/*
* Copyright (C) 2018 René Korthaus
* Copyright (C) 2018 Konstantinos Kolelis
* Rohde & Schwarz Cybersecurity GmbH
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "botan_ec_public_key.h"
#include "botan_util.h"
#include <botan/build.h>
#ifdef BOTAN_HAS_ECDSA
#include <asn1/asn1.h>
#include <asn1/asn1_parser.h>
#include <utils/debug.h>
#include <botan/ffi.h>
typedef struct private_botan_ec_public_key_t private_botan_ec_public_key_t;
/**
* Private data structure with signing context.
*/
struct private_botan_ec_public_key_t {
/**
* Public interface for this signer
*/
botan_ec_public_key_t public;
/**
* Botan ec public key
*/
botan_pubkey_t key;
/**
* Reference counter
*/
refcount_t ref;
};
#define SIG_FORMAT_IEEE_1363 0
#define SIG_FORMAT_DER_SEQUENCE 1
/**
* Verification of a DER encoded signature as in RFC 3279 or as in RFC 4754
*/
static bool verify_signature(private_botan_ec_public_key_t *this,
const char* hash_and_padding, int signature_format, size_t keylen,
chunk_t data, chunk_t signature)
{
chunk_t sig = signature;
if (signature_format == SIG_FORMAT_DER_SEQUENCE)
{
/*
* botan requires a signature in IEEE 1363 format (r||s)
* re-encode from ASN.1 sequence of two integers r,s
*/
chunk_t parse = signature, r, s;
if (asn1_unwrap(&parse, &parse) != ASN1_SEQUENCE ||
asn1_unwrap(&parse, &r) != ASN1_INTEGER ||
asn1_unwrap(&parse, &s) != ASN1_INTEGER)
{
return FALSE;
}
r = chunk_skip_zero(r);
s = chunk_skip_zero(s);
/*
* r and s must be of size m_order.bytes()/2 each
*/
if (r.len > keylen || s.len > keylen)
{
return FALSE;
}
sig = chunk_alloca(2 * keylen);
memset(sig.ptr, 0, sig.len);
memcpy(sig.ptr + (keylen - r.len), r.ptr, r.len);
memcpy(sig.ptr + keylen + (keylen - s.len), s.ptr, s.len);
}
return botan_verify_signature(this->key, hash_and_padding, data, sig);
}
METHOD(public_key_t, get_type, key_type_t,
private_botan_ec_public_key_t *this)
{
return KEY_ECDSA;
}
METHOD(public_key_t, get_keysize, int,
private_botan_ec_public_key_t *this)
{
botan_mp_t p;
size_t bits = 0;
if (botan_mp_init(&p))
{
return 0;
}
if (botan_pubkey_get_field(p, this->key, "p") ||
botan_mp_num_bits(p, &bits))
{
botan_mp_destroy(p);
return 0;
}
botan_mp_destroy(p);
return bits;
}
METHOD(public_key_t, verify, bool,
private_botan_ec_public_key_t *this, signature_scheme_t scheme,
void *params, chunk_t data, chunk_t signature)
{
size_t keylen = (get_keysize(this) + 7) / 8;
const char *hash_and_padding;
int sig_format;
switch (scheme)
{
/* r||s -> Botan::IEEE_1363, data is the hash already */
case SIGN_ECDSA_WITH_NULL:
hash_and_padding = "Raw";
sig_format = SIG_FORMAT_IEEE_1363;
break;
/* DER SEQUENCE of two INTEGERS r,s -> Botan::DER_SEQUENCE */
case SIGN_ECDSA_WITH_SHA1_DER:
hash_and_padding = "EMSA1(SHA-1)";
sig_format = SIG_FORMAT_DER_SEQUENCE;
break;
case SIGN_ECDSA_WITH_SHA256_DER:
hash_and_padding = "EMSA1(SHA-256)";
sig_format = SIG_FORMAT_DER_SEQUENCE;
break;
case SIGN_ECDSA_WITH_SHA384_DER:
hash_and_padding = "EMSA1(SHA-384)";
sig_format = SIG_FORMAT_DER_SEQUENCE;
break;
case SIGN_ECDSA_WITH_SHA512_DER:
hash_and_padding = "EMSA1(SHA-512)";
sig_format = SIG_FORMAT_DER_SEQUENCE;
break;
/* r||s -> Botan::IEEE_1363 */
case SIGN_ECDSA_256:
hash_and_padding = "EMSA1(SHA-256)";
sig_format = SIG_FORMAT_IEEE_1363;
break;
case SIGN_ECDSA_384:
hash_and_padding = "EMSA1(SHA-384)";
sig_format = SIG_FORMAT_IEEE_1363;
break;
case SIGN_ECDSA_521:
hash_and_padding = "EMSA1(SHA-512)";
sig_format = SIG_FORMAT_IEEE_1363;
break;
default:
DBG1(DBG_LIB, "signature scheme %N not supported via botan",
signature_scheme_names, scheme);
return FALSE;
}
return verify_signature(this, hash_and_padding,
sig_format, keylen, data, signature);
}
METHOD(public_key_t, encrypt, bool,
private_botan_ec_public_key_t *this, encryption_scheme_t scheme,
chunk_t crypto, chunk_t *plain)
{
DBG1(DBG_LIB, "EC public key encryption not implemented");
return FALSE;
}
METHOD(public_key_t, get_fingerprint, bool,
private_botan_ec_public_key_t *this, cred_encoding_type_t type,
chunk_t *fingerprint)
{
return botan_get_fingerprint(this->key, this, type, fingerprint);
}
METHOD(public_key_t, get_encoding, bool,
private_botan_ec_public_key_t *this, cred_encoding_type_t type,
chunk_t *encoding)
{
return botan_get_encoding(this->key, type, encoding);
}
METHOD(public_key_t, get_ref, public_key_t*,
private_botan_ec_public_key_t *this)
{
ref_get(&this->ref);
return &this->public.key;
}
METHOD(public_key_t, destroy, void,
private_botan_ec_public_key_t *this)
{
if (ref_put(&this->ref))
{
lib->encoding->clear_cache(lib->encoding, this);
botan_pubkey_destroy(this->key);
free(this);
}
}
/*
* Described in header
*/
botan_ec_public_key_t *botan_ec_public_key_adopt(botan_pubkey_t key)
{
private_botan_ec_public_key_t *this;
INIT(this,
.public = {
.key = {
.get_type = _get_type,
.verify = _verify,
.encrypt = _encrypt,
.get_keysize = _get_keysize,
.equals = public_key_equals,
.get_fingerprint = _get_fingerprint,
.has_fingerprint = public_key_has_fingerprint,
.get_encoding = _get_encoding,
.get_ref = _get_ref,
.destroy = _destroy,
},
},
.key = key,
.ref = 1,
);
return &this->public;
}
#endif
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