Annotation of src/usr.bin/ssh/bufaux.c, Revision 1.13
1.1 deraadt 1: /*
1.6 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.13 ! deraadt 5: * Auxiliary functions for storing and retrieving various data types to/from
! 6: * Buffers.
1.11 markus 7: *
1.13 ! deraadt 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".
1.11 markus 13: *
1.6 deraadt 14: *
1.9 markus 15: * SSH2 packet format added by Markus Friedl
1.13 ! deraadt 16: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.9 markus 17: *
1.13 ! deraadt 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.
1.6 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.13 ! deraadt 40: RCSID("$OpenBSD: bufaux.c,v 1.12 2000/06/20 01:39:39 markus Exp $");
1.1 deraadt 41:
42: #include "ssh.h"
1.10 markus 43: #include <openssl/bn.h>
1.1 deraadt 44: #include "bufaux.h"
45: #include "xmalloc.h"
46: #include "getput.h"
47:
1.6 deraadt 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: */
1.2 provos 52: void
53: buffer_put_bignum(Buffer *buffer, BIGNUM *value)
1.1 deraadt 54: {
1.5 markus 55: int bits = BN_num_bits(value);
56: int bin_size = (bits + 7) / 8;
1.8 markus 57: char unsigned *buf = xmalloc(bin_size);
1.5 markus 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",
65: oi, bin_size);
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. */
1.8 markus 71: buffer_append(buffer, (char *)buf, oi);
1.7 markus 72:
1.5 markus 73: memset(buf, 0, bin_size);
74: xfree(buf);
1.1 deraadt 75: }
76:
1.6 deraadt 77: /*
78: * Retrieves an BIGNUM from the buffer.
79: */
1.2 provos 80: int
81: buffer_get_bignum(Buffer *buffer, BIGNUM *value)
1.1 deraadt 82: {
1.5 markus 83: int bits, bytes;
84: unsigned char buf[2], *bin;
1.1 deraadt 85:
1.5 markus 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");
1.8 markus 93: bin = (unsigned char*) buffer_ptr(buffer);
1.5 markus 94: BN_bin2bn(bin, bytes, value);
95: buffer_consume(buffer, bytes);
1.2 provos 96:
1.5 markus 97: return 2 + bytes;
1.1 deraadt 98: }
99:
1.6 deraadt 100: /*
1.9 markus 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;
107: unsigned char *buf = xmalloc(bytes);
108: int oi;
109: int hasnohigh = 0;
110: buf[0] = '\0';
111: /* Get the value of in binary */
112: oi = BN_bn2bin(value, buf+1);
113: if (oi != bytes-1)
114: fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
115: oi, bytes);
116: hasnohigh = (buf[1] & 0x80) ? 0 : 1;
117: if (value->neg) {
118: /**XXX should be two's-complement */
119: int i, carry;
120: unsigned char *uc = buf;
121: log("negativ!");
122: for(i = bytes-1, carry = 1; i>=0; i--) {
123: uc[i] ^= 0xff;
124: if(carry)
125: carry = !++uc[i];
126: }
127: }
128: buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
129: memset(buf, 0, bytes);
130: xfree(buf);
131: }
132:
133: int
134: buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
135: {
136: /**XXX should be two's-complement */
137: int len;
138: unsigned char *bin = (unsigned char *)buffer_get_string(buffer, (unsigned int *)&len);
139: BN_bin2bn(bin, len, value);
140: xfree(bin);
141: return len;
142: }
143:
144: /*
1.6 deraadt 145: * Returns an integer from the buffer (4 bytes, msb first).
146: */
1.11 markus 147: unsigned int
1.5 markus 148: buffer_get_int(Buffer *buffer)
1.1 deraadt 149: {
1.5 markus 150: unsigned char buf[4];
151: buffer_get(buffer, (char *) buf, 4);
152: return GET_32BIT(buf);
1.1 deraadt 153: }
154:
1.6 deraadt 155: /*
156: * Stores an integer in the buffer in 4 bytes, msb first.
157: */
1.11 markus 158: void
1.5 markus 159: buffer_put_int(Buffer *buffer, unsigned int value)
1.1 deraadt 160: {
1.5 markus 161: char buf[4];
162: PUT_32BIT(buf, value);
163: buffer_append(buffer, buf, 4);
1.1 deraadt 164: }
165:
1.6 deraadt 166: /*
167: * Returns an arbitrary binary string from the buffer. The string cannot
168: * be longer than 256k. The returned value points to memory allocated
169: * with xmalloc; it is the responsibility of the calling function to free
170: * the data. If length_ptr is non-NULL, the length of the returned data
171: * will be stored there. A null character will be automatically appended
172: * to the returned string, and is not counted in length.
173: */
1.5 markus 174: char *
175: buffer_get_string(Buffer *buffer, unsigned int *length_ptr)
1.1 deraadt 176: {
1.5 markus 177: unsigned int len;
178: char *value;
179: /* Get the length. */
180: len = buffer_get_int(buffer);
181: if (len > 256 * 1024)
182: fatal("Received packet with bad string length %d", len);
183: /* Allocate space for the string. Add one byte for a null character. */
184: value = xmalloc(len + 1);
185: /* Get the string. */
186: buffer_get(buffer, value, len);
187: /* Append a null character to make processing easier. */
188: value[len] = 0;
189: /* Optionally return the length of the string. */
190: if (length_ptr)
191: *length_ptr = len;
192: return value;
1.1 deraadt 193: }
194:
1.6 deraadt 195: /*
196: * Stores and arbitrary binary string in the buffer.
197: */
1.11 markus 198: void
1.5 markus 199: buffer_put_string(Buffer *buffer, const void *buf, unsigned int len)
1.1 deraadt 200: {
1.5 markus 201: buffer_put_int(buffer, len);
202: buffer_append(buffer, buf, len);
1.9 markus 203: }
1.11 markus 204: void
1.9 markus 205: buffer_put_cstring(Buffer *buffer, const char *s)
206: {
207: buffer_put_string(buffer, s, strlen(s));
1.1 deraadt 208: }
209:
1.6 deraadt 210: /*
211: * Returns a character from the buffer (0 - 255).
212: */
1.11 markus 213: int
1.5 markus 214: buffer_get_char(Buffer *buffer)
1.1 deraadt 215: {
1.5 markus 216: char ch;
217: buffer_get(buffer, &ch, 1);
218: return (unsigned char) ch;
1.1 deraadt 219: }
220:
1.6 deraadt 221: /*
222: * Stores a character in the buffer.
223: */
1.11 markus 224: void
1.5 markus 225: buffer_put_char(Buffer *buffer, int value)
1.1 deraadt 226: {
1.5 markus 227: char ch = value;
228: buffer_append(buffer, &ch, 1);
1.1 deraadt 229: }
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