implement a CertManager for the certificate chain sent by the server

crypto/cert_manager.go

@@ -0,0 +1,34 @@
+package crypto
+
+import (
+	"errors"
+
+	"github.com/lucas-clemente/quic-go/qerr"
+)
+
+// CertManager manages the certificates sent by the server
+type CertManager struct {
+	chain [][]byte
+}
+
+var errNoCertificateChain = errors.New("No certicifate chain loaded")
+
+// SetData takes the byte-slice sent in the SHLO and decompresses it into the certificate chain
+func (c *CertManager) SetData(data []byte) error {
+	chain, err := decompressChain(data)
+	if err != nil {
+		return qerr.ProofInvalid
+	}
+	c.chain = chain
+
+	return nil
+}
+
+// GetLeafCert returns the leaf certificate of the certificate chain
+// it errors if the certificate chain has not yet been set
+func (c *CertManager) GetLeafCert() []byte {
+	if len(c.chain) == 0 {
+		return nil
+	}
+	return c.chain[0]
+}

crypto/cert_manager_test.go

@@ -0,0 +1,46 @@
+package crypto
+
+import (
+	"github.com/lucas-clemente/quic-go/qerr"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Cert Manager", func() {
+	var cm *CertManager
+
+	BeforeEach(func() {
+		cm = &CertManager{}
+	})
+
+	It("errors when given invalid data", func() {
+		err := cm.SetData([]byte("foobar"))
+		Expect(err).To(MatchError(qerr.ProofInvalid))
+	})
+
+	It("decompresses a certificate chain", func() {
+		cert1 := []byte{0xde, 0xca, 0xfb, 0xad}
+		cert2 := []byte{0xde, 0xad, 0xbe, 0xef, 0x13, 0x37}
+		chain := [][]byte{cert1, cert2}
+		compressed, err := compressChain(chain, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
+		err = cm.SetData(compressed)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(cm.chain).To(Equal(chain))
+	})
+
+	Context("getting the leaf cert", func() {
+		It("gets it", func() {
+			cert1 := []byte{0xc1}
+			cert2 := []byte{0xc2}
+			cm.chain = [][]byte{cert1, cert2}
+			leafCert := cm.GetLeafCert()
+			Expect(leafCert).To(Equal(cert1))
+		})
+
+		It("returns nil if the chain hasn't been set yet", func() {
+			leafCert := cm.GetLeafCert()
+			Expect(leafCert).To(BeNil())
+		})
+	})
+})