michael@0: /*
michael@0:  * aeskeywrap.c - implement AES Key Wrap algorithm from RFC 3394
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifdef FREEBL_NO_DEPEND
michael@0: #include "stubs.h"
michael@0: #endif
michael@0: 
michael@0: #include "prcpucfg.h"
michael@0: #if defined(IS_LITTLE_ENDIAN) || defined(SHA_NO_LONG_LONG)
michael@0: #define BIG_ENDIAN_WITH_64_BIT_REGISTERS 0
michael@0: #else
michael@0: #define BIG_ENDIAN_WITH_64_BIT_REGISTERS 1
michael@0: #endif
michael@0: #include "prtypes.h"	/* for PRUintXX */
michael@0: #include "secport.h"	/* for PORT_XXX */
michael@0: #include "secerr.h"
michael@0: #include "blapi.h"	/* for AES_ functions */
michael@0: #include "rijndael.h"
michael@0: 
michael@0: struct AESKeyWrapContextStr {
michael@0:      unsigned char iv[AES_KEY_WRAP_IV_BYTES];
michael@0:      AESContext    aescx;
michael@0: };
michael@0: 
michael@0: /******************************************/
michael@0: /*
michael@0: ** AES key wrap algorithm, RFC 3394
michael@0: */
michael@0: 
michael@0: AESKeyWrapContext * 
michael@0: AESKeyWrap_AllocateContext(void)
michael@0: {
michael@0:     AESKeyWrapContext * cx = PORT_New(AESKeyWrapContext);
michael@0:     return cx;
michael@0: }
michael@0: 
michael@0: SECStatus  
michael@0: AESKeyWrap_InitContext(AESKeyWrapContext *cx, 
michael@0: 		       const unsigned char *key, 
michael@0: 		       unsigned int keylen,
michael@0: 		       const unsigned char *iv, 
michael@0: 		       int x1,
michael@0: 		       unsigned int encrypt,
michael@0: 		       unsigned int x2)
michael@0: {
michael@0:     SECStatus rv = SECFailure;
michael@0:     if (!cx) {
michael@0: 	PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0:     	return SECFailure;
michael@0:     }
michael@0:     if (iv) {
michael@0:     	memcpy(cx->iv, iv, sizeof cx->iv);
michael@0:     } else {
michael@0: 	memset(cx->iv, 0xA6, sizeof cx->iv);
michael@0:     }
michael@0:     rv = AES_InitContext(&cx->aescx, key, keylen, NULL, NSS_AES, encrypt, 
michael@0:                                   AES_BLOCK_SIZE);
michael@0:     return rv;
michael@0: }
michael@0: 
michael@0: /*
michael@0: ** Create a new AES context suitable for AES encryption/decryption.
michael@0: ** 	"key" raw key data
michael@0: ** 	"keylen" the number of bytes of key data (16, 24, or 32)
michael@0: */
michael@0: extern AESKeyWrapContext *
michael@0: AESKeyWrap_CreateContext(const unsigned char *key, const unsigned char *iv, 
michael@0:                          int encrypt, unsigned int keylen)
michael@0: {
michael@0:     SECStatus rv;
michael@0:     AESKeyWrapContext * cx = AESKeyWrap_AllocateContext();
michael@0:     if (!cx) 
michael@0:     	return NULL;	/* error is already set */
michael@0:     rv = AESKeyWrap_InitContext(cx, key, keylen, iv, 0, encrypt, 0);
michael@0:     if (rv != SECSuccess) {
michael@0:         PORT_Free(cx);
michael@0: 	cx = NULL; 	/* error should already be set */
michael@0:     }
michael@0:     return cx;
michael@0: }
michael@0: 
michael@0: /*
michael@0: ** Destroy a AES KeyWrap context.
michael@0: **	"cx" the context
michael@0: **	"freeit" if PR_TRUE then free the object as well as its sub-objects
michael@0: */
michael@0: extern void 
michael@0: AESKeyWrap_DestroyContext(AESKeyWrapContext *cx, PRBool freeit)
michael@0: {
michael@0:     if (cx) {
michael@0: 	AES_DestroyContext(&cx->aescx, PR_FALSE);
michael@0: /*	memset(cx, 0, sizeof *cx); */
michael@0: 	if (freeit)
michael@0: 	    PORT_Free(cx);
michael@0:     }
michael@0: }
michael@0: 
michael@0: #if !BIG_ENDIAN_WITH_64_BIT_REGISTERS
michael@0: 
michael@0: /* The AES Key Wrap algorithm has 64-bit values that are ALWAYS big-endian
michael@0: ** (Most significant byte first) in memory.  The only ALU operations done
michael@0: ** on them are increment, decrement, and XOR.  So, on little-endian CPUs,
michael@0: ** and on CPUs that lack 64-bit registers, these big-endian 64-bit operations
michael@0: ** are simulated in the following code.  This is thought to be faster and
michael@0: ** simpler than trying to convert the data to little-endian and back.
michael@0: */
michael@0: 
michael@0: /* A and T point to two 64-bit values stored most signficant byte first
michael@0: ** (big endian).  This function increments the 64-bit value T, and then
michael@0: ** XORs it with A, changing A.
michael@0: */ 
michael@0: static void
michael@0: increment_and_xor(unsigned char *A, unsigned char *T)
michael@0: {
michael@0:     if (!++T[7])
michael@0:         if (!++T[6])
michael@0: 	    if (!++T[5])
michael@0: 		if (!++T[4])
michael@0: 		    if (!++T[3])
michael@0: 			if (!++T[2])
michael@0: 			    if (!++T[1])
michael@0: 				 ++T[0];
michael@0: 
michael@0:     A[0] ^= T[0];
michael@0:     A[1] ^= T[1];
michael@0:     A[2] ^= T[2];
michael@0:     A[3] ^= T[3];
michael@0:     A[4] ^= T[4];
michael@0:     A[5] ^= T[5];
michael@0:     A[6] ^= T[6];
michael@0:     A[7] ^= T[7];
michael@0: }
michael@0: 
michael@0: /* A and T point to two 64-bit values stored most signficant byte first
michael@0: ** (big endian).  This function XORs T with A, giving a new A, then 
michael@0: ** decrements the 64-bit value T.
michael@0: */ 
michael@0: static void
michael@0: xor_and_decrement(unsigned char *A, unsigned char *T)
michael@0: {
michael@0:     A[0] ^= T[0];
michael@0:     A[1] ^= T[1];
michael@0:     A[2] ^= T[2];
michael@0:     A[3] ^= T[3];
michael@0:     A[4] ^= T[4];
michael@0:     A[5] ^= T[5];
michael@0:     A[6] ^= T[6];
michael@0:     A[7] ^= T[7];
michael@0: 
michael@0:     if (!T[7]--)
michael@0:         if (!T[6]--)
michael@0: 	    if (!T[5]--)
michael@0: 		if (!T[4]--)
michael@0: 		    if (!T[3]--)
michael@0: 			if (!T[2]--)
michael@0: 			    if (!T[1]--)
michael@0: 				 T[0]--;
michael@0: 
michael@0: }
michael@0: 
michael@0: /* Given an unsigned long t (in host byte order), store this value as a
michael@0: ** 64-bit big-endian value (MSB first) in *pt.
michael@0: */
michael@0: static void
michael@0: set_t(unsigned char *pt, unsigned long t)
michael@0: {
michael@0:     pt[7] = (unsigned char)t; t >>= 8;
michael@0:     pt[6] = (unsigned char)t; t >>= 8;
michael@0:     pt[5] = (unsigned char)t; t >>= 8;
michael@0:     pt[4] = (unsigned char)t; t >>= 8;
michael@0:     pt[3] = (unsigned char)t; t >>= 8;
michael@0:     pt[2] = (unsigned char)t; t >>= 8;
michael@0:     pt[1] = (unsigned char)t; t >>= 8;
michael@0:     pt[0] = (unsigned char)t;
michael@0: }
michael@0: 
michael@0: #endif
michael@0: 
michael@0: /*
michael@0: ** Perform AES key wrap.
michael@0: **	"cx" the context
michael@0: **	"output" the output buffer to store the encrypted data.
michael@0: **	"outputLen" how much data is stored in "output". Set by the routine
michael@0: **	   after some data is stored in output.
michael@0: **	"maxOutputLen" the maximum amount of data that can ever be
michael@0: **	   stored in "output"
michael@0: **	"input" the input data
michael@0: **	"inputLen" the amount of input data
michael@0: */
michael@0: extern SECStatus 
michael@0: AESKeyWrap_Encrypt(AESKeyWrapContext *cx, unsigned char *output,
michael@0:             unsigned int *pOutputLen, unsigned int maxOutputLen,
michael@0:             const unsigned char *input, unsigned int inputLen)
michael@0: {
michael@0:     PRUint64 *     R          = NULL;
michael@0:     unsigned int   nBlocks;
michael@0:     unsigned int   i, j;
michael@0:     unsigned int   aesLen     = AES_BLOCK_SIZE;
michael@0:     unsigned int   outLen     = inputLen + AES_KEY_WRAP_BLOCK_SIZE;
michael@0:     SECStatus      s          = SECFailure;
michael@0:     /* These PRUint64s are ALWAYS big endian, regardless of CPU orientation. */
michael@0:     PRUint64       t;
michael@0:     PRUint64       B[2];
michael@0: 
michael@0: #define A B[0]
michael@0: 
michael@0:     /* Check args */
michael@0:     if (!inputLen || 0 != inputLen % AES_KEY_WRAP_BLOCK_SIZE) {
michael@0: 	PORT_SetError(SEC_ERROR_INPUT_LEN);
michael@0: 	return s;
michael@0:     }
michael@0: #ifdef maybe
michael@0:     if (!output && pOutputLen) {	/* caller is asking for output size */
michael@0:     	*pOutputLen = outLen;
michael@0: 	return SECSuccess;
michael@0:     }
michael@0: #endif
michael@0:     if (maxOutputLen < outLen) {
michael@0: 	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
michael@0: 	return s;
michael@0:     }
michael@0:     if (cx == NULL || output == NULL || input == NULL) {
michael@0: 	PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0: 	return s;
michael@0:     }
michael@0:     nBlocks = inputLen / AES_KEY_WRAP_BLOCK_SIZE;
michael@0:     R = PORT_NewArray(PRUint64, nBlocks + 1);
michael@0:     if (!R)
michael@0:     	return s;	/* error is already set. */
michael@0:     /* 
michael@0:     ** 1) Initialize variables.
michael@0:     */
michael@0:     memcpy(&A, cx->iv, AES_KEY_WRAP_IV_BYTES);
michael@0:     memcpy(&R[1], input, inputLen);
michael@0: #if BIG_ENDIAN_WITH_64_BIT_REGISTERS
michael@0:     t = 0;
michael@0: #else
michael@0:     memset(&t, 0, sizeof t);
michael@0: #endif
michael@0:     /* 
michael@0:     ** 2) Calculate intermediate values.
michael@0:     */
michael@0:     for (j = 0; j < 6; ++j) {
michael@0:     	for (i = 1; i <= nBlocks; ++i) {
michael@0: 	    B[1] = R[i];
michael@0: 	    s = AES_Encrypt(&cx->aescx, (unsigned char *)B, &aesLen, 
michael@0: 	                    sizeof B,  (unsigned char *)B, sizeof B);
michael@0: 	    if (s != SECSuccess) 
michael@0: 	        break;
michael@0: 	    R[i] = B[1];
michael@0: 	    /* here, increment t and XOR A with t (in big endian order); */
michael@0: #if BIG_ENDIAN_WITH_64_BIT_REGISTERS
michael@0:    	    A ^= ++t; 
michael@0: #else
michael@0: 	    increment_and_xor((unsigned char *)&A, (unsigned char *)&t);
michael@0: #endif
michael@0: 	}
michael@0:     }
michael@0:     /* 
michael@0:     ** 3) Output the results.
michael@0:     */
michael@0:     if (s == SECSuccess) {
michael@0:     	R[0] =  A;
michael@0: 	memcpy(output, &R[0], outLen);
michael@0: 	if (pOutputLen)
michael@0: 	    *pOutputLen = outLen;
michael@0:     } else if (pOutputLen) {
michael@0:     	*pOutputLen = 0;
michael@0:     }
michael@0:     PORT_ZFree(R, outLen);
michael@0:     return s;
michael@0: }
michael@0: #undef A
michael@0: 
michael@0: /*
michael@0: ** Perform AES key unwrap.
michael@0: **	"cx" the context
michael@0: **	"output" the output buffer to store the decrypted data.
michael@0: **	"outputLen" how much data is stored in "output". Set by the routine
michael@0: **	   after some data is stored in output.
michael@0: **	"maxOutputLen" the maximum amount of data that can ever be
michael@0: **	   stored in "output"
michael@0: **	"input" the input data
michael@0: **	"inputLen" the amount of input data
michael@0: */
michael@0: extern SECStatus 
michael@0: AESKeyWrap_Decrypt(AESKeyWrapContext *cx, unsigned char *output,
michael@0:             unsigned int *pOutputLen, unsigned int maxOutputLen,
michael@0:             const unsigned char *input, unsigned int inputLen)
michael@0: {
michael@0:     PRUint64 *     R          = NULL;
michael@0:     unsigned int   nBlocks;
michael@0:     unsigned int   i, j;
michael@0:     unsigned int   aesLen     = AES_BLOCK_SIZE;
michael@0:     unsigned int   outLen;
michael@0:     SECStatus      s          = SECFailure;
michael@0:     /* These PRUint64s are ALWAYS big endian, regardless of CPU orientation. */
michael@0:     PRUint64       t;
michael@0:     PRUint64       B[2];
michael@0: 
michael@0: #define A B[0]
michael@0: 
michael@0:     /* Check args */
michael@0:     if (inputLen < 3 * AES_KEY_WRAP_BLOCK_SIZE || 
michael@0:         0 != inputLen % AES_KEY_WRAP_BLOCK_SIZE) {
michael@0: 	PORT_SetError(SEC_ERROR_INPUT_LEN);
michael@0: 	return s;
michael@0:     }
michael@0:     outLen = inputLen - AES_KEY_WRAP_BLOCK_SIZE;
michael@0: #ifdef maybe
michael@0:     if (!output && pOutputLen) {	/* caller is asking for output size */
michael@0:     	*pOutputLen = outLen;
michael@0: 	return SECSuccess;
michael@0:     }
michael@0: #endif
michael@0:     if (maxOutputLen < outLen) {
michael@0: 	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
michael@0: 	return s;
michael@0:     }
michael@0:     if (cx == NULL || output == NULL || input == NULL) {
michael@0: 	PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0: 	return s;
michael@0:     }
michael@0:     nBlocks = inputLen / AES_KEY_WRAP_BLOCK_SIZE;
michael@0:     R = PORT_NewArray(PRUint64, nBlocks);
michael@0:     if (!R)
michael@0:     	return s;	/* error is already set. */
michael@0:     nBlocks--;
michael@0:     /* 
michael@0:     ** 1) Initialize variables.
michael@0:     */
michael@0:     memcpy(&R[0], input, inputLen);
michael@0:     A = R[0];
michael@0: #if BIG_ENDIAN_WITH_64_BIT_REGISTERS
michael@0:     t = 6UL * nBlocks;
michael@0: #else
michael@0:     set_t((unsigned char *)&t, 6UL * nBlocks);
michael@0: #endif
michael@0:     /* 
michael@0:     ** 2) Calculate intermediate values.
michael@0:     */
michael@0:     for (j = 0; j < 6; ++j) {
michael@0:     	for (i = nBlocks; i; --i) {
michael@0: 	    /* here, XOR A with t (in big endian order) and decrement t; */
michael@0: #if BIG_ENDIAN_WITH_64_BIT_REGISTERS
michael@0:    	    A ^= t--; 
michael@0: #else
michael@0: 	    xor_and_decrement((unsigned char *)&A, (unsigned char *)&t);
michael@0: #endif
michael@0: 	    B[1] = R[i];
michael@0: 	    s = AES_Decrypt(&cx->aescx, (unsigned char *)B, &aesLen, 
michael@0: 	                    sizeof B,  (unsigned char *)B, sizeof B);
michael@0: 	    if (s != SECSuccess) 
michael@0: 	        break;
michael@0: 	    R[i] = B[1];
michael@0: 	}
michael@0:     }
michael@0:     /* 
michael@0:     ** 3) Output the results.
michael@0:     */
michael@0:     if (s == SECSuccess) {
michael@0: 	int bad = memcmp(&A, cx->iv, AES_KEY_WRAP_IV_BYTES);
michael@0: 	if (!bad) {
michael@0: 	    memcpy(output, &R[1], outLen);
michael@0: 	    if (pOutputLen)
michael@0: 		*pOutputLen = outLen;
michael@0: 	} else {
michael@0: 	    s = SECFailure;
michael@0: 	    PORT_SetError(SEC_ERROR_BAD_DATA);
michael@0: 	    if (pOutputLen) 
michael@0: 		*pOutputLen = 0;
michael@0:     	}
michael@0:     } else if (pOutputLen) {
michael@0:     	*pOutputLen = 0;
michael@0:     }
michael@0:     PORT_ZFree(R, inputLen);
michael@0:     return s;
michael@0: }
michael@0: #undef A