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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" | |
358b576b | 40 | RCSID("$OpenBSD: bufaux.c,v 1.28 2002/10/23 10:40:16 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 |
53 | buffer_put_bignum(Buffer *buffer, BIGNUM *value) | |
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 | { | |
5260325f | 83 | 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 | |
104 | buffer_put_bignum2(Buffer *buffer, BIGNUM *value) | |
105 | { | |
106 | int bytes = BN_num_bytes(value) + 1; | |
1e3b8b07 | 107 | u_char *buf = xmalloc(bytes); |
7368a6c8 | 108 | int oi; |
109 | int hasnohigh = 0; | |
7528d467 | 110 | |
7368a6c8 | 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", | |
184eed6a | 116 | oi, bytes); |
7368a6c8 | 117 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
118 | if (value->neg) { | |
119 | /**XXX should be two's-complement */ | |
120 | int i, carry; | |
1e3b8b07 | 121 | u_char *uc = buf; |
bbe88b6d | 122 | logit("negativ!"); |
184eed6a | 123 | for (i = bytes-1, carry = 1; i>=0; i--) { |
7368a6c8 | 124 | uc[i] ^= 0xff; |
6aacefa7 | 125 | if (carry) |
7368a6c8 | 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 | ||
b29fe4ea | 134 | /* XXX does not handle negative BNs */ |
4ef6f649 | 135 | void |
7368a6c8 | 136 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
137 | { | |
b29fe4ea | 138 | u_int len; |
139 | u_char *bin = buffer_get_string(buffer, &len); | |
7528d467 | 140 | |
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 | } |
5260325f | 146 | /* |
9b26c596 | 147 | * Returns integers from the buffer (msb first). |
5260325f | 148 | */ |
9b26c596 | 149 | |
150 | u_short | |
151 | buffer_get_short(Buffer *buffer) | |
152 | { | |
153 | u_char buf[2]; | |
7528d467 | 154 | |
9b26c596 | 155 | buffer_get(buffer, (char *) buf, 2); |
156 | return GET_16BIT(buf); | |
157 | } | |
158 | ||
1e3b8b07 | 159 | u_int |
5260325f | 160 | buffer_get_int(Buffer *buffer) |
8efc0c15 | 161 | { |
1e3b8b07 | 162 | u_char buf[4]; |
7528d467 | 163 | |
5260325f | 164 | buffer_get(buffer, (char *) buf, 4); |
165 | return GET_32BIT(buf); | |
8efc0c15 | 166 | } |
167 | ||
f546c780 | 168 | u_int64_t |
169 | buffer_get_int64(Buffer *buffer) | |
170 | { | |
171 | u_char buf[8]; | |
7528d467 | 172 | |
f546c780 | 173 | buffer_get(buffer, (char *) buf, 8); |
174 | return GET_64BIT(buf); | |
175 | } | |
176 | ||
5260325f | 177 | /* |
9b26c596 | 178 | * Stores integers in the buffer, msb first. |
5260325f | 179 | */ |
9b26c596 | 180 | void |
181 | buffer_put_short(Buffer *buffer, u_short value) | |
182 | { | |
183 | char buf[2]; | |
7528d467 | 184 | |
9b26c596 | 185 | PUT_16BIT(buf, value); |
186 | buffer_append(buffer, buf, 2); | |
187 | } | |
188 | ||
35484284 | 189 | void |
1e3b8b07 | 190 | buffer_put_int(Buffer *buffer, u_int value) |
8efc0c15 | 191 | { |
5260325f | 192 | char buf[4]; |
7528d467 | 193 | |
5260325f | 194 | PUT_32BIT(buf, value); |
195 | buffer_append(buffer, buf, 4); | |
8efc0c15 | 196 | } |
197 | ||
f546c780 | 198 | void |
199 | buffer_put_int64(Buffer *buffer, u_int64_t value) | |
200 | { | |
201 | char buf[8]; | |
7528d467 | 202 | |
f546c780 | 203 | PUT_64BIT(buf, value); |
204 | buffer_append(buffer, buf, 8); | |
205 | } | |
206 | ||
5260325f | 207 | /* |
208 | * Returns an arbitrary binary string from the buffer. The string cannot | |
209 | * be longer than 256k. The returned value points to memory allocated | |
210 | * with xmalloc; it is the responsibility of the calling function to free | |
211 | * the data. If length_ptr is non-NULL, the length of the returned data | |
212 | * will be stored there. A null character will be automatically appended | |
213 | * to the returned string, and is not counted in length. | |
214 | */ | |
6c0fa2b1 | 215 | void * |
1e3b8b07 | 216 | buffer_get_string(Buffer *buffer, u_int *length_ptr) |
8efc0c15 | 217 | { |
6c0fa2b1 | 218 | u_char *value; |
7528d467 | 219 | u_int len; |
220 | ||
5260325f | 221 | /* Get the length. */ |
222 | len = buffer_get_int(buffer); | |
223 | if (len > 256 * 1024) | |
358b576b | 224 | fatal("buffer_get_string: bad string length %u", len); |
5260325f | 225 | /* Allocate space for the string. Add one byte for a null character. */ |
226 | value = xmalloc(len + 1); | |
227 | /* Get the string. */ | |
228 | buffer_get(buffer, value, len); | |
229 | /* Append a null character to make processing easier. */ | |
230 | value[len] = 0; | |
231 | /* Optionally return the length of the string. */ | |
232 | if (length_ptr) | |
233 | *length_ptr = len; | |
234 | return value; | |
8efc0c15 | 235 | } |
236 | ||
5260325f | 237 | /* |
238 | * Stores and arbitrary binary string in the buffer. | |
239 | */ | |
35484284 | 240 | void |
1e3b8b07 | 241 | buffer_put_string(Buffer *buffer, const void *buf, u_int len) |
8efc0c15 | 242 | { |
5260325f | 243 | buffer_put_int(buffer, len); |
244 | buffer_append(buffer, buf, len); | |
8efc0c15 | 245 | } |
35484284 | 246 | void |
7368a6c8 | 247 | buffer_put_cstring(Buffer *buffer, const char *s) |
248 | { | |
b625ad75 | 249 | if (s == NULL) |
250 | fatal("buffer_put_cstring: s == NULL"); | |
7368a6c8 | 251 | buffer_put_string(buffer, s, strlen(s)); |
252 | } | |
8efc0c15 | 253 | |
5260325f | 254 | /* |
255 | * Returns a character from the buffer (0 - 255). | |
256 | */ | |
35484284 | 257 | int |
5260325f | 258 | buffer_get_char(Buffer *buffer) |
8efc0c15 | 259 | { |
5260325f | 260 | char ch; |
7528d467 | 261 | |
5260325f | 262 | buffer_get(buffer, &ch, 1); |
1e3b8b07 | 263 | return (u_char) ch; |
8efc0c15 | 264 | } |
265 | ||
5260325f | 266 | /* |
267 | * Stores a character in the buffer. | |
268 | */ | |
35484284 | 269 | void |
5260325f | 270 | buffer_put_char(Buffer *buffer, int value) |
8efc0c15 | 271 | { |
5260325f | 272 | char ch = value; |
7528d467 | 273 | |
5260325f | 274 | buffer_append(buffer, &ch, 1); |
8efc0c15 | 275 | } |