fix(SniHandler): Improve TLS SNI session resumption handling: connections containing a session ticket are now only rejected when no SNI is present and allowSessionTicket is disabled. Updated return values and logging for clearer resumption detection.

changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 2025-03-11 - 3.41.1 - fix(SniHandler)
+Improve TLS SNI session resumption handling: connections containing a session ticket are now only rejected when no SNI is present and allowSessionTicket is disabled. Updated return values and logging for clearer resumption detection.
+
+- Changed SniHandler.hasSessionResumption to return an object with 'isResumption' and 'hasSNI' flags.
+- Adjusted PortProxy logic to only terminate connections when a session ticket is detected without an accompanying SNI (when allowSessionTicket is false).
+- Enhanced debug logging to clearly differentiate between session resumption scenarios with and without SNI.
+
 ## 2025-03-11 - 3.41.0 - feat(PortProxy/TLS)
 Add allowSessionTicket option to control TLS session ticket handling
 

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '3.41.0',
+  version: '3.41.1',
   description: 'A powerful proxy package that effectively handles high traffic, with features such as SSL/TLS support, port proxying, WebSocket handling, dynamic routing with authentication options, and automatic ACME certificate management.'
 }

ts/classes.portproxy.ts

@@ -941,15 +941,23 @@ export class PortProxy {
               // Check for session tickets if allowSessionTicket is disabled
               if (this.settings.allowSessionTicket === false) {
                 // Analyze for session resumption attempt (session ticket or PSK)
-                const hasSessionTicket = SniHandler.hasSessionResumption(renegChunk, this.settings.enableTlsDebugLogging);
+                const resumptionInfo = SniHandler.hasSessionResumption(renegChunk, this.settings.enableTlsDebugLogging);
                 
-                if (hasSessionTicket) {
+                // Only block if there's a session ticket without SNI
+                if (resumptionInfo.isResumption && !resumptionInfo.hasSNI) {
                   console.log(
-                    `[${connectionId}] Session ticket detected in renegotiation with allowSessionTicket=false. ` +
+                    `[${connectionId}] Session ticket detected in renegotiation without SNI and allowSessionTicket=false. ` +
                     `Terminating connection to force new TLS handshake.`
                   );
                   this.initiateCleanupOnce(record, 'session_ticket_blocked');
                   return;
+                } else if (resumptionInfo.isResumption && resumptionInfo.hasSNI) {
+                  if (this.settings.enableTlsDebugLogging) {
+                    console.log(
+                      `[${connectionId}] Session ticket with SNI detected in renegotiation. ` +
+                      `Allowing connection since SNI is present.`
+                    );
+                  }
                 }
               }
               
@@ -1565,11 +1573,12 @@ export class PortProxy {
             // Check for session tickets if allowSessionTicket is disabled
             if (this.settings.allowSessionTicket === false && SniHandler.isClientHello(chunk)) {
               // Analyze for session resumption attempt
-              const hasSessionTicket = SniHandler.hasSessionResumption(chunk, this.settings.enableTlsDebugLogging);
+              const resumptionInfo = SniHandler.hasSessionResumption(chunk, this.settings.enableTlsDebugLogging);
               
-              if (hasSessionTicket) {
+              // Only block if there's a session ticket without SNI
+              if (resumptionInfo.isResumption && !resumptionInfo.hasSNI) {
                 console.log(
-                  `[${connectionId}] Session ticket detected in initial ClientHello with allowSessionTicket=false. ` +
+                  `[${connectionId}] Session ticket detected in initial ClientHello without SNI and allowSessionTicket=false. ` +
                   `Terminating connection to force new TLS handshake.`
                 );
                 if (connectionRecord.incomingTerminationReason === null) {
@@ -1579,6 +1588,13 @@ export class PortProxy {
                 socket.end();
                 this.cleanupConnection(connectionRecord, 'session_ticket_blocked');
                 return;
+              } else if (resumptionInfo.isResumption && resumptionInfo.hasSNI) {
+                if (this.settings.enableTlsDebugLogging) {
+                  console.log(
+                    `[${connectionId}] Session ticket with SNI detected in initial ClientHello. ` +
+                    `Allowing connection since SNI is present.`
+                  );
+                }
               }
             }
             
@@ -1931,11 +1947,12 @@ export class PortProxy {
               // Check for session tickets if allowSessionTicket is disabled
               if (this.settings.allowSessionTicket === false && SniHandler.isClientHello(chunk)) {
                 // Analyze for session resumption attempt
-                const hasSessionTicket = SniHandler.hasSessionResumption(chunk, this.settings.enableTlsDebugLogging);
+                const resumptionInfo = SniHandler.hasSessionResumption(chunk, this.settings.enableTlsDebugLogging);
                 
-                if (hasSessionTicket) {
+                // Only block if there's a session ticket without SNI
+                if (resumptionInfo.isResumption && !resumptionInfo.hasSNI) {
                   console.log(
-                    `[${connectionId}] Session ticket detected in initial ClientHello with allowSessionTicket=false. ` +
+                    `[${connectionId}] Session ticket detected in initial ClientHello without SNI and allowSessionTicket=false. ` +
                     `Terminating connection to force new TLS handshake.`
                   );
                   if (connectionRecord.incomingTerminationReason === null) {
@@ -1945,6 +1962,13 @@ export class PortProxy {
                   socket.end();
                   this.cleanupConnection(connectionRecord, 'session_ticket_blocked');
                   return;
+                } else if (resumptionInfo.isResumption && resumptionInfo.hasSNI) {
+                  if (this.settings.enableTlsDebugLogging) {
+                    console.log(
+                      `[${connectionId}] Session ticket with SNI detected in initial ClientHello. ` +
+                      `Allowing connection since SNI is present.`
+                    );
+                  }
                 }
               }
 

ts/classes.snihandler.ts

@@ -372,6 +372,58 @@ export class SniHandler {
         pos += extensionLength;
       }
       
+      // Check if SNI is included
+      let hasSNI = false;
+      
+      // Reset position and scan again for SNI extension
+      pos = 5 + 1 + 3 + 2; // Reset to after handshake type, length and client version
+      pos += 32; // Skip client random
+      
+      if (pos + 1 <= buffer.length) {
+        const sessionIdLength = buffer[pos];
+        pos += 1 + sessionIdLength;
+        
+        // Skip cipher suites
+        if (pos + 2 <= buffer.length) {
+          const cipherSuitesLength = (buffer[pos] << 8) + buffer[pos + 1];
+          pos += 2 + cipherSuitesLength;
+          
+          // Skip compression methods
+          if (pos + 1 <= buffer.length) {
+            const compressionMethodsLength = buffer[pos];
+            pos += 1 + compressionMethodsLength;
+            
+            // Check for extensions
+            if (pos + 2 <= buffer.length) {
+              const extensionsLength = (buffer[pos] << 8) + buffer[pos + 1];
+              pos += 2;
+              
+              // Extensions end position
+              const extensionsEnd = pos + extensionsLength;
+              if (extensionsEnd <= buffer.length) {
+                // Scan for SNI extension
+                while (pos + 4 <= extensionsEnd) {
+                  const extensionType = (buffer[pos] << 8) + buffer[pos + 1];
+                  pos += 2;
+                  
+                  const extensionLength = (buffer[pos] << 8) + buffer[pos + 1];
+                  pos += 2;
+                  
+                  if (extensionType === this.TLS_SNI_EXTENSION_TYPE) {
+                    hasSNI = true;
+                    log('Found SNI extension');
+                    break;
+                  }
+                  
+                  // Skip extension data
+                  pos += extensionLength;
+                }
+              }
+            }
+          }
+        }
+      }
+      
       // Consider it a resumption if any resumption mechanism is present
       const isResumption = hasSessionTicket || hasPSK || hasEarlyData || 
                          (hasNonEmptySessionId && !hasPSK); // Legacy resumption
@@ -381,13 +433,18 @@ export class SniHandler {
             (hasSessionTicket ? 'session ticket, ' : '') +
             (hasPSK ? 'PSK, ' : '') +
             (hasEarlyData ? 'early data, ' : '') +
-            (hasNonEmptySessionId ? 'session ID' : ''));
+            (hasNonEmptySessionId ? 'session ID' : '') +
+            (hasSNI ? ', with SNI' : ', without SNI'));
       }
       
-      return isResumption;
+      // Return an object with both flags
+      return { 
+        isResumption, 
+        hasSNI 
+      };
     } catch (error) {
       log(`Error checking for session resumption: ${error}`);
-      return false;
+      return { isResumption: false, hasSNI: false };
     }
   }