introduce tls support

README.md

@@ -9,6 +9,7 @@ Dumbiest HTTP proxy ever.
 * Zero-configuration
 * Supports CONNECT method and forwarding of HTTPS connections
 * Supports `Basic` proxy authentication
+* Supports TLS operation mode (HTTP(S) proxy over TLS)
 
 ## Installation
 
@@ -72,6 +73,10 @@ $ ~/go/bin/dumbproxy -h
     	auth parameters (default "none://")
   -bind-address string
     	HTTP proxy listen address (default ":8080")
+  -cert string
+    	enable TLS and use certificate
+  -key string
+    	key for TLS certificate
   -timeout duration
     	timeout for network operations (default 10s)
   -verbosity int

main.go

@@ -26,6 +26,7 @@ type CLIArgs struct {
     auth string
     verbosity int
     timeout time.Duration
+    cert, key string
 }
 
 
@@ -36,6 +37,8 @@ func parse_args() CLIArgs {
     flag.IntVar(&args.verbosity, "verbosity", 20, "logging verbosity " +
             "(10 - debug, 20 - info, 30 - warning, 40 - error, 50 - critical)")
     flag.DurationVar(&args.timeout, "timeout", 10 * time.Second, "timeout for network operations")
+    flag.StringVar(&args.cert, "cert", "", "enable TLS and use certificate")
+    flag.StringVar(&args.key, "key", "", "key for TLS certificate")
     flag.Parse()
     return args
 }
@@ -52,14 +55,30 @@ func run() int {
     proxyLogger := NewCondLogger(log.New(logWriter, "PROXY   : ",
                                 log.LstdFlags | log.Lshortfile),
                                 args.verbosity)
-    mainLogger.Info("Starting proxy server...")
+
     auth, err := NewAuth(args.auth)
     if err != nil {
         mainLogger.Critical("Failed to instantiate auth provider: %v", err)
         return 3
     }
-    handler := NewProxyHandler(args.timeout, auth, proxyLogger)
-    err = http.ListenAndServe(args.bind_address, handler)
+
+    var server http.Server
+    server.Addr = args.bind_address
+    server.Handler = NewProxyHandler(args.timeout, auth, proxyLogger)
+    server.ErrorLog = log.New(logWriter, "HTTPSRV : ", log.LstdFlags | log.Lshortfile)
+
+    mainLogger.Info("Starting proxy server...")
+    if args.cert != "" {
+        cfg, err1 := makeServerTLSConfig(args.cert, args.key, "")
+        if err1 != nil {
+            mainLogger.Critical("TLS config construction failed: %v", err)
+            return 3
+        }
+        server.TLSConfig = cfg
+        err = server.ListenAndServeTLS("", "")
+    } else {
+        err = server.ListenAndServe()
+    }
     mainLogger.Critical("Server terminated with a reason: %v", err)
     mainLogger.Info("Shutting down...")
     return 0

utils.go

@@ -9,6 +9,9 @@ import (
     "errors"
     "net/http"
     "bufio"
+    "crypto/tls"
+    "crypto/x509"
+    "io/ioutil"
 )
 
 const COPY_BUF = 128 * 1024
@@ -108,3 +111,25 @@ func copyBody(wr io.Writer, body io.Reader) {
         }
     }
 }
+
+func makeServerTLSConfig(certfile, keyfile, cafile string) (*tls.Config, error) {
+    var cfg tls.Config
+    cert, err := tls.LoadX509KeyPair(certfile, keyfile)
+    if err != nil {
+        return nil, err
+    }
+    cfg.Certificates = []tls.Certificate{cert}
+    if cafile != "" {
+        roots := x509.NewCertPool()
+        certs, err := ioutil.ReadFile(cafile)
+        if err != nil {
+            return nil, err
+        }
+        if ok := roots.AppendCertsFromPEM(certs); !ok {
+            return nil, errors.New("Failed to load CA certificates")
+        }
+        cfg.ClientCAs = roots
+        cfg.ClientAuth = tls.VerifyClientCertIfGiven
+    }
+    return &cfg, nil
+}