2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Auxiliary functions for storing and retrieving various data types to/from
8 * 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".
15 * SSH2 packet format added by Markus Friedl
16 * Copyright (c) 2000 Markus Friedl. All rights reserved.
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
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.
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.
40 RCSID("$OpenBSD: bufaux.c,v 1.31 2003/11/10 16:23:41 jakob Exp $");
42 #include <openssl/bn.h>
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.
53 buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
55 int bits = BN_num_bits(value);
56 int bin_size = (bits + 7) / 8;
57 u_char *buf = xmalloc(bin_size);
61 /* Get the value of in binary */
62 oi = BN_bn2bin(value, buf);
64 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
67 /* Store the number of bits in the buffer in two bytes, msb first. */
69 buffer_append(buffer, msg, 2);
70 /* Store the binary data. */
71 buffer_append(buffer, (char *)buf, oi);
73 memset(buf, 0, bin_size);
78 * Retrieves an BIGNUM from the buffer.
81 buffer_get_bignum(Buffer *buffer, BIGNUM *value)
86 /* 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;
92 fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
93 if (buffer_len(buffer) < bytes)
94 fatal("buffer_get_bignum: input buffer too small");
95 bin = buffer_ptr(buffer);
96 BN_bin2bn(bin, bytes, value);
97 buffer_consume(buffer, bytes);
101 * Stores an BIGNUM in the buffer in SSH2 format.
104 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
106 u_int bytes = BN_num_bytes(value) + 1;
107 u_char *buf = xmalloc(bytes);
112 /* Get the value of in binary */
113 oi = BN_bn2bin(value, buf+1);
115 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
117 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
119 /**XXX should be two's-complement */
123 for (i = bytes-1, carry = 1; i>=0; i--) {
129 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
130 memset(buf, 0, bytes);
134 /* XXX does not handle negative BNs */
136 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
139 u_char *bin = buffer_get_string(buffer, &len);
142 fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
143 BN_bin2bn(bin, len, value);
147 * Returns integers from the buffer (msb first).
151 buffer_get_short(Buffer *buffer)
155 buffer_get(buffer, (char *) buf, 2);
156 return GET_16BIT(buf);
160 buffer_get_int(Buffer *buffer)
164 buffer_get(buffer, (char *) buf, 4);
165 return GET_32BIT(buf);
169 buffer_get_int64(Buffer *buffer)
173 buffer_get(buffer, (char *) buf, 8);
174 return GET_64BIT(buf);
178 * Stores integers in the buffer, msb first.
181 buffer_put_short(Buffer *buffer, u_short value)
185 PUT_16BIT(buf, value);
186 buffer_append(buffer, buf, 2);
190 buffer_put_int(Buffer *buffer, u_int value)
194 PUT_32BIT(buf, value);
195 buffer_append(buffer, buf, 4);
199 buffer_put_int64(Buffer *buffer, u_int64_t value)
203 PUT_64BIT(buf, value);
204 buffer_append(buffer, buf, 8);
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.
216 buffer_get_string(Buffer *buffer, u_int *length_ptr)
221 /* Get the length. */
222 len = buffer_get_int(buffer);
223 if (len > 256 * 1024)
224 fatal("buffer_get_string: bad string length %u", len);
225 /* 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. */
231 /* Optionally return the length of the string. */
238 * Stores and arbitrary binary string in the buffer.
241 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
243 buffer_put_int(buffer, len);
244 buffer_append(buffer, buf, len);
247 buffer_put_cstring(Buffer *buffer, const char *s)
250 fatal("buffer_put_cstring: s == NULL");
251 buffer_put_string(buffer, s, strlen(s));
255 * Returns a character from the buffer (0 - 255).
258 buffer_get_char(Buffer *buffer)
262 buffer_get(buffer, &ch, 1);
267 * Stores a character in the buffer.
270 buffer_put_char(Buffer *buffer, int value)
274 buffer_append(buffer, &ch, 1);