arno/trezor-firmware
1
0
Fork 0
mirror of https://github.com/trezor/trezor-firmware.git synced 2024-11-22 23:48:12 +00:00
Code Issues Releases Wiki Activity

Remove magic constants

Browse Source 
Use defines for wallet depth and change chain.  Updated some comments
to clarify what is checked.
This commit is contained in:
Jochen Hoenicke 2017-10-30 12:20:47 +01:00 committed by Pavol Rusnak
parent 4805f27e8c
commit a24e8a0484
1 changed files with 25 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
firmware/signing.c
View File

@ -68,11 +68,16 @@ static uint8_t multisig_fp[32];
static uint32_t in_address_n[8];
static size_t in_address_n_count;
/* marker for in_address_n_count to indicate a mismatch in bip32 paths in
/* A marker for in_address_n_count to indicate a mismatch in bip32 paths in
input */
#define BIP32_NOCHANGEALLOWED 1
/* maximum allowed change index */
#define MAX_BIP32_LAST_ELEMENT 1000000
/* The number of bip32 levels used in a wallet (chain and address) */
#define BIP32_WALLET_DEPTH 2
/* The chain id used for change */
#define BIP32_CHANGE_CHAIN 1
/* The maximum allowed change address. This should be large enough for normal
use and still allow to quickly brute-force the correct bip32 path. */
#define BIP32_MAX_LAST_ELEMENT 1000000
enum {
SIGHASH_ALL = 1,
@ -338,7 +343,7 @@ void extract_input_bip32_path(const TxInputType *tinput)
return;
}
size_t count = tinput->address_n_count;
if (count < 2) {
if (count < BIP32_WALLET_DEPTH) {
// no change address allowed
in_address_n_count = BIP32_NOCHANGEALLOWED;
return;
@ -346,16 +351,19 @@ void extract_input_bip32_path(const TxInputType *tinput)
if (in_address_n_count == 0) {
// initialize in_address_n on first input seen
in_address_n_count = count;
// store first N - 2
memcpy(in_address_n, tinput->address_n, (count - 2) * sizeof(uint32_t));
// store the bip32 path up to the account
memcpy(in_address_n, tinput->address_n,
(count - BIP32_WALLET_DEPTH) * sizeof(uint32_t));
return;
}
// check whether they are same length
// check that all addresses use a path of same length
if (in_address_n_count != count) {
in_address_n_count = BIP32_NOCHANGEALLOWED;
return;
}
if (memcmp(in_address_n, tinput->address_n, (count - 2) * sizeof(uint32_t)) != 0) {
// check that the bip32 path up to the account matches
if (memcmp(in_address_n, tinput->address_n,
(count - BIP32_WALLET_DEPTH) * sizeof(uint32_t)) != 0) {
// mismatch -> no change address allowed
in_address_n_count = BIP32_NOCHANGEALLOWED;
return;
@ -366,13 +374,17 @@ bool check_change_bip32_path(const TxOutputType *toutput)
{
size_t count = toutput->address_n_count;
// Note: count >= 2 and count == in_address_n_count
// Check that the change path has the same bip32 path length,
// the same path up to the account, and that the wallet components
// (chain id and address) are as expected.
// Note: count >= BIP32_WALLET_DEPTH and count == in_address_n_count
// imply that in_address_n_count != BIP32_NOCHANGEALLOWED
return (count >= 2
return (count >= BIP32_WALLET_DEPTH
&& count == in_address_n_count
&& 0 == memcmp(in_address_n, toutput->address_n, (count - 2) * sizeof(uint32_t))
&& toutput->address_n[count - 2] == 1
&& toutput->address_n[count - 1] <= MAX_BIP32_LAST_ELEMENT);
&& 0 == memcmp(in_address_n, toutput->address_n,
(count - BIP32_WALLET_DEPTH) * sizeof(uint32_t))
&& toutput->address_n[count - 2] == BIP32_CHANGE_CHAIN
&& toutput->address_n[count - 1] <= BIP32_MAX_LAST_ELEMENT);
}
bool compile_input_script_sig(TxInputType *tinput)