A Fork of Golang TLS Library with Kernel TLS Implementation

This Repo is to add the Kernel TLS (KTLS) support on top of the standard Golang TLS library.

The library is 100% percent compatible with the original Golang TLS library.

The library enables the kernel TLS after the TLS handshake is completed. In other words, the handshake is implemented by golang itself, whereas the symmetric encryption is offloaded to kernel.

Benefits

With KTLS, one can offload the encryption to the kernel or even the NIC, depending on the kernel version and the hardware. This can significantly reduce the CPU utility and improve the throughput of the TLS connection.

How to use

An example of the echo server is available at https://github.com/secure-for-ai/goktls_examples.

• Enable the Kernel TLS on Linux in your terminal.

  sudo modprobe tls

• Add the package into go.mod

  require github.com/secure-for-ai/goktls v1.20.0-rc3.1

  The release version tracks the Golang main release with minor updates.

• Drop in replacement

  Replace

  import "crypto/tls"

  With

  import tls "github.com/secure-for-ai/goktls"

• Run your code with KTLS

  GOKTLS=1 go run main.go

• Print out the debug information

  GOKTLS=1 go run -tag=debug main.go

  If KTLS is enabled, you should be able to see the following in kernel 5.15.

  2023/01/27 16:17:21 kTLS Enabled Status: true
  2023/01/27 16:17:21 Kernel Version: 5.15.0-58-lowlatency
  2023/01/27 16:17:21 ======Supported Features======
  2023/01/27 16:17:21 kTLS TX: true
  2023/01/27 16:17:21 kTLS RX: true
  2023/01/27 16:17:21 kTLS TLS 1.3 TX: true
  2023/01/27 16:17:21 kTLS TLS 1.3 RX: false
  2023/01/27 16:17:21 kTLS TX ZeroCopy: false
  2023/01/27 16:17:21 kTLS RX Expected No Pad: false
  2023/01/27 16:17:21 =========CipherSuites=========
  2023/01/27 16:17:21 kTLS AES-GCM-128: true
  2023/01/27 16:17:21 kTLS AES-GCM-256: true
  2023/01/27 16:17:21 kTLS CHACHA20POLY1305: true
  

  Once received the message, you will see

  2023/01/27 16:20:59 try to enable kernel tls AES_128_GCM for tls 1.2
  2023/01/27 16:20:59
  key: e3104f668dfa699b3bbc49b431a2f8dd
  iv: 2cea73b9
  seq: 0000000000000001
  2023/01/27 16:20:59 kTLS: TLS_TX enabled
  2023/01/27 16:20:59
  key: 299c717c1fa903bbe56abd30567fe09e
  iv: a8b78628
  seq: 0000000000000001
  2023/01/27 16:20:59 kTLS: TLS_RX enabled
  2023/01/27 16:20:59 kTLS: recvmsg, type: 23, payload len: 6
  2023/01/27 16:20:59 kTLS: recvmsg, type: 21, payload len: 2
  

Features

• KTLS 1.2 TX & RX
• KTLS 1.3 TX & RX
• zerocopy and no pad for TLS 1.3
• ciphersuites: AES-GCM-128, AES-GCM-256, CHACHA20POLY1305

TODO

1. KTLS 1.3 RX disabled on kernel < 5.19 as it causes weird package lost
2. zero copy and no pad have not been tested yet. zero copy is enabled on kernel >= 5.19, and no pad is enabled on kernel >= 6.0

Implementation

The implementation was based on @jim3m's implementation, which was based on @FiloSottile's implementation.