Call GetConfigForClient in tls.Config if present

crypto/cert_chain.go

@@ -57,6 +57,15 @@ func (c *certChain) GetLeafCert(sni string) ([]byte, error) {
 
 func (cc *certChain) getCertForSNI(sni string) (*tls.Certificate, error) {
 	c := cc.config
+	if c.GetConfigForClient != nil {
+		var err error
+		c, err = c.GetConfigForClient(&tls.ClientHelloInfo{
+			ServerName: sni,
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
 	// The rest of this function is mostly copied from crypto/tls.getCertificate
 
 	if c.GetCertificate != nil {

crypto/cert_chain_test.go

@@ -127,5 +127,16 @@ var _ = Describe("Proof", func() {
 			_, err := cc.GetLeafCert("invalid domain")
 			Expect(err).To(MatchError(errNoMatchingCertificate))
 		})
+
+		It("respects GetConfigForClient", func() {
+			nestedConfig := &tls.Config{Certificates: []tls.Certificate{cert}}
+			config.GetConfigForClient = func(chi *tls.ClientHelloInfo) (*tls.Config, error) {
+				Expect(chi.ServerName).To(Equal("quic.clemente.io"))
+				return nestedConfig, nil
+			}
+			resultCert, err := cc.getCertForSNI("quic.clemente.io")
+			Expect(err).NotTo(HaveOccurred())
+			Expect(*resultCert).To(Equal(cert))
+		})
 	})
 })