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/*-
* Copyright (c) 2004 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/time.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <machine/pcb.h>
#include <dev/random/randomdev.h>
#define RANDOM_BLOCK_SIZE 256
#define CIPHER_BLOCK_SIZE 16
static void random_nehemiah_init(void);
static void random_nehemiah_deinit(void);
static int random_nehemiah_read(void *, int);
struct random_systat random_nehemiah = {
.ident = "Hardware, VIA Nehemiah",
.init = random_nehemiah_init,
.deinit = random_nehemiah_deinit,
.read = random_nehemiah_read,
.write = (random_write_func_t *)random_null_func,
.reseed = (random_reseed_func_t *)random_null_func,
.seeded = 1,
};
union VIA_ACE_CW {
uint64_t raw;
struct {
u_int round_count : 4;
u_int algorithm_type : 3;
u_int key_generation_type : 1;
u_int intermediate : 1;
u_int decrypt : 1;
u_int key_size : 2;
u_int filler0 : 20;
u_int filler1 : 32;
u_int filler2 : 32;
u_int filler3 : 32;
} field;
};
/* The extra 7 is to allow an 8-byte write on the last byte of the
* arrays. The ACE wants the AES data 16-byte/128-bit aligned, and
* it _always_ writes n*64 bits. The RNG does not care about alignment,
* and it always writes n*32 bits or n*64 bits.
*/
static uint8_t key[CIPHER_BLOCK_SIZE+7] __aligned(16);
static uint8_t iv[CIPHER_BLOCK_SIZE+7] __aligned(16);
static uint8_t in[RANDOM_BLOCK_SIZE+7] __aligned(16);
static uint8_t out[RANDOM_BLOCK_SIZE+7] __aligned(16);
static union VIA_ACE_CW acw __aligned(16);
static struct fpu_kern_ctx *fpu_ctx_save;
static struct mtx random_nehemiah_mtx;
/* ARGSUSED */
static __inline size_t
VIA_RNG_store(void *buf)
{
#ifdef __GNUCLIKE_ASM
uint32_t retval = 0;
uint32_t rate = 0;
/* The .byte line is really VIA C3 "xstore" instruction */
__asm __volatile(
"movl $0,%%edx \n\t"
".byte 0x0f, 0xa7, 0xc0"
: "=a" (retval), "+d" (rate), "+D" (buf)
:
: "memory"
);
if (rate == 0)
return (retval&0x1f);
#endif
return (0);
}
/* ARGSUSED */
static __inline void
VIA_ACE_cbc(void *in, void *out, size_t count, void *key, union VIA_ACE_CW *cw, void *iv)
{
#ifdef __GNUCLIKE_ASM
/* The .byte line is really VIA C3 "xcrypt-cbc" instruction */
__asm __volatile(
"pushf \n\t"
"popf \n\t"
"rep \n\t"
".byte 0x0f, 0xa7, 0xc8"
: "+a" (iv), "+c" (count), "+D" (out), "+S" (in)
: "b" (key), "d" (cw)
: "cc", "memory"
);
#endif
}
static void
random_nehemiah_init(void)
{
acw.raw = 0ULL;
acw.field.round_count = 12;
mtx_init(&random_nehemiah_mtx, "random nehemiah", NULL, MTX_DEF);
fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
}
void
random_nehemiah_deinit(void)
{
fpu_kern_free_ctx(fpu_ctx_save);
mtx_destroy(&random_nehemiah_mtx);
}
static int
random_nehemiah_read(void *buf, int c)
{
int i, error;
size_t count, ret;
uint8_t *p;
mtx_lock(&random_nehemiah_mtx);
error = fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL);
if (error != 0) {
mtx_unlock(&random_nehemiah_mtx);
return (0);
}
/* Get a random AES key */
count = 0;
p = key;
do {
ret = VIA_RNG_store(p);
p += ret;
count += ret;
} while (count < CIPHER_BLOCK_SIZE);
/* Get a random AES IV */
count = 0;
p = iv;
do {
ret = VIA_RNG_store(p);
p += ret;
count += ret;
} while (count < CIPHER_BLOCK_SIZE);
/* Get a block of random bytes */
count = 0;
p = in;
do {
ret = VIA_RNG_store(p);
p += ret;
count += ret;
} while (count < RANDOM_BLOCK_SIZE);
/* This is a Davies-Meyer hash of the most paranoid variety; the
* key, IV and the data are all read directly from the hardware RNG.
* All of these are used precisely once.
*/
VIA_ACE_cbc(in, out, RANDOM_BLOCK_SIZE/CIPHER_BLOCK_SIZE,
key, &acw, iv);
for (i = 0; i < RANDOM_BLOCK_SIZE; i++)
out[i] ^= in[i];
c = MIN(RANDOM_BLOCK_SIZE, c);
memcpy(buf, out, (size_t)c);
fpu_kern_leave(curthread, fpu_ctx_save);
mtx_unlock(&random_nehemiah_mtx);
return (c);
}
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