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 1.36 2005/06/17 02:44:32 djm 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_ret(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 error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d",
70 /* Store the number of bits in the buffer in two bytes, msb first. */
72 buffer_append(buffer, msg, 2);
73 /* Store the binary data. */
74 buffer_append(buffer, (char *)buf, oi);
76 memset(buf, 0, bin_size);
83 buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
85 if (buffer_put_bignum_ret(buffer, value) == -1)
86 fatal("buffer_put_bignum: buffer error");
90 * Retrieves an BIGNUM from the buffer.
93 buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
98 /* Get the number for bits. */
99 if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
100 error("buffer_get_bignum_ret: invalid length");
103 bits = GET_16BIT(buf);
104 /* Compute the number of binary bytes that follow. */
105 bytes = (bits + 7) / 8;
106 if (bytes > 8 * 1024) {
107 error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
110 if (buffer_len(buffer) < bytes) {
111 error("buffer_get_bignum_ret: input buffer too small");
114 bin = buffer_ptr(buffer);
115 BN_bin2bn(bin, bytes, value);
116 if (buffer_consume_ret(buffer, bytes) == -1) {
117 error("buffer_get_bignum_ret: buffer_consume failed");
124 buffer_get_bignum(Buffer *buffer, BIGNUM *value)
126 if (buffer_get_bignum_ret(buffer, value) == -1)
127 fatal("buffer_get_bignum: buffer error");
131 * Stores an BIGNUM in the buffer in SSH2 format.
134 buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value)
141 if (BN_is_zero(value)) {
142 buffer_put_int(buffer, 0);
146 error("buffer_put_bignum2_ret: negative numbers not supported");
149 bytes = BN_num_bytes(value) + 1; /* extra padding byte */
151 error("buffer_put_bignum2_ret: BN too small");
154 buf = xmalloc(bytes);
156 /* Get the value of in binary */
157 oi = BN_bn2bin(value, buf+1);
158 if (oi < 0 || (u_int)oi != bytes - 1) {
159 error("buffer_put_bignum2_ret: BN_bn2bin() failed: "
160 "oi %d != bin_size %d", oi, bytes);
164 hasnohigh = (buf[1] & 0x80) ? 0 : 1;
165 buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
166 memset(buf, 0, bytes);
172 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
174 if (buffer_put_bignum2_ret(buffer, value) == -1)
175 fatal("buffer_put_bignum2: buffer error");
179 buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value)
184 if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) {
185 error("buffer_get_bignum2_ret: invalid bignum");
189 if (len > 0 && (bin[0] & 0x80)) {
190 error("buffer_get_bignum2_ret: negative numbers not supported");
193 if (len > 8 * 1024) {
194 error("buffer_get_bignum2_ret: cannot handle BN of size %d", len);
197 BN_bin2bn(bin, len, value);
203 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
205 if (buffer_get_bignum2_ret(buffer, value) == -1)
206 fatal("buffer_get_bignum2: buffer error");
210 * Returns integers from the buffer (msb first).
214 buffer_get_short_ret(u_short *ret, Buffer *buffer)
218 if (buffer_get_ret(buffer, (char *) buf, 2) == -1)
220 *ret = GET_16BIT(buf);
225 buffer_get_short(Buffer *buffer)
229 if (buffer_get_short_ret(&ret, buffer) == -1)
230 fatal("buffer_get_short: buffer error");
236 buffer_get_int_ret(u_int *ret, Buffer *buffer)
240 if (buffer_get_ret(buffer, (char *) buf, 4) == -1)
242 *ret = GET_32BIT(buf);
247 buffer_get_int(Buffer *buffer)
251 if (buffer_get_int_ret(&ret, buffer) == -1)
252 fatal("buffer_get_int: buffer error");
258 buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer)
262 if (buffer_get_ret(buffer, (char *) buf, 8) == -1)
264 *ret = GET_64BIT(buf);
269 buffer_get_int64(Buffer *buffer)
273 if (buffer_get_int64_ret(&ret, buffer) == -1)
274 fatal("buffer_get_int: buffer error");
280 * Stores integers in the buffer, msb first.
283 buffer_put_short(Buffer *buffer, u_short value)
287 PUT_16BIT(buf, value);
288 buffer_append(buffer, buf, 2);
292 buffer_put_int(Buffer *buffer, u_int value)
296 PUT_32BIT(buf, value);
297 buffer_append(buffer, buf, 4);
301 buffer_put_int64(Buffer *buffer, u_int64_t value)
305 PUT_64BIT(buf, value);
306 buffer_append(buffer, buf, 8);
310 * Returns an arbitrary binary string from the buffer. The string cannot
311 * be longer than 256k. The returned value points to memory allocated
312 * with xmalloc; it is the responsibility of the calling function to free
313 * the data. If length_ptr is non-NULL, the length of the returned data
314 * will be stored there. A null character will be automatically appended
315 * to the returned string, and is not counted in length.
318 buffer_get_string_ret(Buffer *buffer, u_int *length_ptr)
323 /* Get the length. */
324 len = buffer_get_int(buffer);
325 if (len > 256 * 1024) {
326 error("buffer_get_string_ret: bad string length %u", len);
329 /* Allocate space for the string. Add one byte for a null character. */
330 value = xmalloc(len + 1);
331 /* Get the string. */
332 if (buffer_get_ret(buffer, value, len) == -1) {
333 error("buffer_get_string_ret: buffer_get failed");
337 /* Append a null character to make processing easier. */
339 /* Optionally return the length of the string. */
346 buffer_get_string(Buffer *buffer, u_int *length_ptr)
350 if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
351 fatal("buffer_get_string: buffer error");
356 * Stores and arbitrary binary string in the buffer.
359 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
361 buffer_put_int(buffer, len);
362 buffer_append(buffer, buf, len);
365 buffer_put_cstring(Buffer *buffer, const char *s)
368 fatal("buffer_put_cstring: s == NULL");
369 buffer_put_string(buffer, s, strlen(s));
373 * Returns a character from the buffer (0 - 255).
376 buffer_get_char_ret(char *ret, Buffer *buffer)
378 if (buffer_get_ret(buffer, ret, 1) == -1) {
379 error("buffer_get_char_ret: buffer_get_ret failed");
386 buffer_get_char(Buffer *buffer)
390 if (buffer_get_char_ret(&ch, buffer) == -1)
391 fatal("buffer_get_char: buffer error");
396 * Stores a character in the buffer.
399 buffer_put_char(Buffer *buffer, int value)
403 buffer_append(buffer, &ch, 1);