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/*
* Copyright (C) 2018 Denys Vlasenko
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include "tls.h"
typedef uint8_t byte;
typedef uint32_t word32;
#define XMEMSET memset
#define XMEMCPY memcpy
#define TLS_MAJ 3
#define TLS_MIN 3
#define RECHDR_LEN 5
#define OUTBUF_PFX (8 + AES_BLOCK_SIZE)
void FAST_FUNC xorbuf(void* buf, const void* mask, unsigned count)
{
word32 i;
byte* b = (byte*)buf;
const byte* m = (const byte*)mask;
for (i = 0; i < count; i++)
b[i] ^= m[i];
}
/* wolfssl-3.15.3/wolfcrypt/src/aes.c */
static void FlattenSzInBits(byte* buf, word32 sz)
{
/* Multiply the sz by 8 */
word32 szHi = (sz >> (8*sizeof(sz) - 3));
sz <<= 3;
/* copy over the words of the sz into the destination buffer */
buf[0] = (szHi >> 24) & 0xff;
buf[1] = (szHi >> 16) & 0xff;
buf[2] = (szHi >> 8) & 0xff;
buf[3] = szHi & 0xff;
buf[4] = (sz >> 24) & 0xff;
buf[5] = (sz >> 16) & 0xff;
buf[6] = (sz >> 8) & 0xff;
buf[7] = sz & 0xff;
}
static void RIGHTSHIFTX(byte* x)
{
int i;
int carryOut = 0;
int carryIn = 0;
int borrow = x[15] & 0x01;
for (i = 0; i < AES_BLOCK_SIZE; i++) {
carryOut = x[i] & 0x01;
x[i] = (x[i] >> 1) | (carryIn ? 0x80 : 0);
carryIn = carryOut;
}
if (borrow) x[0] ^= 0xE1;
}
static void GMULT(byte* X, byte* Y)
{
byte Z[AES_BLOCK_SIZE];
byte V[AES_BLOCK_SIZE];
int i, j;
XMEMSET(Z, 0, AES_BLOCK_SIZE);
XMEMCPY(V, X, AES_BLOCK_SIZE);
for (i = 0; i < AES_BLOCK_SIZE; i++)
{
byte y = Y[i];
for (j = 0; j < 8; j++)
{
if (y & 0x80) {
xorbuf(Z, V, AES_BLOCK_SIZE);
}
RIGHTSHIFTX(V);
y = y << 1;
}
}
XMEMCPY(X, Z, AES_BLOCK_SIZE);
}
void FAST_FUNC aesgcm_GHASH(byte* h, const byte* a, unsigned aSz, const byte* c,
unsigned cSz, byte* s, unsigned sSz)
{
byte x[AES_BLOCK_SIZE];
byte scratch[AES_BLOCK_SIZE];
word32 blocks, partial;
//was: byte* h = aes->H;
XMEMSET(x, 0, AES_BLOCK_SIZE);
/* Hash in A, the Additional Authentication Data */
if (aSz != 0 && a != NULL) {
blocks = aSz / AES_BLOCK_SIZE;
partial = aSz % AES_BLOCK_SIZE;
while (blocks--) {
xorbuf(x, a, AES_BLOCK_SIZE);
GMULT(x, h);
a += AES_BLOCK_SIZE;
}
if (partial != 0) {
XMEMSET(scratch, 0, AES_BLOCK_SIZE);
XMEMCPY(scratch, a, partial);
xorbuf(x, scratch, AES_BLOCK_SIZE);
GMULT(x, h);
}
}
/* Hash in C, the Ciphertext */
if (cSz != 0 && c != NULL) {
blocks = cSz / AES_BLOCK_SIZE;
partial = cSz % AES_BLOCK_SIZE;
while (blocks--) {
xorbuf(x, c, AES_BLOCK_SIZE);
GMULT(x, h);
c += AES_BLOCK_SIZE;
}
if (partial != 0) {
XMEMSET(scratch, 0, AES_BLOCK_SIZE);
XMEMCPY(scratch, c, partial);
xorbuf(x, scratch, AES_BLOCK_SIZE);
GMULT(x, h);
}
}
/* Hash in the lengths of A and C in bits */
FlattenSzInBits(&scratch[0], aSz);
FlattenSzInBits(&scratch[8], cSz);
xorbuf(x, scratch, AES_BLOCK_SIZE);
GMULT(x, h);
/* Copy the result into s. */
XMEMCPY(s, x, sSz);
}
void FAST_FUNC aesgcm_setkey(uint8_t H[16], struct tls_aes *aes, const byte* key, unsigned len)
{
byte iv[AES_BLOCK_SIZE];
aes_setkey(aes, key, len);
memset(iv, 0, AES_BLOCK_SIZE);
aes_encrypt_one_block(aes, iv, H);
}
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