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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 *
3 * bufaux.c
4 *
5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
6 *
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 * All rights reserved
9 *
10 * Created: Wed Mar 29 02:24:47 1995 ylo
11 *
12 * Auxiliary functions for storing and retrieving various data types to/from
13 * Buffers.
14 *
15 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100016
17#include "includes.h"
Damien Miller5428f641999-11-25 11:54:57 +110018RCSID("$Id: bufaux.c,v 1.7 1999/11/25 00:54:58 damien Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100019
20#include "ssh.h"
Damien Miller7f6ea021999-10-28 13:25:17 +100021
22#ifdef HAVE_OPENSSL
Damien Millerd4a8b7e1999-10-27 13:42:43 +100023#include <openssl/bn.h>
Damien Miller7f6ea021999-10-28 13:25:17 +100024#endif
25#ifdef HAVE_SSL
26#include <ssl/bn.h>
27#endif
28
Damien Millerd4a8b7e1999-10-27 13:42:43 +100029#include "bufaux.h"
30#include "xmalloc.h"
31#include "getput.h"
32
Damien Miller95def091999-11-25 00:26:21 +110033/*
34 * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
35 * by (bits+7)/8 bytes of binary data, msb first.
36 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100037void
38buffer_put_bignum(Buffer *buffer, BIGNUM *value)
39{
Damien Miller95def091999-11-25 00:26:21 +110040 int bits = BN_num_bits(value);
41 int bin_size = (bits + 7) / 8;
42 char *buf = xmalloc(bin_size);
43 int oi;
44 char msg[2];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100045
Damien Miller95def091999-11-25 00:26:21 +110046 /* Get the value of in binary */
47 oi = BN_bn2bin(value, buf);
48 if (oi != bin_size)
49 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
50 oi, bin_size);
51
52 /* Store the number of bits in the buffer in two bytes, msb first. */
53 PUT_16BIT(msg, bits);
54 buffer_append(buffer, msg, 2);
55 /* Store the binary data. */
56 buffer_append(buffer, buf, oi);
Damien Miller5428f641999-11-25 11:54:57 +110057
Damien Miller95def091999-11-25 00:26:21 +110058 memset(buf, 0, bin_size);
59 xfree(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100060}
61
Damien Miller95def091999-11-25 00:26:21 +110062/*
63 * Retrieves an BIGNUM from the buffer.
64 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100065int
66buffer_get_bignum(Buffer *buffer, BIGNUM *value)
67{
Damien Miller95def091999-11-25 00:26:21 +110068 int bits, bytes;
69 unsigned char buf[2], *bin;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100070
Damien Miller95def091999-11-25 00:26:21 +110071 /* Get the number for bits. */
72 buffer_get(buffer, (char *) buf, 2);
73 bits = GET_16BIT(buf);
74 /* Compute the number of binary bytes that follow. */
75 bytes = (bits + 7) / 8;
76 if (buffer_len(buffer) < bytes)
77 fatal("buffer_get_bignum: input buffer too small");
78 bin = buffer_ptr(buffer);
79 BN_bin2bn(bin, bytes, value);
80 buffer_consume(buffer, bytes);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100081
Damien Miller95def091999-11-25 00:26:21 +110082 return 2 + bytes;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100083}
84
Damien Miller95def091999-11-25 00:26:21 +110085/*
86 * Returns an integer from the buffer (4 bytes, msb first).
87 */
88unsigned int
89buffer_get_int(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100090{
Damien Miller95def091999-11-25 00:26:21 +110091 unsigned char buf[4];
92 buffer_get(buffer, (char *) buf, 4);
93 return GET_32BIT(buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100094}
95
Damien Miller95def091999-11-25 00:26:21 +110096/*
97 * Stores an integer in the buffer in 4 bytes, msb first.
98 */
99void
100buffer_put_int(Buffer *buffer, unsigned int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000101{
Damien Miller95def091999-11-25 00:26:21 +1100102 char buf[4];
103 PUT_32BIT(buf, value);
104 buffer_append(buffer, buf, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000105}
106
Damien Miller95def091999-11-25 00:26:21 +1100107/*
108 * Returns an arbitrary binary string from the buffer. The string cannot
109 * be longer than 256k. The returned value points to memory allocated
110 * with xmalloc; it is the responsibility of the calling function to free
111 * the data. If length_ptr is non-NULL, the length of the returned data
112 * will be stored there. A null character will be automatically appended
113 * to the returned string, and is not counted in length.
114 */
115char *
116buffer_get_string(Buffer *buffer, unsigned int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000117{
Damien Miller95def091999-11-25 00:26:21 +1100118 unsigned int len;
119 char *value;
120 /* Get the length. */
121 len = buffer_get_int(buffer);
122 if (len > 256 * 1024)
123 fatal("Received packet with bad string length %d", len);
124 /* Allocate space for the string. Add one byte for a null character. */
125 value = xmalloc(len + 1);
126 /* Get the string. */
127 buffer_get(buffer, value, len);
128 /* Append a null character to make processing easier. */
129 value[len] = 0;
130 /* Optionally return the length of the string. */
131 if (length_ptr)
132 *length_ptr = len;
133 return value;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000134}
135
Damien Miller95def091999-11-25 00:26:21 +1100136/*
137 * Stores and arbitrary binary string in the buffer.
138 */
139void
140buffer_put_string(Buffer *buffer, const void *buf, unsigned int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000141{
Damien Miller95def091999-11-25 00:26:21 +1100142 buffer_put_int(buffer, len);
143 buffer_append(buffer, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000144}
145
Damien Miller95def091999-11-25 00:26:21 +1100146/*
147 * Returns a character from the buffer (0 - 255).
148 */
149int
150buffer_get_char(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000151{
Damien Miller95def091999-11-25 00:26:21 +1100152 char ch;
153 buffer_get(buffer, &ch, 1);
154 return (unsigned char) ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000155}
156
Damien Miller95def091999-11-25 00:26:21 +1100157/*
158 * Stores a character in the buffer.
159 */
160void
161buffer_put_char(Buffer *buffer, int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000162{
Damien Miller95def091999-11-25 00:26:21 +1100163 char ch = value;
164 buffer_append(buffer, &ch, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000165}