Annotation of src/usr.bin/ssh/bufaux.c, Revision 1.23
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"
1.23 ! provos 40: RCSID("$OpenBSD: bufaux.c,v 1.22 2002/01/18 18:14:17 stevesk Exp $");
1.1 deraadt 41:
1.10 markus 42: #include <openssl/bn.h>
1.1 deraadt 43: #include "bufaux.h"
44: #include "xmalloc.h"
45: #include "getput.h"
1.17 markus 46: #include "log.h"
1.1 deraadt 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;
1.14 markus 57: u_char *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",
1.19 deraadt 65: oi, bin_size);
1.5 markus 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: */
1.21 markus 80: void
1.2 provos 81: buffer_get_bignum(Buffer *buffer, BIGNUM *value)
1.1 deraadt 82: {
1.5 markus 83: int bits, bytes;
1.14 markus 84: u_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");
1.22 stevesk 93: bin = buffer_ptr(buffer);
1.5 markus 94: BN_bin2bn(bin, bytes, value);
95: buffer_consume(buffer, bytes);
1.1 deraadt 96: }
97:
1.6 deraadt 98: /*
1.9 markus 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;
1.14 markus 105: u_char *buf = xmalloc(bytes);
1.9 markus 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",
1.19 deraadt 113: oi, bytes);
1.9 markus 114: hasnohigh = (buf[1] & 0x80) ? 0 : 1;
115: if (value->neg) {
116: /**XXX should be two's-complement */
117: int i, carry;
1.14 markus 118: u_char *uc = buf;
1.9 markus 119: log("negativ!");
1.19 deraadt 120: for (i = bytes-1, carry = 1; i>=0; i--) {
1.9 markus 121: uc[i] ^= 0xff;
1.18 deraadt 122: if (carry)
1.9 markus 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:
1.21 markus 131: void
1.9 markus 132: buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
133: {
134: /**XXX should be two's-complement */
135: int len;
1.22 stevesk 136: u_char *bin = buffer_get_string(buffer, (u_int *)&len);
1.9 markus 137: BN_bin2bn(bin, len, value);
138: xfree(bin);
139: }
140:
141: /*
1.6 deraadt 142: * Returns an integer from the buffer (4 bytes, msb first).
143: */
1.14 markus 144: u_int
1.5 markus 145: buffer_get_int(Buffer *buffer)
1.1 deraadt 146: {
1.14 markus 147: u_char buf[4];
1.5 markus 148: buffer_get(buffer, (char *) buf, 4);
149: return GET_32BIT(buf);
1.1 deraadt 150: }
151:
1.15 markus 152: u_int64_t
153: buffer_get_int64(Buffer *buffer)
154: {
155: u_char buf[8];
156: buffer_get(buffer, (char *) buf, 8);
157: return GET_64BIT(buf);
158: }
159:
1.6 deraadt 160: /*
161: * Stores an integer in the buffer in 4 bytes, msb first.
162: */
1.11 markus 163: void
1.14 markus 164: buffer_put_int(Buffer *buffer, u_int value)
1.1 deraadt 165: {
1.5 markus 166: char buf[4];
167: PUT_32BIT(buf, value);
168: buffer_append(buffer, buf, 4);
1.15 markus 169: }
170:
171: void
172: buffer_put_int64(Buffer *buffer, u_int64_t value)
173: {
174: char buf[8];
175: PUT_64BIT(buf, value);
176: buffer_append(buffer, buf, 8);
1.1 deraadt 177: }
178:
1.6 deraadt 179: /*
180: * Returns an arbitrary binary string from the buffer. The string cannot
181: * be longer than 256k. The returned value points to memory allocated
182: * with xmalloc; it is the responsibility of the calling function to free
183: * the data. If length_ptr is non-NULL, the length of the returned data
184: * will be stored there. A null character will be automatically appended
185: * to the returned string, and is not counted in length.
186: */
1.20 stevesk 187: void *
1.14 markus 188: buffer_get_string(Buffer *buffer, u_int *length_ptr)
1.1 deraadt 189: {
1.14 markus 190: u_int len;
1.20 stevesk 191: u_char *value;
1.5 markus 192: /* Get the length. */
193: len = buffer_get_int(buffer);
194: if (len > 256 * 1024)
195: fatal("Received packet with bad string length %d", len);
196: /* Allocate space for the string. Add one byte for a null character. */
197: value = xmalloc(len + 1);
198: /* Get the string. */
199: buffer_get(buffer, value, len);
200: /* Append a null character to make processing easier. */
201: value[len] = 0;
202: /* Optionally return the length of the string. */
203: if (length_ptr)
204: *length_ptr = len;
205: return value;
1.1 deraadt 206: }
207:
1.6 deraadt 208: /*
209: * Stores and arbitrary binary string in the buffer.
210: */
1.11 markus 211: void
1.14 markus 212: buffer_put_string(Buffer *buffer, const void *buf, u_int len)
1.1 deraadt 213: {
1.5 markus 214: buffer_put_int(buffer, len);
215: buffer_append(buffer, buf, len);
1.9 markus 216: }
1.11 markus 217: void
1.9 markus 218: buffer_put_cstring(Buffer *buffer, const char *s)
219: {
1.23 ! provos 220: if (s == NULL)
! 221: fatal("buffer_put_cstring: s == NULL");
1.9 markus 222: buffer_put_string(buffer, s, strlen(s));
1.1 deraadt 223: }
224:
1.6 deraadt 225: /*
226: * Returns a character from the buffer (0 - 255).
227: */
1.11 markus 228: int
1.5 markus 229: buffer_get_char(Buffer *buffer)
1.1 deraadt 230: {
1.5 markus 231: char ch;
232: buffer_get(buffer, &ch, 1);
1.14 markus 233: return (u_char) ch;
1.1 deraadt 234: }
235:
1.6 deraadt 236: /*
237: * Stores a character in the buffer.
238: */
1.11 markus 239: void
1.5 markus 240: buffer_put_char(Buffer *buffer, int value)
1.1 deraadt 241: {
1.5 markus 242: char ch = value;
243: buffer_append(buffer, &ch, 1);
1.1 deraadt 244: }
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