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 $");
43 #include <openssl/bn.h>
50 * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
51 * by (bits+7)/8 bytes of binary data, msb first.
54 buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
56 int bits = BN_num_bits(value);
57 int bin_size = (bits + 7) / 8;
58 u_char *buf = xmalloc(bin_size);
62 /* Get the value of in binary */
63 oi = BN_bn2bin(value, buf);
65 fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
68 /* Store the number of bits in the buffer in two bytes, msb first. */
70 buffer_append(buffer, msg, 2);
71 /* Store the binary data. */
72 buffer_append(buffer, (char *)buf, oi);
74 memset(buf, 0, bin_size);
79 * Retrieves an BIGNUM from the buffer.
82 buffer_get_bignum(Buffer *buffer, BIGNUM *value)
87 /* Get the number for bits. */
88 buffer_get(buffer, (char *) buf, 2);
89 bits = GET_16BIT(buf);
90 /* Compute the number of binary bytes that follow. */
91 bytes = (bits + 7) / 8;
93 fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
94 if (buffer_len(buffer) < bytes)
95 fatal("buffer_get_bignum: input buffer too small");
96 bin = buffer_ptr(buffer);
97 BN_bin2bn(bin, bytes, value);
98 buffer_consume(buffer, bytes);
102 * Stores an BIGNUM in the buffer in SSH2 format.
105 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
112 if (BN_is_zero(value)) {
113 buffer_put_int(buffer, 0);
117 fatal("buffer_put_bignum2: negative numbers not supported");
118 bytes = BN_num_bytes(value) + 1; /* extra padding byte */
120 fatal("buffer_put_bignum2: BN too small");
121 buf = xmalloc(bytes);
123 /* Get the value of in binary */
124 oi = BN_bn2bin(value, buf+1);
126 fatal("buffer_put_bignum2: BN_bn2bin() failed: "
127 "oi %d != bin_size %d", oi, bytes);
128 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
129 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
130 memset(buf, 0, bytes);
135 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
138 u_char *bin = buffer_get_string(buffer, &len);
140 if (len > 0 && (bin[0] & 0x80))
141 fatal("buffer_get_bignum2: negative numbers not supported");
143 fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
144 BN_bin2bn(bin, len, value);
149 * Returns integers from the buffer (msb first).
153 buffer_get_short(Buffer *buffer)
157 buffer_get(buffer, (char *) buf, 2);
158 return GET_16BIT(buf);
162 buffer_get_int(Buffer *buffer)
166 buffer_get(buffer, (char *) buf, 4);
167 return GET_32BIT(buf);
171 buffer_get_int64(Buffer *buffer)
175 buffer_get(buffer, (char *) buf, 8);
176 return GET_64BIT(buf);
180 * Stores integers in the buffer, msb first.
183 buffer_put_short(Buffer *buffer, u_short value)
187 PUT_16BIT(buf, value);
188 buffer_append(buffer, buf, 2);
192 buffer_put_int(Buffer *buffer, u_int value)
196 PUT_32BIT(buf, value);
197 buffer_append(buffer, buf, 4);
201 buffer_put_int64(Buffer *buffer, u_int64_t value)
205 PUT_64BIT(buf, value);
206 buffer_append(buffer, buf, 8);
210 * Returns an arbitrary binary string from the buffer. The string cannot
211 * be longer than 256k. The returned value points to memory allocated
212 * with xmalloc; it is the responsibility of the calling function to free
213 * the data. If length_ptr is non-NULL, the length of the returned data
214 * will be stored there. A null character will be automatically appended
215 * to the returned string, and is not counted in length.
218 buffer_get_string(Buffer *buffer, u_int *length_ptr)
223 /* Get the length. */
224 len = buffer_get_int(buffer);
225 if (len > 256 * 1024)
226 fatal("buffer_get_string: bad string length %u", len);
227 /* Allocate space for the string. Add one byte for a null character. */
228 value = xmalloc(len + 1);
229 /* Get the string. */
230 buffer_get(buffer, value, len);
231 /* Append a null character to make processing easier. */
233 /* Optionally return the length of the string. */
240 * Stores and arbitrary binary string in the buffer.
243 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
245 buffer_put_int(buffer, len);
246 buffer_append(buffer, buf, len);
249 buffer_put_cstring(Buffer *buffer, const char *s)
252 fatal("buffer_put_cstring: s == NULL");
253 buffer_put_string(buffer, s, strlen(s));
257 * Returns a character from the buffer (0 - 255).
260 buffer_get_char(Buffer *buffer)
264 buffer_get(buffer, &ch, 1);
269 * Stores a character in the buffer.
272 buffer_put_char(Buffer *buffer, int value)
276 buffer_append(buffer, &ch, 1);