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Code Issues Releases Wiki Activity

feat(legacy): forbid multisig to singlesig change outputs

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This commit is contained in:
Ondřej Vejpustek 2024-11-22 18:44:19 +01:00
parent 93e3fd925b
commit f3c85e7ec7
2 changed files with 37 additions and 10 deletions
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43
legacy/firmware/signing.c
View File

@ -124,6 +124,9 @@ typedef struct {
bool multisig_fp_set;
bool multisig_fp_mismatch;
uint8_t multisig_fp[32];
bool multisig;
bool multisig_set;
bool multisig_mismatch;
uint32_t in_address_n[8];
size_t in_address_n_count;
InputScriptType in_script_type;
@ -978,6 +981,22 @@ static bool extract_input_multisig_fp(TxInfo *tx_info,
return true;
}
static void extract_multisig(TxInfo *tx_info, const TxInputType *txinput) {
if (tx_info->multisig_mismatch) {
return;
}
if (!tx_info->multisig_set) {
tx_info->multisig = txinput->has_multisig;
tx_info->multisig_set = true;
return;
}
if (txinput->has_multisig != tx_info->multisig) {
tx_info->multisig_mismatch = true;
}
}
bool check_change_multisig_fp(const TxInfo *tx_info,
const TxOutputType *txoutput) {
uint8_t h[32] = {0};
@ -986,6 +1005,12 @@ bool check_change_multisig_fp(const TxInfo *tx_info,
memcmp(tx_info->multisig_fp, h, 32) == 0;
}
bool check_change_multisig(const TxInfo *tx_info,
const TxOutputType *txoutput) {
return tx_info->multisig_set && !tx_info->multisig_mismatch &&
txoutput->has_multisig == tx_info->multisig;
}
static InputScriptType simple_script_type(InputScriptType script_type) {
// SPENDMULTISIG is used only for non-SegWit and is effectively the same as
// SPENDADDRESS. For SegWit inputs and outputs multisig is indicated by the
@ -1245,6 +1270,8 @@ static bool tx_info_init(TxInfo *tx_info, uint32_t inputs_count,
tx_info->min_sequence = SEQUENCE_FINAL;
tx_info->multisig_fp_set = false;
tx_info->multisig_fp_mismatch = false;
tx_info->multisig_set = false;
tx_info->multisig_mismatch = false;
tx_info->in_address_n_count = 0;
tx_info->in_script_type = 0;
tx_info->in_script_type_state = MatchState_UNDEFINED;
@ -1711,6 +1738,10 @@ static bool tx_info_add_input(TxInfo *tx_info, const TxInputType *txinput) {
return false;
}
// Remember whether all inputs are singlesig or all inputs are multisig.
// Change-outputs must be of the same type.
extract_multisig(tx_info, txinput);
// Remember the input's script type. Change-outputs must use the same script
// type as all inputs.
extract_input_script_type(tx_info, txinput);
@ -2069,18 +2100,14 @@ static bool is_change_output(const TxInfo *tx_info,
return false;
}
/*
* Check the multisig fingerprint only for multisig outputs. This means that
* a transfer from a multisig account to a singlesig account is treated as a
* change-output as long as all other change-output conditions are satisfied.
* This goes a bit against the concept of a multisig account, but the other
* cosigners will notice that they are relinquishing control of the funds, so
* there is no security risk.
*/
if (txoutput->has_multisig && !check_change_multisig_fp(tx_info, txoutput)) {
return false;
}
if (!check_change_multisig(tx_info, txoutput)) {
return false;
}
if (!check_change_script_type(tx_info, txoutput)) {
return false;
}

4
tests/device_tests/bitcoin/test_multisig_change.py
View File

@ -226,7 +226,7 @@ def test_external_internal(client: Client):
client,
INP1,
INP2,
change_indices=[] if is_core(client) else [2],
change_indices=[],
foreign_indices=[2],
)
)
@ -262,7 +262,7 @@ def test_internal_external(client: Client):
client,
INP1,
INP2,
change_indices=[] if is_core(client) else [1],
change_indices=[],
foreign_indices=[1],
)
)