Merge pull request #4903

efad808 Avoid reject message feedback loops (Pieter Wuille)

src/main.cpp

@@ -4111,8 +4111,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
     else if (strCommand == "reject")
     {
-        if (fDebug)
-        {
+        if (fDebug) {
+            try {
                 string strMsg; unsigned char ccode; string strReason;
                 vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, 111);
 
@@ -4126,6 +4126,10 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     ss << ": hash " << hash.ToString();
                 }
                 LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
+            } catch (std::ios_base::failure& e) {
+                // Avoid feedback loops by preventing reject messages from triggering a new reject message.
+                LogPrint("net", "Unparseable reject message received\n");
+            }
         }
     }