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trezor-firmware/legacy/firmware/recovery.c

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/*
* This file is part of the Trezor project, https://trezor.io/
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*
* Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
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* Copyright (C) 2016 Jochen Hoenicke <hoenicke@gmail.com>
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*
* 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 "recovery.h"
#include <ctype.h>
#include "bip39.h"
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#include "config.h"
#include "fsm.h"
#include "gettext.h"
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#include "layout2.h"
#include "memzero.h"
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#include "messages.h"
#include "messages.pb.h"
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#include "oled.h"
#include "protect.h"
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#include "recovery-table.h"
#include "rng.h"
#include "usb.h"
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/* number of words expected in the new seed */
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static uint32_t word_count;
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/* recovery mode */
static enum {
RECOVERY_NONE = 0, // recovery not in progress
RECOVERY_SCRAMBLED = 1, // standard recovery by scrambled plain text words
RECOVERY_MATRIX = 2, // advanced recovery by matrix entry
} recovery_mode = RECOVERY_NONE;
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/* True if we should not write anything back to config
* (can be used for testing seed for correctness).
*/
static bool dry_run;
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/* True if we should check that seed corresponds to bip39.
*/
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static bool enforce_wordlist;
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/* For scrambled recovery Trezor may ask for faked words if
* seed is short. This contains the fake word.
*/
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static char fake_word[12];
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/* Word position in the seed that we are currently asking for.
* This is 0 if we ask for a fake word. Only for scrambled recovery.
*/
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static uint32_t word_pos;
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/* Scrambled recovery: How many words has the user already entered.
* Matrix recovery: How many digits has the user already entered.
*/
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static uint32_t word_index;
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/* Order in which we ask for the words. It holds that
* word_order[word_index] == word_pos. Only for scrambled recovery.
*/
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static char word_order[24];
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/* The recovered seed. This is filled during the recovery process.
*/
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static char words[24][12];
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/* The "pincode" of the current word. This is basically the "pin"
* that the user would have entered for the current word if the words
* were displayed in alphabetical order. Note that it is base 9, not
* base 10. Only for matrix recovery.
*/
static uint16_t word_pincode;
/* The pinmatrix currently displayed on screen.
* Only for matrix recovery.
*/
static uint8_t word_matrix[9];
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/* The words are stored in two tables.
*
* The low bits of the first table (TABLE1) store the index into the
* second table, for each of the 81 choices for the first two levels
* of the matrix. The final entry points to the final entry of the
* second table. The difference TABLE1(idx+1)-TABLE1(idx) gives the
* number of choices for the third level. The value
* TABLE2(TABLE1(idx)) gives the index of the first word in the range
* and TABLE2(TABLE1(idx+1))-1 gives the index of the last word.
*
* The low bits of the second table (TABLE2) store the index into the
* word list for each of the choices for the first three levels. The
* final entry stores the value 2048 (number of bip39 words). table.
* The difference TABLE2(idx+1)-TABLE2(idx) gives the number of
* choices for the last level. The value TABLE2(idx) gives the index
* of the first word in the range and TABLE2(idx)-1 gives the index of
* the last word.
*
* The high bits in each table is the "prefix length", i.e. the number
* of significant letters for the corresponding choice. There is no
* prefix length or table for the very first level, as the prefix length
* is always one and there are always nine choices on the second level.
*/
#define MASK_IDX(x) ((x) & 0xfff)
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#define TABLE1(x) MASK_IDX(word_table1[x])
#define TABLE2(x) MASK_IDX(word_table2[x])
/* Helper function to format a two digit number.
* Parameter dest is buffer containing the string. It should already
* start with "##th". The number is written in place.
* Parameter number gives the number that we should format.
*/
static void format_number(char *dest, int number) {
if (number < 10) {
dest[0] = ' ';
} else {
dest[0] = '0' + number / 10;
}
dest[1] = '0' + number % 10;
if (number == 1 || number == 21) {
dest[2] = 's';
dest[3] = 't';
} else if (number == 2 || number == 22) {
dest[2] = 'n';
dest[3] = 'd';
} else if (number == 3 || number == 23) {
dest[2] = 'r';
dest[3] = 'd';
}
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}
/* Send a request for a new word/matrix code to the PC.
*/
static void recovery_request(void) {
WordRequest resp = {0};
memzero(&resp, sizeof(WordRequest));
if (recovery_mode == RECOVERY_SCRAMBLED) {
resp.type = WordRequestType_WordRequestType_Plain;
} else if (word_index % 4 == 3) {
resp.type = WordRequestType_WordRequestType_Matrix6;
} else {
resp.type = WordRequestType_WordRequestType_Matrix9;
}
msg_write(MessageType_MessageType_WordRequest, &resp);
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}
/* Called when the last word was entered.
* Check mnemonic and send success/failure.
*/
static void recovery_done(void) {
char new_mnemonic[MAX_MNEMONIC_LEN + 1] = {0};
strlcpy(new_mnemonic, words[0], sizeof(new_mnemonic));
for (uint32_t i = 1; i < word_count; i++) {
strlcat(new_mnemonic, " ", sizeof(new_mnemonic));
strlcat(new_mnemonic, words[i], sizeof(new_mnemonic));
}
if (!enforce_wordlist || mnemonic_check(new_mnemonic)) {
// New mnemonic is valid.
if (!dry_run) {
// Update mnemonic on config.
if (config_setMnemonic(new_mnemonic)) {
if (!enforce_wordlist) {
// not enforcing => mark config as imported
config_setImported(true);
}
fsm_sendSuccess(_("Device recovered"));
} else {
fsm_sendFailure(FailureType_Failure_ProcessError,
_("Failed to store mnemonic"));
}
memzero(new_mnemonic, sizeof(new_mnemonic));
} else {
// Inform the user about new mnemonic correctness (as well as whether it
// is the same as the current one).
bool match =
(config_isInitialized() && config_containsMnemonic(new_mnemonic));
memzero(new_mnemonic, sizeof(new_mnemonic));
if (match) {
layoutDialog(&bmp_icon_ok, NULL, _("Confirm"), NULL,
_("The seed is valid"), _("and MATCHES"),
_("the one in the device."), NULL, NULL, NULL);
protectButton(ButtonRequestType_ButtonRequest_Other, true);
fsm_sendSuccess(
_("The seed is valid and matches the one in the device"));
} else {
layoutDialog(&bmp_icon_error, NULL, _("Confirm"), NULL,
_("The seed is valid"), _("but does NOT MATCH"),
_("the one in the device."), NULL, NULL, NULL);
protectButton(ButtonRequestType_ButtonRequest_Other, true);
fsm_sendFailure(
FailureType_Failure_DataError,
_("The seed is valid but does not match the one in the device"));
}
}
} else {
// New mnemonic is invalid.
memzero(new_mnemonic, sizeof(new_mnemonic));
if (!dry_run) {
session_clear(true);
} else {
layoutDialog(&bmp_icon_error, NULL, _("Confirm"), NULL, _("The seed is"),
_("INVALID!"), NULL, NULL, NULL, NULL);
protectButton(ButtonRequestType_ButtonRequest_Other, true);
}
fsm_sendFailure(FailureType_Failure_DataError,
_("Invalid seed, are words in correct order?"));
}
memzero(words, sizeof(words));
word_pincode = 0;
recovery_mode = RECOVERY_NONE;
layoutHome();
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}
/* Helper function for matrix recovery:
* Formats a string describing the word range from first to last where
* prefixlen gives the number of characters in first and last that are
* significant, i.e. the word before first or the word after last differ
* exactly at the prefixlen-th character.
*
* Invariants:
* memcmp("first - 1", first, prefixlen) != 0
* memcmp(last, "last + 1", prefixlen) != 0
* first[prefixlen-2] == last[prefixlen-2] except for range WI-Z.
*/
static void add_choice(char choice[12], int prefixlen, const char *first,
const char *last) {
// assert 1 <= prefixlen <= 4
char *dest = choice;
for (int i = 0; i < prefixlen; i++) {
*dest++ = toupper((int)first[i]);
}
if (first[0] != last[0]) {
/* special case WI-Z; also used for T-Z, etc. */
*dest++ = '-';
*dest++ = toupper((int)last[0]);
} else if (last[prefixlen - 1] == first[prefixlen - 1]) {
/* single prefix */
} else if (prefixlen < 3) {
/* AB-AC, etc. */
*dest++ = '-';
for (int i = 0; i < prefixlen; i++) {
*dest++ = toupper((int)last[i]);
}
} else {
/* RE[A-M] etc. */
/* remove last and replace with space */
dest[-1] = ' ';
if (first[prefixlen - 1]) {
/* handle special case: CAN[-D] */
*dest++ = toupper((int)first[prefixlen - 1]);
}
*dest++ = '-';
*dest++ = toupper((int)last[prefixlen - 1]);
}
*dest++ = 0;
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}
/* Helper function for matrix recovery:
* Display the recovery matrix given in choices. If twoColumn is set
* use 2x3 layout, otherwise 3x3 layout. Also generates a random
* scrambling and stores it in word_matrix.
*/
static void display_choices(bool twoColumn, char choices[9][12], int num) {
const int nColumns = twoColumn ? 2 : 3;
const int displayedChoices = nColumns * 3;
for (int i = 0; i < displayedChoices; i++) {
word_matrix[i] = i;
}
/* scramble matrix */
random_permute((char *)word_matrix, displayedChoices);
if (word_index % 4 == 0) {
char desc[] = "##th word";
int nr = (word_index / 4) + 1;
format_number(desc, nr);
layoutDialogSwipe(&bmp_icon_info, NULL, NULL, NULL, _("Please enter the"),
(nr < 10 ? desc + 1 : desc), _("of your mnemonic"), NULL,
NULL, NULL);
} else {
oledBox(0, 27, 127, 63, false);
}
for (int row = 0; row < 3; row++) {
int y = 55 - row * 11;
for (int col = 0; col < nColumns; col++) {
int x = twoColumn ? 64 * col + 32 : 42 * col + 22;
int choice = word_matrix[nColumns * row + col];
const char *text = choice < num ? choices[choice] : "-";
oledDrawString(x - oledStringWidth(text, FONT_STANDARD) / 2, y, text,
FONT_STANDARD);
if (twoColumn) {
oledInvert(x - 32 + 1, y - 1, x - 32 + 63 - 1, y + 8);
} else {
oledInvert(x - 22 + 1, y - 1, x - 22 + 41 - 1, y + 8);
}
}
}
oledRefresh();
/* avoid picking out of range numbers */
for (int i = 0; i < displayedChoices; i++) {
if (word_matrix[i] >= num) word_matrix[i] = 0;
}
/* two column layout: middle column = right column */
if (twoColumn) {
static const uint8_t twolayout[9] = {0, 1, 1, 2, 3, 3, 4, 5, 5};
for (int i = 8; i >= 2; i--) {
word_matrix[i] = word_matrix[twolayout[i]];
}
}
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}
/* Helper function for matrix recovery:
* Generates a new matrix and requests the next pin.
*/
static void next_matrix(void) {
char word_choices[9][12] = {0};
uint32_t idx = 0, num = 0;
bool last = (word_index % 4) == 3;
/* Build the matrix:
* num: number of choices
* word_choices[][]: the strings containing the choices
*/
switch (word_index % 4) {
case 3:
/* last level: show up to six words */
/* idx: index in table2 for the entered choice. */
/* first: the first word. */
/* num: the number of words to choose from. */
idx = TABLE1(word_pincode / 9) + word_pincode % 9;
const uint32_t first = TABLE2(idx);
num = TABLE2(idx + 1) - first;
for (uint32_t i = 0; i < num; i++) {
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strlcpy(word_choices[i], mnemonic_get_word(first + i),
sizeof(word_choices[i]));
}
break;
case 2:
/* third level: show up to nine ranges (using table2) */
/* idx: first index in table2 corresponding to pin code. */
/* num: the number of choices. */
idx = TABLE1(word_pincode);
num = TABLE1(word_pincode + 1) - idx;
for (uint32_t i = 0; i < num; i++) {
add_choice(word_choices[i], (word_table2[idx + i] >> 12),
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mnemonic_get_word(TABLE2(idx + i)),
mnemonic_get_word(TABLE2(idx + i + 1) - 1));
}
break;
case 1:
/* second level: exactly nine ranges (using table1) */
/* idx: first index in table1 corresponding to pin code. */
/* num: the number of choices. */
idx = word_pincode * 9;
num = 9;
for (uint32_t i = 0; i < num; i++) {
add_choice(word_choices[i], (word_table1[idx + i] >> 12),
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mnemonic_get_word(TABLE2(TABLE1(idx + i))),
mnemonic_get_word(TABLE2(TABLE1(idx + i + 1)) - 1));
}
break;
case 0:
/* first level: exactly nine ranges */
/* num: the number of choices. */
num = 9;
for (uint32_t i = 0; i < num; i++) {
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add_choice(word_choices[i], 1, mnemonic_get_word(TABLE2(TABLE1(9 * i))),
mnemonic_get_word(TABLE2(TABLE1(9 * (i + 1))) - 1));
}
break;
}
display_choices(last, word_choices, num);
recovery_request();
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}
/* Function called when a digit was entered by user.
* digit: ascii code of the entered digit ('1'-'9') or
* '\x08' for backspace.
*/
static void recovery_digit(const char digit) {
if (digit == 8) {
/* backspace: undo */
if ((word_index % 4) == 0) {
/* undo complete word */
if (word_index > 0) word_index -= 4;
} else {
word_index--;
word_pincode /= 9;
}
next_matrix();
return;
}
if (digit < '1' || digit > '9') {
recovery_request();
return;
}
int choice = word_matrix[digit - '1'];
if ((word_index % 4) == 3) {
/* received final word */
/* Mark the chosen word for 250 ms */
int y = 54 - ((digit - '1') / 3) * 11;
int x = 64 * (((digit - '1') % 3) > 0);
oledInvert(x + 1, y, x + 62, y + 9);
oledRefresh();
usbTiny(1);
waitAndProcessUSBRequests(250);
usbTiny(0);
/* index of the chosen word */
int idx = TABLE2(TABLE1(word_pincode / 9) + (word_pincode % 9)) + choice;
uint32_t widx = word_index / 4;
word_pincode = 0;
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strlcpy(words[widx], mnemonic_get_word(idx), sizeof(words[widx]));
if (widx + 1 == word_count) {
recovery_done();
return;
}
/* next word */
} else {
word_pincode = word_pincode * 9 + choice;
}
word_index++;
next_matrix();
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}
/* Helper function for scrambled recovery:
* Ask the user for the next word.
*/
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void next_word(void) {
layoutLast = layoutDialogSwipe;
layoutSwipe();
oledDrawStringCenter(OLED_WIDTH / 2, 8, _("Please enter"), FONT_STANDARD);
word_pos = word_order[word_index];
if (word_pos == 0) {
strlcpy(fake_word, mnemonic_get_word(random_uniform(BIP39_WORD_COUNT)),
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sizeof(fake_word));
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oledDrawStringCenter(OLED_WIDTH / 2, 24, fake_word,
FONT_FIXED | FONT_DOUBLE);
} else {
fake_word[0] = 0;
char desc[] = "the ##th word";
format_number(desc + 4, word_pos);
oledDrawStringCenter(OLED_WIDTH / 2, 24, desc, FONT_FIXED | FONT_DOUBLE);
}
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oledDrawStringCenter(OLED_WIDTH / 2, 48, _("on your computer"),
FONT_STANDARD);
// 35 is the maximum pixels used for a pixel row ("the 21st word")
oledSCA(24 - 2, 24 + 15 + 2, 35);
oledInvert(0, 24 - 2, OLED_WIDTH - 1, 24 + 15 + 2);
oledRefresh();
recovery_request();
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}
void recovery_init(uint32_t _word_count, bool passphrase_protection,
bool pin_protection, const char *language, const char *label,
bool _enforce_wordlist, uint32_t input_method,
uint32_t u2f_counter, bool _dry_run) {
if (_word_count != 12 && _word_count != 18 && _word_count != 24) return;
recovery_mode = RECOVERY_NONE;
word_pincode = 0;
word_index = 0;
word_count = _word_count;
enforce_wordlist = _enforce_wordlist;
dry_run = _dry_run;
if (!dry_run) {
layoutDialogSwipe(&bmp_icon_question, _("Cancel"), _("Confirm"), NULL,
_("Do you really want to"), _("recover the device?"),
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NULL, _("By continuing you"), _("agree to trezor.io/tos"),
NULL);
if (!protectButton(ButtonRequestType_ButtonRequest_ProtectCall, false)) {
fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
layoutHome();
return;
}
}
if (!dry_run) {
if (pin_protection && !protectChangePin(false)) {
layoutHome();
return;
}
config_setPassphraseProtection(passphrase_protection);
config_setLanguage(language);
config_setLabel(label);
config_setU2FCounter(u2f_counter);
}
// Prefer matrix recovery if the host supports it.
if ((input_method & RecoveryDeviceInputMethod_Matrix) != 0) {
recovery_mode = RECOVERY_MATRIX;
next_matrix();
} else {
for (uint32_t i = 0; i < word_count; i++) {
word_order[i] = i + 1;
}
for (uint32_t i = word_count; i < 24; i++) {
word_order[i] = 0;
}
random_permute(word_order, 24);
recovery_mode = RECOVERY_SCRAMBLED;
next_word();
}
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}
static void recovery_scrambledword(const char *word) {
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int index = -1;
if (enforce_wordlist) { // check if word is valid
index = mnemonic_find_word(word);
if (index < 0) { // not found
if (!dry_run) {
session_clear(true);
}
fsm_sendFailure(FailureType_Failure_DataError,
_("Word not found in a wordlist"));
recovery_abort();
return;
}
}
if (word_pos != 0) { // ignore fake words
strlcpy(words[word_pos - 1], word, sizeof(words[word_pos - 1]));
}
if (word_index + 1 == 24) { // last one
recovery_done();
} else {
word_index++;
next_word();
}
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}
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/* Function called when a word was entered by user. Used
* for scrambled recovery.
*/
void recovery_word(const char *word) {
switch (recovery_mode) {
case RECOVERY_MATRIX:
recovery_digit(word[0]);
break;
case RECOVERY_SCRAMBLED:
recovery_scrambledword(word);
break;
default:
fsm_sendFailure(FailureType_Failure_UnexpectedMessage,
_("Not in Recovery mode"));
break;
}
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}
/* Abort recovery.
*/
void recovery_abort(void) {
memzero(words, sizeof(words));
word_pincode = 0;
if (recovery_mode != RECOVERY_NONE) {
layoutHome();
recovery_mode = RECOVERY_NONE;
}
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}
#if DEBUG_LINK
const char *recovery_get_fake_word(void) { return fake_word; }
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uint32_t recovery_get_word_pos(void) { return word_pos; }
#endif