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8efc0c15 | 1 | /* |
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 | ||
15 | */ | |
16 | ||
17 | #include "includes.h" | |
18 | RCSID("$Id$"); | |
19 | ||
20 | #include "ssh.h" | |
5881cd60 | 21 | |
22 | #ifdef HAVE_OPENSSL | |
8efc0c15 | 23 | #include <openssl/bn.h> |
5881cd60 | 24 | #endif |
25 | #ifdef HAVE_SSL | |
26 | #include <ssl/bn.h> | |
27 | #endif | |
28 | ||
8efc0c15 | 29 | #include "bufaux.h" |
30 | #include "xmalloc.h" | |
31 | #include "getput.h" | |
32 | ||
33 | /* Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed | |
34 | by (bits+7)/8 bytes of binary data, msb first. */ | |
35 | ||
36 | void | |
37 | buffer_put_bignum(Buffer *buffer, BIGNUM *value) | |
38 | { | |
39 | int bits = BN_num_bits(value); | |
40 | int bin_size = (bits + 7) / 8; | |
41 | char *buf = xmalloc(bin_size); | |
42 | int oi; | |
43 | char msg[2]; | |
44 | ||
45 | /* Get the value of in binary */ | |
46 | oi = BN_bn2bin(value, buf); | |
5bae4ab8 | 47 | if (oi != bin_size) |
48 | fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", | |
49 | oi, bin_size); | |
8efc0c15 | 50 | |
51 | /* Store the number of bits in the buffer in two bytes, msb first. */ | |
52 | PUT_16BIT(msg, bits); | |
53 | buffer_append(buffer, msg, 2); | |
54 | /* Store the binary data. */ | |
55 | buffer_append(buffer, buf, oi); | |
56 | /* Clear the temporary data. */ | |
57 | memset(buf, 0, bin_size); | |
58 | xfree(buf); | |
59 | } | |
60 | ||
61 | /* Retrieves an BIGNUM from the buffer. */ | |
62 | ||
63 | int | |
64 | buffer_get_bignum(Buffer *buffer, BIGNUM *value) | |
65 | { | |
66 | int bits, bytes; | |
67 | unsigned char buf[2], *bin; | |
68 | ||
69 | /* Get the number for bits. */ | |
70 | buffer_get(buffer, (char *)buf, 2); | |
71 | bits = GET_16BIT(buf); | |
72 | /* Compute the number of binary bytes that follow. */ | |
73 | bytes = (bits + 7) / 8; | |
b4ad3727 | 74 | if (buffer_len(buffer) < bytes) |
75 | fatal("buffer_get_bignum: input buffer too small"); | |
76 | bin = buffer_ptr(buffer); | |
8efc0c15 | 77 | BN_bin2bn(bin, bytes, value); |
b4ad3727 | 78 | buffer_consume(buffer, bytes); |
8efc0c15 | 79 | |
80 | return 2 + bytes; | |
81 | } | |
82 | ||
83 | /* Returns an integer from the buffer (4 bytes, msb first). */ | |
84 | ||
85 | unsigned int buffer_get_int(Buffer *buffer) | |
86 | { | |
87 | unsigned char buf[4]; | |
88 | buffer_get(buffer, (char *)buf, 4); | |
89 | return GET_32BIT(buf); | |
90 | } | |
91 | ||
92 | /* Stores an integer in the buffer in 4 bytes, msb first. */ | |
93 | ||
94 | void buffer_put_int(Buffer *buffer, unsigned int value) | |
95 | { | |
96 | char buf[4]; | |
97 | PUT_32BIT(buf, value); | |
98 | buffer_append(buffer, buf, 4); | |
99 | } | |
100 | ||
101 | /* Returns an arbitrary binary string from the buffer. The string cannot | |
102 | be longer than 256k. The returned value points to memory allocated | |
103 | with xmalloc; it is the responsibility of the calling function to free | |
104 | the data. If length_ptr is non-NULL, the length of the returned data | |
105 | will be stored there. A null character will be automatically appended | |
106 | to the returned string, and is not counted in length. */ | |
107 | ||
108 | char *buffer_get_string(Buffer *buffer, unsigned int *length_ptr) | |
109 | { | |
110 | unsigned int len; | |
111 | char *value; | |
112 | /* Get the length. */ | |
113 | len = buffer_get_int(buffer); | |
114 | if (len > 256*1024) | |
115 | fatal("Received packet with bad string length %d", len); | |
116 | /* Allocate space for the string. Add one byte for a null character. */ | |
117 | value = xmalloc(len + 1); | |
118 | /* Get the string. */ | |
119 | buffer_get(buffer, value, len); | |
120 | /* Append a null character to make processing easier. */ | |
121 | value[len] = 0; | |
122 | /* Optionally return the length of the string. */ | |
123 | if (length_ptr) | |
124 | *length_ptr = len; | |
125 | return value; | |
126 | } | |
127 | ||
128 | /* Stores and arbitrary binary string in the buffer. */ | |
129 | ||
130 | void buffer_put_string(Buffer *buffer, const void *buf, unsigned int len) | |
131 | { | |
132 | buffer_put_int(buffer, len); | |
133 | buffer_append(buffer, buf, len); | |
134 | } | |
135 | ||
136 | /* Returns a character from the buffer (0 - 255). */ | |
137 | ||
138 | int buffer_get_char(Buffer *buffer) | |
139 | { | |
140 | char ch; | |
141 | buffer_get(buffer, &ch, 1); | |
142 | return (unsigned char)ch; | |
143 | } | |
144 | ||
145 | /* Stores a character in the buffer. */ | |
146 | ||
147 | void buffer_put_char(Buffer *buffer, int value) | |
148 | { | |
149 | char ch = value; | |
150 | buffer_append(buffer, &ch, 1); | |
151 | } |