66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
package crypto
|
|
|
|
import (
|
|
"crypto"
|
|
"crypto/ecdsa"
|
|
"crypto/rand"
|
|
"crypto/rsa"
|
|
"crypto/sha256"
|
|
"crypto/tls"
|
|
"crypto/x509"
|
|
"encoding/asn1"
|
|
"errors"
|
|
"math/big"
|
|
)
|
|
|
|
type ecdsaSignature struct {
|
|
R, S *big.Int
|
|
}
|
|
|
|
// signServerProof signs CHLO and server config for use in the server proof
|
|
func signServerProof(cert *tls.Certificate, chlo []byte, serverConfigData []byte) ([]byte, error) {
|
|
hash := sha256.New()
|
|
hash.Write([]byte("QUIC CHLO and server config signature\x00"))
|
|
chloHash := sha256.Sum256(chlo)
|
|
hash.Write([]byte{32, 0, 0, 0})
|
|
hash.Write(chloHash[:])
|
|
hash.Write(serverConfigData)
|
|
|
|
key, ok := cert.PrivateKey.(crypto.Signer)
|
|
if !ok {
|
|
return nil, errors.New("expected PrivateKey to implement crypto.Signer")
|
|
}
|
|
|
|
opts := crypto.SignerOpts(crypto.SHA256)
|
|
|
|
if _, ok = key.(*rsa.PrivateKey); ok {
|
|
opts = &rsa.PSSOptions{SaltLength: 32, Hash: crypto.SHA256}
|
|
}
|
|
|
|
return key.Sign(rand.Reader, hash.Sum(nil), opts)
|
|
}
|
|
|
|
// verifyServerProof verifies the server proof signature
|
|
func verifyServerProof(proof []byte, cert *x509.Certificate, chlo []byte, serverConfigData []byte) bool {
|
|
hash := sha256.New()
|
|
hash.Write([]byte("QUIC CHLO and server config signature\x00"))
|
|
chloHash := sha256.Sum256(chlo)
|
|
hash.Write([]byte{32, 0, 0, 0})
|
|
hash.Write(chloHash[:])
|
|
hash.Write(serverConfigData)
|
|
|
|
// RSA
|
|
if cert.PublicKeyAlgorithm == x509.RSA {
|
|
opts := &rsa.PSSOptions{SaltLength: 32, Hash: crypto.SHA256}
|
|
err := rsa.VerifyPSS(cert.PublicKey.(*rsa.PublicKey), crypto.SHA256, hash.Sum(nil), proof, opts)
|
|
return err == nil
|
|
}
|
|
|
|
// ECDSA
|
|
signature := &ecdsaSignature{}
|
|
rest, err := asn1.Unmarshal(proof, signature)
|
|
if err != nil || len(rest) != 0 {
|
|
return false
|
|
}
|
|
return ecdsa.Verify(cert.PublicKey.(*ecdsa.PublicKey), hash.Sum(nil), signature.R, signature.S)
|
|
}
|