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/*
* Copyright (C) 2009 Martin Willi
* 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_builder.h"
#include <utils/debug.h>
#include <credentials/keys/private_key.h>
typedef struct dnskey_rr_t dnskey_rr_t;
typedef enum dnskey_algorithm_t dnskey_algorithm_t;
/**
* Header of a DNSKEY resource record
*/
struct dnskey_rr_t {
uint16_t flags;
uint8_t protocol;
uint8_t algorithm;
uint8_t data[];
} __attribute__((__packed__));
/**
* DNSSEC algorithms, RFC4034 Appendix A.1.
*/
enum dnskey_algorithm_t {
DNSKEY_ALG_RSA_MD5 = 1,
DNSKEY_ALG_DH = 2,
DNSKEY_ALG_DSA = 3,
DNSKEY_ALG_RSA_SHA1 = 5,
DNSKEY_ALG_DSA_NSEC3_SHA1 = 6,
DNSKEY_ALG_RSA_SHA1_NSEC3_SHA1 = 7,
DNSKEY_ALG_RSA_SHA256 = 8,
DNSKEY_ALG_RSA_SHA512 = 10,
DNSKEY_ALG_ECC_GOST = 12,
DNSKEY_ALG_ECDSA_P256_SHA256 = 13,
DNSKEY_ALG_ECDSA_P384_SHA384 = 14
};
/**
* Load a generic public key from a DNSKEY RR blob
*/
static dnskey_public_key_t *parse_public_key(chunk_t blob)
{
dnskey_rr_t *rr = (dnskey_rr_t*)blob.ptr;
if (blob.len < sizeof(dnskey_rr_t))
{
DBG1(DBG_LIB, "DNSKEY too short");
return NULL;
}
blob = chunk_skip(blob, sizeof(dnskey_rr_t));
switch (rr->algorithm)
{
case DNSKEY_ALG_RSA_MD5:
case DNSKEY_ALG_RSA_SHA1:
case DNSKEY_ALG_RSA_SHA1_NSEC3_SHA1:
case DNSKEY_ALG_RSA_SHA256:
case DNSKEY_ALG_RSA_SHA512:
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_BLOB_DNSKEY, blob, BUILD_END);
default:
DBG1(DBG_LIB, "DNSKEY public key algorithm %d not supported",
rr->algorithm);
return NULL;
}
}
/**
* Load a RSA public key from DNSKEY RR data
*/
static dnskey_public_key_t *parse_rsa_public_key(chunk_t blob)
{
chunk_t n, e;
if (blob.len < 3)
{
DBG1(DBG_LIB, "RFC 3110 public key blob too short for exponent length");
return NULL;
}
if (blob.ptr[0])
{
e.len = blob.ptr[0];
blob = chunk_skip(blob, 1);
}
else
{
e.len = blob.ptr[1] * 256 + blob.ptr[2];
blob = chunk_skip(blob, 3);
}
e.ptr = blob.ptr;
if (e.len >= blob.len)
{
DBG1(DBG_LIB, "RFC 3110 public key blob too short for exponent");
return NULL;
}
n = chunk_skip(blob, e.len);
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e,
BUILD_END);
}
/**
* See header.
*/
dnskey_public_key_t *dnskey_public_key_load(key_type_t type, va_list args)
{
chunk_t blob = chunk_empty;
while (TRUE)
{
switch (va_arg(args, builder_part_t))
{
case BUILD_BLOB_DNSKEY:
blob = va_arg(args, chunk_t);
continue;
case BUILD_END:
break;
default:
return NULL;
}
break;
}
if (!blob.ptr)
{
return NULL;
}
switch (type)
{
case KEY_ANY:
return parse_public_key(blob);
case KEY_RSA:
return parse_rsa_public_key(blob);
default:
return NULL;
}
}
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