/*
* Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see bearssl_block.h */
void
br_aes_ct64_ctrcbc_init(br_aes_ct64_ctrcbc_keys *ctx,
const void *key, size_t len)
{
ctx->vtable = &br_aes_ct64_ctrcbc_vtable;
ctx->num_rounds = br_aes_ct64_keysched(ctx->skey, key, len);
}
static void
xorbuf(void *dst, const void *src, size_t len)
{
unsigned char *d;
const unsigned char *s;
d = dst;
s = src;
while (len -- > 0) {
*d ++ ^= *s ++;
}
}
/* see bearssl_block.h */
void
br_aes_ct64_ctrcbc_ctr(const br_aes_ct64_ctrcbc_keys *ctx,
void *ctr, void *data, size_t len)
{
unsigned char *buf;
unsigned char *ivbuf;
uint32_t iv0, iv1, iv2, iv3;
uint64_t sk_exp[120];
br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
/*
* We keep the counter as four 32-bit values, with big-endian
* convention, because that's what is expected for purposes of
* incrementing the counter value.
*/
ivbuf = ctr;
iv0 = br_dec32be(ivbuf + 0);
iv1 = br_dec32be(ivbuf + 4);
iv2 = br_dec32be(ivbuf + 8);
iv3 = br_dec32be(ivbuf + 12);
buf = data;
while (len > 0) {
uint64_t q[8];
uint32_t w[16];
unsigned char tmp[64];
int i, j;
/*
* The bitslice implementation expects values in
* little-endian convention, so we have to byteswap them.
*/
j = (len >= 64) ? 16 : (int)(len >> 2);
for (i = 0; i < j; i += 4) {
uint32_t carry;
w[i + 0] = br_swap32(iv0);
w[i + 1] = br_swap32(iv1);
w[i + 2] = br_swap32(iv2);
w[i + 3] = br_swap32(iv3);
iv3 ++;
carry = ~(iv3 | -iv3) >> 31;
iv2 += carry;
carry &= -(~(iv2 | -iv2) >> 31);
iv1 += carry;
carry &= -(~(iv1 | -iv1) >> 31);
iv0 += carry;
}
memset(w + i, 0, (16 - i) * sizeof(uint32_t));
for (i = 0; i < 4; i ++) {
br_aes_ct64_interleave_in(
&q[i], &q[i + 4], w + (i << 2));
}
br_aes_ct64_ortho(q);
br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
br_aes_ct64_ortho(q);
for (i = 0; i < 4; i ++) {
br_aes_ct64_interleave_out(
w + (i << 2), q[i], q[i + 4]);
}
br_range_enc32le(tmp, w, 16);
if (len <= 64) {
xorbuf(buf, tmp, len);
break;
}
xorbuf(buf, tmp, 64);
buf += 64;
len -= 64;
}
br_enc32be(ivbuf + 0, iv0);
br_enc32be(ivbuf + 4, iv1);
br_enc32be(ivbuf + 8, iv2);
br_enc32be(ivbuf + 12, iv3);
}
/* see bearssl_block.h */
void
br_aes_ct64_ctrcbc_mac(const br_aes_ct64_ctrcbc_keys *ctx,
void *cbcmac, const void *data, size_t len)
{
const unsigned char *buf;
uint32_t cm0, cm1, cm2, cm3;
uint64_t q[8];
uint64_t sk_exp[120];
br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
cm0 = br_dec32le((unsigned char *)cbcmac + 0);
cm1 = br_dec32le((unsigned char *)cbcmac + 4);
cm2 = br_dec32le((unsigned char *)cbcmac + 8);
cm3 = br_dec32le((unsigned char *)cbcmac + 12);
buf = data;
memset(q, 0, sizeof q);
while (len > 0) {
uint32_t w[4];
w[0] = cm0 ^ br_dec32le(buf + 0);
w[1] = cm1 ^ br_dec32le(buf + 4);
w[2] = cm2 ^ br_dec32le(buf + 8);
w[3] = cm3 ^ br_dec32le(buf + 12);
br_aes_ct64_interleave_in(&q[0], &q[4], w);
br_aes_ct64_ortho(q);
br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
br_aes_ct64_ortho(q);
br_aes_ct64_interleave_out(w, q[0], q[4]);
cm0 = w[0];
cm1 = w[1];
cm2 = w[2];
cm3 = w[3];
buf += 16;
len -= 16;
}
br_enc32le((unsigned char *)cbcmac + 0, cm0);
br_enc32le((unsigned char *)cbcmac + 4, cm1);
br_enc32le((unsigned char *)cbcmac + 8, cm2);
br_enc32le((unsigned char *)cbcmac + 12, cm3);
}
/* see bearssl_block.h */
void
br_aes_ct64_ctrcbc_encrypt(const br_aes_ct64_ctrcbc_keys *ctx,
void *ctr, void *cbcmac, void *data, size_t len)
{
/*
* When encrypting, the CBC-MAC processing must be lagging by
* one block, since it operates on the encrypted values, so
* it must wait for that encryption to complete.
*/
unsigned char *buf;
unsigned char *ivbuf;
uint32_t iv0, iv1, iv2, iv3;
uint32_t cm0, cm1, cm2, cm3;
uint64_t sk_exp[120];
uint64_t q[8];
int first_iter;
br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
/*
* We keep the counter as four 32-bit values, with big-endian
* convention, because that's what is expected for purposes of
* incrementing the counter value.
*/
ivbuf = ctr;
iv0 = br_dec32be(ivbuf + 0);
iv1 = br_dec32be(ivbuf + 4);
iv2 = br_dec32be(ivbuf + 8);
iv3 = br_dec32be(ivbuf + 12);
/*
* The current CBC-MAC value is kept in little-endian convention.
*/
cm0 = br_dec32le((unsigned char *)cbcmac + 0);
cm1 = br_dec32le((unsigned char *)cbcmac + 4);
cm2 = br_dec32le((unsigned char *)cbcmac + 8);
cm3 = br_dec32le((unsigned char *)cbcmac + 12);
buf = data;
first_iter = 1;
memset(q, 0, sizeof q);
while (len > 0) {
uint32_t w[8], carry;
/*
* The bitslice implementation expects values in
* little-endian convention, so we have to byteswap them.
*/
w[0] = br_swap32(iv0);
w[1] = br_swap32(iv1);
w[2] = br_swap32(iv2);
w[3] = br_swap32(iv3);
iv3 ++;
carry = ~(iv3 | -iv3) >> 31;
iv2 += carry;
carry &= -(~(iv2 | -iv2) >> 31);
iv1 += carry;
carry &= -(~(iv1 | -iv1) >> 31);
iv0 += carry;
/*
* The block for CBC-MAC.
*/
w[4] = cm0;
w[5] = cm1;
w[6] = cm2;
w[7] = cm3;
br_aes_ct64_interleave_in(&q[0], &q[4], w);
br_aes_ct64_interleave_in(&q[1], &q[5], w + 4);
br_aes_ct64_ortho(q);
br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
br_aes_ct64_ortho(q);
br_aes_ct64_interleave_out(w, q[0], q[4]);
br_aes_ct64_interleave_out(w + 4, q[1], q[5]);
/*
* We do the XOR with the plaintext in 32-bit registers,
* so that the value are available for CBC-MAC processing
* as well.
*/
w[0] ^= br_dec32le(buf + 0);
w[1] ^= br_dec32le(buf + 4);
w[2] ^= br_dec32le(buf + 8);
w[3] ^= br_dec32le(buf + 12);
br_enc32le(buf + 0, w[0]);
br_enc32le(buf + 4, w[1]);
br_enc32le(buf + 8, w[2]);
br_enc32le(buf + 12, w[3]);
buf += 16;
len -= 16;
/*
* We set the cm* values to the block to encrypt in the
* next iteration.
*/
if (first_iter) {
first_iter = 0;
cm0 ^= w[0];
cm1 ^= w[1];
cm2 ^= w[2];
cm3 ^= w[3];
} else {
cm0 = w[0] ^ w[4];
cm1 = w[1] ^ w[5];
cm2 = w[2] ^ w[6];
cm3 = w[3] ^ w[7];
}
/*
* If this was the last iteration, then compute the
* extra block encryption to complete CBC-MAC.
*/
if (len == 0) {
w[0] = cm0;
w[1] = cm1;
w[2] = cm2;
w[3] = cm3;
br_aes_ct64_interleave_in(&q[0], &q[4], w);
br_aes_ct64_ortho(q);
br_aes_ct64_bitslice_encrypt(
ctx->num_rounds, sk_exp, q);
br_aes_ct64_ortho(q);
br_aes_ct64_interleave_out(w, q[0], q[4]);
cm0 = w[0];
cm1 = w[1];
cm2 = w[2];
cm3 = w[3];
break;
}
}
br_enc32be(ivbuf + 0, iv0);
br_enc32be(ivbuf + 4, iv1);
br_enc32be(ivbuf + 8, iv2);
br_enc32be(ivbuf + 12, iv3);
br_enc32le((unsigned char *)cbcmac + 0, cm0);
br_enc32le((unsigned char *)cbcmac + 4, cm1);
br_enc32le((unsigned char *)cbcmac + 8, cm2);
br_enc32le((unsigned char *)cbcmac + 12, cm3);
}
/* see bearssl_block.h */
void
br_aes_ct64_ctrcbc_decrypt(const br_aes_ct64_ctrcbc_keys *ctx,
void *ctr, void *cbcmac, void *data, size_t len)
{
unsigned char *buf;
unsigned char *ivbuf;
uint32_t iv0, iv1, iv2, iv3;
uint32_t cm0, cm1, cm2, cm3;
uint64_t sk_exp[120];
uint64_t q[8];
br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
/*
* We keep the counter as four 32-bit values, with big-endian
* convention, because that's what is expected for purposes of
* incrementing the counter value.
*/
ivbuf = ctr;
iv0 = br_dec32be(ivbuf + 0);
iv1 = br_dec32be(ivbuf + 4);
iv2 = br_dec32be(ivbuf + 8);
iv3 = br_dec32be(ivbuf + 12);
/*
* The current CBC-MAC value is kept in little-endian convention.
*/
cm0 = br_dec32le((unsigned char *)cbcmac + 0);
cm1 = br_dec32le((unsigned char *)cbcmac + 4);
cm2 = br_dec32le((unsigned char *)cbcmac + 8);
cm3 = br_dec32le((unsigned char *)cbcmac + 12);
buf = data;
memset(q, 0, sizeof q);
while (len > 0) {
uint32_t w[8], carry;
unsigned char tmp[16];
/*
* The bitslice implementation expects values in
* little-endian convention, so we have to byteswap them.
*/
w[0] = br_swap32(iv0);
w[1] = br_swap32(iv1);
w[2] = br_swap32(iv2);
w[3] = br_swap32(iv3);
iv3 ++;
carry = ~(iv3 | -iv3) >> 31;
iv2 += carry;
carry &= -(~(iv2 | -iv2) >> 31);
iv1 += carry;
carry &= -(~(iv1 | -iv1) >> 31);
iv0 += carry;
/*
* The block for CBC-MAC.
*/
w[4] = cm0 ^ br_dec32le(buf + 0);
w[5] = cm1 ^ br_dec32le(buf + 4);
w[6] = cm2 ^ br_dec32le(buf + 8);
w[7] = cm3 ^ br_dec32le(buf + 12);
br_aes_ct64_interleave_in(&q[0], &q[4], w);
br_aes_ct64_interleave_in(&q[1], &q[5], w + 4);
br_aes_ct64_ortho(q);
br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
br_aes_ct64_ortho(q);
br_aes_ct64_interleave_out(w, q[0], q[4]);
br_aes_ct64_interleave_out(w + 4, q[1], q[5]);
br_enc32le(tmp + 0, w[0]);
br_enc32le(tmp + 4, w[1]);
br_enc32le(tmp + 8, w[2]);
br_enc32le(tmp + 12, w[3]);
xorbuf(buf, tmp, 16);
cm0 = w[4];
cm1 = w[5];
cm2 = w[6];
cm3 = w[7];
buf += 16;
len -= 16;
}
br_enc32be(ivbuf + 0, iv0);
br_enc32be(ivbuf + 4, iv1);
br_enc32be(ivbuf + 8, iv2);
br_enc32be(ivbuf + 12, iv3);
br_enc32le((unsigned char *)cbcmac + 0, cm0);
br_enc32le((unsigned char *)cbcmac + 4, cm1);
br_enc32le((unsigned char *)cbcmac + 8, cm2);
br_enc32le((unsigned char *)cbcmac + 12, cm3);
}
/* see bearssl_block.h */
const br_block_ctrcbc_class br_aes_ct64_ctrcbc_vtable = {
sizeof(br_aes_ct64_ctrcbc_keys),
16,
4,
(void (*)(const br_block_ctrcbc_class **, const void *, size_t))
&br_aes_ct64_ctrcbc_init,
(void (*)(const br_block_ctrcbc_class *const *,
void *, void *, void *, size_t))
&br_aes_ct64_ctrcbc_encrypt,
(void (*)(const br_block_ctrcbc_class *const *,
void *, void *, void *, size_t))
&br_aes_ct64_ctrcbc_decrypt,
(void (*)(const br_block_ctrcbc_class *const *,
void *, void *, size_t))
&br_aes_ct64_ctrcbc_ctr,
(void (*)(const br_block_ctrcbc_class *const *,
void *, const void *, size_t))
&br_aes_ct64_ctrcbc_mac
};