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Commit | Line | Data |
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8efc0c15 | 1 | /* |
5260325f | 2 | * |
3 | * bufaux.c | |
4 | * | |
5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | * | |
7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | * All rights reserved | |
9 | * | |
10 | * Created: Wed Mar 29 02:24:47 1995 ylo | |
11 | * | |
12 | * Auxiliary functions for storing and retrieving various data types to/from | |
13 | * Buffers. | |
14 | * | |
7368a6c8 | 15 | * SSH2 packet format added by Markus Friedl |
16 | * | |
5260325f | 17 | */ |
8efc0c15 | 18 | |
19 | #include "includes.h" | |
20 | RCSID("$Id$"); | |
21 | ||
22 | #include "ssh.h" | |
5881cd60 | 23 | |
24 | #ifdef HAVE_OPENSSL | |
8efc0c15 | 25 | #include <openssl/bn.h> |
5881cd60 | 26 | #endif |
27 | #ifdef HAVE_SSL | |
28 | #include <ssl/bn.h> | |
29 | #endif | |
30 | ||
8efc0c15 | 31 | #include "bufaux.h" |
32 | #include "xmalloc.h" | |
33 | #include "getput.h" | |
34 | ||
5260325f | 35 | /* |
36 | * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed | |
37 | * by (bits+7)/8 bytes of binary data, msb first. | |
38 | */ | |
8efc0c15 | 39 | void |
40 | buffer_put_bignum(Buffer *buffer, BIGNUM *value) | |
41 | { | |
5260325f | 42 | int bits = BN_num_bits(value); |
43 | int bin_size = (bits + 7) / 8; | |
610cd5c6 | 44 | char unsigned *buf = xmalloc(bin_size); |
5260325f | 45 | int oi; |
46 | char msg[2]; | |
47 | ||
48 | /* Get the value of in binary */ | |
49 | oi = BN_bn2bin(value, buf); | |
50 | if (oi != bin_size) | |
51 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
52 | oi, bin_size); | |
53 | ||
54 | /* Store the number of bits in the buffer in two bytes, msb first. */ | |
55 | PUT_16BIT(msg, bits); | |
56 | buffer_append(buffer, msg, 2); | |
57 | /* Store the binary data. */ | |
610cd5c6 | 58 | buffer_append(buffer, (char *)buf, oi); |
aa3378df | 59 | |
5260325f | 60 | memset(buf, 0, bin_size); |
61 | xfree(buf); | |
8efc0c15 | 62 | } |
63 | ||
5260325f | 64 | /* |
65 | * Retrieves an BIGNUM from the buffer. | |
66 | */ | |
8efc0c15 | 67 | int |
68 | buffer_get_bignum(Buffer *buffer, BIGNUM *value) | |
69 | { | |
5260325f | 70 | int bits, bytes; |
71 | unsigned char buf[2], *bin; | |
72 | ||
73 | /* Get the number for bits. */ | |
74 | buffer_get(buffer, (char *) buf, 2); | |
75 | bits = GET_16BIT(buf); | |
76 | /* Compute the number of binary bytes that follow. */ | |
77 | bytes = (bits + 7) / 8; | |
78 | if (buffer_len(buffer) < bytes) | |
79 | fatal("buffer_get_bignum: input buffer too small"); | |
610cd5c6 | 80 | bin = (unsigned char*) buffer_ptr(buffer); |
5260325f | 81 | BN_bin2bn(bin, bytes, value); |
82 | buffer_consume(buffer, bytes); | |
83 | ||
84 | return 2 + bytes; | |
8efc0c15 | 85 | } |
86 | ||
7368a6c8 | 87 | /* |
88 | * Stores an BIGNUM in the buffer in SSH2 format. | |
89 | */ | |
90 | void | |
91 | buffer_put_bignum2(Buffer *buffer, BIGNUM *value) | |
92 | { | |
93 | int bytes = BN_num_bytes(value) + 1; | |
94 | unsigned char *buf = xmalloc(bytes); | |
95 | int oi; | |
96 | int hasnohigh = 0; | |
97 | buf[0] = '\0'; | |
98 | /* Get the value of in binary */ | |
99 | oi = BN_bn2bin(value, buf+1); | |
100 | if (oi != bytes-1) | |
101 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
102 | oi, bytes); | |
103 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; | |
104 | if (value->neg) { | |
105 | /**XXX should be two's-complement */ | |
106 | int i, carry; | |
107 | unsigned char *uc = buf; | |
108 | log("negativ!"); | |
109 | for(i = bytes-1, carry = 1; i>=0; i--) { | |
110 | uc[i] ^= 0xff; | |
111 | if(carry) | |
112 | carry = !++uc[i]; | |
113 | } | |
114 | } | |
115 | buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); | |
116 | memset(buf, 0, bytes); | |
117 | xfree(buf); | |
118 | } | |
119 | ||
120 | int | |
121 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) | |
122 | { | |
123 | /**XXX should be two's-complement */ | |
124 | int len; | |
125 | unsigned char *bin = (unsigned char *)buffer_get_string(buffer, (unsigned int *)&len); | |
126 | BN_bin2bn(bin, len, value); | |
127 | xfree(bin); | |
128 | return len; | |
129 | } | |
130 | ||
5260325f | 131 | /* |
132 | * Returns an integer from the buffer (4 bytes, msb first). | |
133 | */ | |
134 | unsigned int | |
135 | buffer_get_int(Buffer *buffer) | |
8efc0c15 | 136 | { |
5260325f | 137 | unsigned char buf[4]; |
138 | buffer_get(buffer, (char *) buf, 4); | |
139 | return GET_32BIT(buf); | |
8efc0c15 | 140 | } |
141 | ||
5260325f | 142 | /* |
143 | * Stores an integer in the buffer in 4 bytes, msb first. | |
144 | */ | |
145 | void | |
146 | buffer_put_int(Buffer *buffer, unsigned int value) | |
8efc0c15 | 147 | { |
5260325f | 148 | char buf[4]; |
149 | PUT_32BIT(buf, value); | |
150 | buffer_append(buffer, buf, 4); | |
8efc0c15 | 151 | } |
152 | ||
5260325f | 153 | /* |
154 | * Returns an arbitrary binary string from the buffer. The string cannot | |
155 | * be longer than 256k. The returned value points to memory allocated | |
156 | * with xmalloc; it is the responsibility of the calling function to free | |
157 | * the data. If length_ptr is non-NULL, the length of the returned data | |
158 | * will be stored there. A null character will be automatically appended | |
159 | * to the returned string, and is not counted in length. | |
160 | */ | |
161 | char * | |
162 | buffer_get_string(Buffer *buffer, unsigned int *length_ptr) | |
8efc0c15 | 163 | { |
5260325f | 164 | unsigned int len; |
165 | char *value; | |
166 | /* Get the length. */ | |
167 | len = buffer_get_int(buffer); | |
168 | if (len > 256 * 1024) | |
169 | fatal("Received packet with bad string length %d", len); | |
170 | /* Allocate space for the string. Add one byte for a null character. */ | |
171 | value = xmalloc(len + 1); | |
172 | /* Get the string. */ | |
173 | buffer_get(buffer, value, len); | |
174 | /* Append a null character to make processing easier. */ | |
175 | value[len] = 0; | |
176 | /* Optionally return the length of the string. */ | |
177 | if (length_ptr) | |
178 | *length_ptr = len; | |
179 | return value; | |
8efc0c15 | 180 | } |
181 | ||
5260325f | 182 | /* |
183 | * Stores and arbitrary binary string in the buffer. | |
184 | */ | |
185 | void | |
186 | buffer_put_string(Buffer *buffer, const void *buf, unsigned int len) | |
8efc0c15 | 187 | { |
5260325f | 188 | buffer_put_int(buffer, len); |
189 | buffer_append(buffer, buf, len); | |
8efc0c15 | 190 | } |
7368a6c8 | 191 | void |
192 | buffer_put_cstring(Buffer *buffer, const char *s) | |
193 | { | |
194 | buffer_put_string(buffer, s, strlen(s)); | |
195 | } | |
8efc0c15 | 196 | |
5260325f | 197 | /* |
198 | * Returns a character from the buffer (0 - 255). | |
199 | */ | |
200 | int | |
201 | buffer_get_char(Buffer *buffer) | |
8efc0c15 | 202 | { |
5260325f | 203 | char ch; |
204 | buffer_get(buffer, &ch, 1); | |
205 | return (unsigned char) ch; | |
8efc0c15 | 206 | } |
207 | ||
5260325f | 208 | /* |
209 | * Stores a character in the buffer. | |
210 | */ | |
211 | void | |
212 | buffer_put_char(Buffer *buffer, int value) | |
8efc0c15 | 213 | { |
5260325f | 214 | char ch = value; |
215 | buffer_append(buffer, &ch, 1); | |
8efc0c15 | 216 | } |