proxmark3/common/mbedtls/havege.c
2021-05-14 14:07:59 +02:00

231 lines
8.7 KiB
C

/**
* \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* The HAVEGE RNG was designed by Andre Seznec in 2002.
*
* http://www.irisa.fr/caps/projects/hipsor/publi.php
*
* Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr
*/
#include "common.h"
#if defined(MBEDTLS_HAVEGE_C)
#include "mbedtls/havege.h"
#include "mbedtls/timing.h"
#include "mbedtls/platform_util.h"
#include <stdint.h>
#include <string.h>
/* ------------------------------------------------------------------------
* On average, one iteration accesses two 8-word blocks in the havege WALK
* table, and generates 16 words in the RES array.
*
* The data read in the WALK table is updated and permuted after each use.
* The result of the hardware clock counter read is used for this update.
*
* 25 conditional tests are present. The conditional tests are grouped in
* two nested groups of 12 conditional tests and 1 test that controls the
* permutation; on average, there should be 6 tests executed and 3 of them
* should be mispredicted.
* ------------------------------------------------------------------------
*/
#define SWAP(X,Y) { uint32_t *T = (X); (X) = (Y); (Y) = T; }
#define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
#define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1;
#define TST1_LEAVE U1++; }
#define TST2_LEAVE U2++; }
#define ONE_ITERATION \
\
PTEST = PT1 >> 20; \
\
TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \
\
TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \
\
PTX = (PT1 >> 18) & 7; \
PT1 &= 0x1FFF; \
PT2 &= 0x1FFF; \
CLK = (uint32_t) mbedtls_timing_hardclock(); \
\
i = 0; \
A = &WALK[PT1 ]; RES[i++] ^= *A; \
B = &WALK[PT2 ]; RES[i++] ^= *B; \
C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \
D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \
\
IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \
*A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \
*B = IN ^ U1; \
*C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \
*D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \
\
A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \
B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \
C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \
D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \
\
if( PTEST & 1 ) SWAP( A, C ); \
\
IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \
*A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \
*B = IN; CLK = (uint32_t) mbedtls_timing_hardclock(); \
*C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \
*D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \
\
A = &WALK[PT1 ^ 4]; \
B = &WALK[PT2 ^ 1]; \
\
PTEST = PT2 >> 1; \
\
PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \
PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \
PTY = (PT2 >> 10) & 7; \
\
TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \
\
TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \
\
C = &WALK[PT1 ^ 5]; \
D = &WALK[PT2 ^ 5]; \
\
RES[i++] ^= *A; \
RES[i++] ^= *B; \
RES[i++] ^= *C; \
RES[i++] ^= *D; \
\
IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \
*A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \
*B = IN ^ U2; \
*C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \
*D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \
\
A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \
B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \
C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \
D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \
\
IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \
*A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \
*B = IN; \
*C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \
*D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \
\
PT1 = ( RES[( i - 8 ) ^ PTX] ^ \
WALK[PT1 ^ PTX ^ 7] ) & (~1); \
PT1 ^= (PT2 ^ 0x10) & 0x10; \
\
for( n++, i = 0; i < 16; i++ ) \
hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i];
/*
* Entropy gathering function
*/
static void havege_fill(mbedtls_havege_state *hs) {
size_t n = 0;
size_t i;
uint32_t U1, U2, *A, *B, *C, *D;
uint32_t PT1, PT2, *WALK, RES[16];
uint32_t PTX, PTY, CLK, PTEST, IN;
WALK = hs->WALK;
PT1 = hs->PT1;
PT2 = hs->PT2;
PTX = U1 = 0;
PTY = U2 = 0;
(void)PTX;
memset(RES, 0, sizeof(RES));
while (n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4) {
ONE_ITERATION
ONE_ITERATION
ONE_ITERATION
ONE_ITERATION
}
hs->PT1 = PT1;
hs->PT2 = PT2;
hs->offset[0] = 0;
hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2;
}
/*
* HAVEGE initialization
*/
void mbedtls_havege_init(mbedtls_havege_state *hs) {
memset(hs, 0, sizeof(mbedtls_havege_state));
havege_fill(hs);
}
void mbedtls_havege_free(mbedtls_havege_state *hs) {
if (hs == NULL)
return;
mbedtls_platform_zeroize(hs, sizeof(mbedtls_havege_state));
}
/*
* HAVEGE rand function
*/
int mbedtls_havege_random(void *p_rng, unsigned char *buf, size_t len) {
uint32_t val;
size_t use_len;
mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng;
unsigned char *p = buf;
while (len > 0) {
use_len = len;
if (use_len > sizeof(val))
use_len = sizeof(val);
if (hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE)
havege_fill(hs);
val = hs->pool[hs->offset[0]++];
val ^= hs->pool[hs->offset[1]++];
memcpy(p, &val, use_len);
len -= use_len;
p += use_len;
}
return (0);
}
#endif /* MBEDTLS_HAVEGE_C */