path: root/src/nss/ciphers.c

/** 
 * XMLSec library
 *
 * This is free software; see Copyright file in the source
 * distribution for preciese wording.
 * 
 * Copyright (C) 2002-2003 Aleksey Sanin <aleksey@aleksey.com>
 * Copyright (c) 2003 America Online, Inc.  All rights reserved.
 */
#include "globals.h"

#include <string.h>

#include <nspr.h>
#include <nss.h>
#include <secoid.h>
#include <pk11func.h>

#include <xmlsec/xmlsec.h>
#include <xmlsec/keys.h>
#include <xmlsec/transforms.h>
#include <xmlsec/errors.h>

#include <xmlsec/nss/crypto.h>

#define XMLSEC_NSS_MAX_KEY_SIZE		32
#define XMLSEC_NSS_MAX_IV_SIZE		32
#define XMLSEC_NSS_MAX_BLOCK_SIZE	32

/**************************************************************************
 *
 * Internal Nss Block cipher CTX
 *
 *****************************************************************************/
typedef struct _xmlSecNssBlockCipherCtx		xmlSecNssBlockCipherCtx,
							*xmlSecNssBlockCipherCtxPtr;
struct _xmlSecNssBlockCipherCtx {
    CK_MECHANISM_TYPE	cipher;
    PK11Context*	cipherCtx;
    xmlSecKeyDataId	keyId;
    int			keyInitialized;
    int			ctxInitialized;
    xmlSecByte		key[XMLSEC_NSS_MAX_KEY_SIZE];
    xmlSecSize		keySize;
    xmlSecByte		iv[XMLSEC_NSS_MAX_IV_SIZE];
    xmlSecSize		ivSize;
};
static int 	xmlSecNssBlockCipherCtxInit		(xmlSecNssBlockCipherCtxPtr ctx,
							 xmlSecBufferPtr in,
							 xmlSecBufferPtr out,
							 int encrypt,
							 const xmlChar* cipherName,
							 xmlSecTransformCtxPtr transformCtx);
static int 	xmlSecNssBlockCipherCtxUpdate	(xmlSecNssBlockCipherCtxPtr ctx,
							 xmlSecBufferPtr in,
							 xmlSecBufferPtr out,
							 int encrypt,
							 const xmlChar* cipherName,
							 xmlSecTransformCtxPtr transformCtx);
static int 	xmlSecNssBlockCipherCtxFinal		(xmlSecNssBlockCipherCtxPtr ctx,
							 xmlSecBufferPtr in,
							 xmlSecBufferPtr out,
							 int encrypt,
							 const xmlChar* cipherName,
							 xmlSecTransformCtxPtr transformCtx);
static int 
xmlSecNssBlockCipherCtxInit(xmlSecNssBlockCipherCtxPtr ctx,
				xmlSecBufferPtr in, xmlSecBufferPtr out,
				int encrypt,
				const xmlChar* cipherName,
				xmlSecTransformCtxPtr transformCtx) {
    SECItem keyItem;
    SECItem ivItem;
    PK11SlotInfo* slot;
    PK11SymKey* symKey;
    int ivLen;
    SECStatus rv;
    int ret;

    xmlSecAssert2(ctx != NULL, -1);
    xmlSecAssert2(ctx->cipher != 0, -1);
    xmlSecAssert2(ctx->cipherCtx == NULL, -1);
    xmlSecAssert2(ctx->keyInitialized != 0, -1);
    xmlSecAssert2(ctx->ctxInitialized == 0, -1);
    xmlSecAssert2(in != NULL, -1);
    xmlSecAssert2(out != NULL, -1);
    xmlSecAssert2(transformCtx != NULL, -1);

    ivLen = PK11_GetIVLength(ctx->cipher);
    xmlSecAssert2(ivLen > 0, -1);
    xmlSecAssert2((xmlSecSize)ivLen <= sizeof(ctx->iv), -1);
    
    if(encrypt) {
        /* generate random iv */
        rv = PK11_GenerateRandom(ctx->iv, ivLen);
	if(rv != SECSuccess) {
	    xmlSecError(XMLSEC_ERRORS_HERE,
			xmlSecErrorsSafeString(cipherName),
			"PK11_GenerateRandom",
			XMLSEC_ERRORS_R_CRYPTO_FAILED,
			"size=%d", ivLen);
	    return(-1);    
	}
	
	/* write iv to the output */
	ret = xmlSecBufferAppend(out, ctx->iv, ivLen);
	if(ret < 0) {
	    xmlSecError(XMLSEC_ERRORS_HERE, 
			xmlSecErrorsSafeString(cipherName),
			"xmlSecBufferAppend",
			XMLSEC_ERRORS_R_XMLSEC_FAILED,
			"size=%d", ivLen);
	    return(-1);
	}
	
    } else {
	/* if we don't have enough data, exit and hope that 
	 * we'll have iv next time */
	if(xmlSecBufferGetSize(in) < (xmlSecSize)ivLen) {
	    return(0);
	}
	
	/* copy iv to our buffer*/
	xmlSecAssert2(xmlSecBufferGetData(in) != NULL, -1);
	memcpy(ctx->iv, xmlSecBufferGetData(in), ivLen);
	
	/* and remove from input */
	ret = xmlSecBufferRemoveHead(in, ivLen);
	if(ret < 0) {
	    xmlSecError(XMLSEC_ERRORS_HERE, 
			xmlSecErrorsSafeString(cipherName),
			"xmlSecBufferRemoveHead",
			XMLSEC_ERRORS_R_XMLSEC_FAILED,
			"size=%d", ivLen);
	    return(-1);
	}
    }

    memset(&keyItem, 0, sizeof(keyItem));
    keyItem.data = ctx->key;
    keyItem.len  = ctx->keySize; 
    memset(&ivItem, 0, sizeof(ivItem));
    ivItem.data = ctx->iv;
    ivItem.len  = ctx->ivSize; 

    slot = PK11_GetBestSlot(ctx->cipher, NULL);
    if(slot == NULL) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "PK11_GetBestSlot",
		    XMLSEC_ERRORS_R_CRYPTO_FAILED,
		    XMLSEC_ERRORS_NO_MESSAGE);
	return(-1);
    }
	
    symKey = PK11_ImportSymKey(slot, ctx->cipher, PK11_OriginDerive, 
			       CKA_SIGN, &keyItem, NULL);
    if(symKey == NULL) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "PK11_ImportSymKey",
		    XMLSEC_ERRORS_R_CRYPTO_FAILED,
		    XMLSEC_ERRORS_NO_MESSAGE);
        PK11_FreeSlot(slot);
	return(-1);
    }

    ctx->cipherCtx = PK11_CreateContextBySymKey(ctx->cipher, 
			(encrypt) ? CKA_ENCRYPT : CKA_DECRYPT, 
			symKey, &ivItem);
    if(ctx->cipherCtx == NULL) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "PK11_CreateContextBySymKey",
		    XMLSEC_ERRORS_R_CRYPTO_FAILED,
		    XMLSEC_ERRORS_NO_MESSAGE);
	PK11_FreeSymKey(symKey);
        PK11_FreeSlot(slot);
	return(-1);
    }

    ctx->ctxInitialized = 1;
    PK11_FreeSymKey(symKey);
    PK11_FreeSlot(slot);
    return(0);
}

static int 
xmlSecNssBlockCipherCtxUpdate(xmlSecNssBlockCipherCtxPtr ctx,
				  xmlSecBufferPtr in, xmlSecBufferPtr out,
				  int encrypt,
				  const xmlChar* cipherName,
				  xmlSecTransformCtxPtr transformCtx) {
    xmlSecSize inSize, inBlocks, outSize;
    int blockLen;
    int outLen = 0;
    xmlSecByte* outBuf;
    SECStatus rv;
    int ret;
    
    xmlSecAssert2(ctx != NULL, -1);
    xmlSecAssert2(ctx->cipher != 0, -1);
    xmlSecAssert2(ctx->cipherCtx != NULL, -1);
    xmlSecAssert2(ctx->ctxInitialized != 0, -1);
    xmlSecAssert2(in != NULL, -1);
    xmlSecAssert2(out != NULL, -1);
    xmlSecAssert2(transformCtx != NULL, -1);

    blockLen = PK11_GetBlockSize(ctx->cipher, NULL);
    xmlSecAssert2(blockLen > 0, -1);

    inSize = xmlSecBufferGetSize(in);
    outSize = xmlSecBufferGetSize(out);
    
    if(inSize < (xmlSecSize)blockLen) {
	return(0);
    }

    if(encrypt) {
        inBlocks = inSize / ((xmlSecSize)blockLen);
    } else {
	/* we want to have the last block in the input buffer 
	 * for padding check */
        inBlocks = (inSize - 1) / ((xmlSecSize)blockLen);
    }
    inSize = inBlocks * ((xmlSecSize)blockLen);

    /* we write out the input size plus may be one block */
    ret = xmlSecBufferSetMaxSize(out, outSize + inSize + blockLen);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferSetMaxSize",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", outSize + inSize + blockLen);
	return(-1);
    }
    outBuf = xmlSecBufferGetData(out) + outSize;
    
    rv = PK11_CipherOp(ctx->cipherCtx, outBuf, &outLen, inSize + blockLen,
			xmlSecBufferGetData(in), inSize);
    if(rv != SECSuccess) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "PK11_CipherOp",
		    XMLSEC_ERRORS_R_CRYPTO_FAILED,
		    XMLSEC_ERRORS_NO_MESSAGE);
	return(-1);
    }
    xmlSecAssert2((xmlSecSize)outLen == inSize, -1);
    
    /* set correct output buffer size */
    ret = xmlSecBufferSetSize(out, outSize + outLen);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferSetSize",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", outSize + outLen);
	return(-1);
    }
        
    /* remove the processed block from input */
    ret = xmlSecBufferRemoveHead(in, inSize);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferRemoveHead",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", inSize);
	return(-1);
    }
    return(0);
}

static int 
xmlSecNssBlockCipherCtxFinal(xmlSecNssBlockCipherCtxPtr ctx,
				 xmlSecBufferPtr in,
				 xmlSecBufferPtr out,
				 int encrypt,
				 const xmlChar* cipherName,
				 xmlSecTransformCtxPtr transformCtx) {
    xmlSecSize inSize, outSize;
    int blockLen, outLen = 0;
    xmlSecByte* inBuf;
    xmlSecByte* outBuf;
    SECStatus rv;
    int ret;
    
    xmlSecAssert2(ctx != NULL, -1);
    xmlSecAssert2(ctx->cipher != 0, -1);
    xmlSecAssert2(ctx->cipherCtx != NULL, -1);
    xmlSecAssert2(ctx->ctxInitialized != 0, -1);
    xmlSecAssert2(in != NULL, -1);
    xmlSecAssert2(out != NULL, -1);
    xmlSecAssert2(transformCtx != NULL, -1);

    blockLen = PK11_GetBlockSize(ctx->cipher, NULL);
    xmlSecAssert2(blockLen > 0, -1);

    inSize = xmlSecBufferGetSize(in);
    outSize = xmlSecBufferGetSize(out);

    if(encrypt != 0) {
        xmlSecAssert2(inSize < (xmlSecSize)blockLen, -1);        
    
	/* create padding */
        ret = xmlSecBufferSetMaxSize(in, blockLen);
	if(ret < 0) {
	    xmlSecError(XMLSEC_ERRORS_HERE, 
			xmlSecErrorsSafeString(cipherName),
			"xmlSecBufferSetMaxSize",
			XMLSEC_ERRORS_R_XMLSEC_FAILED,
			"size=%d", blockLen);
	    return(-1);
	}
	inBuf = xmlSecBufferGetData(in);

        /* generate random padding */
	if((xmlSecSize)blockLen > (inSize + 1)) {
	    rv = PK11_GenerateRandom(inBuf + inSize, blockLen - inSize - 1);
	    if(rv != SECSuccess) {
		xmlSecError(XMLSEC_ERRORS_HERE,
			    xmlSecErrorsSafeString(cipherName),
			    "PK11_GenerateRandom",
			    XMLSEC_ERRORS_R_CRYPTO_FAILED,
			    "size=%d", blockLen - inSize - 1); 
		return(-1);    
	    }
	}
	inBuf[blockLen - 1] = blockLen - inSize;
	inSize = blockLen;
    } else {
	if(inSize != (xmlSecSize)blockLen) {
	    xmlSecError(XMLSEC_ERRORS_HERE, 
			xmlSecErrorsSafeString(cipherName),
			NULL,
			XMLSEC_ERRORS_R_INVALID_DATA,
			"data=%d;block=%d", inSize, blockLen);
	    return(-1);
	}
    }
    
    /* process last block */
    ret = xmlSecBufferSetMaxSize(out, outSize + 2 * blockLen);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferSetMaxSize",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", outSize + 2 * blockLen);
	return(-1);
    }
    outBuf = xmlSecBufferGetData(out) + outSize;

    rv = PK11_CipherOp(ctx->cipherCtx, outBuf, &outLen, 2 * blockLen,
			xmlSecBufferGetData(in), inSize);
    if(rv != SECSuccess) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "PK11_CipherOp",
		    XMLSEC_ERRORS_R_CRYPTO_FAILED,
		    XMLSEC_ERRORS_NO_MESSAGE);
	return(-1);
    }
    xmlSecAssert2((xmlSecSize)outLen == inSize, -1);
    
    if(encrypt == 0) {
	/* check padding */
	if(outLen < outBuf[blockLen - 1]) {
	    xmlSecError(XMLSEC_ERRORS_HERE,
			xmlSecErrorsSafeString(cipherName),
			NULL,
			XMLSEC_ERRORS_R_INVALID_DATA,
			"padding=%d;buffer=%d",
			outBuf[blockLen - 1], outLen);
	    return(-1);	
	}
	outLen -= outBuf[blockLen - 1];
    } 

    /* set correct output buffer size */
    ret = xmlSecBufferSetSize(out, outSize + outLen);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferSetSize",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", outSize + outLen);
	return(-1);
    }

    /* remove the processed block from input */
    ret = xmlSecBufferRemoveHead(in, inSize);
    if(ret < 0) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(cipherName),
		    "xmlSecBufferRemoveHead",
		    XMLSEC_ERRORS_R_XMLSEC_FAILED,
		    "size=%d", inSize);
	return(-1);
    }

    return(0);
}


/******************************************************************************
 *
 * EVP Block Cipher transforms
 *
 * xmlSecNssBlockCipherCtx block is located after xmlSecTransform structure
 * 
 *****************************************************************************/
#define xmlSecNssBlockCipherSize	\
    (sizeof(xmlSecTransform) + sizeof(xmlSecNssBlockCipherCtx))
#define xmlSecNssBlockCipherGetCtx(transform) \
    ((xmlSecNssBlockCipherCtxPtr)(((xmlSecByte*)(transform)) + sizeof(xmlSecTransform)))

static int	xmlSecNssBlockCipherInitialize	(xmlSecTransformPtr transform);
static void	xmlSecNssBlockCipherFinalize		(xmlSecTransformPtr transform);
static int  	xmlSecNssBlockCipherSetKeyReq	(xmlSecTransformPtr transform, 
							 xmlSecKeyReqPtr keyReq);
static int	xmlSecNssBlockCipherSetKey		(xmlSecTransformPtr transform,
							 xmlSecKeyPtr key);
static int	xmlSecNssBlockCipherExecute		(xmlSecTransformPtr transform,
							 int last,
							 xmlSecTransformCtxPtr transformCtx);
static int	xmlSecNssBlockCipherCheckId		(xmlSecTransformPtr transform);
							 


static int
xmlSecNssBlockCipherCheckId(xmlSecTransformPtr transform) {
#ifndef XMLSEC_NO_DES
    if(xmlSecTransformCheckId(transform, xmlSecNssTransformDes3CbcId)) {
	return(1);
    }
#endif /* XMLSEC_NO_DES */

#ifndef XMLSEC_NO_AES
    if(xmlSecTransformCheckId(transform, xmlSecNssTransformAes128CbcId) ||
       xmlSecTransformCheckId(transform, xmlSecNssTransformAes192CbcId) ||
       xmlSecTransformCheckId(transform, xmlSecNssTransformAes256CbcId)) {
       
       return(1);
    }
#endif /* XMLSEC_NO_AES */
    
    return(0);
}

static int 
xmlSecNssBlockCipherInitialize(xmlSecTransformPtr transform) {
    xmlSecNssBlockCipherCtxPtr ctx;
    
    xmlSecAssert2(xmlSecNssBlockCipherCheckId(transform), -1);
    xmlSecAssert2(xmlSecTransformCheckSize(transform, xmlSecNssBlockCipherSize), -1);

    ctx = xmlSecNssBlockCipherGetCtx(transform);
    xmlSecAssert2(ctx != NULL, -1);
    
    memset(ctx, 0, sizeof(xmlSecNssBlockCipherCtx));

#ifndef XMLSEC_NO_DES
    if(transform->id == xmlSecNssTransformDes3CbcId) {
	ctx->cipher 	= CKM_DES3_CBC;
	ctx->keyId 	= xmlSecNssKeyDataDesId;
	ctx->keySize	= 24;
    } else 
#endif /* XMLSEC_NO_DES */

#ifndef XMLSEC_NO_AES
    if(transform->id == xmlSecNssTransformAes128CbcId) {
	ctx->cipher 	= CKM_AES_CBC;	
	ctx->keyId 	= xmlSecNssKeyDataAesId;
	ctx->keySize	= 16;
    } else if(transform->id == xmlSecNssTransformAes192CbcId) {
	ctx->cipher 	= CKM_AES_CBC;	
	ctx->keyId 	= xmlSecNssKeyDataAesId;
	ctx->keySize	= 24;
    } else if(transform->id == xmlSecNssTransformAes256CbcId) {
	ctx->cipher 	= CKM_AES_CBC;	
	ctx->keyId 	= xmlSecNssKeyDataAesId;
	ctx->keySize	= 32;
    } else 
#endif /* XMLSEC_NO_AES */

    if(1) {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
		    NULL,
		    XMLSEC_ERRORS_R_INVALID_TRANSFORM,
		    XMLSEC_ERRORS_NO_MESSAGE);
	return(-1);
    }        
    
    return(0);
}

static void 
xmlSecNssBlockCipherFinalize(xmlSecTransformPtr transform) {
    xmlSecNssBlockCipherCtxPtr ctx;

    xmlSecAssert(xmlSecNssBlockCipherCheckId(transform));
    xmlSecAssert(xmlSecTransformCheckSize(transform, xmlSecNssBlockCipherSize));

    ctx = xmlSecNssBlockCipherGetCtx(transform);
    xmlSecAssert(ctx != NULL);

    if(ctx->cipherCtx != NULL) {
        PK11_DestroyContext(ctx->cipherCtx, PR_TRUE);
    }
    
    memset(ctx, 0, sizeof(xmlSecNssBlockCipherCtx));
}

static int  
xmlSecNssBlockCipherSetKeyReq(xmlSecTransformPtr transform,  xmlSecKeyReqPtr keyReq) {
    xmlSecNssBlockCipherCtxPtr ctx;

    xmlSecAssert2(xmlSecNssBlockCipherCheckId(transform), -1);
    xmlSecAssert2((transform->operation == xmlSecTransformOperationEncrypt) || (transform->operation == xmlSecTransformOperationDecrypt), -1);
    xmlSecAssert2(xmlSecTransformCheckSize(transform, xmlSecNssBlockCipherSize), -1);
    xmlSecAssert2(keyReq != NULL, -1);

    ctx = xmlSecNssBlockCipherGetCtx(transform);
    xmlSecAssert2(ctx != NULL, -1);
    xmlSecAssert2(ctx->keyId != NULL, -1);

    keyReq->keyId 	= ctx->keyId;
    keyReq->keyType 	= xmlSecKeyDataTypeSymmetric;
    if(transform->operation == xmlSecTransformOperationEncrypt) {
	keyReq->keyUsage = xmlSecKeyUsageEncrypt;
    } else {
	keyReq->keyUsage = xmlSecKeyUsageDecrypt;
    }
    keyReq->keyBitsSize = 8 * ctx->keySize;
    return(0);
}

static int
xmlSecNssBlockCipherSetKey(xmlSecTransformPtr transform, xmlSecKeyPtr key) {
    xmlSecNssBlockCipherCtxPtr ctx;
    xmlSecBufferPtr buffer;
    
    xmlSecAssert2(xmlSecNssBlockCipherCheckId(transform), -1);
    xmlSecAssert2((transform->operation == xmlSecTransformOperationEncrypt) || (transform->operation == xmlSecTransformOperationDecrypt), -1);
    xmlSecAssert2(xmlSecTransformCheckSize(transform, xmlSecNssBlockCipherSize), -1);
    xmlSecAssert2(key != NULL, -1);

    ctx = xmlSecNssBlockCipherGetCtx(transform);
    xmlSecAssert2(ctx != NULL, -1);
    xmlSecAssert2(ctx->cipher != 0, -1);
    xmlSecAssert2(ctx->keyInitialized == 0, -1);
    xmlSecAssert2(ctx->keyId != NULL, -1);
    xmlSecAssert2(xmlSecKeyCheckId(key, ctx->keyId), -1);

    xmlSecAssert2(ctx->keySize > 0, -1);
    xmlSecAssert2(ctx->keySize <= sizeof(ctx->key), -1);

    buffer = xmlSecKeyDataBinaryValueGetBuffer(xmlSecKeyGetValue(key));
    xmlSecAssert2(buffer != NULL, -1);

    if(xmlSecBufferGetSize(buffer) < ctx->keySize) {
	xmlSecError(XMLSEC_ERRORS_HERE,
		    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
		    NULL,
		    XMLSEC_ERRORS_R_INVALID_KEY_DATA_SIZE,
		    "keySize=%d;expected=%d",
		    xmlSecBufferGetSize(buffer), ctx->keySize);
	return(-1);
    }
    
    xmlSecAssert2(xmlSecBufferGetData(buffer) != NULL, -1);
    memcpy(ctx->key, xmlSecBufferGetData(buffer), ctx->keySize);
    
    ctx->keyInitialized = 1;
    return(0);
}

static int 
xmlSecNssBlockCipherExecute(xmlSecTransformPtr transform, int last, xmlSecTransformCtxPtr transformCtx) {
    xmlSecNssBlockCipherCtxPtr ctx;
    xmlSecBufferPtr in, out;
    int ret;
    
    xmlSecAssert2(xmlSecNssBlockCipherCheckId(transform), -1);
    xmlSecAssert2((transform->operation == xmlSecTransformOperationEncrypt) || (transform->operation == xmlSecTransformOperationDecrypt), -1);
    xmlSecAssert2(xmlSecTransformCheckSize(transform, xmlSecNssBlockCipherSize), -1);
    xmlSecAssert2(transformCtx != NULL, -1);

    in = &(transform->inBuf);
    out = &(transform->outBuf);

    ctx = xmlSecNssBlockCipherGetCtx(transform);
    xmlSecAssert2(ctx != NULL, -1);

    if(transform->status == xmlSecTransformStatusNone) {
	transform->status = xmlSecTransformStatusWorking;
    }

    if(transform->status == xmlSecTransformStatusWorking) {
	if(ctx->ctxInitialized == 0) {
	    ret = xmlSecNssBlockCipherCtxInit(ctx, in, out, 
			(transform->operation == xmlSecTransformOperationEncrypt) ? 1 : 0,
			xmlSecTransformGetName(transform), transformCtx);
	    if(ret < 0) {
		xmlSecError(XMLSEC_ERRORS_HERE, 
			    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
			    "xmlSecNssBlockCipherCtxInit",
			    XMLSEC_ERRORS_R_XMLSEC_FAILED,
			    XMLSEC_ERRORS_NO_MESSAGE);
		return(-1);
	    }
	}
	if((ctx->ctxInitialized == 0) && (last != 0)) {
	    xmlSecError(XMLSEC_ERRORS_HERE, 
			xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
			NULL,
			XMLSEC_ERRORS_R_INVALID_DATA,
			"not enough data to initialize transform");
	    return(-1);
	}

	if(ctx->ctxInitialized != 0) {
	    ret = xmlSecNssBlockCipherCtxUpdate(ctx, in, out, 
			(transform->operation == xmlSecTransformOperationEncrypt) ? 1 : 0,
			xmlSecTransformGetName(transform), transformCtx);
	    if(ret < 0) {
		xmlSecError(XMLSEC_ERRORS_HERE, 
			    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
			    "xmlSecNssBlockCipherCtxUpdate",
			    XMLSEC_ERRORS_R_XMLSEC_FAILED,
			    XMLSEC_ERRORS_NO_MESSAGE);
		return(-1);
	    }
	}
	
	if(last) {
	    ret = xmlSecNssBlockCipherCtxFinal(ctx, in, out, 
			(transform->operation == xmlSecTransformOperationEncrypt) ? 1 : 0,
			xmlSecTransformGetName(transform), transformCtx);
	    if(ret < 0) {
		xmlSecError(XMLSEC_ERRORS_HERE, 
			    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
			    "xmlSecNssBlockCipherCtxFinal",
			    XMLSEC_ERRORS_R_XMLSEC_FAILED,
			    XMLSEC_ERRORS_NO_MESSAGE);
		return(-1);
	    }
	    transform->status = xmlSecTransformStatusFinished;
	} 
    } else if(transform->status == xmlSecTransformStatusFinished) {
	/* the only way we can get here is if there is no input */
	xmlSecAssert2(xmlSecBufferGetSize(in) == 0, -1);
    } else if(transform->status == xmlSecTransformStatusNone) {
	/* the only way we can get here is if there is no enough data in the input */
	xmlSecAssert2(last == 0, -1);
    } else {
	xmlSecError(XMLSEC_ERRORS_HERE, 
		    xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
		    NULL,
		    XMLSEC_ERRORS_R_INVALID_STATUS,
		    "status=%d", transform->status);
	return(-1);
    }
    
    return(0);
}


#ifndef XMLSEC_NO_AES
/*********************************************************************
 *
 * AES CBC cipher transforms
 *
 ********************************************************************/
static xmlSecTransformKlass xmlSecNssAes128CbcKlass = {
    /* klass/object sizes */
    sizeof(xmlSecTransformKlass),		/* xmlSecSize klassSize */
    xmlSecNssBlockCipherSize,		/* xmlSecSize objSize */

    xmlSecNameAes128Cbc,			/* const xmlChar* name; */
    xmlSecHrefAes128Cbc,			/* const xmlChar* href; */
    xmlSecTransformUsageEncryptionMethod,	/* xmlSecAlgorithmUsage usage; */

    xmlSecNssBlockCipherInitialize, 		/* xmlSecTransformInitializeMethod initialize; */
    xmlSecNssBlockCipherFinalize,		/* xmlSecTransformFinalizeMethod finalize; */
    NULL,					/* xmlSecTransformNodeReadMethod readNode; */
    NULL,					/* xmlSecTransformNodeWriteMethod writeNode; */
    xmlSecNssBlockCipherSetKeyReq,		/* xmlSecTransformSetKeyMethod setKeyReq; */
    xmlSecNssBlockCipherSetKey,		/* xmlSecTransformSetKeyMethod setKey; */
    NULL,					/* xmlSecTransformValidateMethod validate; */
    xmlSecTransformDefaultGetDataType,		/* xmlSecTransformGetDataTypeMethod getDataType; */
    xmlSecTransformDefaultPushBin,		/* xmlSecTransformPushBinMethod pushBin; */
    xmlSecTransformDefaultPopBin,		/* xmlSecTransformPopBinMethod popBin; */
    NULL,					/* xmlSecTransformPushXmlMethod pushXml; */
    NULL,					/* xmlSecTransformPopXmlMethod popXml; */
    xmlSecNssBlockCipherExecute,		/* xmlSecTransformExecuteMethod execute; */

    NULL,					/* void* reserved0; */
    NULL,					/* void* reserved1; */
};

/**
 * xmlSecNssTransformAes128CbcGetKlass:
 * 
 * AES 128 CBC encryption transform klass.
 * 
 * Returns: pointer to AES 128 CBC encryption transform.
 */ 
xmlSecTransformId 
xmlSecNssTransformAes128CbcGetKlass(void) {
    return(&xmlSecNssAes128CbcKlass);
}

static xmlSecTransformKlass xmlSecNssAes192CbcKlass = {
    /* klass/object sizes */
    sizeof(xmlSecTransformKlass),		/* xmlSecSize klassSize */
    xmlSecNssBlockCipherSize,		/* xmlSecSize objSize */

    xmlSecNameAes192Cbc,			/* const xmlChar* name; */
    xmlSecHrefAes192Cbc,			/* const xmlChar* href; */
    xmlSecTransformUsageEncryptionMethod,	/* xmlSecAlgorithmUsage usage; */

    xmlSecNssBlockCipherInitialize, 		/* xmlSecTransformInitializeMethod initialize; */
    xmlSecNssBlockCipherFinalize,		/* xmlSecTransformFinalizeMethod finalize; */
    NULL,					/* xmlSecTransformNodeReadMethod readNode; */
    NULL,					/* xmlSecTransformNodeWriteMethod writeNode; */
    xmlSecNssBlockCipherSetKeyReq,		/* xmlSecTransformSetKeyMethod setKeyReq; */
    xmlSecNssBlockCipherSetKey,		/* xmlSecTransformSetKeyMethod setKey; */
    NULL,					/* xmlSecTransformValidateMethod validate; */
    xmlSecTransformDefaultGetDataType,		/* xmlSecTransformGetDataTypeMethod getDataType; */
    xmlSecTransformDefaultPushBin,		/* xmlSecTransformPushBinMethod pushBin; */
    xmlSecTransformDefaultPopBin,		/* xmlSecTransformPopBinMethod popBin; */
    NULL,					/* xmlSecTransformPushXmlMethod pushXml; */
    NULL,					/* xmlSecTransformPopXmlMethod popXml; */
    xmlSecNssBlockCipherExecute,		/* xmlSecTransformExecuteMethod execute; */
    
    NULL,					/* void* reserved0; */
    NULL,					/* void* reserved1; */
};

/**
 * xmlSecNssTransformAes192CbcGetKlass:
 * 
 * AES 192 CBC encryption transform klass.
 * 
 * Returns: pointer to AES 192 CBC encryption transform.
 */ 
xmlSecTransformId 
xmlSecNssTransformAes192CbcGetKlass(void) {
    return(&xmlSecNssAes192CbcKlass);
}

static xmlSecTransformKlass xmlSecNssAes256CbcKlass = {
    /* klass/object sizes */
    sizeof(xmlSecTransformKlass),		/* xmlSecSize klassSize */
    xmlSecNssBlockCipherSize,		/* xmlSecSize objSize */

    xmlSecNameAes256Cbc,			/* const xmlChar* name; */
    xmlSecHrefAes256Cbc,			/* const xmlChar* href; */
    xmlSecTransformUsageEncryptionMethod,	/* xmlSecAlgorithmUsage usage; */

    xmlSecNssBlockCipherInitialize, 		/* xmlSecTransformInitializeMethod initialize; */
    xmlSecNssBlockCipherFinalize,		/* xmlSecTransformFinalizeMethod finalize; */
    NULL,					/* xmlSecTransformNodeReadMethod readNode; */
    NULL,					/* xmlSecTransformNodeWriteMethod writeNode; */
    xmlSecNssBlockCipherSetKeyReq,		/* xmlSecTransformSetKeyMethod setKeyReq; */
    xmlSecNssBlockCipherSetKey,		/* xmlSecTransformSetKeyMethod setKey; */
    NULL,					/* xmlSecTransformValidateMethod validate; */
    xmlSecTransformDefaultGetDataType,		/* xmlSecTransformGetDataTypeMethod getDataType; */
    xmlSecTransformDefaultPushBin,		/* xmlSecTransformPushBinMethod pushBin; */
    xmlSecTransformDefaultPopBin,		/* xmlSecTransformPopBinMethod popBin; */
    NULL,					/* xmlSecTransformPushXmlMethod pushXml; */
    NULL,					/* xmlSecTransformPopXmlMethod popXml; */
    xmlSecNssBlockCipherExecute,		/* xmlSecTransformExecuteMethod execute; */
    
    NULL,					/* void* reserved0; */
    NULL,					/* void* reserved1; */
};

/**
 * xmlSecNssTransformAes256CbcGetKlass:
 * 
 * AES 256 CBC encryption transform klass.
 * 
 * Returns: pointer to AES 256 CBC encryption transform.
 */ 
xmlSecTransformId 
xmlSecNssTransformAes256CbcGetKlass(void) {
    return(&xmlSecNssAes256CbcKlass);
}

#endif /* XMLSEC_NO_AES */

#ifndef XMLSEC_NO_DES
static xmlSecTransformKlass xmlSecNssDes3CbcKlass = {
    /* klass/object sizes */
    sizeof(xmlSecTransformKlass),		/* xmlSecSize klassSize */
    xmlSecNssBlockCipherSize,		/* xmlSecSize objSize */

    xmlSecNameDes3Cbc,				/* const xmlChar* name; */
    xmlSecHrefDes3Cbc, 				/* const xmlChar* href; */
    xmlSecTransformUsageEncryptionMethod,	/* xmlSecAlgorithmUsage usage; */

    xmlSecNssBlockCipherInitialize, 		/* xmlSecTransformInitializeMethod initialize; */
    xmlSecNssBlockCipherFinalize,		/* xmlSecTransformFinalizeMethod finalize; */
    NULL,					/* xmlSecTransformNodeReadMethod readNode; */
    NULL,					/* xmlSecTransformNodeWriteMethod writeNode; */
    xmlSecNssBlockCipherSetKeyReq,		/* xmlSecTransformSetKeyMethod setKeyReq; */
    xmlSecNssBlockCipherSetKey,		/* xmlSecTransformSetKeyMethod setKey; */
    NULL,					/* xmlSecTransformValidateMethod validate; */
    xmlSecTransformDefaultGetDataType,		/* xmlSecTransformGetDataTypeMethod getDataType; */
    xmlSecTransformDefaultPushBin,		/* xmlSecTransformPushBinMethod pushBin; */
    xmlSecTransformDefaultPopBin,		/* xmlSecTransformPopBinMethod popBin; */
    NULL,					/* xmlSecTransformPushXmlMethod pushXml; */
    NULL,					/* xmlSecTransformPopXmlMethod popXml; */
    xmlSecNssBlockCipherExecute,		/* xmlSecTransformExecuteMethod execute; */
    
    NULL,					/* void* reserved0; */
    NULL,					/* void* reserved1; */
};

/** 
 * xmlSecNssTransformDes3CbcGetKlass:
 *
 * Triple DES CBC encryption transform klass.
 * 
 * Returns: pointer to Triple DES encryption transform.
 */
xmlSecTransformId 
xmlSecNssTransformDes3CbcGetKlass(void) {
    return(&xmlSecNssDes3CbcKlass);
}
#endif /* XMLSEC_NO_DES */