fix invalid memory access that I added when merging descriptor wallets

Thanks, ubsan + fuzzer!
apoelstra · Dec 16, 2020 · b9ee1a6 · b9ee1a6
1 parent 5c8273c
commit b9ee1a6
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
@@ -498,11 +498,11 @@ bool SignTransaction(CMutableTransaction& mtx, const SigningProvider* keystore,
             prevTxOut = GetPeginOutputFromWitness(mtx.witness.vtxinwit[i].m_pegin_witness);
         } else {
             auto coin = coins.find(txin.prevout);
-            prevTxOut = coin->second.out;
             if (coin == coins.end() || coin->second.IsSpent()) {
                 input_errors[i] = "Input not found or already spent";
                 continue;
             }
+            prevTxOut = coin->second.out;
         }
 
         const CScript& prevPubKey = prevTxOut.scriptPubKey;