/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
 * This file implements the Symkey wrapper and the PKCS context
 * Interfaces.
 */

#include "seccomon.h"
#include "secmod.h"
#include "nssilock.h"
#include "secmodi.h"
#include "secmodti.h"
#include "pkcs11.h"
#include "pk11func.h"
#include "secitem.h"
#include "key.h"
#include "secasn1.h"
#include "sechash.h"
#include "cert.h"
#include "secerr.h"

/*
 * find an RSA public key on a card
 */
static CK_OBJECT_HANDLE
pk11_FindRSAPubKey(PK11SlotInfo *slot)
{
    CK_KEY_TYPE key_type = CKK_RSA;
    CK_OBJECT_CLASS class_type = CKO_PUBLIC_KEY;
    CK_ATTRIBUTE theTemplate[2];
    int template_count = sizeof(theTemplate)/sizeof(theTemplate[0]);
    CK_ATTRIBUTE *attrs = theTemplate;

    PK11_SETATTRS(attrs,CKA_CLASS,&class_type,sizeof(class_type)); attrs++;
    PK11_SETATTRS(attrs,CKA_KEY_TYPE,&key_type,sizeof(key_type)); attrs++;
    template_count = attrs - theTemplate;
    PR_ASSERT(template_count <= sizeof(theTemplate)/sizeof(CK_ATTRIBUTE));

    return pk11_FindObjectByTemplate(slot,theTemplate,template_count);
}

PK11SymKey *
pk11_KeyExchange(PK11SlotInfo *slot,CK_MECHANISM_TYPE type,
		 CK_ATTRIBUTE_TYPE operation, CK_FLAGS flags, 
					PRBool isPerm, PK11SymKey *symKey)
{
    PK11SymKey *newSymKey = NULL;
    SECStatus rv;
    /* performance improvement can go here --- use a generated key at startup
     * to generate a per token wrapping key. If it exists, use it, otherwise 
     * do a full key exchange. */

    /* find a common Key Exchange algorithm */
    /* RSA */
    if (PK11_DoesMechanism(symKey->slot, CKM_RSA_PKCS) && 
				PK11_DoesMechanism(slot,CKM_RSA_PKCS)) {
	CK_OBJECT_HANDLE pubKeyHandle = CK_INVALID_HANDLE;
	CK_OBJECT_HANDLE privKeyHandle = CK_INVALID_HANDLE;
	SECKEYPublicKey *pubKey = NULL;
	SECKEYPrivateKey *privKey = NULL;
	SECItem wrapData;
	unsigned int     symKeyLength = PK11_GetKeyLength(symKey);

	wrapData.data = NULL;

	/* find RSA Public Key on target */
	pubKeyHandle = pk11_FindRSAPubKey(slot);
	if (pubKeyHandle != CK_INVALID_HANDLE) {
	    privKeyHandle = PK11_MatchItem(slot,pubKeyHandle,CKO_PRIVATE_KEY);
	}

	/* if no key exists, generate a key pair */
	if (privKeyHandle == CK_INVALID_HANDLE) {
	    PK11RSAGenParams rsaParams;

	    if (symKeyLength > 53) /* bytes */ {
		/* we'd have to generate an RSA key pair > 512 bits long,
		** and that's too costly.  Don't even try. 
		*/
		PORT_SetError( SEC_ERROR_CANNOT_MOVE_SENSITIVE_KEY );
		goto rsa_failed;
	    }
	    rsaParams.keySizeInBits = 
	        (symKeyLength > 21 || symKeyLength == 0) ? 512 : 256;
	    rsaParams.pe  = 0x10001;
	    privKey = PK11_GenerateKeyPair(slot,CKM_RSA_PKCS_KEY_PAIR_GEN, 
			    &rsaParams, &pubKey,PR_FALSE,PR_TRUE,symKey->cx);
	} else {
	    /* if keys exist, build SECKEY data structures for them */
	    privKey = PK11_MakePrivKey(slot,nullKey, PR_TRUE, privKeyHandle,
					symKey->cx);
	    if (privKey != NULL) {
    		pubKey = PK11_ExtractPublicKey(slot, rsaKey, pubKeyHandle);
		if (pubKey && pubKey->pkcs11Slot) {
		    PK11_FreeSlot(pubKey->pkcs11Slot);
		    pubKey->pkcs11Slot = NULL;
		    pubKey->pkcs11ID = CK_INVALID_HANDLE;
		}
	    }
	}
	if (privKey == NULL) goto rsa_failed;
	if (pubKey == NULL)  goto rsa_failed;

        wrapData.len  = SECKEY_PublicKeyStrength(pubKey);
        if (!wrapData.len) goto rsa_failed;
        wrapData.data = PORT_Alloc(wrapData.len);
        if (wrapData.data == NULL) goto rsa_failed;

	/* now wrap the keys in and out */
	rv = PK11_PubWrapSymKey(CKM_RSA_PKCS, pubKey, symKey, &wrapData);
	if (rv == SECSuccess) {
	    newSymKey = PK11_PubUnwrapSymKeyWithFlagsPerm(privKey,
			&wrapData,type,operation,symKeyLength,flags,isPerm);
	    /* make sure we wound up where we wanted to be! */
	    if (newSymKey && newSymKey->slot != slot) {
		PK11_FreeSymKey(newSymKey);
		newSymKey = NULL;
	    }
	}
rsa_failed:
	if (wrapData.data != NULL) PORT_Free(wrapData.data);
	if (privKey != NULL) SECKEY_DestroyPrivateKey(privKey);
	if (pubKey != NULL) SECKEY_DestroyPublicKey(pubKey);

	return  newSymKey;
    }
    PORT_SetError( SEC_ERROR_NO_MODULE );
    return NULL;
}