Generate certificates on demand

cert.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/ed25519"
 	"crypto/rand"
+	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
 	"math/big"
@@ -14,27 +15,25 @@ import (
 )
 
 // CertificateStore maps hostnames to certificates.
-type CertificateStore struct {
-	store map[string]*x509.Certificate // map of hostnames to certificates
+type CertificateStore map[string]*tls.Certificate
+
+// NewCertificateStore creates and returns a new certificate store.
+func NewCertificateStore() CertificateStore {
+	return map[string]*tls.Certificate{}
 }
 
-func NewCertificateStore() *CertificateStore {
-	return &CertificateStore{
-		store: map[string]*x509.Certificate{},
+// NewCertificate creates and returns a new parsed certificate.
+func NewCertificate(host string, duration time.Duration) (tls.Certificate, error) {
+	crt, key, err := NewRawCertificate(host, duration)
+	if err != nil {
+		return tls.Certificate{}, err
 	}
+	return tls.X509KeyPair(crt, key)
 }
 
-func (c *CertificateStore) Put(hostname string, cert *x509.Certificate) {
-	c.store[hostname] = cert
-}
-
-func (c *CertificateStore) Get(hostname string) *x509.Certificate {
-	return c.store[hostname]
-}
-
-// NewCertificate creates and returns a raw certificate for the given host.
+// NewRawCertificate creates and returns a raw certificate for the given host.
 // It generates a self-signed TLS certificate and a ED25519 private key.
-func NewCertificate(host string) (crt, key []byte, err error) {
+func NewRawCertificate(host string, duration time.Duration) (crt, key []byte, err error) {
 	// Generate a ED25519 private key
 	_, priv, err := ed25519.GenerateKey(rand.Reader)
 	if err != nil {
@@ -47,8 +46,7 @@ func NewCertificate(host string) (crt, key []byte, err error) {
 	keyUsage := x509.KeyUsageDigitalSignature
 
 	notBefore := time.Now()
-	validFor := 365 * 24 * time.Hour
-	notAfter := notBefore.Add(validFor)
+	notAfter := notBefore.Add(duration)
 
 	// Generate the serial number
 	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)

client.go

@@ -185,11 +185,11 @@ type Client struct {
 	KnownHosts KnownHosts
 
 	// CertificateStore contains all the certificates that the client has stored.
-	CertificateStore *CertificateStore
+	CertificateStore CertificateStore
 
 	// GetCertificate, if not nil, will be called to determine which certificate
 	// (if any) should be used for a request.
-	GetCertificate func(req *Request, store *CertificateStore) *tls.Certificate
+	GetCertificate func(hostname string, store CertificateStore) *tls.Certificate
 
 	// TrustCertificate, if not nil, will be called to determine whether the
 	// client should trust the given certificate.
@@ -205,14 +205,14 @@ func (c *Client) Send(req *Request) (*Response, error) {
 		MinVersion:         tls.VersionTLS12,
 		GetClientCertificate: func(info *tls.CertificateRequestInfo) (*tls.Certificate, error) {
 			if c.GetCertificate != nil {
-				if cert := c.GetCertificate(req, c.CertificateStore); cert != nil {
+				if cert := c.GetCertificate(req.Hostname(), c.CertificateStore); cert != nil {
 					return cert, nil
 				}
 			}
-			if req.Certificate == nil {
-				return &tls.Certificate{}, nil
-			}
+			if req.Certificate != nil {
 				return req.Certificate, nil
+			}
+			return &tls.Certificate{}, nil
 		},
 		VerifyPeerCertificate: func(rawCerts [][]byte, _ [][]*x509.Certificate) error {
 			// Parse the certificate

examples/cert/cert.go

@@ -4,19 +4,21 @@ package main
 
 import (
 	"log"
+	"time"
 
-	"git.sr.ht/~adnano/go-gemini"
+	gmi "git.sr.ht/~adnano/go-gemini"
 )
 
 func main() {
 	host := "localhost"
 
-	crt, key, err := gemini.NewCertificate(host)
+	duration := 365 * 24 * time.Hour
+	crt, key, err := gmi.NewRawCertificate(host, duration)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	if err := gemini.WriteCertificate(host, crt, key); err != nil {
+	if err := gmi.WriteCertificate(host, crt, key); err != nil {
 		log.Fatal(err)
 	}
 }

examples/client/client.go

@@ -4,21 +4,22 @@ package main
 
 import (
 	"bufio"
+	"crypto/tls"
 	"crypto/x509"
 	"fmt"
 	"os"
+	"time"
 
-	"git.sr.ht/~adnano/go-gemini"
+	gmi "git.sr.ht/~adnano/go-gemini"
 )
 
 var (
 	scanner = bufio.NewScanner(os.Stdin)
-	client  *gmi.Client
+	client  = &gmi.Client{}
 )
 
 func init() {
 	// Initialize the client
-	client = &gmi.Client{}
 	client.KnownHosts.Load() // Load known hosts
 	client.TrustCertificate = func(hostname string, cert *x509.Certificate, knownHosts *gmi.KnownHosts) error {
 		err := knownHosts.Lookup(hostname, cert)
@@ -45,6 +46,21 @@ func init() {
 		}
 		return err
 	}
+
+	client.CertificateStore = gmi.NewCertificateStore()
+	client.GetCertificate = func(hostname string, store gmi.CertificateStore) *tls.Certificate {
+		if cert, ok := store[hostname]; ok {
+			return cert
+		}
+		// Generate a certificate
+		duration := time.Hour
+		cert, err := gmi.NewCertificate(hostname, duration)
+		if err != nil {
+			return nil
+		}
+		store[hostname] = &cert
+		return &cert
+	}
 }
 
 // sendRequest sends a request to the given URL.
@@ -67,7 +83,7 @@ func sendRequest(req *gmi.Request) error {
 	case gmi.StatusClassRedirect:
 		fmt.Println("Redirecting to", resp.Meta)
 		// Make the request to the same host
-		red, err := gmi.NewRequestTo(req.Host, resp.Meta)
+		red, err := gmi.NewRequestTo(resp.Meta, req.Host)
 		if err != nil {
 			return err
 		}