Annotation of src/usr.bin/ssh/bufaux.c, Revision 1.7
1.1 deraadt 1: /*
1.6 deraadt 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: */
1.1 deraadt 16:
17: #include "includes.h"
1.7 ! markus 18: RCSID("$Id: bufaux.c,v 1.6 1999/11/24 00:26:01 deraadt Exp $");
1.1 deraadt 19:
20: #include "ssh.h"
1.2 provos 21: #include <ssl/bn.h>
1.1 deraadt 22: #include "bufaux.h"
23: #include "xmalloc.h"
24: #include "getput.h"
25:
1.6 deraadt 26: /*
27: * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
28: * by (bits+7)/8 bytes of binary data, msb first.
29: */
1.2 provos 30: void
31: buffer_put_bignum(Buffer *buffer, BIGNUM *value)
1.1 deraadt 32: {
1.5 markus 33: int bits = BN_num_bits(value);
34: int bin_size = (bits + 7) / 8;
35: char *buf = xmalloc(bin_size);
36: int oi;
37: char msg[2];
38:
39: /* Get the value of in binary */
40: oi = BN_bn2bin(value, buf);
41: if (oi != bin_size)
42: fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
43: oi, bin_size);
44:
45: /* Store the number of bits in the buffer in two bytes, msb first. */
46: PUT_16BIT(msg, bits);
47: buffer_append(buffer, msg, 2);
48: /* Store the binary data. */
49: buffer_append(buffer, buf, oi);
1.7 ! markus 50:
1.5 markus 51: memset(buf, 0, bin_size);
52: xfree(buf);
1.1 deraadt 53: }
54:
1.6 deraadt 55: /*
56: * Retrieves an BIGNUM from the buffer.
57: */
1.2 provos 58: int
59: buffer_get_bignum(Buffer *buffer, BIGNUM *value)
1.1 deraadt 60: {
1.5 markus 61: int bits, bytes;
62: unsigned char buf[2], *bin;
1.1 deraadt 63:
1.5 markus 64: /* Get the number for bits. */
65: buffer_get(buffer, (char *) buf, 2);
66: bits = GET_16BIT(buf);
67: /* Compute the number of binary bytes that follow. */
68: bytes = (bits + 7) / 8;
69: if (buffer_len(buffer) < bytes)
70: fatal("buffer_get_bignum: input buffer too small");
71: bin = buffer_ptr(buffer);
72: BN_bin2bn(bin, bytes, value);
73: buffer_consume(buffer, bytes);
1.2 provos 74:
1.5 markus 75: return 2 + bytes;
1.1 deraadt 76: }
77:
1.6 deraadt 78: /*
79: * Returns an integer from the buffer (4 bytes, msb first).
80: */
1.5 markus 81: unsigned int
82: buffer_get_int(Buffer *buffer)
1.1 deraadt 83: {
1.5 markus 84: unsigned char buf[4];
85: buffer_get(buffer, (char *) buf, 4);
86: return GET_32BIT(buf);
1.1 deraadt 87: }
88:
1.6 deraadt 89: /*
90: * Stores an integer in the buffer in 4 bytes, msb first.
91: */
1.5 markus 92: void
93: buffer_put_int(Buffer *buffer, unsigned int value)
1.1 deraadt 94: {
1.5 markus 95: char buf[4];
96: PUT_32BIT(buf, value);
97: buffer_append(buffer, buf, 4);
1.1 deraadt 98: }
99:
1.6 deraadt 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: */
1.5 markus 108: char *
109: buffer_get_string(Buffer *buffer, unsigned int *length_ptr)
1.1 deraadt 110: {
1.5 markus 111: unsigned int len;
112: char *value;
113: /* Get the length. */
114: len = buffer_get_int(buffer);
115: if (len > 256 * 1024)
116: fatal("Received packet with bad string length %d", len);
117: /* Allocate space for the string. Add one byte for a null character. */
118: value = xmalloc(len + 1);
119: /* Get the string. */
120: buffer_get(buffer, value, len);
121: /* Append a null character to make processing easier. */
122: value[len] = 0;
123: /* Optionally return the length of the string. */
124: if (length_ptr)
125: *length_ptr = len;
126: return value;
1.1 deraadt 127: }
128:
1.6 deraadt 129: /*
130: * Stores and arbitrary binary string in the buffer.
131: */
1.5 markus 132: void
133: buffer_put_string(Buffer *buffer, const void *buf, unsigned int len)
1.1 deraadt 134: {
1.5 markus 135: buffer_put_int(buffer, len);
136: buffer_append(buffer, buf, len);
1.1 deraadt 137: }
138:
1.6 deraadt 139: /*
140: * Returns a character from the buffer (0 - 255).
141: */
1.5 markus 142: int
143: buffer_get_char(Buffer *buffer)
1.1 deraadt 144: {
1.5 markus 145: char ch;
146: buffer_get(buffer, &ch, 1);
147: return (unsigned char) ch;
1.1 deraadt 148: }
149:
1.6 deraadt 150: /*
151: * Stores a character in the buffer.
152: */
1.5 markus 153: void
154: buffer_put_char(Buffer *buffer, int value)
1.1 deraadt 155: {
1.5 markus 156: char ch = value;
157: buffer_append(buffer, &ch, 1);
1.1 deraadt 158: }
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