mirror of
https://github.com/slackhq/nebula.git
synced 2026-07-01 19:10:29 +02:00
Wade Simmons
93 lines
2.7 KiB
Go
93 lines
2.7 KiB
Go
//go:build !boringcrypto
|
|
|
|
package noiseutil
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/cipher"
|
|
"encoding/binary"
|
|
|
|
// unsafe needed for go:linkname
|
|
_ "unsafe"
|
|
|
|
"github.com/flynn/noise"
|
|
)
|
|
|
|
// TODO: Use NewGCMWithCounterNonce or NewGCMForQUIC once available:
|
|
// - https://github.com/golang/go/issues/73110
|
|
// - https://github.com/golang/go/issues/79219
|
|
// Using tls.aeadAESGCMTLS13 gives us the TLS 1.3 GCM, which also verifies
|
|
// that the nonce is strictly increasing.
|
|
//
|
|
//go:linkname aeadAESGCMTLS13 crypto/tls.aeadAESGCMTLS13
|
|
func aeadAESGCMTLS13(key, noncePrefix []byte) cipher.AEAD
|
|
|
|
type cipherFn struct {
|
|
fn func([32]byte) noise.Cipher
|
|
name string
|
|
}
|
|
|
|
func (c cipherFn) Cipher(k [32]byte) noise.Cipher { return c.fn(k) }
|
|
func (c cipherFn) CipherName() string { return c.name }
|
|
|
|
// CipherAESGCM is the AES256-GCM AEAD cipher (using aeadAESGCM when fips140 is enabled)
|
|
var CipherAESGCMFIPS140 noise.CipherFunc = cipherFn{cipherAESGCMFIPS140, "AESGCM"}
|
|
|
|
// tls.aeadAESGCMTLS13 uses a 4 byte static prefix and an 8 byte XOR mask
|
|
var emptyPrefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
|
|
var emptyNonce = []byte{0, 0, 0, 0, 0, 0, 0, 0}
|
|
|
|
func cipherAESGCMFIPS140(k [32]byte) noise.Cipher {
|
|
gcm := aeadAESGCMTLS13(k[:], emptyPrefix)
|
|
return &aeadCipher{
|
|
AEAD: gcm,
|
|
ready: false,
|
|
nonce: func(n uint64) []byte {
|
|
// tls.aeadAESGCMTLS13 uses a 4 byte static prefix and an 8 byte nonce
|
|
var nonce [8]byte
|
|
binary.BigEndian.PutUint64(nonce[:], n)
|
|
return nonce[:]
|
|
},
|
|
}
|
|
}
|
|
|
|
func (c *aeadCipher) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
|
|
// runtime.Breakpoint()
|
|
if !c.ready {
|
|
// crypto/tls.aeadAESGCMTLS13 expected that the first call to Seal
|
|
// is with a counter of `0`, this is how it extracts the nonce mask.
|
|
// We can clean this up in the future when NewGCMWithCounterNonce or
|
|
// NewGCMForQUIC are available:
|
|
if !bytes.Equal(emptyNonce, nonce) {
|
|
c.AEAD.Seal([]byte{}, emptyNonce, []byte{}, []byte{})
|
|
}
|
|
c.ready = true
|
|
}
|
|
return c.AEAD.Seal(dst, nonce, plaintext, additionalData)
|
|
}
|
|
|
|
type aeadCipher struct {
|
|
cipher.AEAD
|
|
ready bool
|
|
nonce func(uint64) []byte
|
|
}
|
|
|
|
func (c *aeadCipher) Encrypt(out []byte, n uint64, ad, plaintext []byte) []byte {
|
|
return c.Seal(out, c.nonce(n), plaintext, ad)
|
|
}
|
|
|
|
func (c *aeadCipher) Decrypt(out []byte, n uint64, ad, ciphertext []byte) ([]byte, error) {
|
|
return c.Open(out, c.nonce(n), ciphertext, ad)
|
|
}
|
|
|
|
func (c *aeadCipher) EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error) {
|
|
binary.BigEndian.PutUint64(nb[4:], n)
|
|
out = c.Seal(out, nb[4:], plaintext, ad)
|
|
return out, nil
|
|
}
|
|
|
|
func (c *aeadCipher) DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error) {
|
|
binary.BigEndian.PutUint64(nb[4:], n)
|
|
return c.Open(out, nb[4:], ciphertext, ad)
|
|
}
|