mirror of
https://github.com/Mbed-TLS/mbedtls.git
synced 2025-10-30 10:45:34 +03:00
227 lines
8.2 KiB
C
227 lines
8.2 KiB
C
/**
|
|
* \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
|
|
*
|
|
* Copyright The Mbed TLS Contributors
|
|
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
|
|
*/
|
|
/*
|
|
* 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 */
|