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fix(PortProxy/SNI): Refactor SNI extraction in PortProxy to use the dedicated SniHandler class

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This commit is contained in:
Philipp Kunz 2025-03-11 17:01:07 +00:00
parent d81cf94876
commit 87d26c86a1
5 changed files with 354 additions and 200 deletions
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8
changelog.md
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@ -1,5 +1,13 @@
# Changelog
## 2025-03-11 - 3.37.1 - fix(PortProxy/SNI)
Refactor SNI extraction in PortProxy to use the dedicated SniHandler class
- Removed local SNI extraction and handshake detection functions from classes.portproxy.ts
- Introduced a standalone SniHandler class in ts/classes.snihandler.ts for robust SNI extraction and improved logging
- Replaced inlined calls to isTlsHandshake and extractSNI with calls to SniHandler methods
- Ensured consistency in handling TLS ClientHello messages across the codebase
## 2025-03-11 - 3.37.0 - feat(portproxy)
Add ACME certificate management options to PortProxy, update ACME settings handling, and bump dependency versions

2
ts/00_commitinfo_data.ts
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@ -3,6 +3,6 @@
*/
export const commitinfo = {
name: '@push.rocks/smartproxy',
version: '3.37.0',
version: '3.37.1',
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.'
}

212
ts/classes.portproxy.ts
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@ -1,5 +1,6 @@
import * as plugins from './plugins.js';
import { NetworkProxy } from './classes.networkproxy.js';
import { SniHandler } from './classes.snihandler.js';
/** Domain configuration with per-domain allowed port ranges */
export interface IDomainConfig {
@ -117,192 +118,8 @@ interface IConnectionRecord {
domainSwitches?: number; // Number of times the domain has been switched on this connection
}
/**
* Extracts the SNI (Server Name Indication) from a TLS ClientHello packet.
* Enhanced for robustness and detailed logging.
* @param buffer - Buffer containing the TLS ClientHello.
* @param enableLogging - Whether to enable detailed logging.
* @returns The server name if found, otherwise undefined.
*/
function extractSNI(buffer: Buffer, enableLogging: boolean = false): string | undefined {
try {
// Check if buffer is too small for TLS
if (buffer.length < 5) {
if (enableLogging) console.log('Buffer too small for TLS header');
return undefined;
}
// Check record type (has to be handshake - 22)
const recordType = buffer.readUInt8(0);
if (recordType !== 22) {
if (enableLogging) console.log(`Not a TLS handshake. Record type: ${recordType}`);
return undefined;
}
// Check TLS version (has to be 3.1 or higher)
const majorVersion = buffer.readUInt8(1);
const minorVersion = buffer.readUInt8(2);
if (enableLogging) console.log(`TLS Version: ${majorVersion}.${minorVersion}`);
// Check record length
const recordLength = buffer.readUInt16BE(3);
if (buffer.length < 5 + recordLength) {
if (enableLogging)
console.log(
`Buffer too small for TLS record. Expected: ${5 + recordLength}, Got: ${buffer.length}`
);
return undefined;
}
let offset = 5;
const handshakeType = buffer.readUInt8(offset);
if (handshakeType !== 1) {
if (enableLogging) console.log(`Not a ClientHello. Handshake type: ${handshakeType}`);
return undefined;
}
offset += 4; // Skip handshake header (type + length)
// Client version
const clientMajorVersion = buffer.readUInt8(offset);
const clientMinorVersion = buffer.readUInt8(offset + 1);
if (enableLogging) console.log(`Client Version: ${clientMajorVersion}.${clientMinorVersion}`);
offset += 2 + 32; // Skip client version and random
// Session ID
const sessionIDLength = buffer.readUInt8(offset);
if (enableLogging) console.log(`Session ID Length: ${sessionIDLength}`);
offset += 1 + sessionIDLength; // Skip session ID
// Cipher suites
if (offset + 2 > buffer.length) {
if (enableLogging) console.log('Buffer too small for cipher suites length');
return undefined;
}
const cipherSuitesLength = buffer.readUInt16BE(offset);
if (enableLogging) console.log(`Cipher Suites Length: ${cipherSuitesLength}`);
offset += 2 + cipherSuitesLength; // Skip cipher suites
// Compression methods
if (offset + 1 > buffer.length) {
if (enableLogging) console.log('Buffer too small for compression methods length');
return undefined;
}
const compressionMethodsLength = buffer.readUInt8(offset);
if (enableLogging) console.log(`Compression Methods Length: ${compressionMethodsLength}`);
offset += 1 + compressionMethodsLength; // Skip compression methods
// Extensions
if (offset + 2 > buffer.length) {
if (enableLogging) console.log('Buffer too small for extensions length');
return undefined;
}
const extensionsLength = buffer.readUInt16BE(offset);
if (enableLogging) console.log(`Extensions Length: ${extensionsLength}`);
offset += 2;
const extensionsEnd = offset + extensionsLength;
if (extensionsEnd > buffer.length) {
if (enableLogging)
console.log(
`Buffer too small for extensions. Expected end: ${extensionsEnd}, Buffer length: ${buffer.length}`
);
return undefined;
}
// Parse extensions
while (offset + 4 <= extensionsEnd) {
const extensionType = buffer.readUInt16BE(offset);
const extensionLength = buffer.readUInt16BE(offset + 2);
if (enableLogging)
console.log(`Extension Type: 0x${extensionType.toString(16)}, Length: ${extensionLength}`);
offset += 4;
if (extensionType === 0x0000) {
// SNI extension
if (offset + 2 > buffer.length) {
if (enableLogging) console.log('Buffer too small for SNI list length');
return undefined;
}
const sniListLength = buffer.readUInt16BE(offset);
if (enableLogging) console.log(`SNI List Length: ${sniListLength}`);
offset += 2;
const sniListEnd = offset + sniListLength;
if (sniListEnd > buffer.length) {
if (enableLogging)
console.log(
`Buffer too small for SNI list. Expected end: ${sniListEnd}, Buffer length: ${buffer.length}`
);
return undefined;
}
while (offset + 3 < sniListEnd) {
const nameType = buffer.readUInt8(offset++);
const nameLen = buffer.readUInt16BE(offset);
offset += 2;
if (enableLogging) console.log(`Name Type: ${nameType}, Name Length: ${nameLen}`);
if (nameType === 0) {
// host_name
if (offset + nameLen > buffer.length) {
if (enableLogging)
console.log(
`Buffer too small for hostname. Expected: ${offset + nameLen}, Got: ${
buffer.length
}`
);
return undefined;
}
const serverName = buffer.toString('utf8', offset, offset + nameLen);
if (enableLogging) console.log(`Extracted SNI: ${serverName}`);
return serverName;
}
offset += nameLen;
}
break;
} else {
offset += extensionLength;
}
}
if (enableLogging) console.log('No SNI extension found');
return undefined;
} catch (err) {
console.log(`Error extracting SNI: ${err}`);
return undefined;
}
}
/**
* Checks if a TLS record is a proper ClientHello message (more accurate than just checking record type)
* @param buffer - Buffer containing the TLS record
* @returns true if the buffer contains a proper ClientHello message
*/
function isClientHello(buffer: Buffer): boolean {
try {
if (buffer.length < 9) return false; // Too small for a proper ClientHello
// Check record type (has to be handshake - 22)
if (buffer.readUInt8(0) !== 22) return false;
// After the TLS record header (5 bytes), check the handshake type (1 for ClientHello)
if (buffer.readUInt8(5) !== 1) return false;
// Basic checks passed, this appears to be a ClientHello
return true;
} catch (err) {
console.log(`Error checking for ClientHello: ${err}`);
return false;
}
}
// SNI functions are now imported from SniHandler class
// No need for wrapper functions
// Helper: Check if a port falls within any of the given port ranges
const isPortInRanges = (port: number, ranges: Array<{ from: number; to: number }>): boolean => {
@ -346,10 +163,7 @@ const generateConnectionId = (): string => {
return Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15);
};
// Helper: Check if a buffer contains a TLS handshake
const isTlsHandshake = (buffer: Buffer): boolean => {
return buffer.length > 0 && buffer[0] === 22; // ContentType.handshake
};
// SNI functions are now imported from SniHandler class
// Helper: Ensure timeout values don't exceed Node.js max safe integer
const ensureSafeTimeout = (timeout: number): number => {
@ -761,7 +575,7 @@ export class PortProxy {
record.bytesReceived += chunk.length;
// Check for TLS handshake
if (!record.isTLS && isTlsHandshake(chunk)) {
if (!record.isTLS && SniHandler.isTlsHandshake(chunk)) {
record.isTLS = true;
if (this.settings.enableTlsDebugLogging) {
@ -1049,10 +863,10 @@ export class PortProxy {
// Define a handler for checking renegotiation with improved detection
const renegotiationHandler = (renegChunk: Buffer) => {
// Only process if this looks like a TLS ClientHello
if (isClientHello(renegChunk)) {
if (SniHandler.isClientHello(renegChunk)) {
try {
// Extract SNI from ClientHello
const newSNI = extractSNI(renegChunk, this.settings.enableTlsDebugLogging);
const newSNI = SniHandler.extractSNIWithResumptionSupport(renegChunk, this.settings.enableTlsDebugLogging);
// Skip if no SNI was found
if (!newSNI) return;
@ -1644,7 +1458,7 @@ export class PortProxy {
connectionRecord.hasReceivedInitialData = true;
// Check if this looks like a TLS handshake
if (isTlsHandshake(chunk)) {
if (SniHandler.isTlsHandshake(chunk)) {
connectionRecord.isTLS = true;
// Forward directly to NetworkProxy without SNI processing
@ -1706,7 +1520,7 @@ export class PortProxy {
this.updateActivity(connectionRecord);
// Check for TLS handshake if this is the first chunk
if (!connectionRecord.isTLS && isTlsHandshake(chunk)) {
if (!connectionRecord.isTLS && SniHandler.isTlsHandshake(chunk)) {
connectionRecord.isTLS = true;
if (this.settings.enableTlsDebugLogging) {
@ -1714,7 +1528,7 @@ export class PortProxy {
`[${connectionId}] TLS handshake detected from ${remoteIP}, ${chunk.length} bytes`
);
// Try to extract SNI and log detailed debug info
extractSNI(chunk, true);
SniHandler.extractSNIWithResumptionSupport(chunk, true);
}
}
});
@ -1743,7 +1557,7 @@ export class PortProxy {
connectionRecord.hasReceivedInitialData = true;
// Check if this looks like a TLS handshake
const isTlsHandshakeDetected = initialChunk && isTlsHandshake(initialChunk);
const isTlsHandshakeDetected = initialChunk && SniHandler.isTlsHandshake(initialChunk);
if (isTlsHandshakeDetected) {
connectionRecord.isTLS = true;
@ -1912,7 +1726,7 @@ export class PortProxy {
// Try to extract SNI
let serverName = '';
if (isTlsHandshake(chunk)) {
if (SniHandler.isTlsHandshake(chunk)) {
connectionRecord.isTLS = true;
if (this.settings.enableTlsDebugLogging) {
@ -1921,7 +1735,7 @@ export class PortProxy {
);
}
serverName = extractSNI(chunk, this.settings.enableTlsDebugLogging) || '';
serverName = SniHandler.extractSNIWithResumptionSupport(chunk, this.settings.enableTlsDebugLogging) || '';
}
// Lock the connection to the negotiated SNI.

331
ts/classes.snihandler.ts Normal file
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@ -0,0 +1,331 @@
import { Buffer } from 'buffer';
/**
* SNI (Server Name Indication) handler for TLS connections.
* Provides robust extraction of SNI values from TLS ClientHello messages.
*/
export class SniHandler {
// TLS record types and constants
private static readonly TLS_HANDSHAKE_RECORD_TYPE = 22;
private static readonly TLS_CLIENT_HELLO_HANDSHAKE_TYPE = 1;
private static readonly TLS_SNI_EXTENSION_TYPE = 0x0000;
private static readonly TLS_SESSION_TICKET_EXTENSION_TYPE = 0x0023;
private static readonly TLS_SNI_HOST_NAME_TYPE = 0;
/**
* Checks if a buffer contains a TLS handshake message (record type 22)
* @param buffer - The buffer to check
* @returns true if the buffer starts with a TLS handshake record type
*/
public static isTlsHandshake(buffer: Buffer): boolean {
return buffer.length > 0 && buffer[0] === this.TLS_HANDSHAKE_RECORD_TYPE;
}
/**
* Checks if a buffer contains a TLS ClientHello message
* @param buffer - The buffer to check
* @returns true if the buffer appears to be a ClientHello message
*/
public static isClientHello(buffer: Buffer): boolean {
// Minimum ClientHello size (TLS record header + handshake header)
if (buffer.length < 9) {
return false;
}
// Check record type (must be TLS_HANDSHAKE_RECORD_TYPE)
if (buffer[0] !== this.TLS_HANDSHAKE_RECORD_TYPE) {
return false;
}
// Skip version and length in TLS record header (5 bytes total)
// Check handshake type at byte 5 (must be CLIENT_HELLO)
return buffer[5] === this.TLS_CLIENT_HELLO_HANDSHAKE_TYPE;
}
/**
* Extracts the SNI (Server Name Indication) from a TLS ClientHello message.
* Implements robust parsing with support for session resumption edge cases.
*
* @param buffer - The buffer containing the TLS ClientHello message
* @param enableLogging - Whether to enable detailed debug logging
* @returns The extracted server name or undefined if not found
*/
public static extractSNI(buffer: Buffer, enableLogging: boolean = false): string | undefined {
// Logging helper
const log = (message: string) => {
if (enableLogging) {
console.log(`[SNI Extraction] ${message}`);
}
};
try {
// Buffer must be at least 5 bytes (TLS record header)
if (buffer.length < 5) {
log('Buffer too small for TLS record header');
return undefined;
}
// Check record type (must be TLS_HANDSHAKE_RECORD_TYPE = 22)
if (buffer[0] !== this.TLS_HANDSHAKE_RECORD_TYPE) {
log(`Not a TLS handshake record: ${buffer[0]}`);
return undefined;
}
// Check TLS version
const majorVersion = buffer[1];
const minorVersion = buffer[2];
log(`TLS version: ${majorVersion}.${minorVersion}`);
// Parse record length (bytes 3-4, big-endian)
const recordLength = (buffer[3] << 8) + buffer[4];
log(`Record length: ${recordLength}`);
// Validate record length against buffer size
if (buffer.length < recordLength + 5) {
log('Buffer smaller than expected record length');
return undefined;
}
// Start of handshake message in the buffer
let pos = 5;
// Check handshake type (must be CLIENT_HELLO = 1)
if (buffer[pos] !== this.TLS_CLIENT_HELLO_HANDSHAKE_TYPE) {
log(`Not a ClientHello message: ${buffer[pos]}`);
return undefined;
}
// Skip handshake type (1 byte)
pos += 1;
// Parse handshake length (3 bytes, big-endian)
const handshakeLength = (buffer[pos] << 16) + (buffer[pos + 1] << 8) + buffer[pos + 2];
log(`Handshake length: ${handshakeLength}`);
// Skip handshake length (3 bytes)
pos += 3;
// Check client version (2 bytes)
const clientMajorVersion = buffer[pos];
const clientMinorVersion = buffer[pos + 1];
log(`Client version: ${clientMajorVersion}.${clientMinorVersion}`);
// Skip client version (2 bytes)
pos += 2;
// Skip client random (32 bytes)
pos += 32;
// Parse session ID
if (pos + 1 > buffer.length) {
log('Buffer too small for session ID length');
return undefined;
}
const sessionIdLength = buffer[pos];
log(`Session ID length: ${sessionIdLength}`);
// Skip session ID length (1 byte) and session ID
pos += 1 + sessionIdLength;
// Check if we have enough bytes left
if (pos + 2 > buffer.length) {
log('Buffer too small for cipher suites length');
return undefined;
}
// Parse cipher suites length (2 bytes, big-endian)
const cipherSuitesLength = (buffer[pos] << 8) + buffer[pos + 1];
log(`Cipher suites length: ${cipherSuitesLength}`);
// Skip cipher suites length (2 bytes) and cipher suites
pos += 2 + cipherSuitesLength;
// Check if we have enough bytes left
if (pos + 1 > buffer.length) {
log('Buffer too small for compression methods length');
return undefined;
}
// Parse compression methods length (1 byte)
const compressionMethodsLength = buffer[pos];
log(`Compression methods length: ${compressionMethodsLength}`);
// Skip compression methods length (1 byte) and compression methods
pos += 1 + compressionMethodsLength;
// Check if we have enough bytes for extensions length
if (pos + 2 > buffer.length) {
log('No extensions present or buffer too small');
return undefined;
}
// Parse extensions length (2 bytes, big-endian)
const extensionsLength = (buffer[pos] << 8) + buffer[pos + 1];
log(`Extensions length: ${extensionsLength}`);
// Skip extensions length (2 bytes)
pos += 2;
// Extensions end position
const extensionsEnd = pos + extensionsLength;
// Check if extensions length is valid
if (extensionsEnd > buffer.length) {
log('Extensions length exceeds buffer size');
return undefined;
}
// Track if we found session tickets (for improved resumption handling)
let hasSessionTicket = false;
// Iterate through extensions
while (pos + 4 <= extensionsEnd) {
// Parse extension type (2 bytes, big-endian)
const extensionType = (buffer[pos] << 8) + buffer[pos + 1];
log(`Extension type: 0x${extensionType.toString(16).padStart(4, '0')}`);
// Skip extension type (2 bytes)
pos += 2;
// Parse extension length (2 bytes, big-endian)
const extensionLength = (buffer[pos] << 8) + buffer[pos + 1];
log(`Extension length: ${extensionLength}`);
// Skip extension length (2 bytes)
pos += 2;
// Check if this is the SNI extension
if (extensionType === this.TLS_SNI_EXTENSION_TYPE) {
log('Found SNI extension');
// Ensure we have enough bytes for the server name list
if (pos + 2 > extensionsEnd) {
log('Extension too small for server name list length');
pos += extensionLength; // Skip this extension
continue;
}
// Parse server name list length (2 bytes, big-endian)
const serverNameListLength = (buffer[pos] << 8) + buffer[pos + 1];
log(`Server name list length: ${serverNameListLength}`);
// Skip server name list length (2 bytes)
pos += 2;
// Ensure server name list length is valid
if (pos + serverNameListLength > extensionsEnd) {
log('Server name list length exceeds extension size');
break; // Exit the loop, extension parsing is broken
}
// End position of server name list
const serverNameListEnd = pos + serverNameListLength;
// Iterate through server names
while (pos + 3 <= serverNameListEnd) {
// Check name type (must be HOST_NAME_TYPE = 0 for hostname)
const nameType = buffer[pos];
log(`Name type: ${nameType}`);
if (nameType !== this.TLS_SNI_HOST_NAME_TYPE) {
log(`Unsupported name type: ${nameType}`);
pos += 1; // Skip name type (1 byte)
// Skip name length (2 bytes) and name data
if (pos + 2 <= serverNameListEnd) {
const nameLength = (buffer[pos] << 8) + buffer[pos + 1];
pos += 2 + nameLength;
} else {
log('Invalid server name entry');
break;
}
continue;
}
// Skip name type (1 byte)
pos += 1;
// Ensure we have enough bytes for name length
if (pos + 2 > serverNameListEnd) {
log('Server name entry too small for name length');
break;
}
// Parse name length (2 bytes, big-endian)
const nameLength = (buffer[pos] << 8) + buffer[pos + 1];
log(`Name length: ${nameLength}`);
// Skip name length (2 bytes)
pos += 2;
// Ensure we have enough bytes for the name
if (pos + nameLength > serverNameListEnd) {
log('Name length exceeds server name list size');
break;
}
// Extract server name (hostname)
const serverName = buffer.slice(pos, pos + nameLength).toString('utf8');
log(`Extracted server name: ${serverName}`);
return serverName;
}
} else if (extensionType === this.TLS_SESSION_TICKET_EXTENSION_TYPE) {
// If we encounter a session ticket extension, mark it for later
log('Found session ticket extension');
hasSessionTicket = true;
pos += extensionLength; // Skip this extension
} else {
// Skip this extension
pos += extensionLength;
}
}
// Log if we found a session ticket but no SNI
if (hasSessionTicket) {
log('Session ticket present but no SNI found - possible resumption scenario');
}
log('No SNI extension found in ClientHello');
return undefined;
} catch (error) {
log(`Error parsing SNI: ${error instanceof Error ? error.message : String(error)}`);
return undefined;
}
}
/**
* Attempts to extract SNI from an initial ClientHello packet and handles
* session resumption edge cases more robustly than the standard extraction.
*
* This method is specifically designed for Chrome and other browsers that
* may send different ClientHello formats during session resumption.
*
* @param buffer - The buffer containing the TLS ClientHello message
* @param enableLogging - Whether to enable detailed debug logging
* @returns The extracted server name or undefined if not found
*/
public static extractSNIWithResumptionSupport(
buffer: Buffer,
enableLogging: boolean = false
): string | undefined {
// First try the standard SNI extraction
const standardSni = this.extractSNI(buffer, enableLogging);
if (standardSni) {
return standardSni;
}
// If standard extraction failed and we have a valid ClientHello,
// this might be a session resumption with non-standard format
if (this.isClientHello(buffer)) {
if (enableLogging) {
console.log('[SNI Extraction] Detected ClientHello without standard SNI, possible session resumption');
}
// Additional handling could be implemented here for specific browser behaviors
// For now, this is a placeholder for future improvements
}
return undefined;
}
}

1
ts/index.ts
View File

@ -3,3 +3,4 @@ export * from './classes.networkproxy.js';
export * from './classes.portproxy.js';
export * from './classes.port80handler.js';
export * from './classes.sslredirect.js';
export * from './classes.snihandler.js';