92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/*
|
|
* Copyright (C) 2013 Andreas Steffen
|
|
* HSR Hochschule fuer Technik Rapperswil
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*/
|
|
|
|
#include "dnskey_encoder.h"
|
|
|
|
#include <utils/debug.h>
|
|
|
|
/**
|
|
* Encode an RSA public key in DNSKEY format (RFC 3110)
|
|
*/
|
|
bool build_pub(chunk_t *encoding, va_list args)
|
|
{
|
|
chunk_t n, e, pubkey;
|
|
size_t exp_len;
|
|
u_char *pos;
|
|
|
|
if (cred_encoding_args(args, CRED_PART_RSA_MODULUS, &n,
|
|
CRED_PART_RSA_PUB_EXP, &e, CRED_PART_END))
|
|
{
|
|
/* remove leading zeros in exponent and modulus */
|
|
while (*e.ptr == 0)
|
|
{
|
|
e = chunk_skip(e, 1);
|
|
}
|
|
while (*n.ptr == 0)
|
|
{
|
|
n = chunk_skip(n, 1);
|
|
}
|
|
|
|
if (e.len < 256)
|
|
{
|
|
/* exponent length fits into a single octet */
|
|
exp_len = 1;
|
|
pubkey = chunk_alloc(exp_len + e.len + n.len);
|
|
pubkey.ptr[0] = (char)e.len;
|
|
}
|
|
else if (e.len < 65536)
|
|
{
|
|
/* exponent length fits into two octets preceded by zero octet */
|
|
exp_len = 3;
|
|
pubkey = chunk_alloc(exp_len + e.len + n.len);
|
|
pubkey.ptr[0] = 0x00;
|
|
htoun16(pubkey.ptr + 1, e.len);
|
|
}
|
|
else
|
|
{
|
|
/* exponent length is too large */
|
|
return FALSE;
|
|
}
|
|
|
|
/* copy exponent and modulus and convert to base64 format */
|
|
pos = pubkey.ptr + exp_len;
|
|
memcpy(pos, e.ptr, e.len);
|
|
pos += e.len;
|
|
memcpy(pos, n.ptr, n.len);
|
|
*encoding = chunk_to_base64(pubkey, NULL);
|
|
chunk_free(&pubkey);
|
|
|
|
return TRUE;
|
|
}
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* See header.
|
|
*/
|
|
bool dnskey_encoder_encode(cred_encoding_type_t type, chunk_t *encoding,
|
|
va_list args)
|
|
{
|
|
switch (type)
|
|
{
|
|
case PUBKEY_DNSKEY:
|
|
return build_pub(encoding, args);
|
|
default:
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
|