores a character in the buffer.
243 */
Damien Miller5f056372000-04-16 12:31:48 +1000244void
Damien Miller95def091999-11-25 00:26:21 +1100245buffer_put_char(Buffer *buffer, int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000246{
Damien Miller95def091999-11-25 00:26:21 +1100247 char ch = value;
248 buffer_append(buffer, &ch, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000249}