strongswan/src/libstrongswan/plugins/openssl/openssl_ec_public_key.c

353 lines
8.0 KiB
C

/*
* Copyright (C) 2009 Martin Willi
* Copyright (C) 2008 Tobias Brunner
* 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 <openssl/opensslconf.h>
#ifndef OPENSSL_NO_EC
#include "openssl_ec_public_key.h"
#include "openssl_util.h"
#include <debug.h>
#include <openssl/evp.h>
#include <openssl/ecdsa.h>
#include <openssl/x509.h>
typedef struct private_openssl_ec_public_key_t private_openssl_ec_public_key_t;
/**
* Private data structure with signing context.
*/
struct private_openssl_ec_public_key_t {
/**
* Public interface for this signer.
*/
openssl_ec_public_key_t public;
/**
* EC key object
*/
EC_KEY *ec;
/**
* reference counter
*/
refcount_t ref;
};
/**
* Verification of a signature as in RFC 4754
*/
static bool verify_signature(private_openssl_ec_public_key_t *this,
chunk_t hash, chunk_t signature)
{
bool valid = FALSE;
ECDSA_SIG *sig;
sig = ECDSA_SIG_new();
if (sig)
{
/* split the signature chunk in r and s */
if (openssl_bn_split(signature, sig->r, sig->s))
{
valid = (ECDSA_do_verify(hash.ptr, hash.len, sig, this->ec) == 1);
}
ECDSA_SIG_free(sig);
}
return valid;
}
/**
* Verify a RFC 4754 signature for a specified curve and hash algorithm
*/
static bool verify_curve_signature(private_openssl_ec_public_key_t *this,
signature_scheme_t scheme, int nid_hash,
int nid_curve, chunk_t data, chunk_t signature)
{
const EC_GROUP *my_group;
EC_GROUP *req_group;
chunk_t hash;
bool valid;
req_group = EC_GROUP_new_by_curve_name(nid_curve);
if (!req_group)
{
DBG1(DBG_LIB, "signature scheme %N not supported in EC (required curve "
"not supported)", signature_scheme_names, scheme);
return FALSE;
}
my_group = EC_KEY_get0_group(this->ec);
if (EC_GROUP_cmp(my_group, req_group, NULL) != 0)
{
DBG1(DBG_LIB, "signature scheme %N not supported by private key",
signature_scheme_names, scheme);
return FALSE;
}
EC_GROUP_free(req_group);
if (!openssl_hash_chunk(nid_hash, data, &hash))
{
return FALSE;
}
valid = verify_signature(this, hash, signature);
chunk_free(&hash);
return valid;
}
/**
* Verification of a DER encoded signature as in RFC 3279
*/
static bool verify_der_signature(private_openssl_ec_public_key_t *this,
int nid_hash, chunk_t data, chunk_t signature)
{
chunk_t hash;
bool valid = FALSE;
/* remove any preceding 0-bytes from signature */
while (signature.len && signature.ptr[0] == 0x00)
{
signature = chunk_skip(signature, 1);
}
if (openssl_hash_chunk(nid_hash, data, &hash))
{
valid = ECDSA_verify(0, hash.ptr, hash.len,
signature.ptr, signature.len, this->ec);
free(hash.ptr);
}
return valid;
}
METHOD(public_key_t, get_type, key_type_t,
private_openssl_ec_public_key_t *this)
{
return KEY_ECDSA;
}
METHOD(public_key_t, verify, bool,
private_openssl_ec_public_key_t *this, signature_scheme_t scheme,
chunk_t data, chunk_t signature)
{
switch (scheme)
{
case SIGN_ECDSA_WITH_SHA1_DER:
return verify_der_signature(this, NID_sha1, data, signature);
case SIGN_ECDSA_WITH_SHA256_DER:
return verify_der_signature(this, NID_sha256, data, signature);
case SIGN_ECDSA_WITH_SHA384_DER:
return verify_der_signature(this, NID_sha384, data, signature);
case SIGN_ECDSA_WITH_SHA512_DER:
return verify_der_signature(this, NID_sha512, data, signature);
case SIGN_ECDSA_WITH_NULL:
return verify_signature(this, data, signature);
case SIGN_ECDSA_256:
return verify_curve_signature(this, scheme, NID_sha256,
NID_X9_62_prime256v1, data, signature);
case SIGN_ECDSA_384:
return verify_curve_signature(this, scheme, NID_sha384,
NID_secp384r1, data, signature);
case SIGN_ECDSA_521:
return verify_curve_signature(this, scheme, NID_sha512,
NID_secp521r1, data, signature);
default:
DBG1(DBG_LIB, "signature scheme %N not supported in EC",
signature_scheme_names, scheme);
return FALSE;
}
}
METHOD(public_key_t, encrypt, bool,
private_openssl_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_keysize, size_t,
private_openssl_ec_public_key_t *this)
{
return EC_FIELD_ELEMENT_LEN(EC_KEY_get0_group(this->ec));
}
/**
* Calculate fingerprint from a EC_KEY, also used in ec private key.
*/
bool openssl_ec_fingerprint(EC_KEY *ec, cred_encoding_type_t type, chunk_t *fp)
{
hasher_t *hasher;
chunk_t key;
u_char *p;
if (lib->encoding->get_cache(lib->encoding, type, ec, fp))
{
return TRUE;
}
switch (type)
{
case KEYID_PUBKEY_SHA1:
key = chunk_alloc(i2o_ECPublicKey(ec, NULL));
p = key.ptr;
i2o_ECPublicKey(ec, &p);
break;
case KEYID_PUBKEY_INFO_SHA1:
key = chunk_alloc(i2d_EC_PUBKEY(ec, NULL));
p = key.ptr;
i2d_EC_PUBKEY(ec, &p);
break;
default:
return FALSE;
}
hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
if (!hasher)
{
DBG1(DBG_LIB, "SHA1 hash algorithm not supported, fingerprinting failed");
free(key.ptr);
return FALSE;
}
hasher->allocate_hash(hasher, key, fp);
hasher->destroy(hasher);
free(key.ptr);
lib->encoding->cache(lib->encoding, type, ec, *fp);
return TRUE;
}
METHOD(public_key_t, get_fingerprint, bool,
private_openssl_ec_public_key_t *this, cred_encoding_type_t type,
chunk_t *fingerprint)
{
return openssl_ec_fingerprint(this->ec, type, fingerprint);
}
METHOD(public_key_t, get_encoding, bool,
private_openssl_ec_public_key_t *this, cred_encoding_type_t type,
chunk_t *encoding)
{
u_char *p;
switch (type)
{
case PUBKEY_SPKI_ASN1_DER:
case PUBKEY_PEM:
{
bool success = TRUE;
*encoding = chunk_alloc(i2d_EC_PUBKEY(this->ec, NULL));
p = encoding->ptr;
i2d_EC_PUBKEY(this->ec, &p);
if (type == PUBKEY_PEM)
{
chunk_t asn1_encoding = *encoding;
success = lib->encoding->encode(lib->encoding, PUBKEY_PEM,
NULL, encoding, CRED_PART_ECDSA_PUB_ASN1_DER,
asn1_encoding, CRED_PART_END);
chunk_clear(&asn1_encoding);
}
return success;
}
default:
return FALSE;
}
}
METHOD(public_key_t, get_ref, public_key_t*,
private_openssl_ec_public_key_t *this)
{
ref_get(&this->ref);
return &this->public.key;
}
METHOD(public_key_t, destroy, void,
private_openssl_ec_public_key_t *this)
{
if (ref_put(&this->ref))
{
if (this->ec)
{
lib->encoding->clear_cache(lib->encoding, this->ec);
EC_KEY_free(this->ec);
}
free(this);
}
}
/**
* Generic private constructor
*/
static private_openssl_ec_public_key_t *create_empty()
{
private_openssl_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,
},
.ref = 1,
);
return this;
}
/**
* See header.
*/
openssl_ec_public_key_t *openssl_ec_public_key_load(key_type_t type,
va_list args)
{
private_openssl_ec_public_key_t *this;
chunk_t blob = chunk_empty;
if (type != KEY_ECDSA)
{
return NULL;
}
while (TRUE)
{
switch (va_arg(args, builder_part_t))
{
case BUILD_BLOB_ASN1_DER:
blob = va_arg(args, chunk_t);
continue;
case BUILD_END:
break;
default:
return NULL;
}
break;
}
this = create_empty();
this->ec = d2i_EC_PUBKEY(NULL, (const u_char**)&blob.ptr, blob.len);
if (!this->ec)
{
destroy(this);
return NULL;
}
return &this->public;
}
#endif /* OPENSSL_NO_EC */