/* 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 "blapii.h"
#include "blapit.h"
#include "gcm.h"
#include "ctr.h"
#include "secerr.h"
#include "prtypes.h"
#include "pkcs11t.h"
#include <limits.h>
/**************************************************************************
* First implement the Galois hash function of GCM (gcmHash) *
**************************************************************************/
#define GCM_HASH_LEN_LEN 8 /* gcm hash defines lengths to be 64 bits */
typedef struct gcmHashContextStr gcmHashContext;
static SECStatus gcmHash_InitContext(gcmHashContext *hash,
const unsigned char *H,
unsigned int blocksize);
static void gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit);
static SECStatus gcmHash_Update(gcmHashContext *ghash,
const unsigned char *buf, unsigned int len,
unsigned int blocksize);
static SECStatus gcmHash_Sync(gcmHashContext *ghash, unsigned int blocksize);
static SECStatus gcmHash_Final(gcmHashContext *gcm, unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
unsigned int blocksize);
static SECStatus gcmHash_Reset(gcmHashContext *ghash,
const unsigned char *inbuf,
unsigned int inbufLen, unsigned int blocksize);
/* compile time defines to select how the GF2 multiply is calculated.
* There are currently 2 algorithms implemented here: MPI and ALGORITHM_1.
*
* MPI uses the GF2m implemented in mpi to support GF2 ECC.
* ALGORITHM_1 is the Algorithm 1 in both NIST SP 800-38D and
* "The Galois/Counter Mode of Operation (GCM)", McGrew & Viega.
*/
#if !defined(GCM_USE_ALGORITHM_1) && !defined(GCM_USE_MPI)
#define GCM_USE_MPI 1 /* MPI is about 5x faster with the
* same or less complexity. It's possible to use
* tables to speed things up even more */
#endif
/* GCM defines the bit string to be LSB first, which is exactly
* opposite everyone else, including hardware. build array
* to reverse everything. */
static const unsigned char gcm_byte_rev[256] = {
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
};
#ifdef GCM_TRACE
#include <stdio.h>
#define GCM_TRACE_X(ghash,label) { \
unsigned char _X[MAX_BLOCK_SIZE]; int i; \
gcm_getX(ghash, _X, blocksize); \
printf(label,(ghash)->m); \
for (i=0; i < blocksize; i++) printf("%02x",_X[i]); \
printf("\n"); }
#define GCM_TRACE_BLOCK(label,buf,blocksize) {\
printf(label); \
for (i=0; i < blocksize; i++) printf("%02x",buf[i]); \
printf("\n"); }
#else
#define GCM_TRACE_X(ghash,label)
#define GCM_TRACE_BLOCK(label,buf,blocksize)
#endif
#ifdef GCM_USE_MPI
#ifdef GCM_USE_ALGORITHM_1
#error "Only define one of GCM_USE_MPI, GCM_USE_ALGORITHM_1"
#endif
/* use the MPI functions to calculate Xn = (Xn-1^C_i)*H mod poly */
#include "mpi.h"
#include "secmpi.h"
#include "mplogic.h"
#include "mp_gf2m.h"
/* state needed to handle GCM Hash function */
struct gcmHashContextStr {
mp_int H;
mp_int X;
mp_int C_i;
const unsigned int *poly;
unsigned char buffer[MAX_BLOCK_SIZE];
unsigned int bufLen;
int m; /* XXX what is m? */
unsigned char counterBuf[2*GCM_HASH_LEN_LEN];
PRUint64 cLen;
};
/* f = x^128 + x^7 + x^2 + x + 1 */
static const unsigned int poly_128[] = { 128, 7, 2, 1, 0 };
/* sigh, GCM defines the bit strings exactly backwards from everything else */
static void
gcm_reverse(unsigned char *target, const unsigned char *src,
unsigned int blocksize)
{
unsigned int i;
for (i=0; i < blocksize; i++) {
target[blocksize-i-1] = gcm_byte_rev[src[i]];
}
}
/* Initialize a gcmHashContext */
static SECStatus
gcmHash_InitContext(gcmHashContext *ghash, const unsigned char *H,
unsigned int blocksize)
{
mp_err err = MP_OKAY;
unsigned char H_rev[MAX_BLOCK_SIZE];
MP_DIGITS(&ghash->H) = 0;
MP_DIGITS(&ghash->X) = 0;
MP_DIGITS(&ghash->C_i) = 0;
CHECK_MPI_OK( mp_init(&ghash->H) );
CHECK_MPI_OK( mp_init(&ghash->X) );
CHECK_MPI_OK( mp_init(&ghash->C_i) );
mp_zero(&ghash->X);
gcm_reverse(H_rev, H, blocksize);
CHECK_MPI_OK( mp_read_unsigned_octets(&ghash->H, H_rev, blocksize) );
/* set the irreducible polynomial. Each blocksize has its own polynomial.
* for now only blocksize 16 (=128 bits) is defined */
switch (blocksize) {
case 16: /* 128 bits */
ghash->poly = poly_128;
break;
default:
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto cleanup;
}
ghash->cLen = 0;
ghash->bufLen = 0;
ghash->m = 0;
PORT_Memset(ghash->counterBuf, 0, sizeof(ghash->counterBuf));
return SECSuccess;
cleanup:
gcmHash_DestroyContext(ghash, PR_FALSE);
return SECFailure;
}
/* Destroy a HashContext (Note we zero the digits so this function
* is idempotent if called with freeit == PR_FALSE */
static void
gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit)
{
mp_clear(&ghash->H);
mp_clear(&ghash->X);
mp_clear(&ghash->C_i);
MP_DIGITS(&ghash->H) = 0;
MP_DIGITS(&ghash->X) = 0;
MP_DIGITS(&ghash->C_i) = 0;
if (freeit) {
PORT_Free(ghash);
}
}
static SECStatus
gcm_getX(gcmHashContext *ghash, unsigned char *T, unsigned int blocksize)
{
int len;
mp_err err;
unsigned char tmp_buf[MAX_BLOCK_SIZE];
unsigned char *X;
len = mp_unsigned_octet_size(&ghash->X);
if (len <= 0) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
X = tmp_buf;
PORT_Assert((unsigned int)len <= blocksize);
if ((unsigned int)len > blocksize) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
/* zero pad the result */
if (len != blocksize) {
PORT_Memset(X,0,blocksize-len);
X += blocksize-len;
}
err = mp_to_unsigned_octets(&ghash->X, X, len);
if (err < 0) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
gcm_reverse(T, tmp_buf, blocksize);
return SECSuccess;
}
static SECStatus
gcm_HashMult(gcmHashContext *ghash, const unsigned char *buf,
unsigned int count, unsigned int blocksize)
{
SECStatus rv = SECFailure;
mp_err err = MP_OKAY;
unsigned char tmp_buf[MAX_BLOCK_SIZE];
unsigned int i;
for (i=0; i < count; i++, buf += blocksize) {
ghash->m++;
gcm_reverse(tmp_buf, buf, blocksize);
CHECK_MPI_OK(mp_read_unsigned_octets(&ghash->C_i, tmp_buf, blocksize));
CHECK_MPI_OK(mp_badd(&ghash->X, &ghash->C_i, &ghash->C_i));
/*
* Looking to speed up GCM, this the the place to do it.
* There are two areas that can be exploited to speed up this code.
*
* 1) H is a constant in this multiply. We can precompute H * (0 - 255)
* at init time and this becomes an blockize xors of our table lookup.
*
* 2) poly is a constant for each blocksize. We can calculate the
* modulo reduction by a series of adds and shifts.
*
* For now we are after functionality, so we will go ahead and use
* the builtin bmulmod from mpi
*/
CHECK_MPI_OK(mp_bmulmod(&ghash->C_i, &ghash->H,
ghash->poly, &ghash->X));
GCM_TRACE_X(ghash, "X%d = ")
}
rv = SECSuccess;
cleanup:
if (rv != SECSuccess) {
MP_TO_SEC_ERROR(err);
}
return rv;
}
static void
gcm_zeroX(gcmHashContext *ghash)
{
mp_zero(&ghash->X);
ghash->m = 0;
}
#endif
#ifdef GCM_USE_ALGORITHM_1
/* use algorithm 1 of McGrew & Viega "The Galois/Counter Mode of Operation" */
#define GCM_ARRAY_SIZE (MAX_BLOCK_SIZE/sizeof(unsigned long))
struct gcmHashContextStr {
unsigned long H[GCM_ARRAY_SIZE];
unsigned long X[GCM_ARRAY_SIZE];
unsigned long R;
unsigned char buffer[MAX_BLOCK_SIZE];
unsigned int bufLen;
int m;
unsigned char counterBuf[2*GCM_HASH_LEN_LEN];
PRUint64 cLen;
};
static void
gcm_bytes_to_longs(unsigned long *l, const unsigned char *c, unsigned int len)
{
int i,j;
int array_size = len/sizeof(unsigned long);
PORT_Assert(len % sizeof(unsigned long) == 0);
for (i=0; i < array_size; i++) {
unsigned long tmp = 0;
int byte_offset = i * sizeof(unsigned long);
for (j=sizeof(unsigned long)-1; j >= 0; j--) {
tmp = (tmp << PR_BITS_PER_BYTE) | gcm_byte_rev[c[byte_offset+j]];
}
l[i] = tmp;
}
}
static void
gcm_longs_to_bytes(const unsigned long *l, unsigned char *c, unsigned int len)
{
int i,j;
int array_size = len/sizeof(unsigned long);
PORT_Assert(len % sizeof(unsigned long) == 0);
for (i=0; i < array_size; i++) {
unsigned long tmp = l[i];
int byte_offset = i * sizeof(unsigned long);
for (j=0; j < sizeof(unsigned long); j++) {
c[byte_offset+j] = gcm_byte_rev[tmp & 0xff];
tmp = (tmp >> PR_BITS_PER_BYTE);
}
}
}
/* Initialize a gcmHashContext */
static SECStatus
gcmHash_InitContext(gcmHashContext *ghash, const unsigned char *H,
unsigned int blocksize)
{
PORT_Memset(ghash->X, 0, sizeof(ghash->X));
PORT_Memset(ghash->H, 0, sizeof(ghash->H));
gcm_bytes_to_longs(ghash->H, H, blocksize);
/* set the irreducible polynomial. Each blocksize has its own polynommial
* for now only blocksize 16 (=128 bits) is defined */
switch (blocksize) {
case 16: /* 128 bits */
ghash->R = (unsigned long) 0x87; /* x^7 + x^2 + x +1 */
break;
default:
PORT_SetError(SEC_ERROR_INVALID_ARGS);
goto cleanup;
}
ghash->cLen = 0;
ghash->bufLen = 0;
ghash->m = 0;
PORT_Memset(ghash->counterBuf, 0, sizeof(ghash->counterBuf));
return SECSuccess;
cleanup:
return SECFailure;
}
/* Destroy a HashContext (Note we zero the digits so this function
* is idempotent if called with freeit == PR_FALSE */
static void
gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit)
{
if (freeit) {
PORT_Free(ghash);
}
}
static unsigned long
gcm_shift_one(unsigned long *t, unsigned int count)
{
unsigned long carry = 0;
unsigned long nextcarry = 0;
unsigned int i;
for (i=0; i < count; i++) {
nextcarry = t[i] >> ((sizeof(unsigned long)*PR_BITS_PER_BYTE)-1);
t[i] = (t[i] << 1) | carry;
carry = nextcarry;
}
return carry;
}
static SECStatus
gcm_getX(gcmHashContext *ghash, unsigned char *T, unsigned int blocksize)
{
gcm_longs_to_bytes(ghash->X, T, blocksize);
return SECSuccess;
}
#define GCM_XOR(t, s, len) \
for (l=0; l < len; l++) t[l] ^= s[l]
static SECStatus
gcm_HashMult(gcmHashContext *ghash, const unsigned char *buf,
unsigned int count, unsigned int blocksize)
{
unsigned long C_i[GCM_ARRAY_SIZE];
unsigned int arraysize = blocksize/sizeof(unsigned long);
unsigned int i, j, k, l;
for (i=0; i < count; i++, buf += blocksize) {
ghash->m++;
gcm_bytes_to_longs(C_i, buf, blocksize);
GCM_XOR(C_i, ghash->X, arraysize);
/* multiply X = C_i * H */
PORT_Memset(ghash->X, 0, sizeof(ghash->X));
for (j=0; j < arraysize; j++) {
unsigned long H = ghash->H[j];
for (k=0; k < sizeof(unsigned long)*PR_BITS_PER_BYTE; k++) {
if (H & 1) {
GCM_XOR(ghash->X, C_i, arraysize);
}
if (gcm_shift_one(C_i, arraysize)) {
C_i[0] = C_i[0] ^ ghash->R;
}
H = H >> 1;
}
}
GCM_TRACE_X(ghash, "X%d = ")
}
return SECSuccess;
}
static void
gcm_zeroX(gcmHashContext *ghash)
{
PORT_Memset(ghash->X, 0, sizeof(ghash->X));
ghash->m = 0;
}
#endif
/*
* implement GCM GHASH using the freebl GHASH function. The gcm_HashMult
* function always takes blocksize lengths of data. gcmHash_Update will
* format the data properly.
*/
static SECStatus
gcmHash_Update(gcmHashContext *ghash, const unsigned char *buf,
unsigned int len, unsigned int blocksize)
{
unsigned int blocks;
SECStatus rv;
ghash->cLen += (len*PR_BITS_PER_BYTE);
/* first deal with the current buffer of data. Try to fill it out so
* we can hash it */
if (ghash->bufLen) {
unsigned int needed = PR_MIN(len, blocksize - ghash->bufLen);
if (needed != 0) {
PORT_Memcpy(ghash->buffer+ghash->bufLen, buf, needed);
}
buf += needed;
len -= needed;
ghash->bufLen += needed;
if (len == 0) {
/* didn't add enough to hash the data, nothing more do do */
return SECSuccess;
}
PORT_Assert(ghash->bufLen == blocksize);
/* hash the buffer and clear it */
rv = gcm_HashMult(ghash, ghash->buffer, 1, blocksize);
PORT_Memset(ghash->buffer, 0, blocksize);
ghash->bufLen = 0;
if (rv != SECSuccess) {
return SECFailure;
}
}
/* now hash any full blocks remaining in the data stream */
blocks = len/blocksize;
if (blocks) {
rv = gcm_HashMult(ghash, buf, blocks, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
buf += blocks*blocksize;
len -= blocks*blocksize;
}
/* save any remainder in the buffer to be hashed with the next call */
if (len != 0) {
PORT_Memcpy(ghash->buffer, buf, len);
ghash->bufLen = len;
}
return SECSuccess;
}
/*
* write out any partial blocks zero padded through the GHASH engine,
* save the lengths for the final completion of the hash
*/
static SECStatus
gcmHash_Sync(gcmHashContext *ghash, unsigned int blocksize)
{
int i;
SECStatus rv;
/* copy the previous counter to the upper block */
PORT_Memcpy(ghash->counterBuf, &ghash->counterBuf[GCM_HASH_LEN_LEN],
GCM_HASH_LEN_LEN);
/* copy the current counter in the lower block */
for (i=0; i < GCM_HASH_LEN_LEN; i++) {
ghash->counterBuf[GCM_HASH_LEN_LEN+i] =
(ghash->cLen >> ((GCM_HASH_LEN_LEN-1-i)*PR_BITS_PER_BYTE)) & 0xff;
}
ghash->cLen = 0;
/* now zero fill the buffer and hash the last block */
if (ghash->bufLen) {
PORT_Memset(ghash->buffer+ghash->bufLen, 0, blocksize - ghash->bufLen);
rv = gcm_HashMult(ghash, ghash->buffer, 1, blocksize);
PORT_Memset(ghash->buffer, 0, blocksize);
ghash->bufLen = 0;
if (rv != SECSuccess) {
return SECFailure;
}
}
return SECSuccess;
}
/*
* This does the final sync, hashes the lengths, then returns
* "T", the hashed output.
*/
static SECStatus
gcmHash_Final(gcmHashContext *ghash, unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
unsigned int blocksize)
{
unsigned char T[MAX_BLOCK_SIZE];
SECStatus rv;
rv = gcmHash_Sync(ghash, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
rv = gcm_HashMult(ghash, ghash->counterBuf, (GCM_HASH_LEN_LEN*2)/blocksize,
blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
GCM_TRACE_X(ghash, "GHASH(H,A,C) = ")
rv = gcm_getX(ghash, T, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
if (maxout > blocksize) maxout = blocksize;
PORT_Memcpy(outbuf, T, maxout);
*outlen = maxout;
return SECSuccess;
}
SECStatus
gcmHash_Reset(gcmHashContext *ghash, const unsigned char *AAD,
unsigned int AADLen, unsigned int blocksize)
{
SECStatus rv;
ghash->cLen = 0;
PORT_Memset(ghash->counterBuf, 0, GCM_HASH_LEN_LEN*2);
ghash->bufLen = 0;
gcm_zeroX(ghash);
/* now kick things off by hashing the Additional Authenticated Data */
if (AADLen != 0) {
rv = gcmHash_Update(ghash, AAD, AADLen, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
rv = gcmHash_Sync(ghash, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
}
return SECSuccess;
}
/**************************************************************************
* Now implement the GCM using gcmHash and CTR *
**************************************************************************/
/* state to handle the full GCM operation (hash and counter) */
struct GCMContextStr {
gcmHashContext ghash_context;
CTRContext ctr_context;
unsigned long tagBits;
unsigned char tagKey[MAX_BLOCK_SIZE];
};
GCMContext *
GCM_CreateContext(void *context, freeblCipherFunc cipher,
const unsigned char *params, unsigned int blocksize)
{
GCMContext *gcm = NULL;
gcmHashContext *ghash;
unsigned char H[MAX_BLOCK_SIZE];
unsigned int tmp;
PRBool freeCtr = PR_FALSE;
PRBool freeHash = PR_FALSE;
const CK_GCM_PARAMS *gcmParams = (const CK_GCM_PARAMS *)params;
CK_AES_CTR_PARAMS ctrParams;
SECStatus rv;
if (blocksize > MAX_BLOCK_SIZE || blocksize > sizeof(ctrParams.cb)) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return NULL;
}
gcm = PORT_ZNew(GCMContext);
if (gcm == NULL) {
return NULL;
}
/* first fill in the ghash context */
ghash = &gcm->ghash_context;
PORT_Memset(H, 0, blocksize);
rv = (*cipher)(context, H, &tmp, blocksize, H, blocksize, blocksize);
if (rv != SECSuccess) {
goto loser;
}
rv = gcmHash_InitContext(ghash, H, blocksize);
if (rv != SECSuccess) {
goto loser;
}
freeHash = PR_TRUE;
/* fill in the Counter context */
ctrParams.ulCounterBits = 32;
PORT_Memset(ctrParams.cb, 0, sizeof(ctrParams.cb));
if ((blocksize == 16) && (gcmParams->ulIvLen == 12)) {
PORT_Memcpy(ctrParams.cb, gcmParams->pIv, gcmParams->ulIvLen);
ctrParams.cb[blocksize-1] = 1;
} else {
rv = gcmHash_Update(ghash, gcmParams->pIv, gcmParams->ulIvLen,
blocksize);
if (rv != SECSuccess) {
goto loser;
}
rv = gcmHash_Final(ghash, ctrParams.cb, &tmp, blocksize, blocksize);
if (rv != SECSuccess) {
goto loser;
}
}
rv = CTR_InitContext(&gcm->ctr_context, context, cipher,
(unsigned char *)&ctrParams, blocksize);
if (rv != SECSuccess) {
goto loser;
}
freeCtr = PR_TRUE;
/* fill in the gcm structure */
gcm->tagBits = gcmParams->ulTagBits; /* save for final step */
/* calculate the final tag key. NOTE: gcm->tagKey is zero to start with.
* if this assumption changes, we would need to explicitly clear it here */
rv = CTR_Update(&gcm->ctr_context, gcm->tagKey, &tmp, blocksize,
gcm->tagKey, blocksize, blocksize);
if (rv != SECSuccess) {
goto loser;
}
/* finally mix in the AAD data */
rv = gcmHash_Reset(ghash, gcmParams->pAAD, gcmParams->ulAADLen, blocksize);
if (rv != SECSuccess) {
goto loser;
}
return gcm;
loser:
if (freeCtr) {
CTR_DestroyContext(&gcm->ctr_context, PR_FALSE);
}
if (freeHash) {
gcmHash_DestroyContext(&gcm->ghash_context, PR_FALSE);
}
if (gcm) {
PORT_Free(gcm);
}
return NULL;
}
void
GCM_DestroyContext(GCMContext *gcm, PRBool freeit)
{
/* these two are statically allocated and will be freed when we free
* gcm. call their destroy functions to free up any locally
* allocated data (like mp_int's) */
CTR_DestroyContext(&gcm->ctr_context, PR_FALSE);
gcmHash_DestroyContext(&gcm->ghash_context, PR_FALSE);
if (freeit) {
PORT_Free(gcm);
}
}
static SECStatus
gcm_GetTag(GCMContext *gcm, unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
unsigned int blocksize)
{
unsigned int tagBytes;
unsigned int extra;
unsigned int i;
SECStatus rv;
tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
extra = tagBytes*PR_BITS_PER_BYTE - gcm->tagBits;
if (outbuf == NULL) {
*outlen = tagBytes;
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
if (maxout < tagBytes) {
*outlen = tagBytes;
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
return SECFailure;
}
maxout = tagBytes;
rv = gcmHash_Final(&gcm->ghash_context, outbuf, outlen, maxout, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
GCM_TRACE_BLOCK("GHASH=", outbuf, blocksize);
GCM_TRACE_BLOCK("Y0=", gcm->tagKey, blocksize);
for (i=0; i < *outlen; i++) {
outbuf[i] ^= gcm->tagKey[i];
}
GCM_TRACE_BLOCK("Y0=", gcm->tagKey, blocksize);
GCM_TRACE_BLOCK("T=", outbuf, blocksize);
/* mask off any extra bits we got */
if (extra) {
outbuf[tagBytes-1] &= ~((1 << extra)-1);
}
return SECSuccess;
}
/*
* See The Galois/Counter Mode of Operation, McGrew and Viega.
* GCM is basically counter mode with a specific initialization and
* built in macing operation.
*/
SECStatus
GCM_EncryptUpdate(GCMContext *gcm, unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
const unsigned char *inbuf, unsigned int inlen,
unsigned int blocksize)
{
SECStatus rv;
unsigned int tagBytes;
unsigned int len;
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;
}
rv = CTR_Update(&gcm->ctr_context, outbuf, outlen, maxout,
inbuf, inlen, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
rv = gcmHash_Update(&gcm->ghash_context, outbuf, *outlen, blocksize);
if (rv != SECSuccess) {
PORT_Memset(outbuf, 0, *outlen); /* clear the output buffer */
*outlen = 0;
return SECFailure;
}
rv = gcm_GetTag(gcm, outbuf + *outlen, &len, maxout - *outlen, blocksize);
if (rv != SECSuccess) {
PORT_Memset(outbuf, 0, *outlen); /* clear the output buffer */
*outlen = 0;
return SECFailure;
};
*outlen += len;
return SECSuccess;
}
/*
* See The Galois/Counter Mode of Operation, McGrew and Viega.
* GCM is basically counter mode with a specific initialization and
* built in macing operation. NOTE: the only difference between Encrypt
* and Decrypt is when we calculate the mac. That is because the mac must
* always be calculated on the cipher text, not the plain text, so for
* encrypt, we do the CTR update first and for decrypt we do the mac first.
*/
SECStatus
GCM_DecryptUpdate(GCMContext *gcm, unsigned char *outbuf,
unsigned int *outlen, unsigned int maxout,
const unsigned char *inbuf, unsigned int inlen,
unsigned int blocksize)
{
SECStatus rv;
unsigned int tagBytes;
unsigned char tag[MAX_BLOCK_SIZE];
const unsigned char *intag;
unsigned int len;
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;
/* verify the block */
rv = gcmHash_Update(&gcm->ghash_context, inbuf, inlen, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
rv = gcm_GetTag(gcm, tag, &len, blocksize, blocksize);
if (rv != SECSuccess) {
return SECFailure;
}
/* Don't decrypt if we can't authenticate the encrypted data!
* This assumes that if tagBits is not a multiple of 8, intag will
* preserve the masked off missing bits. */
if (NSS_SecureMemcmp(tag, intag, tagBytes) != 0) {
/* force a CKR_ENCRYPTED_DATA_INVALID error at in softoken */
PORT_SetError(SEC_ERROR_BAD_DATA);
return SECFailure;
}
/* finish the decryption */
return CTR_Update(&gcm->ctr_context, outbuf, outlen, maxout,
inbuf, inlen, blocksize);
}