Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 1 | /* $OpenBSD: bufbn.c,v 1.7 2013/05/17 00:13:13 djm Exp $*/ |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 2 | /* |
| 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 5 | * All rights reserved |
| 6 | * Auxiliary functions for storing and retrieving various data types to/from |
| 7 | * Buffers. |
| 8 | * |
| 9 | * As far as I am concerned, the code I have written for this software |
| 10 | * can be used freely for any purpose. Any derived versions of this |
| 11 | * software must be clearly marked as such, and if the derived work is |
| 12 | * incompatible with the protocol description in the RFC file, it must be |
| 13 | * called by a name other than "ssh" or "Secure Shell". |
| 14 | * |
| 15 | * |
| 16 | * SSH2 packet format added by Markus Friedl |
| 17 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 18 | * |
| 19 | * Redistribution and use in source and binary forms, with or without |
| 20 | * modification, are permitted provided that the following conditions |
| 21 | * are met: |
| 22 | * 1. Redistributions of source code must retain the above copyright |
| 23 | * notice, this list of conditions and the following disclaimer. |
| 24 | * 2. Redistributions in binary form must reproduce the above copyright |
| 25 | * notice, this list of conditions and the following disclaimer in the |
| 26 | * documentation and/or other materials provided with the distribution. |
| 27 | * |
| 28 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 29 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 30 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 31 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 33 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 34 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 35 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 36 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 37 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 38 | */ |
| 39 | |
| 40 | #include "includes.h" |
| 41 | |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 42 | #include <sys/types.h> |
| 43 | |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 44 | #include <openssl/bn.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 45 | |
| 46 | #include <string.h> |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 47 | #include <stdarg.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 48 | |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 49 | #include "xmalloc.h" |
Damien Miller | d783435 | 2006-08-05 12:39:39 +1000 | [diff] [blame] | 50 | #include "buffer.h" |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 51 | #include "log.h" |
| 52 | #include "misc.h" |
| 53 | |
| 54 | /* |
| 55 | * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed |
| 56 | * by (bits+7)/8 bytes of binary data, msb first. |
| 57 | */ |
| 58 | int |
| 59 | buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value) |
| 60 | { |
| 61 | int bits = BN_num_bits(value); |
| 62 | int bin_size = (bits + 7) / 8; |
| 63 | u_char *buf = xmalloc(bin_size); |
| 64 | int oi; |
| 65 | char msg[2]; |
| 66 | |
| 67 | /* Get the value of in binary */ |
| 68 | oi = BN_bn2bin(value, buf); |
| 69 | if (oi != bin_size) { |
| 70 | error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d", |
| 71 | oi, bin_size); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 72 | free(buf); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 73 | return (-1); |
| 74 | } |
| 75 | |
| 76 | /* Store the number of bits in the buffer in two bytes, msb first. */ |
| 77 | put_u16(msg, bits); |
| 78 | buffer_append(buffer, msg, 2); |
| 79 | /* Store the binary data. */ |
| 80 | buffer_append(buffer, buf, oi); |
| 81 | |
| 82 | memset(buf, 0, bin_size); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 83 | free(buf); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 84 | |
| 85 | return (0); |
| 86 | } |
| 87 | |
| 88 | void |
| 89 | buffer_put_bignum(Buffer *buffer, const BIGNUM *value) |
| 90 | { |
| 91 | if (buffer_put_bignum_ret(buffer, value) == -1) |
| 92 | fatal("buffer_put_bignum: buffer error"); |
| 93 | } |
| 94 | |
| 95 | /* |
Darren Tucker | 591322a | 2007-02-19 22:17:28 +1100 | [diff] [blame] | 96 | * Retrieves a BIGNUM from the buffer. |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 97 | */ |
| 98 | int |
| 99 | buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value) |
| 100 | { |
| 101 | u_int bits, bytes; |
| 102 | u_char buf[2], *bin; |
| 103 | |
Darren Tucker | 591322a | 2007-02-19 22:17:28 +1100 | [diff] [blame] | 104 | /* Get the number of bits. */ |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 105 | if (buffer_get_ret(buffer, (char *) buf, 2) == -1) { |
| 106 | error("buffer_get_bignum_ret: invalid length"); |
| 107 | return (-1); |
| 108 | } |
| 109 | bits = get_u16(buf); |
| 110 | /* Compute the number of binary bytes that follow. */ |
| 111 | bytes = (bits + 7) / 8; |
| 112 | if (bytes > 8 * 1024) { |
| 113 | error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes); |
| 114 | return (-1); |
| 115 | } |
| 116 | if (buffer_len(buffer) < bytes) { |
| 117 | error("buffer_get_bignum_ret: input buffer too small"); |
| 118 | return (-1); |
| 119 | } |
| 120 | bin = buffer_ptr(buffer); |
Darren Tucker | 0bc8557 | 2006-11-07 23:14:41 +1100 | [diff] [blame] | 121 | if (BN_bin2bn(bin, bytes, value) == NULL) { |
| 122 | error("buffer_get_bignum_ret: BN_bin2bn failed"); |
| 123 | return (-1); |
| 124 | } |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 125 | if (buffer_consume_ret(buffer, bytes) == -1) { |
| 126 | error("buffer_get_bignum_ret: buffer_consume failed"); |
| 127 | return (-1); |
| 128 | } |
| 129 | return (0); |
| 130 | } |
| 131 | |
| 132 | void |
| 133 | buffer_get_bignum(Buffer *buffer, BIGNUM *value) |
| 134 | { |
| 135 | if (buffer_get_bignum_ret(buffer, value) == -1) |
| 136 | fatal("buffer_get_bignum: buffer error"); |
| 137 | } |
| 138 | |
| 139 | /* |
Darren Tucker | 591322a | 2007-02-19 22:17:28 +1100 | [diff] [blame] | 140 | * Stores a BIGNUM in the buffer in SSH2 format. |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 141 | */ |
| 142 | int |
| 143 | buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value) |
| 144 | { |
| 145 | u_int bytes; |
| 146 | u_char *buf; |
| 147 | int oi; |
| 148 | u_int hasnohigh = 0; |
| 149 | |
| 150 | if (BN_is_zero(value)) { |
| 151 | buffer_put_int(buffer, 0); |
| 152 | return 0; |
| 153 | } |
| 154 | if (value->neg) { |
| 155 | error("buffer_put_bignum2_ret: negative numbers not supported"); |
| 156 | return (-1); |
| 157 | } |
| 158 | bytes = BN_num_bytes(value) + 1; /* extra padding byte */ |
| 159 | if (bytes < 2) { |
| 160 | error("buffer_put_bignum2_ret: BN too small"); |
| 161 | return (-1); |
| 162 | } |
| 163 | buf = xmalloc(bytes); |
| 164 | buf[0] = 0x00; |
| 165 | /* Get the value of in binary */ |
| 166 | oi = BN_bn2bin(value, buf+1); |
| 167 | if (oi < 0 || (u_int)oi != bytes - 1) { |
| 168 | error("buffer_put_bignum2_ret: BN_bn2bin() failed: " |
| 169 | "oi %d != bin_size %d", oi, bytes); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 170 | free(buf); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 171 | return (-1); |
| 172 | } |
| 173 | hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
| 174 | buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); |
| 175 | memset(buf, 0, bytes); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 176 | free(buf); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 177 | return (0); |
| 178 | } |
| 179 | |
| 180 | void |
| 181 | buffer_put_bignum2(Buffer *buffer, const BIGNUM *value) |
| 182 | { |
| 183 | if (buffer_put_bignum2_ret(buffer, value) == -1) |
| 184 | fatal("buffer_put_bignum2: buffer error"); |
| 185 | } |
| 186 | |
| 187 | int |
| 188 | buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value) |
| 189 | { |
| 190 | u_int len; |
| 191 | u_char *bin; |
| 192 | |
| 193 | if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) { |
| 194 | error("buffer_get_bignum2_ret: invalid bignum"); |
| 195 | return (-1); |
| 196 | } |
| 197 | |
| 198 | if (len > 0 && (bin[0] & 0x80)) { |
| 199 | error("buffer_get_bignum2_ret: negative numbers not supported"); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 200 | free(bin); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 201 | return (-1); |
| 202 | } |
| 203 | if (len > 8 * 1024) { |
Darren Tucker | 7b21cb5 | 2007-06-05 18:29:35 +1000 | [diff] [blame] | 204 | error("buffer_get_bignum2_ret: cannot handle BN of size %d", |
| 205 | len); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 206 | free(bin); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 207 | return (-1); |
| 208 | } |
Darren Tucker | 0bc8557 | 2006-11-07 23:14:41 +1100 | [diff] [blame] | 209 | if (BN_bin2bn(bin, len, value) == NULL) { |
| 210 | error("buffer_get_bignum2_ret: BN_bin2bn failed"); |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 211 | free(bin); |
Darren Tucker | 0bc8557 | 2006-11-07 23:14:41 +1100 | [diff] [blame] | 212 | return (-1); |
| 213 | } |
Darren Tucker | a627d42 | 2013-06-02 07:31:17 +1000 | [diff] [blame] | 214 | free(bin); |
Damien Miller | 58629fa | 2006-04-23 12:08:19 +1000 | [diff] [blame] | 215 | return (0); |
| 216 | } |
| 217 | |
| 218 | void |
| 219 | buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
| 220 | { |
| 221 | if (buffer_get_bignum2_ret(buffer, value) == -1) |
| 222 | fatal("buffer_get_bignum2: buffer error"); |
| 223 | } |