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Do not trigger a DoS ban if SCRIPT_VERIFY_NULLDUMMY fails

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Peter Todd 2014-03-10 22:36:46 -04:00 committed by langerhans
parent ec389a30e5
commit b6faba6035
2 changed files with 24 additions and 6 deletions
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24
src/main.cpp
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@ -1682,14 +1682,26 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCach
pvChecks->push_back(CScriptCheck());
check.swap(pvChecks->back());
} else if (!check()) {
if (flags & SCRIPT_VERIFY_STRICTENC) {
// For now, check whether the failure was caused by non-canonical
// encodings or not; if so, don't trigger DoS protection.
CScriptCheck check(coins, tx, i, flags & (~SCRIPT_VERIFY_STRICTENC), 0);
if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) {
// Check whether the failure was caused by a
// non-mandatory script verification check, such as
// non-standard DER encodings or non-null dummy
// arguments; if so, don't trigger DoS protection to
// avoid splitting the network between upgraded and
// non-upgraded nodes.
CScriptCheck check(coins, tx, i,
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, 0);
if (check())
return state.Invalid(false, REJECT_NONSTANDARD, "non-canonical");
return state.Invalid(false, REJECT_NONSTANDARD, "non-mandatory-script-verify-flag");
}
return state.DoS(100,false, REJECT_NONSTANDARD, "non-canonical");
// Failures of other flags indicate a transaction that is
// invalid in new blocks, e.g. a invalid P2SH. We DoS ban
// such nodes as they are not following the protocol. That
// said during an upgrade careful thought should be taken
// as to the correct behavior - we may want to continue
// peering with non-upgraded nodes even after a soft-fork
// super-majority vote has passed.
return state.DoS(100,false, REJECT_INVALID, "mandatory-script-verify-flag-failed");
}
}
}

6
src/script.h
View file

@ -197,6 +197,9 @@ enum
// them to be valid. (but old blocks may not comply with) Currently just P2SH,
// but in the future other flags may be added, such as a soft-fork to enforce
// strict DER encoding.
//
// Failing one of these tests may trigger a DoS ban - see CheckInputs() for
// details.
static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
// Standard script verification flags that standard transactions will comply
@ -206,6 +209,9 @@ static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY
SCRIPT_VERIFY_STRICTENC |
SCRIPT_VERIFY_NULLDUMMY;
// For convenience, standard but not mandatory verify flags.
static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;
enum txnouttype
{
TX_NONSTANDARD,