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3c0ef626 | 1 | /* |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Auxiliary functions for storing and retrieving various data types to/from | |
6 | * Buffers. | |
7 | * | |
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". | |
13 | * | |
14 | * | |
15 | * SSH2 packet format added by Markus Friedl | |
16 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
17 | * | |
18 | * Redistribution and use in source and binary forms, with or without | |
19 | * modification, are permitted provided that the following conditions | |
20 | * are met: | |
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. | |
26 | * | |
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. | |
37 | */ | |
38 | ||
39 | #include "includes.h" | |
680cee3b | 40 | RCSID("$OpenBSD: bufaux.c,v 1.27 2002/06/26 08:53:12 markus Exp $"); |
3c0ef626 | 41 | |
42 | #include <openssl/bn.h> | |
43 | #include "bufaux.h" | |
44 | #include "xmalloc.h" | |
45 | #include "getput.h" | |
46 | #include "log.h" | |
47 | ||
48 | /* | |
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. | |
51 | */ | |
52 | void | |
53 | buffer_put_bignum(Buffer *buffer, BIGNUM *value) | |
54 | { | |
55 | int bits = BN_num_bits(value); | |
56 | int bin_size = (bits + 7) / 8; | |
57 | u_char *buf = xmalloc(bin_size); | |
58 | int oi; | |
59 | char msg[2]; | |
60 | ||
61 | /* Get the value of in binary */ | |
62 | oi = BN_bn2bin(value, buf); | |
63 | if (oi != bin_size) | |
64 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
e9a17296 | 65 | oi, bin_size); |
3c0ef626 | 66 | |
67 | /* Store the number of bits in the buffer in two bytes, msb first. */ | |
68 | PUT_16BIT(msg, bits); | |
69 | buffer_append(buffer, msg, 2); | |
70 | /* Store the binary data. */ | |
71 | buffer_append(buffer, (char *)buf, oi); | |
72 | ||
73 | memset(buf, 0, bin_size); | |
74 | xfree(buf); | |
75 | } | |
76 | ||
77 | /* | |
78 | * Retrieves an BIGNUM from the buffer. | |
79 | */ | |
e9a17296 | 80 | void |
3c0ef626 | 81 | buffer_get_bignum(Buffer *buffer, BIGNUM *value) |
82 | { | |
83 | int bits, bytes; | |
84 | u_char buf[2], *bin; | |
85 | ||
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; | |
680cee3b | 91 | if (bytes > 8 * 1024) |
92 | fatal("buffer_get_bignum: cannot handle BN of size %d", bytes); | |
3c0ef626 | 93 | if (buffer_len(buffer) < bytes) |
94 | fatal("buffer_get_bignum: input buffer too small"); | |
e9a17296 | 95 | bin = buffer_ptr(buffer); |
3c0ef626 | 96 | BN_bin2bn(bin, bytes, value); |
97 | buffer_consume(buffer, bytes); | |
3c0ef626 | 98 | } |
99 | ||
100 | /* | |
101 | * Stores an BIGNUM in the buffer in SSH2 format. | |
102 | */ | |
103 | void | |
104 | buffer_put_bignum2(Buffer *buffer, BIGNUM *value) | |
105 | { | |
106 | int bytes = BN_num_bytes(value) + 1; | |
107 | u_char *buf = xmalloc(bytes); | |
108 | int oi; | |
109 | int hasnohigh = 0; | |
680cee3b | 110 | |
3c0ef626 | 111 | buf[0] = '\0'; |
112 | /* Get the value of in binary */ | |
113 | oi = BN_bn2bin(value, buf+1); | |
114 | if (oi != bytes-1) | |
115 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
e9a17296 | 116 | oi, bytes); |
3c0ef626 | 117 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
118 | if (value->neg) { | |
119 | /**XXX should be two's-complement */ | |
120 | int i, carry; | |
121 | u_char *uc = buf; | |
122 | log("negativ!"); | |
e9a17296 | 123 | for (i = bytes-1, carry = 1; i>=0; i--) { |
3c0ef626 | 124 | uc[i] ^= 0xff; |
e9a17296 | 125 | if (carry) |
3c0ef626 | 126 | carry = !++uc[i]; |
127 | } | |
128 | } | |
129 | buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); | |
130 | memset(buf, 0, bytes); | |
131 | xfree(buf); | |
132 | } | |
133 | ||
680cee3b | 134 | /* XXX does not handle negative BNs */ |
e9a17296 | 135 | void |
3c0ef626 | 136 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
137 | { | |
680cee3b | 138 | u_int len; |
139 | u_char *bin = buffer_get_string(buffer, &len); | |
140 | ||
141 | if (len > 8 * 1024) | |
142 | fatal("buffer_get_bignum2: cannot handle BN of size %d", len); | |
3c0ef626 | 143 | BN_bin2bn(bin, len, value); |
144 | xfree(bin); | |
3c0ef626 | 145 | } |
3c0ef626 | 146 | /* |
700318f3 | 147 | * Returns integers from the buffer (msb first). |
3c0ef626 | 148 | */ |
700318f3 | 149 | |
150 | u_short | |
151 | buffer_get_short(Buffer *buffer) | |
152 | { | |
153 | u_char buf[2]; | |
680cee3b | 154 | |
700318f3 | 155 | buffer_get(buffer, (char *) buf, 2); |
156 | return GET_16BIT(buf); | |
157 | } | |
158 | ||
3c0ef626 | 159 | u_int |
160 | buffer_get_int(Buffer *buffer) | |
161 | { | |
162 | u_char buf[4]; | |
680cee3b | 163 | |
3c0ef626 | 164 | buffer_get(buffer, (char *) buf, 4); |
165 | return GET_32BIT(buf); | |
166 | } | |
167 | ||
168 | #ifdef HAVE_U_INT64_T | |
169 | u_int64_t | |
170 | buffer_get_int64(Buffer *buffer) | |
171 | { | |
172 | u_char buf[8]; | |
680cee3b | 173 | |
3c0ef626 | 174 | buffer_get(buffer, (char *) buf, 8); |
175 | return GET_64BIT(buf); | |
176 | } | |
177 | #endif | |
178 | ||
179 | /* | |
700318f3 | 180 | * Stores integers in the buffer, msb first. |
3c0ef626 | 181 | */ |
700318f3 | 182 | void |
183 | buffer_put_short(Buffer *buffer, u_short value) | |
184 | { | |
185 | char buf[2]; | |
680cee3b | 186 | |
700318f3 | 187 | PUT_16BIT(buf, value); |
188 | buffer_append(buffer, buf, 2); | |
189 | } | |
190 | ||
3c0ef626 | 191 | void |
192 | buffer_put_int(Buffer *buffer, u_int value) | |
193 | { | |
194 | char buf[4]; | |
680cee3b | 195 | |
3c0ef626 | 196 | PUT_32BIT(buf, value); |
197 | buffer_append(buffer, buf, 4); | |
198 | } | |
199 | ||
200 | #ifdef HAVE_U_INT64_T | |
201 | void | |
202 | buffer_put_int64(Buffer *buffer, u_int64_t value) | |
203 | { | |
204 | char buf[8]; | |
680cee3b | 205 | |
3c0ef626 | 206 | PUT_64BIT(buf, value); |
207 | buffer_append(buffer, buf, 8); | |
208 | } | |
209 | #endif | |
210 | ||
211 | /* | |
212 | * Returns an arbitrary binary string from the buffer. The string cannot | |
213 | * be longer than 256k. The returned value points to memory allocated | |
214 | * with xmalloc; it is the responsibility of the calling function to free | |
215 | * the data. If length_ptr is non-NULL, the length of the returned data | |
216 | * will be stored there. A null character will be automatically appended | |
217 | * to the returned string, and is not counted in length. | |
218 | */ | |
e9a17296 | 219 | void * |
3c0ef626 | 220 | buffer_get_string(Buffer *buffer, u_int *length_ptr) |
221 | { | |
e9a17296 | 222 | u_char *value; |
680cee3b | 223 | u_int len; |
224 | ||
3c0ef626 | 225 | /* Get the length. */ |
226 | len = buffer_get_int(buffer); | |
227 | if (len > 256 * 1024) | |
700318f3 | 228 | fatal("buffer_get_string: bad string length %d", len); |
3c0ef626 | 229 | /* Allocate space for the string. Add one byte for a null character. */ |
230 | value = xmalloc(len + 1); | |
231 | /* Get the string. */ | |
232 | buffer_get(buffer, value, len); | |
233 | /* Append a null character to make processing easier. */ | |
234 | value[len] = 0; | |
235 | /* Optionally return the length of the string. */ | |
236 | if (length_ptr) | |
237 | *length_ptr = len; | |
238 | return value; | |
239 | } | |
240 | ||
241 | /* | |
242 | * Stores and arbitrary binary string in the buffer. | |
243 | */ | |
244 | void | |
245 | buffer_put_string(Buffer *buffer, const void *buf, u_int len) | |
246 | { | |
247 | buffer_put_int(buffer, len); | |
248 | buffer_append(buffer, buf, len); | |
249 | } | |
250 | void | |
251 | buffer_put_cstring(Buffer *buffer, const char *s) | |
252 | { | |
700318f3 | 253 | if (s == NULL) |
254 | fatal("buffer_put_cstring: s == NULL"); | |
3c0ef626 | 255 | buffer_put_string(buffer, s, strlen(s)); |
256 | } | |
257 | ||
258 | /* | |
259 | * Returns a character from the buffer (0 - 255). | |
260 | */ | |
261 | int | |
262 | buffer_get_char(Buffer *buffer) | |
263 | { | |
264 | char ch; | |
680cee3b | 265 | |
3c0ef626 | 266 | buffer_get(buffer, &ch, 1); |
267 | return (u_char) ch; | |
268 | } | |
269 | ||
270 | /* | |
271 | * Stores a character in the buffer. | |
272 | */ | |
273 | void | |
274 | buffer_put_char(Buffer *buffer, int value) | |
275 | { | |
276 | char ch = value; | |
680cee3b | 277 | |
3c0ef626 | 278 | buffer_append(buffer, &ch, 1); |
279 | } |