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trezor-firmware/embed/extmod/modtrezorutils/modtrezorutils.c

112 lines
3.7 KiB
C

/*
* Copyright (c) Jan Pochyla, SatoshiLabs
*
* Licensed under TREZOR License
* see LICENSE file for details
*/
#include "py/runtime.h"
#if MICROPY_PY_TREZORUTILS
#include <string.h>
#include "common.h"
/// def consteq(sec: bytes, pub: bytes) -> bool:
/// '''
/// Compares the private information in `sec` with public, user-provided
/// information in `pub`. Runs in constant time, corresponding to a length
/// of `pub`. Can access memory behind valid length of `sec`, caller is
/// expected to avoid any invalid memory access.
/// '''
STATIC mp_obj_t mod_trezorutils_consteq(mp_obj_t sec, mp_obj_t pub) {
mp_buffer_info_t secbuf;
mp_get_buffer_raise(sec, &secbuf, MP_BUFFER_READ);
mp_buffer_info_t pubbuf;
mp_get_buffer_raise(pub, &pubbuf, MP_BUFFER_READ);
size_t diff = secbuf.len - pubbuf.len;
for (size_t i = 0; i < pubbuf.len; i++) {
const uint8_t *s = (uint8_t *)secbuf.buf;
const uint8_t *p = (uint8_t *)pubbuf.buf;
diff |= s[i] - p[i];
}
if (diff == 0) {
return mp_const_true;
} else {
return mp_const_false;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorutils_consteq_obj, mod_trezorutils_consteq);
/// def memcpy(dst: bytearray, dst_ofs: int,
/// src: bytearray, src_ofs: int,
/// n: int) -> int:
/// '''
/// Copies at most `n` bytes from `src` at offset `src_ofs` to
/// `dst` at offset `dst_ofs`. Returns the number of actually
/// copied bytes.
/// '''
STATIC mp_obj_t mod_trezorutils_memcpy(size_t n_args, const mp_obj_t *args) {
mp_arg_check_num(n_args, 0, 5, 5, false);
mp_buffer_info_t dst;
mp_get_buffer_raise(args[0], &dst, MP_BUFFER_WRITE);
int dst_ofs = mp_obj_get_int(args[1]);
if (dst_ofs < 0) {
mp_raise_ValueError("Invalid dst offset (has to be >= 0)");
}
mp_buffer_info_t src;
mp_get_buffer_raise(args[2], &src, MP_BUFFER_READ);
int src_ofs = mp_obj_get_int(args[3]);
if (src_ofs < 0) {
mp_raise_ValueError("Invalid src offset (has to be >= 0)");
}
int n = mp_obj_get_int(args[4]);
if (n < 0) {
mp_raise_ValueError("Invalid byte count (has to be >= 0)");
}
size_t dst_rem = (dst_ofs < dst.len) ? dst.len - dst_ofs : 0;
size_t src_rem = (src_ofs < src.len) ? src.len - src_ofs : 0;
size_t ncpy = MIN(n, MIN(src_rem, dst_rem));
memmove(((char*)dst.buf) + dst_ofs, ((const char*)src.buf) + src_ofs, ncpy);
return mp_obj_new_int(ncpy);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorutils_memcpy_obj, 5, 5, mod_trezorutils_memcpy);
/// def halt(msg: str = None) -> None:
/// '''
/// Halts execution.
/// '''
STATIC mp_obj_t mod_trezorutils_halt(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t msg;
if (n_args > 0 && mp_get_buffer(args[0], &msg, MP_BUFFER_READ)) {
ensure(secfalse, msg.buf);
} else {
ensure(secfalse, "halt");
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorutils_halt_obj, 0, 1, mod_trezorutils_halt);
STATIC const mp_rom_map_elem_t mp_module_trezorutils_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_trezorutils) },
{ MP_ROM_QSTR(MP_QSTR_consteq), MP_ROM_PTR(&mod_trezorutils_consteq_obj) },
{ MP_ROM_QSTR(MP_QSTR_memcpy), MP_ROM_PTR(&mod_trezorutils_memcpy_obj) },
{ MP_ROM_QSTR(MP_QSTR_halt), MP_ROM_PTR(&mod_trezorutils_halt_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_trezorutils_globals, mp_module_trezorutils_globals_table);
const mp_obj_module_t mp_module_trezorutils = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t*)&mp_module_trezorutils_globals,
};
#endif // MICROPY_PY_TREZORUTILS