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trezor-firmware/firmware/protect.c
Jochen Hoenicke 286ee0525c PIN handling - constant time.
This diff contains three changes.
1. Make timing isPinCorrect independent of storage.pin, to avoid timing attacks
2. Only update failed PIN counter if the user entered a PIN.
   Of course, the fail counter is still incremented, before the PIN is checked.
3. Don't cache the PIN, but just the fact that the PIN was entered.  The
   cache should be in sync with storage.pin in any case.
2015-02-22 15:42:31 +01:00

235 lines
5.9 KiB
C

/*
* This file is part of the TREZOR project.
*
* Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "protect.h"
#include "storage.h"
#include "messages.h"
#include "usb.h"
#include "oled.h"
#include "buttons.h"
#include "pinmatrix.h"
#include "fsm.h"
#include "layout2.h"
#include "util.h"
#include "debug.h"
bool protectAbortedByInitialize = false;
bool protectButton(ButtonRequestType type, bool confirm_only)
{
ButtonRequest resp;
bool result = false;
bool acked = false;
#if DEBUG_LINK
bool debug_decided = false;
#endif
memset(&resp, 0, sizeof(ButtonRequest));
resp.has_code = true;
resp.code = type;
usbTiny(1);
msg_write(MessageType_MessageType_ButtonRequest, &resp);
for (;;) {
usbPoll();
// check for ButtonAck
if (msg_tiny_id == MessageType_MessageType_ButtonAck) {
msg_tiny_id = 0xFFFF;
acked = true;
}
// button acked - check buttons
if (acked) {
delay(100000);
buttonUpdate();
if (button.YesUp) {
result = true;
break;
}
if (!confirm_only && button.NoUp) {
result = false;
break;
}
}
// check for Cancel / Initialize
if (msg_tiny_id == MessageType_MessageType_Cancel || msg_tiny_id == MessageType_MessageType_Initialize) {
if (msg_tiny_id == MessageType_MessageType_Initialize) {
protectAbortedByInitialize = true;
}
msg_tiny_id = 0xFFFF;
result = false;
break;
}
#if DEBUG_LINK
// check DebugLink
if (msg_tiny_id == MessageType_MessageType_DebugLinkDecision) {
msg_tiny_id = 0xFFFF;
DebugLinkDecision *dld = (DebugLinkDecision *)msg_tiny;
result = dld->yes_no;
debug_decided = true;
}
if (acked && debug_decided) {
break;
}
if (msg_tiny_id == MessageType_MessageType_DebugLinkGetState) {
msg_tiny_id = 0xFFFF;
fsm_msgDebugLinkGetState((DebugLinkGetState *)msg_tiny);
}
#endif
}
usbTiny(0);
return result;
}
const char *requestPin(PinMatrixRequestType type, const char *text)
{
PinMatrixRequest resp;
memset(&resp, 0, sizeof(PinMatrixRequest));
resp.has_type = true;
resp.type = type;
usbTiny(1);
msg_write(MessageType_MessageType_PinMatrixRequest, &resp);
pinmatrix_start(text);
for (;;) {
usbPoll();
if (msg_tiny_id == MessageType_MessageType_PinMatrixAck) {
msg_tiny_id = 0xFFFF;
PinMatrixAck *pma = (PinMatrixAck *)msg_tiny;
pinmatrix_done(pma->pin); // convert via pinmatrix
usbTiny(0);
return pma->pin;
}
if (msg_tiny_id == MessageType_MessageType_Cancel || msg_tiny_id == MessageType_MessageType_Initialize) {
pinmatrix_done(0);
if (msg_tiny_id == MessageType_MessageType_Initialize) {
protectAbortedByInitialize = true;
}
msg_tiny_id = 0xFFFF;
usbTiny(0);
return 0;
}
#if DEBUG_LINK
if (msg_tiny_id == MessageType_MessageType_DebugLinkGetState) {
msg_tiny_id = 0xFFFF;
fsm_msgDebugLinkGetState((DebugLinkGetState *)msg_tiny);
}
#endif
}
}
bool protectPin(bool use_cached)
{
if (!storage.has_pin || strlen(storage.pin) == 0 || (use_cached && session_isPinCached())) {
return true;
}
uint32_t fails = storage_getPinFails();
if (fails) {
if (fails > 2) {
layoutDialogSwipe(DIALOG_ICON_INFO, NULL, NULL, NULL, "Wrong PIN entered", NULL, "Please wait ...", NULL, NULL, NULL);
}
uint32_t wait;
wait = (fails < 32) ? (1u << fails) : 0xFFFFFFFF;
while (--wait > 0) {
delay(10000000);
}
}
const char *pin;
pin = requestPin(PinMatrixRequestType_PinMatrixRequestType_Current, "Please enter current PIN:");
if (!pin) {
fsm_sendFailure(FailureType_Failure_PinCancelled, "PIN Cancelled");
return false;
}
storage_increasePinFails();
bool increase_failed = (fails >= storage_getPinFails());
if (storage_isPinCorrect(pin) && !increase_failed) {
session_cachePin();
storage_resetPinFails();
return true;
} else {
fsm_sendFailure(FailureType_Failure_PinInvalid, "Invalid PIN");
return false;
}
}
bool protectChangePin(void)
{
const char *pin;
char pin1[17], pin2[17];
pin = requestPin(PinMatrixRequestType_PinMatrixRequestType_NewFirst, "Please enter new PIN:");
if (!pin) {
return false;
}
strlcpy(pin1, pin, sizeof(pin1));
pin = requestPin(PinMatrixRequestType_PinMatrixRequestType_NewSecond, "Please re-enter new PIN:");
if (!pin) {
return false;
}
strlcpy(pin2, pin, sizeof(pin2));
if (strcmp(pin1, pin2) == 0) {
storage_setPin(pin1);
return true;
} else {
return false;
}
}
bool protectPassphrase(void)
{
if (!storage.has_passphrase_protection || !storage.passphrase_protection || session_isPassphraseCached()) {
return true;
}
PassphraseRequest resp;
memset(&resp, 0, sizeof(PassphraseRequest));
usbTiny(1);
msg_write(MessageType_MessageType_PassphraseRequest, &resp);
layoutDialogSwipe(DIALOG_ICON_INFO, NULL, NULL, NULL, "Please enter your", "passphrase using", "the computer's", "keyboard.", NULL, NULL);
bool result;
for (;;) {
usbPoll();
if (msg_tiny_id == MessageType_MessageType_PassphraseAck) {
msg_tiny_id = 0xFFFF;
PassphraseAck *ppa = (PassphraseAck *)msg_tiny;
session_cachePassphrase(ppa->passphrase);
result = true;
break;
}
if (msg_tiny_id == MessageType_MessageType_Cancel || msg_tiny_id == MessageType_MessageType_Initialize) {
if (msg_tiny_id == MessageType_MessageType_Initialize) {
protectAbortedByInitialize = true;
}
msg_tiny_id = 0xFFFF;
result = false;
break;
}
}
usbTiny(0);
layoutHome();
return result;
}