Annotation of src/usr.bin/ssh/bufaux.c, Revision 1.32
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"
1.32 ! markus 40: RCSID("$OpenBSD: bufaux.c,v 1.31 2003/11/10 16:23:41 jakob 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: {
1.32 ! markus 106: u_int bytes;
! 107: u_char *buf;
1.9 markus 108: int oi;
1.30 miod 109: u_int hasnohigh = 0;
1.26 deraadt 110:
1.32 ! markus 111: if (BN_is_zero(value)) {
! 112: buffer_put_int(buffer, 0);
! 113: return;
! 114: }
! 115: if (value->neg)
! 116: fatal("buffer_put_bignum2: negative numbers not supported");
! 117: bytes = BN_num_bytes(value) + 1; /* extra padding byte */
! 118: if (bytes < 2)
! 119: fatal("buffer_put_bignum2: BN too small");
! 120: buf = xmalloc(bytes);
1.9 markus 121: buf[0] = '\0';
122: /* Get the value of in binary */
123: oi = BN_bn2bin(value, buf+1);
124: if (oi != bytes-1)
1.32 ! markus 125: fatal("buffer_put_bignum2: BN_bn2bin() failed: "
! 126: "oi %d != bin_size %d", oi, bytes);
1.9 markus 127: hasnohigh = (buf[1] & 0x80) ? 0 : 1;
128: buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
129: memset(buf, 0, bytes);
130: xfree(buf);
131: }
132:
1.21 markus 133: void
1.9 markus 134: buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
135: {
1.27 markus 136: u_int len;
137: u_char *bin = buffer_get_string(buffer, &len);
1.26 deraadt 138:
1.32 ! markus 139: if (len > 0 && (bin[0] & 0x80))
! 140: fatal("buffer_get_bignum2: negative numbers not supported");
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: }
1.32 ! markus 146:
1.9 markus 147: /*
1.25 markus 148: * Returns integers from the buffer (msb first).
1.6 deraadt 149: */
1.25 markus 150:
151: u_short
152: buffer_get_short(Buffer *buffer)
153: {
154: u_char buf[2];
1.26 deraadt 155:
1.25 markus 156: buffer_get(buffer, (char *) buf, 2);
157: return GET_16BIT(buf);
158: }
159:
1.14 markus 160: u_int
1.5 markus 161: buffer_get_int(Buffer *buffer)
1.1 deraadt 162: {
1.14 markus 163: u_char buf[4];
1.26 deraadt 164:
1.5 markus 165: buffer_get(buffer, (char *) buf, 4);
166: return GET_32BIT(buf);
1.1 deraadt 167: }
168:
1.15 markus 169: u_int64_t
170: buffer_get_int64(Buffer *buffer)
171: {
172: u_char buf[8];
1.26 deraadt 173:
1.15 markus 174: buffer_get(buffer, (char *) buf, 8);
175: return GET_64BIT(buf);
176: }
177:
1.6 deraadt 178: /*
1.25 markus 179: * Stores integers in the buffer, msb first.
1.6 deraadt 180: */
1.25 markus 181: void
182: buffer_put_short(Buffer *buffer, u_short value)
183: {
184: char buf[2];
1.26 deraadt 185:
1.25 markus 186: PUT_16BIT(buf, value);
187: buffer_append(buffer, buf, 2);
188: }
189:
1.11 markus 190: void
1.14 markus 191: buffer_put_int(Buffer *buffer, u_int value)
1.1 deraadt 192: {
1.5 markus 193: char buf[4];
1.26 deraadt 194:
1.5 markus 195: PUT_32BIT(buf, value);
196: buffer_append(buffer, buf, 4);
1.15 markus 197: }
198:
199: void
200: buffer_put_int64(Buffer *buffer, u_int64_t value)
201: {
202: char buf[8];
1.26 deraadt 203:
1.15 markus 204: PUT_64BIT(buf, value);
205: buffer_append(buffer, buf, 8);
1.1 deraadt 206: }
207:
1.6 deraadt 208: /*
209: * Returns an arbitrary binary string from the buffer. The string cannot
210: * be longer than 256k. The returned value points to memory allocated
211: * with xmalloc; it is the responsibility of the calling function to free
212: * the data. If length_ptr is non-NULL, the length of the returned data
213: * will be stored there. A null character will be automatically appended
214: * to the returned string, and is not counted in length.
215: */
1.20 stevesk 216: void *
1.14 markus 217: buffer_get_string(Buffer *buffer, u_int *length_ptr)
1.1 deraadt 218: {
1.26 deraadt 219: u_char *value;
1.14 markus 220: u_int len;
1.26 deraadt 221:
1.5 markus 222: /* Get the length. */
223: len = buffer_get_int(buffer);
224: if (len > 256 * 1024)
1.28 markus 225: fatal("buffer_get_string: bad string length %u", len);
1.5 markus 226: /* Allocate space for the string. Add one byte for a null character. */
227: value = xmalloc(len + 1);
228: /* Get the string. */
229: buffer_get(buffer, value, len);
230: /* Append a null character to make processing easier. */
231: value[len] = 0;
232: /* Optionally return the length of the string. */
233: if (length_ptr)
234: *length_ptr = len;
235: return value;
1.1 deraadt 236: }
237:
1.6 deraadt 238: /*
239: * Stores and arbitrary binary string in the buffer.
240: */
1.11 markus 241: void
1.14 markus 242: buffer_put_string(Buffer *buffer, const void *buf, u_int len)
1.1 deraadt 243: {
1.5 markus 244: buffer_put_int(buffer, len);
245: buffer_append(buffer, buf, len);
1.9 markus 246: }
1.11 markus 247: void
1.9 markus 248: buffer_put_cstring(Buffer *buffer, const char *s)
249: {
1.23 provos 250: if (s == NULL)
251: fatal("buffer_put_cstring: s == NULL");
1.9 markus 252: buffer_put_string(buffer, s, strlen(s));
1.1 deraadt 253: }
254:
1.6 deraadt 255: /*
256: * Returns a character from the buffer (0 - 255).
257: */
1.11 markus 258: int
1.5 markus 259: buffer_get_char(Buffer *buffer)
1.1 deraadt 260: {
1.5 markus 261: char ch;
1.26 deraadt 262:
1.5 markus 263: buffer_get(buffer, &ch, 1);
1.14 markus 264: return (u_char) ch;
1.1 deraadt 265: }
266:
1.6 deraadt 267: /*
268: * Stores a character in the buffer.
269: */
1.11 markus 270: void
1.5 markus 271: buffer_put_char(Buffer *buffer, int value)
1.1 deraadt 272: {
1.5 markus 273: char ch = value;
1.26 deraadt 274:
1.5 markus 275: buffer_append(buffer, &ch, 1);
1.1 deraadt 276: }
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