/* 
 * Copyright (C) 2008 Stef Walter
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "p11-capi.h"
#include "p11-capi-der.h"
#include "p11-capi-key.h"
#include "p11-capi-object.h"

/* 
 * Portions derived from NSS source files: 
 *     lib/ckfw/capi/crsa.c
 */

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Netscape security libraries.
 *
 * The Initial Developer of the Original Code is
 * Red Hat, Inc.
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Bob Relyea (rrelyea@redhat.com)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#define SSL3_SHAMD5_HASH_SIZE  36 /* LEN_MD5 (16) + LEN_SHA1 (20) */

/*
 * PKCS #11 sign for RSA expects to take a fully DER-encoded hash value, 
 * which includes the hash OID. CAPI expects to take a Hash Context. While 
 * CAPI does have the capability of setting a raw hash value, it does not 
 * have the ability to sign an arbitrary value. This function tries to
 * reduce the passed in data into something that CAPI could actually sign.
 */
static CK_BYTE_PTR
parse_rsa_pkcs_der_hash(CK_BYTE_PTR input, CK_ULONG n_input,
                        ALG_ID* algorithm, CK_ULONG_PTR n_hash)
{
	BYTE* algid;
	BYTE* oid;
	BYTE* hash_data;
	BYTE* oid_str;
	DWORD n_oid;
	DWORD n_algid;

	/*
	 * there are 2 types of hashes NSS typically tries to sign, regular
	 * RSA signature format (with encoded DER_OIDS), and SSL3 Signed hashes.
	 * CAPI knows not to add any oids to SSL3_Signed hashes, so if we have any
	 * random hash that is exactly the same size as an SSL3 hash, then we can
	 * just pass the data through. CAPI has know way of knowing if the value
	 * is really a combined hash or some other arbitrary data, so it's safe to
	 * handle this case first.
	 */
	if(SSL3_SHAMD5_HASH_SIZE == n_input)
	{
		*n_hash = n_input;
		*algorithm = CALG_SSL3_SHAMD5;
		return input;
	}

	/* make sure we have a sequence tag */
	if((P11C_DER_SEQUENCE | P11C_DER_CONSTRUCTED) != *input)
		return NULL;

	/* 
	 * parse the input block to get 1) the hash oid, and 2) the raw hash value.
	 * unfortunatly CAPI doesn't have a builtin function to do this work, so
	 * we go ahead and do it by hand here.
	 *
	 * format is:
	 *  SEQUENCE {
	 *     SECQUENCE { // algid
	 *       OID {}    // oid
	 *       ANY {}    // optional params 
	 *     }
	 *     OCTECT {}   // hash
	 */

	/* unwrap */
	algid = p11c_der_unwrap(input, n_input, &n_algid, NULL);
	if(!algid)
		return NULL;
	
	/* make sure there is not extra data at the end */
	if(algid + n_algid != input + n_input)
		return NULL;

	/* wasn't an algid */
	if((P11C_DER_SEQUENCE | P11C_DER_CONSTRUCTED) != *algid)
		return NULL;

	oid = p11c_der_unwrap(algid, n_algid, &n_oid, &hash_data);
	if(!oid || !hash_data)
		return NULL;

	if(algorithm)
	{
		/* 
		 * get the real oid as a string. Again, Microsoft does not
		 * export anything that does this for us 
		 */
		oid_str = p11c_der_read_oid(oid, n_oid);
		if(!oid_str)
			return NULL;

		/* look up the hash alg from the oid (fortunately CAPI does to this) */ 
		*algorithm = CertOIDToAlgId(oid_str);
		free(oid_str);
	}

	/* wasn't a hash? */
	if(P11C_DER_OCTET_STRING != *hash_data)
		return NULL;

	/* get the real raw hash */
	return p11c_der_unwrap(hash_data, n_algid - (hash_data - algid), 
	                         n_hash, NULL);
}

CK_RV
p11c_rsa_pkcs_sign_init(P11cObjectData *keydata, void** operation)
{
	CRYPT_KEY_PROV_INFO* prov_info;

	ASSERT(keydata);
	ASSERT(operation);
	ASSERT(!*operation);
	
	prov_info = p11c_key_object_data_get_prov_info(keydata);
	if(prov_info->dwProvType != PROV_RSA_FULL)
		return CKR_KEY_TYPE_INCONSISTENT;

	*operation = keydata;
	return CKR_OK;
}

CK_RV
p11c_rsa_pkcs_sign_perform (CK_BYTE_PTR data, CK_ULONG n_data,
                            CK_BYTE_PTR signature, CK_ULONG_PTR n_signature,
                            void** operation)
{
	CRYPT_KEY_PROV_INFO* prov_info;
	P11cObjectData* keydata;
	ALG_ID algorithm;
	BYTE* hash_data;
	DWORD n_hash_data;
	BOOL capifail;
	DWORD len, check;
	DWORD bits;
	CK_RV ret;

	HCRYPTPROV prov = 0;
	HCRYPTHASH hash = 0;


	ASSERT(operation);
	ASSERT(*operation);

	if(!data || !n_data)
		return CKR_ARGUMENTS_BAD;

	keydata = (P11cObjectData*)*operation;

	prov_info = p11c_key_object_data_get_prov_info(keydata);
	ASSERT(prov_info);

	/* Calculate the number of bits */
	bits = p11c_key_object_data_get_bits (keydata);
	if(!bits)
		return CKR_GENERAL_ERROR;

	/* Want to know the length */
	if(!signature) 
	{
		*n_signature = bits / 8;
		return CKR_OK;
	}

	/* TODO: Support arbitrary input on Vista */

	/*
	 * PKCS #11 sign for RSA expects to take a fully DER-encoded hash value, 
	 * which includes the hash OID. CAPI expects to take a Hash Context. While 
	 * CAPI does have the capability of setting a raw hash value, it does not 
	 * have the ability to sign an arbitrary value. This function tries to
	 * reduce the passed in data into something that CAPI could actually sign.
	 */
	hash_data = parse_rsa_pkcs_der_hash(data, n_data, &algorithm, &n_hash_data);
	if(!hash_data)
		return CKR_DATA_INVALID;

	capifail = TRUE;
	if(CryptAcquireContextW(&prov, prov_info->pwszContainerName, prov_info->pwszProvName,
	                        prov_info->dwProvType, 0))
	{
		if(CryptCreateHash(prov, algorithm, 0, 0, &hash))
		{
			/* make sure the hash lens match before we set it */
			len = sizeof(DWORD);
			if(CryptGetHashParam(hash, HP_HASHSIZE, (BYTE*)&check, &len, 0))
			{
				if(check != n_hash_data) 
				{
					capifail = FALSE;
					ret = CKR_DATA_INVALID;
				}

				/* 
				 * we have an explicit hash, set it, note that the length is
		 		 * implicit by the hashAlg used in create 
				 */
				if(CryptSetHashParam(hash, HP_HASHVAL, hash_data, 0))
				{
					/* OK, we have the data in a hash structure, sign it! */
					if(CryptSignHash(hash, prov_info->dwKeySpec, 
					                 NULL, 0, signature, n_signature))
					{
						/* 
						 * OK, Microsoft likes to do things completely 
						 * differently than anyone else. We need to reverse 
						 * the data we recieved here 
						 */
						if(signature)
							p11c_reverse_memory(signature, *n_signature);
	
						capifail = FALSE;
						ret = CKR_OK;
					}
				}
			}
		}
	}

	if(capifail)
		ret = p11c_winerr_to_ckr(GetLastError());

	if(hash)
		CryptDestroyHash(hash);
	if(prov)
		CryptReleaseContext(prov, 0);

	return ret;
}

void
p11c_rsa_pkcs_sign_cleanup (void* operation)
{
	/* Nothing to do */
}


CK_RV
p11c_rsa_pkcs_decrypt_init(P11cObjectData* keydata, void** operation)
{
	CRYPT_KEY_PROV_INFO* prov_info;

	ASSERT(keydata);
	ASSERT(operation);
	ASSERT(!*operation);
	
	prov_info = p11c_key_object_data_get_prov_info(keydata);
	if(prov_info->dwProvType != PROV_RSA_FULL)
		return CKR_KEY_TYPE_INCONSISTENT;

	*operation = keydata;
	return CKR_OK;
}

CK_RV
p11c_rsa_pkcs_decrypt_perform(CK_BYTE_PTR encdata, CK_ULONG n_encdata,
                              CK_BYTE_PTR result, CK_ULONG_PTR n_result,
                              void** operation)
{
	CRYPT_KEY_PROV_INFO* prov_info;
	P11cObjectData* keydata;
	BOOL capifail;
	DWORD bits, error;
	CK_RV ret;

	HCRYPTPROV prov = 0;
	HCRYPTKEY key = 0;
	void* buffer = NULL;

	ASSERT(operation);
	ASSERT(*operation);
	ASSERT(encdata);
	ASSERT(n_encdata);

	keydata = (P11cObjectData*)*operation;

	prov_info = p11c_key_object_data_get_prov_info(keydata);
	ASSERT(prov_info);

	/* Calculate the number of bits */
	bits = p11c_key_object_data_get_bits (keydata);
	if(!bits)
		return CKR_GENERAL_ERROR;

	/* Want to know the length */
	if(!result) 
	{
		*n_result = bits / 8;
		return CKR_OK;
	}

	/* 
	 * Copy the input, since CAPI operates in place, and 
	 * we must also reverse it properly.
	 */
	buffer = malloc(n_encdata);
	if(!buffer)
		return CKR_HOST_MEMORY;

	memcpy(buffer, encdata, n_encdata);
	p11c_reverse_memory(buffer, n_encdata);

	capifail = TRUE;
	if(CryptAcquireContextW(&prov, prov_info->pwszContainerName, prov_info->pwszProvName,
	                        prov_info->dwProvType, 0))
	{
		if(CryptGetUserKey(prov, prov_info->dwKeySpec, &key))
		{
			*n_result = n_encdata;
			if(CryptDecrypt(key, 0, TRUE, 0, buffer, n_result))
			{
				capifail = FALSE;
				ret = CKR_OK;
			}
		}
	}

	if(capifail)
	{
		error = GetLastError();
		switch(error)
		{
		case NTE_BAD_DATA:
			ret = CKR_ENCRYPTED_DATA_INVALID;
		default:
			ret = p11c_winerr_to_ckr(error);
		};
	}

	/* Copy the memory out to the result buffer */
	if(ret == CKR_OK)
		ret = p11c_return_data_raw(result, n_result, buffer, *n_result);

	if(key)
		CryptDestroyKey(key);
	if(prov)
		CryptReleaseContext(prov, 0);
	if(buffer)
		free(buffer);

	return ret;
}

void
p11c_rsa_pkcs_decrypt_cleanup(void* operation)
{
	/* Nothing to do */
}

void
p11c_rsa_pkcs_get_info(CK_MECHANISM_TYPE mech, CK_MECHANISM_INFO_PTR info)
{
	ASSERT(mech == CKM_RSA_PKCS);
	ASSERT(info != NULL);

	info->ulMinKeySize = 384;
	info->ulMaxKeySize = 16384;
	info->flags = 0;
}