mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-24 16:38:15 +00:00
113 lines
3.1 KiB
C
113 lines
3.1 KiB
C
/**
|
|
* Copyright (c) SatoshiLabs
|
|
*
|
|
* 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 <assert.h>
|
|
#include <stdatomic.h>
|
|
#include <stdbool.h>
|
|
|
|
#include "memzero.h"
|
|
#include "rand.h"
|
|
#include "zkp_context.h"
|
|
|
|
#include "vendor/secp256k1-zkp/include/secp256k1.h"
|
|
|
|
static uint8_t context_buffer[SECP256K1_CONTEXT_SIZE];
|
|
static secp256k1_context *context;
|
|
static volatile atomic_flag locked;
|
|
|
|
// returns 0 on success
|
|
int secp256k1_context_writable_randomize(secp256k1_context *context_writable) {
|
|
uint8_t seed[32] = {0};
|
|
random_buffer(seed, sizeof(seed));
|
|
int returned = secp256k1_context_randomize(context_writable, seed);
|
|
memzero(seed, sizeof(seed));
|
|
|
|
if (returned != 1) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
bool zkp_context_is_initialized(void) { return context != NULL; }
|
|
|
|
// returns 0 on success
|
|
int zkp_context_init(void) {
|
|
assert(context == NULL);
|
|
|
|
const unsigned int context_flags =
|
|
SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY;
|
|
|
|
const size_t context_size =
|
|
secp256k1_context_preallocated_size(context_flags);
|
|
// Assert the context is as small as possible
|
|
assert(context_size == SECP256K1_CONTEXT_SIZE);
|
|
if (context_size == 0 || context_size > SECP256K1_CONTEXT_SIZE) {
|
|
return 1;
|
|
}
|
|
|
|
context =
|
|
secp256k1_context_preallocated_create(context_buffer, context_flags);
|
|
if (context == NULL) {
|
|
return 1;
|
|
}
|
|
|
|
secp256k1_context_writable_randomize(context);
|
|
|
|
atomic_flag_clear(&locked);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void zkp_context_destroy(void) {
|
|
assert(context != NULL);
|
|
|
|
secp256k1_context_preallocated_destroy(context);
|
|
memzero(context_buffer, sizeof(context_buffer));
|
|
atomic_flag_clear(&locked);
|
|
context = NULL;
|
|
}
|
|
|
|
const secp256k1_context *zkp_context_get_read_only(void) {
|
|
assert(context != NULL);
|
|
|
|
return context;
|
|
}
|
|
|
|
// returns NULL if context cannot be acquired
|
|
secp256k1_context *zkp_context_acquire_writable(void) {
|
|
assert(context != NULL);
|
|
|
|
// We don't expect the context to be used by multiple threads
|
|
if (atomic_flag_test_and_set(&locked)) {
|
|
return NULL;
|
|
}
|
|
|
|
return context;
|
|
}
|
|
|
|
void zkp_context_release_writable(void) {
|
|
assert(context != NULL);
|
|
|
|
atomic_flag_clear(&locked);
|
|
}
|