Annotation of src/usr.bin/ssh/bufaux.c, Revision 1.31
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"
1.31 ! jakob 40: RCSID("$OpenBSD: bufaux.c,v 1.30 2003/09/18 13:02:21 miod 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
1.31 ! jakob 53: buffer_put_bignum(Buffer *buffer, const 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: {
1.30 miod 83: u_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;
1.27 markus 91: if (bytes > 8 * 1024)
92: fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
1.5 markus 93: if (buffer_len(buffer) < bytes)
94: fatal("buffer_get_bignum: input buffer too small");
1.22 stevesk 95: bin = buffer_ptr(buffer);
1.5 markus 96: BN_bin2bn(bin, bytes, value);
97: buffer_consume(buffer, 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
1.31 ! jakob 104: buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
1.9 markus 105: {
1.30 miod 106: u_int bytes = BN_num_bytes(value) + 1;
1.14 markus 107: u_char *buf = xmalloc(bytes);
1.9 markus 108: int oi;
1.30 miod 109: u_int hasnohigh = 0;
1.26 deraadt 110:
1.9 markus 111: buf[0] = '\0';
112: /* Get the value of in binary */
113: oi = BN_bn2bin(value, buf+1);
114: if (oi != bytes-1)
115: fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
1.19 deraadt 116: oi, bytes);
1.9 markus 117: hasnohigh = (buf[1] & 0x80) ? 0 : 1;
118: if (value->neg) {
119: /**XXX should be two's-complement */
120: int i, carry;
1.14 markus 121: u_char *uc = buf;
1.29 itojun 122: logit("negativ!");
1.19 deraadt 123: for (i = bytes-1, carry = 1; i>=0; i--) {
1.9 markus 124: uc[i] ^= 0xff;
1.18 deraadt 125: if (carry)
1.9 markus 126: carry = !++uc[i];
127: }
128: }
129: buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
130: memset(buf, 0, bytes);
131: xfree(buf);
132: }
133:
1.27 markus 134: /* XXX does not handle negative BNs */
1.21 markus 135: void
1.9 markus 136: buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
137: {
1.27 markus 138: u_int len;
139: u_char *bin = buffer_get_string(buffer, &len);
1.26 deraadt 140:
1.27 markus 141: if (len > 8 * 1024)
142: fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
1.9 markus 143: BN_bin2bn(bin, len, value);
144: xfree(bin);
145: }
146: /*
1.25 markus 147: * Returns integers from the buffer (msb first).
1.6 deraadt 148: */
1.25 markus 149:
150: u_short
151: buffer_get_short(Buffer *buffer)
152: {
153: u_char buf[2];
1.26 deraadt 154:
1.25 markus 155: buffer_get(buffer, (char *) buf, 2);
156: return GET_16BIT(buf);
157: }
158:
1.14 markus 159: u_int
1.5 markus 160: buffer_get_int(Buffer *buffer)
1.1 deraadt 161: {
1.14 markus 162: u_char buf[4];
1.26 deraadt 163:
1.5 markus 164: buffer_get(buffer, (char *) buf, 4);
165: return GET_32BIT(buf);
1.1 deraadt 166: }
167:
1.15 markus 168: u_int64_t
169: buffer_get_int64(Buffer *buffer)
170: {
171: u_char buf[8];
1.26 deraadt 172:
1.15 markus 173: buffer_get(buffer, (char *) buf, 8);
174: return GET_64BIT(buf);
175: }
176:
1.6 deraadt 177: /*
1.25 markus 178: * Stores integers in the buffer, msb first.
1.6 deraadt 179: */
1.25 markus 180: void
181: buffer_put_short(Buffer *buffer, u_short value)
182: {
183: char buf[2];
1.26 deraadt 184:
1.25 markus 185: PUT_16BIT(buf, value);
186: buffer_append(buffer, buf, 2);
187: }
188:
1.11 markus 189: void
1.14 markus 190: buffer_put_int(Buffer *buffer, u_int value)
1.1 deraadt 191: {
1.5 markus 192: char buf[4];
1.26 deraadt 193:
1.5 markus 194: PUT_32BIT(buf, value);
195: buffer_append(buffer, buf, 4);
1.15 markus 196: }
197:
198: void
199: buffer_put_int64(Buffer *buffer, u_int64_t value)
200: {
201: char buf[8];
1.26 deraadt 202:
1.15 markus 203: PUT_64BIT(buf, value);
204: buffer_append(buffer, buf, 8);
1.1 deraadt 205: }
206:
1.6 deraadt 207: /*
208: * Returns an arbitrary binary string from the buffer. The string cannot
209: * be longer than 256k. The returned value points to memory allocated
210: * with xmalloc; it is the responsibility of the calling function to free
211: * the data. If length_ptr is non-NULL, the length of the returned data
212: * will be stored there. A null character will be automatically appended
213: * to the returned string, and is not counted in length.
214: */
1.20 stevesk 215: void *
1.14 markus 216: buffer_get_string(Buffer *buffer, u_int *length_ptr)
1.1 deraadt 217: {
1.26 deraadt 218: u_char *value;
1.14 markus 219: u_int len;
1.26 deraadt 220:
1.5 markus 221: /* Get the length. */
222: len = buffer_get_int(buffer);
223: if (len > 256 * 1024)
1.28 markus 224: fatal("buffer_get_string: bad string length %u", len);
1.5 markus 225: /* Allocate space for the string. Add one byte for a null character. */
226: value = xmalloc(len + 1);
227: /* Get the string. */
228: buffer_get(buffer, value, len);
229: /* Append a null character to make processing easier. */
230: value[len] = 0;
231: /* Optionally return the length of the string. */
232: if (length_ptr)
233: *length_ptr = len;
234: return value;
1.1 deraadt 235: }
236:
1.6 deraadt 237: /*
238: * Stores and arbitrary binary string in the buffer.
239: */
1.11 markus 240: void
1.14 markus 241: buffer_put_string(Buffer *buffer, const void *buf, u_int len)
1.1 deraadt 242: {
1.5 markus 243: buffer_put_int(buffer, len);
244: buffer_append(buffer, buf, len);
1.9 markus 245: }
1.11 markus 246: void
1.9 markus 247: buffer_put_cstring(Buffer *buffer, const char *s)
248: {
1.23 provos 249: if (s == NULL)
250: fatal("buffer_put_cstring: s == NULL");
1.9 markus 251: buffer_put_string(buffer, s, strlen(s));
1.1 deraadt 252: }
253:
1.6 deraadt 254: /*
255: * Returns a character from the buffer (0 - 255).
256: */
1.11 markus 257: int
1.5 markus 258: buffer_get_char(Buffer *buffer)
1.1 deraadt 259: {
1.5 markus 260: char ch;
1.26 deraadt 261:
1.5 markus 262: buffer_get(buffer, &ch, 1);
1.14 markus 263: return (u_char) ch;
1.1 deraadt 264: }
265:
1.6 deraadt 266: /*
267: * Stores a character in the buffer.
268: */
1.11 markus 269: void
1.5 markus 270: buffer_put_char(Buffer *buffer, int value)
1.1 deraadt 271: {
1.5 markus 272: char ch = value;
1.26 deraadt 273:
1.5 markus 274: buffer_append(buffer, &ch, 1);
1.1 deraadt 275: }
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