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Diffstat (limited to '')
| -rw-r--r-- | bufbn.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/bufbn.c b/bufbn.c new file mode 100644 index 000000000..56f4f6d5b --- /dev/null +++ b/bufbn.c @@ -0,0 +1,209 @@ +/* $OpenBSD: bufbn.c,v 1.1 2006/04/18 10:44:28 dtucker Exp $*/ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * Auxiliary functions for storing and retrieving various data types to/from + * Buffers. + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * + * SSH2 packet format added by Markus Friedl + * Copyright (c) 2000 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#include <openssl/bn.h> +#include "bufaux.h" +#include "xmalloc.h" +#include "log.h" +#include "misc.h" + +/* + * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed + * by (bits+7)/8 bytes of binary data, msb first. + */ +int +buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value) +{ + int bits = BN_num_bits(value); + int bin_size = (bits + 7) / 8; + u_char *buf = xmalloc(bin_size); + int oi; + char msg[2]; + + /* Get the value of in binary */ + oi = BN_bn2bin(value, buf); + if (oi != bin_size) { + error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d", + oi, bin_size); + xfree(buf); + return (-1); + } + + /* Store the number of bits in the buffer in two bytes, msb first. */ + put_u16(msg, bits); + buffer_append(buffer, msg, 2); + /* Store the binary data. */ + buffer_append(buffer, buf, oi); + + memset(buf, 0, bin_size); + xfree(buf); + + return (0); +} + +void +buffer_put_bignum(Buffer *buffer, const BIGNUM *value) +{ + if (buffer_put_bignum_ret(buffer, value) == -1) + fatal("buffer_put_bignum: buffer error"); +} + +/* + * Retrieves an BIGNUM from the buffer. + */ +int +buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value) +{ + u_int bits, bytes; + u_char buf[2], *bin; + + /* Get the number for bits. */ + if (buffer_get_ret(buffer, (char *) buf, 2) == -1) { + error("buffer_get_bignum_ret: invalid length"); + return (-1); + } + bits = get_u16(buf); + /* Compute the number of binary bytes that follow. */ + bytes = (bits + 7) / 8; + if (bytes > 8 * 1024) { + error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes); + return (-1); + } + if (buffer_len(buffer) < bytes) { + error("buffer_get_bignum_ret: input buffer too small"); + return (-1); + } + bin = buffer_ptr(buffer); + BN_bin2bn(bin, bytes, value); + if (buffer_consume_ret(buffer, bytes) == -1) { + error("buffer_get_bignum_ret: buffer_consume failed"); + return (-1); + } + return (0); +} + +void +buffer_get_bignum(Buffer *buffer, BIGNUM *value) +{ + if (buffer_get_bignum_ret(buffer, value) == -1) + fatal("buffer_get_bignum: buffer error"); +} + +/* + * Stores an BIGNUM in the buffer in SSH2 format. + */ +int +buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value) +{ + u_int bytes; + u_char *buf; + int oi; + u_int hasnohigh = 0; + + if (BN_is_zero(value)) { + buffer_put_int(buffer, 0); + return 0; + } + if (value->neg) { + error("buffer_put_bignum2_ret: negative numbers not supported"); + return (-1); + } + bytes = BN_num_bytes(value) + 1; /* extra padding byte */ + if (bytes < 2) { + error("buffer_put_bignum2_ret: BN too small"); + return (-1); + } + buf = xmalloc(bytes); + buf[0] = 0x00; + /* Get the value of in binary */ + oi = BN_bn2bin(value, buf+1); + if (oi < 0 || (u_int)oi != bytes - 1) { + error("buffer_put_bignum2_ret: BN_bn2bin() failed: " + "oi %d != bin_size %d", oi, bytes); + xfree(buf); + return (-1); + } + hasnohigh = (buf[1] & 0x80) ? 0 : 1; + buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); + memset(buf, 0, bytes); + xfree(buf); + return (0); +} + +void +buffer_put_bignum2(Buffer *buffer, const BIGNUM *value) +{ + if (buffer_put_bignum2_ret(buffer, value) == -1) + fatal("buffer_put_bignum2: buffer error"); +} + +int +buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value) +{ + u_int len; + u_char *bin; + + if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) { + error("buffer_get_bignum2_ret: invalid bignum"); + return (-1); + } + + if (len > 0 && (bin[0] & 0x80)) { + error("buffer_get_bignum2_ret: negative numbers not supported"); + xfree(bin); + return (-1); + } + if (len > 8 * 1024) { + error("buffer_get_bignum2_ret: cannot handle BN of size %d", len); + xfree(bin); + return (-1); + } + BN_bin2bn(bin, len, value); + xfree(bin); + return (0); +} + +void +buffer_get_bignum2(Buffer *buffer, BIGNUM *value) +{ + if (buffer_get_bignum2_ret(buffer, value) == -1) + fatal("buffer_get_bignum2: buffer error"); +} |