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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" | |
700318f3 | 40 | RCSID("$OpenBSD: bufaux.c,v 1.25 2002/04/20 09:14:58 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; | |
91 | if (buffer_len(buffer) < bytes) | |
92 | fatal("buffer_get_bignum: input buffer too small"); | |
e9a17296 | 93 | bin = buffer_ptr(buffer); |
3c0ef626 | 94 | BN_bin2bn(bin, bytes, value); |
95 | buffer_consume(buffer, bytes); | |
3c0ef626 | 96 | } |
97 | ||
98 | /* | |
99 | * Stores an BIGNUM in the buffer in SSH2 format. | |
100 | */ | |
101 | void | |
102 | buffer_put_bignum2(Buffer *buffer, BIGNUM *value) | |
103 | { | |
104 | int bytes = BN_num_bytes(value) + 1; | |
105 | u_char *buf = xmalloc(bytes); | |
106 | int oi; | |
107 | int hasnohigh = 0; | |
108 | buf[0] = '\0'; | |
109 | /* Get the value of in binary */ | |
110 | oi = BN_bn2bin(value, buf+1); | |
111 | if (oi != bytes-1) | |
112 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
e9a17296 | 113 | oi, bytes); |
3c0ef626 | 114 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
115 | if (value->neg) { | |
116 | /**XXX should be two's-complement */ | |
117 | int i, carry; | |
118 | u_char *uc = buf; | |
119 | log("negativ!"); | |
e9a17296 | 120 | for (i = bytes-1, carry = 1; i>=0; i--) { |
3c0ef626 | 121 | uc[i] ^= 0xff; |
e9a17296 | 122 | if (carry) |
3c0ef626 | 123 | carry = !++uc[i]; |
124 | } | |
125 | } | |
126 | buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); | |
127 | memset(buf, 0, bytes); | |
128 | xfree(buf); | |
129 | } | |
130 | ||
e9a17296 | 131 | void |
3c0ef626 | 132 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
133 | { | |
134 | /**XXX should be two's-complement */ | |
135 | int len; | |
e9a17296 | 136 | u_char *bin = buffer_get_string(buffer, (u_int *)&len); |
3c0ef626 | 137 | BN_bin2bn(bin, len, value); |
138 | xfree(bin); | |
3c0ef626 | 139 | } |
3c0ef626 | 140 | /* |
700318f3 | 141 | * Returns integers from the buffer (msb first). |
3c0ef626 | 142 | */ |
700318f3 | 143 | |
144 | u_short | |
145 | buffer_get_short(Buffer *buffer) | |
146 | { | |
147 | u_char buf[2]; | |
148 | buffer_get(buffer, (char *) buf, 2); | |
149 | return GET_16BIT(buf); | |
150 | } | |
151 | ||
3c0ef626 | 152 | u_int |
153 | buffer_get_int(Buffer *buffer) | |
154 | { | |
155 | u_char buf[4]; | |
156 | buffer_get(buffer, (char *) buf, 4); | |
157 | return GET_32BIT(buf); | |
158 | } | |
159 | ||
160 | #ifdef HAVE_U_INT64_T | |
161 | u_int64_t | |
162 | buffer_get_int64(Buffer *buffer) | |
163 | { | |
164 | u_char buf[8]; | |
165 | buffer_get(buffer, (char *) buf, 8); | |
166 | return GET_64BIT(buf); | |
167 | } | |
168 | #endif | |
169 | ||
170 | /* | |
700318f3 | 171 | * Stores integers in the buffer, msb first. |
3c0ef626 | 172 | */ |
700318f3 | 173 | void |
174 | buffer_put_short(Buffer *buffer, u_short value) | |
175 | { | |
176 | char buf[2]; | |
177 | PUT_16BIT(buf, value); | |
178 | buffer_append(buffer, buf, 2); | |
179 | } | |
180 | ||
3c0ef626 | 181 | void |
182 | buffer_put_int(Buffer *buffer, u_int value) | |
183 | { | |
184 | char buf[4]; | |
185 | PUT_32BIT(buf, value); | |
186 | buffer_append(buffer, buf, 4); | |
187 | } | |
188 | ||
189 | #ifdef HAVE_U_INT64_T | |
190 | void | |
191 | buffer_put_int64(Buffer *buffer, u_int64_t value) | |
192 | { | |
193 | char buf[8]; | |
194 | PUT_64BIT(buf, value); | |
195 | buffer_append(buffer, buf, 8); | |
196 | } | |
197 | #endif | |
198 | ||
199 | /* | |
200 | * Returns an arbitrary binary string from the buffer. The string cannot | |
201 | * be longer than 256k. The returned value points to memory allocated | |
202 | * with xmalloc; it is the responsibility of the calling function to free | |
203 | * the data. If length_ptr is non-NULL, the length of the returned data | |
204 | * will be stored there. A null character will be automatically appended | |
205 | * to the returned string, and is not counted in length. | |
206 | */ | |
e9a17296 | 207 | void * |
3c0ef626 | 208 | buffer_get_string(Buffer *buffer, u_int *length_ptr) |
209 | { | |
210 | u_int len; | |
e9a17296 | 211 | u_char *value; |
3c0ef626 | 212 | /* Get the length. */ |
213 | len = buffer_get_int(buffer); | |
214 | if (len > 256 * 1024) | |
700318f3 | 215 | fatal("buffer_get_string: bad string length %d", len); |
3c0ef626 | 216 | /* Allocate space for the string. Add one byte for a null character. */ |
217 | value = xmalloc(len + 1); | |
218 | /* Get the string. */ | |
219 | buffer_get(buffer, value, len); | |
220 | /* Append a null character to make processing easier. */ | |
221 | value[len] = 0; | |
222 | /* Optionally return the length of the string. */ | |
223 | if (length_ptr) | |
224 | *length_ptr = len; | |
225 | return value; | |
226 | } | |
227 | ||
228 | /* | |
229 | * Stores and arbitrary binary string in the buffer. | |
230 | */ | |
231 | void | |
232 | buffer_put_string(Buffer *buffer, const void *buf, u_int len) | |
233 | { | |
234 | buffer_put_int(buffer, len); | |
235 | buffer_append(buffer, buf, len); | |
236 | } | |
237 | void | |
238 | buffer_put_cstring(Buffer *buffer, const char *s) | |
239 | { | |
700318f3 | 240 | if (s == NULL) |
241 | fatal("buffer_put_cstring: s == NULL"); | |
3c0ef626 | 242 | buffer_put_string(buffer, s, strlen(s)); |
243 | } | |
244 | ||
245 | /* | |
246 | * Returns a character from the buffer (0 - 255). | |
247 | */ | |
248 | int | |
249 | buffer_get_char(Buffer *buffer) | |
250 | { | |
251 | char ch; | |
252 | buffer_get(buffer, &ch, 1); | |
253 | return (u_char) ch; | |
254 | } | |
255 | ||
256 | /* | |
257 | * Stores a character in the buffer. | |
258 | */ | |
259 | void | |
260 | buffer_put_char(Buffer *buffer, int value) | |
261 | { | |
262 | char ch = value; | |
263 | buffer_append(buffer, &ch, 1); | |
264 | } |