/* arcfour.c - the arc four algorithm.

 *

 * 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/. */

#ifdef FREEBL_NO_DEPEND

#include "stubs.h"

#endif

#include "prerr.h"

#include "secerr.h"

#include "prtypes.h"

#include "blapi.h"

/* Architecture-dependent defines */

#if defined(SOLARIS) || defined(HPUX) || defined(NSS_X86) || \

    defined(_WIN64)

/* Convert the byte-stream to a word-stream */

#define CONVERT_TO_WORDS

#endif

#if defined(AIX) || defined(OSF1) || defined(NSS_BEVAND_ARCFOUR)

/* Treat array variables as words, not bytes, on CPUs that take 

 * much longer to write bytes than to write words, or when using 

 * assembler code that required it.

 */

#define USE_WORD

#endif

#if defined(IS_64) || defined(NSS_BEVAND_ARCFOUR)

typedef PRUint64 WORD;

#else

typedef PRUint32 WORD;

#endif

#define WORDSIZE sizeof(WORD)

#if defined(USE_WORD)

typedef WORD Stype;

#else

typedef PRUint8 Stype;

#endif

#define ARCFOUR_STATE_SIZE 256

#define MASK1BYTE (WORD)(0xff)

#define SWAP(a, b) \

	tmp = a; \

	a = b; \

	b = tmp;

/*

 * State information for stream cipher.

 */

struct RC4ContextStr

{

#if defined(NSS_ARCFOUR_IJ_B4_S) || defined(NSS_BEVAND_ARCFOUR)

	Stype i;

	Stype j;

	Stype S[ARCFOUR_STATE_SIZE];

#else

	Stype S[ARCFOUR_STATE_SIZE];

	Stype i;

	Stype j;

#endif

};

/*

 * array indices [0..255] to initialize cx->S array (faster than loop).

 */

static const Stype Kinit[256] = {

	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,

	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,

	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,

	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,

	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,

	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,

	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,

	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,

	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,

	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,

	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,

	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,

	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,

	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,

	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,

	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,

	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,

	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,

	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,

	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,

	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,

	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,

	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,

	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,

	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,

	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,

	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,

	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,

	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,

	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,

	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff

};

RC4Context *

RC4_AllocateContext(void)

{

    return PORT_ZNew(RC4Context);

}

SECStatus   

RC4_InitContext(RC4Context *cx, const unsigned char *key, unsigned int len,

	        const unsigned char * unused1, int unused2, 

		unsigned int unused3, unsigned int unused4)

{

	unsigned int i;

	PRUint8 j, tmp;

	PRUint8 K[256];

	PRUint8 *L;

	/* verify the key length. */

	PORT_Assert(len > 0 && len < ARCFOUR_STATE_SIZE);

	if (len == 0 || len >= ARCFOUR_STATE_SIZE) {

		PORT_SetError(SEC_ERROR_BAD_KEY);

		return SECFailure;

	}

	if (cx == NULL) {

	    PORT_SetError(SEC_ERROR_INVALID_ARGS);

	    return SECFailure;

	}

	/* Initialize the state using array indices. */

	memcpy(cx->S, Kinit, sizeof cx->S);

	/* Fill in K repeatedly with values from key. */

	L = K;

	for (i = sizeof K; i > len; i-= len) {

		memcpy(L, key, len);

		L += len;

	}

	memcpy(L, key, i);

	/* Stir the state of the generator.  At this point it is assumed

	 * that the key is the size of the state buffer.  If this is not

	 * the case, the key bytes are repeated to fill the buffer.

	 */

	j = 0;

#define ARCFOUR_STATE_STIR(ii) \

	j = j + cx->S[ii] + K[ii]; \

	SWAP(cx->S[ii], cx->S[j]);

	for (i=0; i

		ARCFOUR_STATE_STIR(i);

	}

	cx->i = 0;

	cx->j = 0;

	return SECSuccess;

}

/*

 * Initialize a new generator.

 */

RC4Context *

RC4_CreateContext(const unsigned char *key, int len)

{

    RC4Context *cx = RC4_AllocateContext();

    if (cx) {

	SECStatus rv = RC4_InitContext(cx, key, len, NULL, 0, 0, 0);

	if (rv != SECSuccess) {

	    PORT_ZFree(cx, sizeof(*cx));

	    cx = NULL;

	}

    }

    return cx;

}

void 

RC4_DestroyContext(RC4Context *cx, PRBool freeit)

{

	if (freeit)

		PORT_ZFree(cx, sizeof(*cx));

}

#if defined(NSS_BEVAND_ARCFOUR)

extern void ARCFOUR(RC4Context *cx, WORD inputLen, 

	const unsigned char *input, unsigned char *output);

#else

/*

 * Generate the next byte in the stream.

 */

#define ARCFOUR_NEXT_BYTE() \

	tmpSi = cx->S[++tmpi]; \

	tmpj += tmpSi; \

	tmpSj = cx->S[tmpj]; \

	cx->S[tmpi] = tmpSj; \

	cx->S[tmpj] = tmpSi; \

	t = tmpSi + tmpSj;

#ifdef CONVERT_TO_WORDS

/*

 * Straight ARCFOUR op.  No optimization.

 */

static SECStatus 

rc4_no_opt(RC4Context *cx, unsigned char *output,

           unsigned int *outputLen, unsigned int maxOutputLen,

           const unsigned char *input, unsigned int inputLen)

{

    PRUint8 t;

	Stype tmpSi, tmpSj;

	register PRUint8 tmpi = cx->i;

	register PRUint8 tmpj = cx->j;

	unsigned int index;

	PORT_Assert(maxOutputLen >= inputLen);

	if (maxOutputLen < inputLen) {

		PORT_SetError(SEC_ERROR_OUTPUT_LEN);

		return SECFailure;

	}

	for (index=0; index < inputLen; index++) {

		/* Generate next byte from stream. */

		ARCFOUR_NEXT_BYTE();

		/* output = next stream byte XOR next input byte */

		output[index] = cx->S[t] ^ input[index];

	}

	*outputLen = inputLen;

	cx->i = tmpi;

	cx->j = tmpj;

	return SECSuccess;

}

#else

/* !CONVERT_TO_WORDS */

/*

 * Byte-at-a-time ARCFOUR, unrolling the loop into 8 pieces.

 */

static SECStatus 

rc4_unrolled(RC4Context *cx, unsigned char *output,

             unsigned int *outputLen, unsigned int maxOutputLen,

             const unsigned char *input, unsigned int inputLen)

{

	PRUint8 t;

	Stype tmpSi, tmpSj;

	register PRUint8 tmpi = cx->i;

	register PRUint8 tmpj = cx->j;

	int index;

	PORT_Assert(maxOutputLen >= inputLen);

	if (maxOutputLen < inputLen) {

		PORT_SetError(SEC_ERROR_OUTPUT_LEN);

		return SECFailure;

	}

	for (index = inputLen / 8; index-- > 0; input += 8, output += 8) {

		ARCFOUR_NEXT_BYTE();

		output[0] = cx->S[t] ^ input[0];

		ARCFOUR_NEXT_BYTE();

		output[1] = cx->S[t] ^ input[1];

		ARCFOUR_NEXT_BYTE();

		output[2] = cx->S[t] ^ input[2];

		ARCFOUR_NEXT_BYTE();

		output[3] = cx->S[t] ^ input[3];

		ARCFOUR_NEXT_BYTE();

		output[4] = cx->S[t] ^ input[4];

		ARCFOUR_NEXT_BYTE();

		output[5] = cx->S[t] ^ input[5];

		ARCFOUR_NEXT_BYTE();

		output[6] = cx->S[t] ^ input[6];

		ARCFOUR_NEXT_BYTE();

		output[7] = cx->S[t] ^ input[7];

	}

	index = inputLen % 8;

	if (index) {

		input += index;

		output += index;

		switch (index) {

		case 7:

			ARCFOUR_NEXT_BYTE();

			output[-7] = cx->S[t] ^ input[-7]; /* FALLTHRU */

		case 6:

			ARCFOUR_NEXT_BYTE();

			output[-6] = cx->S[t] ^ input[-6]; /* FALLTHRU */

		case 5:

			ARCFOUR_NEXT_BYTE();

			output[-5] = cx->S[t] ^ input[-5]; /* FALLTHRU */

		case 4:

			ARCFOUR_NEXT_BYTE();

			output[-4] = cx->S[t] ^ input[-4]; /* FALLTHRU */

		case 3:

			ARCFOUR_NEXT_BYTE();

			output[-3] = cx->S[t] ^ input[-3]; /* FALLTHRU */

		case 2:

			ARCFOUR_NEXT_BYTE();

			output[-2] = cx->S[t] ^ input[-2]; /* FALLTHRU */

		case 1:

			ARCFOUR_NEXT_BYTE();

			output[-1] = cx->S[t] ^ input[-1]; /* FALLTHRU */

		default:

			/* FALLTHRU */

			; /* hp-ux build breaks without this */

		}

	}

	cx->i = tmpi;

	cx->j = tmpj;

	*outputLen = inputLen;

	return SECSuccess;

}

#endif

#ifdef IS_LITTLE_ENDIAN

#define ARCFOUR_NEXT4BYTES_L(n) \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n     ); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n +  8); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n + 16); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n + 24);

#else

#define ARCFOUR_NEXT4BYTES_B(n) \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n + 24); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n + 16); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n +  8); \

	ARCFOUR_NEXT_BYTE(); streamWord |= (WORD)cx->S[t] << (n     );

#endif

#if (defined(IS_64) && !defined(__sparc)) || defined(NSS_USE_64)

/* 64-bit wordsize */

#ifdef IS_LITTLE_ENDIAN

#define ARCFOUR_NEXT_WORD() \

	{ streamWord = 0; ARCFOUR_NEXT4BYTES_L(0); ARCFOUR_NEXT4BYTES_L(32); }

#else

#define ARCFOUR_NEXT_WORD() \

	{ streamWord = 0; ARCFOUR_NEXT4BYTES_B(32); ARCFOUR_NEXT4BYTES_B(0); }

#endif

#else

/* 32-bit wordsize */

#ifdef IS_LITTLE_ENDIAN

#define ARCFOUR_NEXT_WORD() \

	{ streamWord = 0; ARCFOUR_NEXT4BYTES_L(0); }

#else

#define ARCFOUR_NEXT_WORD() \

	{ streamWord = 0; ARCFOUR_NEXT4BYTES_B(0); }

#endif

#endif

#ifdef IS_LITTLE_ENDIAN

#define RSH <<

#define LSH >>

#else

#define RSH >>

#define LSH <<

#endif

#ifdef IS_LITTLE_ENDIAN

#define LEFTMOST_BYTE_SHIFT 0

#define NEXT_BYTE_SHIFT(shift) shift + 8

#else

#define LEFTMOST_BYTE_SHIFT 8*(WORDSIZE - 1)

#define NEXT_BYTE_SHIFT(shift) shift - 8

#endif

#ifdef CONVERT_TO_WORDS

static SECStatus 

rc4_wordconv(RC4Context *cx, unsigned char *output,

             unsigned int *outputLen, unsigned int maxOutputLen,

             const unsigned char *input, unsigned int inputLen)

{

	PR_STATIC_ASSERT(sizeof(PRUword) == sizeof(ptrdiff_t));

	unsigned int inOffset = (PRUword)input % WORDSIZE;

	unsigned int outOffset = (PRUword)output % WORDSIZE;

	register WORD streamWord;

	register const WORD *pInWord;

	register WORD *pOutWord;

	register WORD inWord, nextInWord;

	PRUint8 t;

	register Stype tmpSi, tmpSj;

	register PRUint8 tmpi = cx->i;

	register PRUint8 tmpj = cx->j;

	unsigned int bufShift, invBufShift;

	unsigned int i;

	const unsigned char *finalIn;

	unsigned char *finalOut;

	PORT_Assert(maxOutputLen >= inputLen);

	if (maxOutputLen < inputLen) {

		PORT_SetError(SEC_ERROR_OUTPUT_LEN);

		return SECFailure;

	}

	if (inputLen < 2*WORDSIZE) {

		/* Ignore word conversion, do byte-at-a-time */

		return rc4_no_opt(cx, output, outputLen, maxOutputLen, input, inputLen);

	}

	*outputLen = inputLen;

	pInWord = (const WORD *)(input - inOffset);

	pOutWord = (WORD *)(output - outOffset);

	if (inOffset <= outOffset) {

		bufShift = 8*(outOffset - inOffset);

		invBufShift = 8*WORDSIZE - bufShift;

	} else {

		invBufShift = 8*(inOffset - outOffset);

		bufShift = 8*WORDSIZE - invBufShift;

	}

	/*****************************************************************/

	/* Step 1:                                                       */

	/* If the first output word is partial, consume the bytes in the */

	/* first partial output word by loading one or two words of      */

	/* input and shifting them accordingly.  Otherwise, just load    */

	/* in the first word of input.  At the end of this block, at     */

	/* least one partial word of input should ALWAYS be loaded.      */

	/*****************************************************************/

	if (outOffset) {

		unsigned int byteCount = WORDSIZE - outOffset; 

		for (i = 0; i < byteCount; i++) {

			ARCFOUR_NEXT_BYTE();

			output[i] = cx->S[t] ^ input[i];

		}

		/* Consumed byteCount bytes of input */

		inputLen -= byteCount;

		pInWord++;

		/* move to next word of output */

		pOutWord++;

		/* If buffers are relatively misaligned, shift the bytes in inWord

		 * to be aligned to the output buffer.

		 */

		if (inOffset < outOffset) {

			/* The first input word (which may be partial) has more bytes

			 * than needed.  Copy the remainder to inWord.

			 */

			unsigned int shift = LEFTMOST_BYTE_SHIFT;

			inWord = 0;

			for (i = 0; i < outOffset - inOffset; i++) {

				inWord |= (WORD)input[byteCount + i] << shift;

				shift = NEXT_BYTE_SHIFT(shift);

			}

		} else if (inOffset > outOffset) {

			/* Consumed some bytes in the second input word.  Copy the

			 * remainder to inWord.

			 */

			inWord = *pInWord++;

			inWord = inWord LSH invBufShift;

		} else {

			inWord = 0;

		}

	} else {

		/* output is word-aligned */

		if (inOffset) {

			/* Input is not word-aligned.  The first word load of input 

			 * will not produce a full word of input bytes, so one word

			 * must be pre-loaded.  The main loop below will load in the

			 * next input word and shift some of its bytes into inWord

			 * in order to create a full input word.  Note that the main

			 * loop must execute at least once because the input must

			 * be at least two words.

			 */

			unsigned int shift = LEFTMOST_BYTE_SHIFT;

			inWord = 0;

			for (i = 0; i < WORDSIZE - inOffset; i++) {

				inWord |= (WORD)input[i] << shift;

				shift = NEXT_BYTE_SHIFT(shift);

			}

			pInWord++;

		} else {

			/* Input is word-aligned.  The first word load of input 

			 * will produce a full word of input bytes, so nothing

			 * needs to be loaded here.

			 */

			inWord = 0;

		}

	}

	/*****************************************************************/

	/* Step 2: main loop                                             */

	/* At this point the output buffer is word-aligned.  Any unused  */

	/* bytes from above will be in inWord (shifted correctly).  If   */

	/* the input buffer is unaligned relative to the output buffer,  */

	/* shifting has to be done.                                      */

	/*****************************************************************/

	if (bufShift) {

		/* preloadedByteCount is the number of input bytes pre-loaded

		 * in inWord.

		 */

		unsigned int preloadedByteCount = bufShift/8;

		for (; inputLen >= preloadedByteCount + WORDSIZE;

		     inputLen -= WORDSIZE) {

			nextInWord = *pInWord++;

			inWord |= nextInWord RSH bufShift;

			nextInWord = nextInWord LSH invBufShift;

			ARCFOUR_NEXT_WORD();

			*pOutWord++ = inWord ^ streamWord;

			inWord = nextInWord;

		}

		if (inputLen == 0) {

			/* Nothing left to do. */

			cx->i = tmpi;

			cx->j = tmpj;

			return SECSuccess;

		}

		finalIn = (const unsigned char *)pInWord - preloadedByteCount;

	} else {

		for (; inputLen >= WORDSIZE; inputLen -= WORDSIZE) {

			inWord = *pInWord++;

			ARCFOUR_NEXT_WORD();

			*pOutWord++ = inWord ^ streamWord;

		}

		if (inputLen == 0) {

			/* Nothing left to do. */

			cx->i = tmpi;

			cx->j = tmpj;

			return SECSuccess;

		}

		finalIn = (const unsigned char *)pInWord;

	}

	/*****************************************************************/

	/* Step 3:                                                       */

	/* Do the remaining partial word of input one byte at a time.    */

	/*****************************************************************/

	finalOut = (unsigned char *)pOutWord;

	for (i = 0; i < inputLen; i++) {

		ARCFOUR_NEXT_BYTE();

		finalOut[i] = cx->S[t] ^ finalIn[i];

	}

	cx->i = tmpi;

	cx->j = tmpj;

	return SECSuccess;

}

#endif

#endif /* NSS_BEVAND_ARCFOUR */

SECStatus 

RC4_Encrypt(RC4Context *cx, unsigned char *output,

            unsigned int *outputLen, unsigned int maxOutputLen,

            const unsigned char *input, unsigned int inputLen)

{

	PORT_Assert(maxOutputLen >= inputLen);

	if (maxOutputLen < inputLen) {

		PORT_SetError(SEC_ERROR_OUTPUT_LEN);

		return SECFailure;

	}

#if defined(NSS_BEVAND_ARCFOUR)

	ARCFOUR(cx, inputLen, input, output);

        *outputLen = inputLen;

	return SECSuccess;

#elif defined( CONVERT_TO_WORDS )

	/* Convert the byte-stream to a word-stream */

	return rc4_wordconv(cx, output, outputLen, maxOutputLen, input, inputLen);

#else

	/* Operate on bytes, but unroll the main loop */

	return rc4_unrolled(cx, output, outputLen, maxOutputLen, input, inputLen);

#endif

}

SECStatus RC4_Decrypt(RC4Context *cx, unsigned char *output,

                      unsigned int *outputLen, unsigned int maxOutputLen,

                      const unsigned char *input, unsigned int inputLen)

{

	PORT_Assert(maxOutputLen >= inputLen);

	if (maxOutputLen < inputLen) {

		PORT_SetError(SEC_ERROR_OUTPUT_LEN);

		return SECFailure;

	}

	/* decrypt and encrypt are same operation. */

#if defined(NSS_BEVAND_ARCFOUR)

	ARCFOUR(cx, inputLen, input, output);

        *outputLen = inputLen;

	return SECSuccess;

#elif defined( CONVERT_TO_WORDS )

	/* Convert the byte-stream to a word-stream */

	return rc4_wordconv(cx, output, outputLen, maxOutputLen, input, inputLen);

#else

	/* Operate on bytes, but unroll the main loop */

	return rc4_unrolled(cx, output, outputLen, maxOutputLen, input, inputLen);

#endif

}

#undef CONVERT_TO_WORDS

#undef USE_WORD