net: reduce likelihood of race conditions on keep-alive timeout calculation between http1.1 servers and clients

Fixes: #47130
Fixes: #52649

Author: zanettea

lib/_http_agent.js

@@ -488,6 +488,7 @@ Agent.prototype.keepSocketAlive = function keepSocketAlive(socket) {
   socket.unref();
 
   let agentTimeout = this.options.timeout || 0;
+  let canKeepSocketAlive = true;
 
   if (socket._httpMessage?.res) {
     const keepAliveHint = socket._httpMessage.res.headers['keep-alive'];
@@ -498,11 +499,15 @@ Agent.prototype.keepSocketAlive = function keepSocketAlive(socket) {
       if (hint) {
         // Let the timer expires before the announced timeout to reduce
         // the likelihood of ECONNRESET errors
-        let serverHintTimeout = ( NumberParseInt(hint) * 1000 ) - 1000;
+        let serverHintTimeout = (NumberParseInt(hint) * 1000) - 1000;
         serverHintTimeout = serverHintTimeout > 0 ? serverHintTimeout : 0;
-
-        if (serverHintTimeout < agentTimeout) {
-          agentTimeout = serverHintTimeout;
+        if (serverHintTimeout === 0) {
+          // cannot safely reuse the socket because the server timeout is too short
+          canKeepSocketAlive = false;
+        } else {
+          if (serverHintTimeout < agentTimeout) {
+            agentTimeout = serverHintTimeout;
+          }
         }
       }
     }
@@ -512,7 +517,7 @@ Agent.prototype.keepSocketAlive = function keepSocketAlive(socket) {
     socket.setTimeout(agentTimeout);
   }
 
-  return true;
+  return canKeepSocketAlive;
 };
 
 Agent.prototype.reuseSocket = function reuseSocket(socket, req) {