From b58bc8cffda22edb8ace72e96489b3943492c400 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Thu, 10 Nov 2016 18:33:24 +0700
Subject: [PATCH] parse server config sent in the SHLO in client CryptoSetup

---
 handshake/crypto_setup_client.go       | 11 +++++++++++
 handshake/crypto_setup_client_test.go  | 23 +++++++++++++++++++++++
 handshake/server_config_client_test.go | 21 +++++++++++++--------
 3 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/handshake/crypto_setup_client.go b/handshake/crypto_setup_client.go
index ce7365b7c..42a4562db 100644
--- a/handshake/crypto_setup_client.go
+++ b/handshake/crypto_setup_client.go
@@ -82,13 +82,24 @@ func (h *cryptoSetupClient) HandleCryptoStream() error {
 
 func (h *cryptoSetupClient) handleREJMessage(cryptoData map[Tag][]byte) error {
 	utils.Debugf("Got REJ:\n%s", printHandshakeMessage(cryptoData))
+
+	var err error
+
 	if stk, ok := cryptoData[TagSTK]; ok {
 		h.stk = stk
 	}
+
 	if sno, ok := cryptoData[TagSNO]; ok {
 		h.sno = sno
 	}
 
+	if scfg, ok := cryptoData[TagSCFG]; ok {
+		h.serverConfig, err = parseServerConfig(scfg)
+		if err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
diff --git a/handshake/crypto_setup_client_test.go b/handshake/crypto_setup_client_test.go
index d214626f1..247540571 100644
--- a/handshake/crypto_setup_client_test.go
+++ b/handshake/crypto_setup_client_test.go
@@ -62,6 +62,29 @@ var _ = Describe("Crypto setup", func() {
 			Expect(err).ToNot(HaveOccurred())
 			Expect(cs.sno).To(Equal(nonc))
 		})
+
+		Context("Reading server configs", func() {
+			It("reads a server config", func() {
+				b := &bytes.Buffer{}
+				scfg := getDefaultServerConfigClient()
+				WriteHandshakeMessage(b, TagSCFG, scfg)
+				tagMap[TagSCFG] = b.Bytes()
+				err := cs.handleREJMessage(tagMap)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(cs.serverConfig).ToNot(BeNil())
+				Expect(cs.serverConfig.ID).To(Equal(scfg[TagSCID]))
+			})
+
+			It("passes on errors from reading the server config", func() {
+				b := &bytes.Buffer{}
+				WriteHandshakeMessage(b, TagSHLO, make(map[Tag][]byte))
+				tagMap[TagSCFG] = b.Bytes()
+				_, origErr := parseServerConfig(b.Bytes())
+				err := cs.handleREJMessage(tagMap)
+				Expect(err).To(HaveOccurred())
+				Expect(err).To(MatchError(origErr))
+			})
+		})
 	})
 
 	Context("CHLO generation", func() {
diff --git a/handshake/server_config_client_test.go b/handshake/server_config_client_test.go
index bfae57cf5..2625de939 100644
--- a/handshake/server_config_client_test.go
+++ b/handshake/server_config_client_test.go
@@ -9,18 +9,23 @@ import (
 	. "github.com/onsi/gomega"
 )
 
+// This tagMap can be passed to parseValues and is garantueed to not cause any errors
+func getDefaultServerConfigClient() map[Tag][]byte {
+	return map[Tag][]byte{
+		TagSCID: bytes.Repeat([]byte{'F'}, 16),
+		TagKEXS: []byte("C255"),
+		TagAEAD: []byte("AESG"),
+		TagPUBS: bytes.Repeat([]byte{0}, 35),
+		TagOBIT: bytes.Repeat([]byte{0}, 8),
+		TagEXPY: bytes.Repeat([]byte{0}, 8),
+	}
+}
+
 var _ = Describe("Server Config", func() {
 	var tagMap map[Tag][]byte
 
 	BeforeEach(func() {
-		// This tagMap can be passed to parseValues and doesn't cause any errors
-		tagMap = make(map[Tag][]byte)
-		tagMap[TagSCID] = bytes.Repeat([]byte{'F'}, 16)
-		tagMap[TagKEXS] = []byte("C255")
-		tagMap[TagAEAD] = []byte("AESG")
-		tagMap[TagPUBS] = bytes.Repeat([]byte{0}, 35)
-		tagMap[TagOBIT] = bytes.Repeat([]byte{0}, 8)
-		tagMap[TagEXPY] = bytes.Repeat([]byte{0}, 8)
+		tagMap = getDefaultServerConfigClient()
 	})
 
 	It("returns the parsed server config", func() {