Summary

This PR fixes issue #819 where tlsx hangs indefinitely when processing large target lists (~25k+ hosts). The output gets cut mid-line (e.g., mid-JSON key) because the process hangs during a write operation.

Root Causes

1. Broken timeout in ztls handshake: The tlsHandshakeWithTimeout function ran the handshake inline in a select statement instead of a goroutine, making the timeout ineffective. The handshake would block forever for unresponsive servers.

2. Missing timeout contexts: Cipher enumeration in tls, ztls, and jarm packages used context.Background() or context.TODO() for pool.Acquire() calls, allowing indefinite blocking.

3. Context leak in openssl: Using defer cancel() inside a loop caused context leaks.

4. No periodic buffer flush: The file writer only flushed on close, so if the process hung, buffered data was lost.

Fixes

ztls/ztls.go

• Fixed tlsHandshakeWithTimeout to run handshake in a goroutine with proper context cancellation
• Added timeout contexts to cipher enumeration

tls/tls.go

• Added timeout contexts to cipher enumeration
• Used HandshakeContext for proper timeout support

jarm/jarm.go

• Added timeout contexts to pool.Acquire() calls

openssl/openssl.go

• Fixed context leak by calling cancel() immediately instead of deferring in loop
• Added proper timeout for dial operations

output/file_writer.go

• Added periodic flush (every 100 writes) to prevent data loss

Testing

Added timeout_test.go with tests that verify:

• Handshake properly times out for unresponsive servers (2s timeout works)
• Cipher enumeration completes with timeout errors rather than hanging

Before/After

Before: Process hangs indefinitely, output truncated mid-line After: Operations time out gracefully, process completes

/claim #819

Summary by CodeRabbit

• Bug Fixes

  • Improved timeout handling across TLS operations with default 5-second timeouts to prevent hanging operations.
  • Enhanced context cancellation and lifecycle management for increased reliability.
  • Mitigated data loss on crash through periodic flushing of output data.

• Tests

  • Added timeout and cipher enumeration tests to ensure operations complete reliably under constrained conditions.