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 1.37 2005/11/05 05:01:15 djm 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_ret(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 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");
194 if (len > 8 * 1024) {
195 error("buffer_get_bignum2_ret: cannot handle BN of size %d", len);
199 BN_bin2bn(bin, len, value);
205 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
207 if (buffer_get_bignum2_ret(buffer, value) == -1)
208 fatal("buffer_get_bignum2: buffer error");
212 * Returns integers from the buffer (msb first).
216 buffer_get_short_ret(u_short *ret, Buffer *buffer)
220 if (buffer_get_ret(buffer, (char *) buf, 2) == -1)
222 *ret = GET_16BIT(buf);
227 buffer_get_short(Buffer *buffer)
231 if (buffer_get_short_ret(&ret, buffer) == -1)
232 fatal("buffer_get_short: buffer error");
238 buffer_get_int_ret(u_int *ret, Buffer *buffer)
242 if (buffer_get_ret(buffer, (char *) buf, 4) == -1)
244 *ret = GET_32BIT(buf);
249 buffer_get_int(Buffer *buffer)
253 if (buffer_get_int_ret(&ret, buffer) == -1)
254 fatal("buffer_get_int: buffer error");
260 buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer)
264 if (buffer_get_ret(buffer, (char *) buf, 8) == -1)
266 *ret = GET_64BIT(buf);
271 buffer_get_int64(Buffer *buffer)
275 if (buffer_get_int64_ret(&ret, buffer) == -1)
276 fatal("buffer_get_int: buffer error");
282 * Stores integers in the buffer, msb first.
285 buffer_put_short(Buffer *buffer, u_short value)
289 PUT_16BIT(buf, value);
290 buffer_append(buffer, buf, 2);
294 buffer_put_int(Buffer *buffer, u_int value)
298 PUT_32BIT(buf, value);
299 buffer_append(buffer, buf, 4);
303 buffer_put_int64(Buffer *buffer, u_int64_t value)
307 PUT_64BIT(buf, value);
308 buffer_append(buffer, buf, 8);
312 * Returns an arbitrary binary string from the buffer. The string cannot
313 * be longer than 256k. The returned value points to memory allocated
314 * with xmalloc; it is the responsibility of the calling function to free
315 * the data. If length_ptr is non-NULL, the length of the returned data
316 * will be stored there. A null character will be automatically appended
317 * to the returned string, and is not counted in length.
320 buffer_get_string_ret(Buffer *buffer, u_int *length_ptr)
325 /* Get the length. */
326 len = buffer_get_int(buffer);
327 if (len > 256 * 1024) {
328 error("buffer_get_string_ret: bad string length %u", len);
331 /* Allocate space for the string. Add one byte for a null character. */
332 value = xmalloc(len + 1);
333 /* Get the string. */
334 if (buffer_get_ret(buffer, value, len) == -1) {
335 error("buffer_get_string_ret: buffer_get failed");
339 /* Append a null character to make processing easier. */
341 /* Optionally return the length of the string. */
348 buffer_get_string(Buffer *buffer, u_int *length_ptr)
352 if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
353 fatal("buffer_get_string: buffer error");
358 * Stores and arbitrary binary string in the buffer.
361 buffer_put_string(Buffer *buffer, const void *buf, u_int len)
363 buffer_put_int(buffer, len);
364 buffer_append(buffer, buf, len);
367 buffer_put_cstring(Buffer *buffer, const char *s)
370 fatal("buffer_put_cstring: s == NULL");
371 buffer_put_string(buffer, s, strlen(s));
375 * Returns a character from the buffer (0 - 255).
378 buffer_get_char_ret(char *ret, Buffer *buffer)
380 if (buffer_get_ret(buffer, ret, 1) == -1) {
381 error("buffer_get_char_ret: buffer_get_ret failed");
388 buffer_get_char(Buffer *buffer)
392 if (buffer_get_char_ret(&ch, buffer) == -1)
393 fatal("buffer_get_char: buffer error");
398 * Stores a character in the buffer.
401 buffer_put_char(Buffer *buffer, int value)
405 buffer_append(buffer, &ch, 1);