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 1.32 2004/02/23 15:12:46 markus 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)
111 if (BN_is_zero(value)) {
112 buffer_put_int(buffer, 0);
116 fatal("buffer_put_bignum2: negative numbers not supported");
117 bytes = BN_num_bytes(value) + 1; /* extra padding byte */
119 fatal("buffer_put_bignum2: BN too small");
120 buf = xmalloc(bytes);
122 /* Get the value of in binary */
123 oi = BN_bn2bin(value, buf+1);
125 fatal("buffer_put_bignum2: BN_bn2bin() failed: "
126 "oi %d != bin_size %d", oi, bytes);
127 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
128 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
129 memset(buf, 0, bytes);
134 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
137 u_char *bin = buffer_get_string(buffer, &len);
139 if (len > 0 && (bin[0] & 0x80))
140 fatal("buffer_get_bignum2: negative numbers not supported");
142 fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
143 BN_bin2bn(bin, len, value);
148 * Returns integers from the buffer (msb first).
152 buffer_get_short(Buffer *buffer)
156 buffer_get(buffer, (char *) buf, 2);
157 return GET_16BIT(buf);
161 buffer_get_int(Buffer *buffer)
165 buffer_get(buffer, (char *) buf, 4);
166 return GET_32BIT(buf);
170 buffer_get_int64(Buffer *buffer)
174 buffer_get(buffer, (char *) buf, 8);
175 return GET_64BIT(buf);
179 * Stores integers in the buffer, msb first.
182 buffer_put_short(Buffer *buffer, u_short value)
186 PUT_16BIT(buf, value);
187 buffer_append(buffer, buf, 2);
191 buffer_put_int(Buffer *buffer, u_int value)
195 PUT_32BIT(buf, value);
196 buffer_append(buffer, buf, 4);
200 buffer_put_int64(Buffer *buffer, u_int64_t value)
204 PUT_64BIT(buf, value);
205 buffer_append(buffer, buf, 8);
209 * Returns an arbitrary binary string from the buffer. The string cannot
210 * be longer than 256k. The returned value points to memory allocated
211 * with xmalloc; it is the responsibility of the calling function to free
212 * the data. If length_ptr is non-NULL, the length of the returned data
213 * will be stored there. A null character will be automatically appended
214 * to the returned string, and is not counted in length.
217 buffer_get_string(Buffer *buffer, u_int *length_ptr)
222 /* Get the length. */
223 len = buffer_get_int(buffer);
224 if (len > 256 * 1024)
225 fatal("buffer_get_string: bad string length %u", len);
226 /* Allocate space for the string. Add one byte for a null character. */
227 value = xmalloc(len + 1);
228 /* Get the string. */
229 buffer_get(buffer, value, len);
230 /* Append a null character to make processing easier. */
232 /* Optionally return the length of the string. */
239 * Stores and arbitrary binary string in the buffer.
242 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
244 buffer_put_int(buffer, len);
245 buffer_append(buffer, buf, len);
248 buffer_put_cstring(Buffer *buffer, const char *s)
251 fatal("buffer_put_cstring: s == NULL");
252 buffer_put_string(buffer, s, strlen(s));
256 * Returns a character from the buffer (0 - 255).
259 buffer_get_char(Buffer *buffer)
263 buffer_get(buffer, &ch, 1);
268 * Stores a character in the buffer.
271 buffer_put_char(Buffer *buffer, int value)
275 buffer_append(buffer, &ch, 1);