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