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-rw-r--r--src/core_read.cpp59
1 files changed, 50 insertions, 9 deletions
diff --git a/src/core_read.cpp b/src/core_read.cpp
index a2eebbd528..7687a86185 100644
--- a/src/core_read.cpp
+++ b/src/core_read.cpp
@@ -126,31 +126,72 @@ static bool CheckTxScriptsSanity(const CMutableTransaction& tx)
static bool DecodeTx(CMutableTransaction& tx, const std::vector<unsigned char>& tx_data, bool try_no_witness, bool try_witness)
{
+ // General strategy:
+ // - Decode both with extended serialization (which interprets the 0x0001 tag as a marker for
+ // the presense of witnesses) and with legacy serialization (which interprets the tag as a
+ // 0-input 1-output incomplete transaction).
+ // - Restricted by try_no_witness (which disables legacy if false) and try_witness (which
+ // disables extended if false).
+ // - Ignore serializations that do not fully consume the hex string.
+ // - If neither succeeds, fail.
+ // - If only one succeeds, return that one.
+ // - If both decode attempts succeed:
+ // - If only one passes the CheckTxScriptsSanity check, return that one.
+ // - If neither or both pass CheckTxScriptsSanity, return the extended one.
+
+ CMutableTransaction tx_extended, tx_legacy;
+ bool ok_extended = false, ok_legacy = false;
+
+ // Try decoding with extended serialization support, and remember if the result successfully
+ // consumes the entire input.
if (try_witness) {
CDataStream ssData(tx_data, SER_NETWORK, PROTOCOL_VERSION);
try {
- ssData >> tx;
- // If transaction looks sane, we don't try other mode even if requested
- if (ssData.empty() && (!try_no_witness || CheckTxScriptsSanity(tx))) {
- return true;
- }
+ ssData >> tx_extended;
+ if (ssData.empty()) ok_extended = true;
} catch (const std::exception&) {
// Fall through.
}
}
+ // Optimization: if extended decoding succeeded and the result passes CheckTxScriptsSanity,
+ // don't bother decoding the other way.
+ if (ok_extended && CheckTxScriptsSanity(tx_extended)) {
+ tx = std::move(tx_extended);
+ return true;
+ }
+
+ // Try decoding with legacy serialization, and remember if the result successfully consumes the entire input.
if (try_no_witness) {
CDataStream ssData(tx_data, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
try {
- ssData >> tx;
- if (ssData.empty()) {
- return true;
- }
+ ssData >> tx_legacy;
+ if (ssData.empty()) ok_legacy = true;
} catch (const std::exception&) {
// Fall through.
}
}
+ // If legacy decoding succeeded and passes CheckTxScriptsSanity, that's our answer, as we know
+ // at this point that extended decoding either failed or doesn't pass the sanity check.
+ if (ok_legacy && CheckTxScriptsSanity(tx_legacy)) {
+ tx = std::move(tx_legacy);
+ return true;
+ }
+
+ // If extended decoding succeeded, and neither decoding passes sanity, return the extended one.
+ if (ok_extended) {
+ tx = std::move(tx_extended);
+ return true;
+ }
+
+ // If legacy decoding succeeded and extended didn't, return the legacy one.
+ if (ok_legacy) {
+ tx = std::move(tx_legacy);
+ return true;
+ }
+
+ // If none succeeded, we failed.
return false;
}