make handshake and crypto internal packages

internal/crypto/cert_chain.go

@@ -0,0 +1,113 @@
+package crypto
+
+import (
+	"crypto/tls"
+	"errors"
+	"strings"
+)
+
+// A CertChain holds a certificate and a private key
+type CertChain interface {
+	SignServerProof(sni string, chlo []byte, serverConfigData []byte) ([]byte, error)
+	GetCertsCompressed(sni string, commonSetHashes, cachedHashes []byte) ([]byte, error)
+	GetLeafCert(sni string) ([]byte, error)
+}
+
+// proofSource stores a key and a certificate for the server proof
+type certChain struct {
+	config *tls.Config
+}
+
+var _ CertChain = &certChain{}
+
+var errNoMatchingCertificate = errors.New("no matching certificate found")
+
+// NewCertChain loads the key and cert from files
+func NewCertChain(tlsConfig *tls.Config) CertChain {
+	return &certChain{config: tlsConfig}
+}
+
+// SignServerProof signs CHLO and server config for use in the server proof
+func (c *certChain) SignServerProof(sni string, chlo []byte, serverConfigData []byte) ([]byte, error) {
+	cert, err := c.getCertForSNI(sni)
+	if err != nil {
+		return nil, err
+	}
+
+	return signServerProof(cert, chlo, serverConfigData)
+}
+
+// GetCertsCompressed gets the certificate in the format described by the QUIC crypto doc
+func (c *certChain) GetCertsCompressed(sni string, pCommonSetHashes, pCachedHashes []byte) ([]byte, error) {
+	cert, err := c.getCertForSNI(sni)
+	if err != nil {
+		return nil, err
+	}
+	return getCompressedCert(cert.Certificate, pCommonSetHashes, pCachedHashes)
+}
+
+// GetLeafCert gets the leaf certificate
+func (c *certChain) GetLeafCert(sni string) ([]byte, error) {
+	cert, err := c.getCertForSNI(sni)
+	if err != nil {
+		return nil, err
+	}
+	return cert.Certificate[0], nil
+}
+
+func (cc *certChain) getCertForSNI(sni string) (*tls.Certificate, error) {
+	c := cc.config
+	c, err := maybeGetConfigForClient(c, sni)
+	if err != nil {
+		return nil, err
+	}
+	// The rest of this function is mostly copied from crypto/tls.getCertificate
+
+	if c.GetCertificate != nil {
+		cert, err := c.GetCertificate(&tls.ClientHelloInfo{ServerName: sni})
+		if cert != nil || err != nil {
+			return cert, err
+		}
+	}
+
+	if len(c.Certificates) == 0 {
+		return nil, errNoMatchingCertificate
+	}
+
+	if len(c.Certificates) == 1 || c.NameToCertificate == nil {
+		// There's only one choice, so no point doing any work.
+		return &c.Certificates[0], nil
+	}
+
+	name := strings.ToLower(sni)
+	for len(name) > 0 && name[len(name)-1] == '.' {
+		name = name[:len(name)-1]
+	}
+
+	if cert, ok := c.NameToCertificate[name]; ok {
+		return cert, nil
+	}
+
+	// try replacing labels in the name with wildcards until we get a
+	// match.
+	labels := strings.Split(name, ".")
+	for i := range labels {
+		labels[i] = "*"
+		candidate := strings.Join(labels, ".")
+		if cert, ok := c.NameToCertificate[candidate]; ok {
+			return cert, nil
+		}
+	}
+
+	// If nothing matches, return the first certificate.
+	return &c.Certificates[0], nil
+}
+
+func maybeGetConfigForClient(c *tls.Config, sni string) (*tls.Config, error) {
+	if c.GetConfigForClient == nil {
+		return c, nil
+	}
+	return c.GetConfigForClient(&tls.ClientHelloInfo{
+		ServerName: sni,
+	})
+}