SECStatus intel_AES_GCM_DecryptUpdate(intel_AES_GCMContext *gcm,
unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
const unsigned char *inbuf, unsigned int inlen,
unsigned int blocksize)
{
unsigned int tagBytes;
unsigned char T[AES_BLOCK_SIZE];
const unsigned char *intag;
tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
/* get the authentication block */
if (inlen < tagBytes) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return SECFailure;
}
inlen -= tagBytes;
intag = inbuf + inlen;
if (maxout < inlen) {
*outlen = inlen;
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
intel_aes_gcmDEC(
inbuf,
outbuf,
gcm,
inlen);
gcm->Mlen += inlen;
intel_aes_gcmTAG(
gcm->Htbl,
gcm->T,
gcm->Mlen,
gcm->Alen,
gcm->X0,
T);
if (NSS_SecureMemcmp(T, intag, tagBytes) != 0) {
memset(outbuf, 0, inlen);
*outlen = 0;
/* force a CKR_ENCRYPTED_DATA_INVALID error at in softoken */
PORT_SetError(SEC_ERROR_BAD_DATA);
return SECFailure;
}
*outlen = inlen;
return SECSuccess;
}
SECStatus intel_AES_GCM_EncryptUpdate(intel_AES_GCMContext *gcm,
unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
const unsigned char *inbuf, unsigned int inlen,
unsigned int blocksize)
{
unsigned int tagBytes;
unsigned char T[AES_BLOCK_SIZE];
int j;
tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
if (UINT_MAX - inlen < tagBytes) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
return SECFailure;
}
if (maxout < inlen + tagBytes) {
*outlen = inlen + tagBytes;
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
intel_aes_gcmENC(
inbuf,
outbuf,
gcm,
inlen);
gcm->Mlen += inlen;
intel_aes_gcmTAG(
gcm->Htbl,
gcm->T,
gcm->Mlen,
gcm->Alen,
gcm->X0,
T);
*outlen = inlen + tagBytes;
for(j=0; j<tagBytes; j++)
{
outbuf[inlen+j] = T[j];
}
return SECSuccess;
}
intel_AES_GCMContext *intel_AES_GCM_CreateContext(void *context,
freeblCipherFunc cipher,
const unsigned char *params,
unsigned int blocksize)
{
intel_AES_GCMContext *gcm = NULL;
AESContext *aes = (AESContext*)context;
const CK_GCM_PARAMS *gcmParams = (const CK_GCM_PARAMS *)params;
unsigned char buff[AES_BLOCK_SIZE]; /* aux buffer */
int IV_whole_len = gcmParams->ulIvLen&(~0xf);
int IV_remainder_len = gcmParams->ulIvLen&0xf;
int AAD_whole_len = gcmParams->ulAADLen&(~0xf);
int AAD_remainder_len = gcmParams->ulAADLen&0xf;
__m128i BSWAP_MASK = _mm_setr_epi8(15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0);
__m128i ONE = _mm_set_epi32(0,0,0,1);
unsigned int j;
SECStatus rv;
if (blocksize != AES_BLOCK_SIZE) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return NULL;
}
gcm = PORT_ZNew(intel_AES_GCMContext);
if (gcm == NULL) {
return NULL;
}
/* initialize context fields */
gcm->aes_context = aes;
gcm->tagBits = gcmParams->ulTagBits;
gcm->Alen = 0;
gcm->Mlen = 0;
/* first prepare H and its derivatives for ghash */
intel_aes_gcmINIT(gcm->Htbl, (unsigned char*)aes->expandedKey, aes->Nr);
/* Initial TAG value is zero*/
_mm_storeu_si128((__m128i*)gcm->T, _mm_setzero_si128());
_mm_storeu_si128((__m128i*)gcm->X0, _mm_setzero_si128());
/* Init the counter */
if(gcmParams->ulIvLen == 12) {
_mm_storeu_si128((__m128i*)gcm->CTR, _mm_setr_epi32(((unsigned int*)gcmParams->pIv)[0], ((unsigned int*)gcmParams->pIv)[1], ((unsigned int*)gcmParams->pIv)[2], 0x01000000));
} else {
/* If IV size is not 96 bits, then the initial counter value is GHASH of the IV */
intel_aes_gcmAAD(gcm->Htbl, gcmParams->pIv, IV_whole_len, gcm->T);
/* Partial block */
if(IV_remainder_len) {
PORT_Memset(buff, 0, AES_BLOCK_SIZE);
PORT_Memcpy(buff, gcmParams->pIv + IV_whole_len, IV_remainder_len);
intel_aes_gcmAAD(gcm->Htbl, buff, AES_BLOCK_SIZE, gcm->T);
}
intel_aes_gcmTAG
(
gcm->Htbl,
gcm->T,
gcmParams->ulIvLen,
0,
gcm->X0,
gcm->CTR
);
/* TAG should be zero again */
_mm_storeu_si128((__m128i*)gcm->T, _mm_setzero_si128());
}
/* Encrypt the initial counter, will be used to encrypt the GHASH value, in the end */
rv = (*cipher)(context, gcm->X0, &j, AES_BLOCK_SIZE, gcm->CTR, AES_BLOCK_SIZE, AES_BLOCK_SIZE);
if (rv != SECSuccess) {
goto loser;
}
/* Promote the counter by 1 */
_mm_storeu_si128((__m128i*)gcm->CTR, _mm_shuffle_epi8(_mm_add_epi32(ONE, _mm_shuffle_epi8(_mm_loadu_si128((__m128i*)gcm->CTR), BSWAP_MASK)), BSWAP_MASK));
/* Now hash AAD - it would actually make sense to seperate the context creation from the AAD,
* because that would allow to reuse the H, which only changes when the AES key changes,
* and not every package, like the IV and AAD */
intel_aes_gcmAAD(gcm->Htbl, gcmParams->pAAD, AAD_whole_len, gcm->T);
if(AAD_remainder_len) {
PORT_Memset(buff, 0, AES_BLOCK_SIZE);
PORT_Memcpy(buff, gcmParams->pAAD + AAD_whole_len, AAD_remainder_len);
intel_aes_gcmAAD(gcm->Htbl, buff, AES_BLOCK_SIZE, gcm->T);
}
gcm->Alen += gcmParams->ulAADLen;
return gcm;
loser:
if (gcm) {
PORT_Free(gcm);
}
return NULL;
}
