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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
4 | * All rights reserved | |
5260325f | 5 | * Auxiliary functions for storing and retrieving various data types to/from |
6 | * Buffers. | |
7 | * | |
bcbf86ec | 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 | * | |
7368a6c8 | 15 | * SSH2 packet format added by Markus Friedl |
bcbf86ec | 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. | |
7368a6c8 | 26 | * |
bcbf86ec | 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. | |
5260325f | 37 | */ |
8efc0c15 | 38 | |
39 | #include "includes.h" | |
155890b3 | 40 | RCSID("$OpenBSD: bufaux.c,v 1.32 2004/02/23 15:12:46 markus Exp $"); |
8efc0c15 | 41 | |
8efc0c15 | 42 | #include <openssl/bn.h> |
43 | #include "bufaux.h" | |
44 | #include "xmalloc.h" | |
45 | #include "getput.h" | |
42f11eb2 | 46 | #include "log.h" |
8efc0c15 | 47 | |
5260325f | 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 | */ | |
8efc0c15 | 52 | void |
b6c7b7b7 | 53 | buffer_put_bignum(Buffer *buffer, const BIGNUM *value) |
8efc0c15 | 54 | { |
5260325f | 55 | int bits = BN_num_bits(value); |
56 | int bin_size = (bits + 7) / 8; | |
1e3b8b07 | 57 | u_char *buf = xmalloc(bin_size); |
5260325f | 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", | |
184eed6a | 65 | oi, bin_size); |
5260325f | 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. */ | |
610cd5c6 | 71 | buffer_append(buffer, (char *)buf, oi); |
aa3378df | 72 | |
5260325f | 73 | memset(buf, 0, bin_size); |
74 | xfree(buf); | |
8efc0c15 | 75 | } |
76 | ||
5260325f | 77 | /* |
78 | * Retrieves an BIGNUM from the buffer. | |
79 | */ | |
4ef6f649 | 80 | void |
8efc0c15 | 81 | buffer_get_bignum(Buffer *buffer, BIGNUM *value) |
82 | { | |
bb92e5cc | 83 | u_int bits, bytes; |
1e3b8b07 | 84 | u_char buf[2], *bin; |
5260325f | 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; | |
b29fe4ea | 91 | if (bytes > 8 * 1024) |
92 | fatal("buffer_get_bignum: cannot handle BN of size %d", bytes); | |
5260325f | 93 | if (buffer_len(buffer) < bytes) |
94 | fatal("buffer_get_bignum: input buffer too small"); | |
e6207598 | 95 | bin = buffer_ptr(buffer); |
5260325f | 96 | BN_bin2bn(bin, bytes, value); |
97 | buffer_consume(buffer, bytes); | |
8efc0c15 | 98 | } |
99 | ||
7368a6c8 | 100 | /* |
101 | * Stores an BIGNUM in the buffer in SSH2 format. | |
102 | */ | |
103 | void | |
b6c7b7b7 | 104 | buffer_put_bignum2(Buffer *buffer, const BIGNUM *value) |
7368a6c8 | 105 | { |
155890b3 | 106 | u_int bytes; |
107 | u_char *buf; | |
7368a6c8 | 108 | int oi; |
bb92e5cc | 109 | u_int hasnohigh = 0; |
7528d467 | 110 | |
155890b3 | 111 | if (BN_is_zero(value)) { |
112 | buffer_put_int(buffer, 0); | |
113 | return; | |
114 | } | |
115 | if (value->neg) | |
116 | fatal("buffer_put_bignum2: negative numbers not supported"); | |
117 | bytes = BN_num_bytes(value) + 1; /* extra padding byte */ | |
118 | if (bytes < 2) | |
119 | fatal("buffer_put_bignum2: BN too small"); | |
120 | buf = xmalloc(bytes); | |
7368a6c8 | 121 | buf[0] = '\0'; |
122 | /* Get the value of in binary */ | |
123 | oi = BN_bn2bin(value, buf+1); | |
124 | if (oi != bytes-1) | |
155890b3 | 125 | fatal("buffer_put_bignum2: BN_bn2bin() failed: " |
126 | "oi %d != bin_size %d", oi, bytes); | |
7368a6c8 | 127 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
7368a6c8 | 128 | buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); |
129 | memset(buf, 0, bytes); | |
130 | xfree(buf); | |
131 | } | |
132 | ||
4ef6f649 | 133 | void |
7368a6c8 | 134 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
135 | { | |
b29fe4ea | 136 | u_int len; |
137 | u_char *bin = buffer_get_string(buffer, &len); | |
7528d467 | 138 | |
155890b3 | 139 | if (len > 0 && (bin[0] & 0x80)) |
140 | fatal("buffer_get_bignum2: negative numbers not supported"); | |
b29fe4ea | 141 | if (len > 8 * 1024) |
142 | fatal("buffer_get_bignum2: cannot handle BN of size %d", len); | |
7368a6c8 | 143 | BN_bin2bn(bin, len, value); |
144 | xfree(bin); | |
7368a6c8 | 145 | } |
155890b3 | 146 | |
5260325f | 147 | /* |
9b26c596 | 148 | * Returns integers from the buffer (msb first). |
5260325f | 149 | */ |
9b26c596 | 150 | |
151 | u_short | |
152 | buffer_get_short(Buffer *buffer) | |
153 | { | |
154 | u_char buf[2]; | |
7528d467 | 155 | |
9b26c596 | 156 | buffer_get(buffer, (char *) buf, 2); |
157 | return GET_16BIT(buf); | |
158 | } | |
159 | ||
1e3b8b07 | 160 | u_int |
5260325f | 161 | buffer_get_int(Buffer *buffer) |
8efc0c15 | 162 | { |
1e3b8b07 | 163 | u_char buf[4]; |
7528d467 | 164 | |
5260325f | 165 | buffer_get(buffer, (char *) buf, 4); |
166 | return GET_32BIT(buf); | |
8efc0c15 | 167 | } |
168 | ||
f546c780 | 169 | u_int64_t |
170 | buffer_get_int64(Buffer *buffer) | |
171 | { | |
172 | u_char buf[8]; | |
7528d467 | 173 | |
f546c780 | 174 | buffer_get(buffer, (char *) buf, 8); |
175 | return GET_64BIT(buf); | |
176 | } | |
177 | ||
5260325f | 178 | /* |
9b26c596 | 179 | * Stores integers in the buffer, msb first. |
5260325f | 180 | */ |
9b26c596 | 181 | void |
182 | buffer_put_short(Buffer *buffer, u_short value) | |
183 | { | |
184 | char buf[2]; | |
7528d467 | 185 | |
9b26c596 | 186 | PUT_16BIT(buf, value); |
187 | buffer_append(buffer, buf, 2); | |
188 | } | |
189 | ||
35484284 | 190 | void |
1e3b8b07 | 191 | buffer_put_int(Buffer *buffer, u_int value) |
8efc0c15 | 192 | { |
5260325f | 193 | char buf[4]; |
7528d467 | 194 | |
5260325f | 195 | PUT_32BIT(buf, value); |
196 | buffer_append(buffer, buf, 4); | |
8efc0c15 | 197 | } |
198 | ||
f546c780 | 199 | void |
200 | buffer_put_int64(Buffer *buffer, u_int64_t value) | |
201 | { | |
202 | char buf[8]; | |
7528d467 | 203 | |
f546c780 | 204 | PUT_64BIT(buf, value); |
205 | buffer_append(buffer, buf, 8); | |
206 | } | |
207 | ||
5260325f | 208 | /* |
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. | |
215 | */ | |
6c0fa2b1 | 216 | void * |
1e3b8b07 | 217 | buffer_get_string(Buffer *buffer, u_int *length_ptr) |
8efc0c15 | 218 | { |
6c0fa2b1 | 219 | u_char *value; |
7528d467 | 220 | u_int len; |
221 | ||
5260325f | 222 | /* Get the length. */ |
223 | len = buffer_get_int(buffer); | |
224 | if (len > 256 * 1024) | |
358b576b | 225 | fatal("buffer_get_string: bad string length %u", len); |
5260325f | 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. */ | |
231 | value[len] = 0; | |
232 | /* Optionally return the length of the string. */ | |
233 | if (length_ptr) | |
234 | *length_ptr = len; | |
235 | return value; | |
8efc0c15 | 236 | } |
237 | ||
5260325f | 238 | /* |
239 | * Stores and arbitrary binary string in the buffer. | |
240 | */ | |
35484284 | 241 | void |
1e3b8b07 | 242 | buffer_put_string(Buffer *buffer, const void *buf, u_int len) |
8efc0c15 | 243 | { |
5260325f | 244 | buffer_put_int(buffer, len); |
245 | buffer_append(buffer, buf, len); | |
8efc0c15 | 246 | } |
35484284 | 247 | void |
7368a6c8 | 248 | buffer_put_cstring(Buffer *buffer, const char *s) |
249 | { | |
b625ad75 | 250 | if (s == NULL) |
251 | fatal("buffer_put_cstring: s == NULL"); | |
7368a6c8 | 252 | buffer_put_string(buffer, s, strlen(s)); |
253 | } | |
8efc0c15 | 254 | |
5260325f | 255 | /* |
256 | * Returns a character from the buffer (0 - 255). | |
257 | */ | |
35484284 | 258 | int |
5260325f | 259 | buffer_get_char(Buffer *buffer) |
8efc0c15 | 260 | { |
5260325f | 261 | char ch; |
7528d467 | 262 | |
5260325f | 263 | buffer_get(buffer, &ch, 1); |
1e3b8b07 | 264 | return (u_char) ch; |
8efc0c15 | 265 | } |
266 | ||
5260325f | 267 | /* |
268 | * Stores a character in the buffer. | |
269 | */ | |
35484284 | 270 | void |
5260325f | 271 | buffer_put_char(Buffer *buffer, int value) |
8efc0c15 | 272 | { |
5260325f | 273 | char ch = value; |
7528d467 | 274 | |
5260325f | 275 | buffer_append(buffer, &ch, 1); |
8efc0c15 | 276 | } |