Merge #8976: libconsensus: Add input validation of flags

5ca8ef2 libconsensus: Add input validation of flags (Wladimir J. van der Laan)

2 files changed, 13 insertions, 0 deletions

diff --git a/src/script/bitcoinconsensus.cpp b/src/script/bitcoinconsensus.cpp
index b629f4278..1d0ca0c5a 100644
--- a/src/script/bitcoinconsensus.cpp
+++ b/src/script/bitcoinconsensus.cpp
@@ -69,10 +69,19 @@ struct ECCryptoClosure
 ECCryptoClosure instance_of_eccryptoclosure;
 }
 
+/** Check that all specified flags are part of the libconsensus interface. */
+static bool verify_flags(unsigned int flags)
+{
+    return (flags & ~(bitcoinconsensus_SCRIPT_FLAGS_VERIFY_ALL)) == 0;
+}
+
 static int verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, CAmount amount,
                                     const unsigned char *txTo        , unsigned int txToLen,
                                     unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
 {
+    if (!verify_flags(flags)) {
+        return bitcoinconsensus_ERR_INVALID_FLAGS;
+    }
     try {
         TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
         CTransaction tx;
diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h
index 1d2d5c23e..1bef4fe9e 100644
--- a/src/script/bitcoinconsensus.h
+++ b/src/script/bitcoinconsensus.h
@@ -42,6 +42,7 @@ typedef enum bitcoinconsensus_error_t
     bitcoinconsensus_ERR_TX_SIZE_MISMATCH,
     bitcoinconsensus_ERR_TX_DESERIALIZE,
     bitcoinconsensus_ERR_AMOUNT_REQUIRED,
+    bitcoinconsensus_ERR_INVALID_FLAGS,
 } bitcoinconsensus_error;
 
 /** Script verification flags */
@@ -54,6 +55,9 @@ enum
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9), // enable CHECKLOCKTIMEVERIFY (BIP65)
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY = (1U << 10), // enable CHECKSEQUENCEVERIFY (BIP112)
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS             = (1U << 11), // enable WITNESS (BIP141)
+    bitcoinconsensus_SCRIPT_FLAGS_VERIFY_ALL                 = bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG |
+                                                               bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NULLDUMMY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY |
+                                                               bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS
 };
 
 /// Returns 1 if the input nIn of the serialized transaction pointed to by