Split and move auth into a separate package (#224)

* Split and move auth into a separate package

This change will make it easier to implement additional authentication
methods, such as OpenID Connect. For now, only the existing "apikeys"
authentication method is supported.

* Use absolute site prefix to prevent redirect loop

auth/apikeys/apikeys.go

@@ -1,4 +1,4 @@
-package main
+package apikeys
 
 import (
 	"bufio"
@@ -24,16 +24,18 @@ const (
 type AuthOptions struct {
 	AuthFile      string
 	UnauthMethods []string
+	BasicAuth     bool
+	SiteName      string
+	SitePath      string
 }
 
-type auth struct {
+type ApiKeysMiddleware struct {
 	successHandler http.Handler
-	failureHandler http.Handler
 	authKeys       []string
 	o              AuthOptions
 }
 
-func readAuthKeys(authFile string) []string {
+func ReadAuthKeys(authFile string) []string {
 	var authKeys []string
 
 	f, err := os.Open(authFile)
@@ -55,7 +57,7 @@ func readAuthKeys(authFile string) []string {
 	return authKeys
 }
 
-func checkAuth(authKeys []string, key string) (result bool, err error) {
+func CheckAuth(authKeys []string, key string) (result bool, err error) {
 	checkKey, err := scrypt.Key([]byte(key), []byte(scryptSalt), scryptN, scryptr, scryptp, scryptKeyLen)
 	if err != nil {
 		return
@@ -73,53 +75,74 @@ func checkAuth(authKeys []string, key string) (result bool, err error) {
 	return
 }
 
-func (a auth) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if sliceContains(a.o.UnauthMethods, r.Method) {
+func (a ApiKeysMiddleware) getSitePrefix() string {
+	prefix := a.o.SitePath
+	if len(prefix) <= 0 || prefix[0] != '/' {
+		prefix = "/" + prefix
+	}
+	return prefix
+}
+
+func (a ApiKeysMiddleware) goodAuthorizationHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Location", a.getSitePrefix())
+	w.WriteHeader(http.StatusFound)
+}
+
+func (a ApiKeysMiddleware) badAuthorizationHandler(w http.ResponseWriter, r *http.Request) {
+	if a.o.BasicAuth {
+		rs := ""
+		if a.o.SiteName != "" {
+			rs = fmt.Sprintf(` realm="%s"`, a.o.SiteName)
+		}
+		w.Header().Set("WWW-Authenticate", `Basic`+rs)
+	}
+	http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
+}
+
+func (a ApiKeysMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var successHandler http.Handler
+	prefix := a.getSitePrefix()
+
+	if r.URL.Path == prefix+"auth" {
+		successHandler = http.HandlerFunc(a.goodAuthorizationHandler)
+	} else {
+		successHandler = a.successHandler
+	}
+
+	if sliceContains(a.o.UnauthMethods, r.Method) && r.URL.Path != prefix+"auth" {
 		// allow unauthenticated methods
-		a.successHandler.ServeHTTP(w, r)
+		successHandler.ServeHTTP(w, r)
 		return
 	}
 
 	key := r.Header.Get("Linx-Api-Key")
-	if key == "" && Config.basicAuth {
+	if key == "" && a.o.BasicAuth {
 		_, password, ok := r.BasicAuth()
 		if ok {
 			key = password
 		}
 	}
 
-	result, err := checkAuth(a.authKeys, key)
+	result, err := CheckAuth(a.authKeys, key)
 	if err != nil || !result {
-		a.failureHandler.ServeHTTP(w, r)
+		http.HandlerFunc(a.badAuthorizationHandler).ServeHTTP(w, r)
 		return
 	}
 
-	a.successHandler.ServeHTTP(w, r)
+	successHandler.ServeHTTP(w, r)
 }
 
-func UploadAuth(o AuthOptions) func(*web.C, http.Handler) http.Handler {
+func NewApiKeysMiddleware(o AuthOptions) func(*web.C, http.Handler) http.Handler {
 	fn := func(c *web.C, h http.Handler) http.Handler {
-		return auth{
+		return ApiKeysMiddleware{
 			successHandler: h,
-			failureHandler: http.HandlerFunc(badAuthorizationHandler),
-			authKeys:       readAuthKeys(o.AuthFile),
+			authKeys:       ReadAuthKeys(o.AuthFile),
 			o:              o,
 		}
 	}
 	return fn
 }
 
-func badAuthorizationHandler(w http.ResponseWriter, r *http.Request) {
-	if Config.basicAuth {
-		rs := ""
-		if Config.siteName != "" {
-			rs = fmt.Sprintf(` realm="%s"`, Config.siteName)
-		}
-		w.Header().Set("WWW-Authenticate", `Basic`+rs)
-	}
-	http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
-}
-
 func sliceContains(slice []string, s string) bool {
 	for _, v := range slice {
 		if s == v {

auth/apikeys/apikeys_test.go

@@ -1,4 +1,4 @@
-package main
+package apikeys
 
 import (
 	"testing"
@@ -10,15 +10,15 @@ func TestCheckAuth(t *testing.T) {
 		"vFpNprT9wbHgwAubpvRxYCCpA2FQMAK6hFqPvAGrdZo=",
 	}
 
-	if r, err := checkAuth(authKeys, ""); err != nil && r {
+	if r, err := CheckAuth(authKeys, ""); err != nil && r {
 		t.Fatal("Authorization passed for empty key")
 	}
 
-	if r, err := checkAuth(authKeys, "thisisnotvalid"); err != nil && r {
+	if r, err := CheckAuth(authKeys, "thisisnotvalid"); err != nil && r {
 		t.Fatal("Authorization passed for invalid key")
 	}
 
-	if r, err := checkAuth(authKeys, "haPVipRnGJ0QovA9nyqK"); err != nil && !r {
+	if r, err := CheckAuth(authKeys, "haPVipRnGJ0QovA9nyqK"); err != nil && !r {
 		t.Fatal("Authorization failed for valid key")
 	}
 }

server.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	rice "github.com/GeertJohan/go.rice"
+	"github.com/andreimarcu/linx-server/auth/apikeys"
 	"github.com/andreimarcu/linx-server/backends"
 	"github.com/andreimarcu/linx-server/backends/localfs"
 	"github.com/andreimarcu/linx-server/backends/s3"
@@ -110,9 +111,12 @@ func setup() *web.Mux {
 	mux.Use(AddHeaders(Config.addHeaders))
 
 	if Config.authFile != "" {
-		mux.Use(UploadAuth(AuthOptions{
+		mux.Use(apikeys.NewApiKeysMiddleware(apikeys.AuthOptions{
 			AuthFile:      Config.authFile,
 			UnauthMethods: []string{"GET", "HEAD", "OPTIONS", "TRACE"},
+			BasicAuth:     Config.basicAuth,
+			SiteName:      Config.siteName,
+			SitePath:      Config.sitePath,
 		}))
 	}
 
@@ -196,29 +200,10 @@ func setup() *web.Mux {
 		mux.Get(Config.sitePath+"upload/", uploadRemote)
 
 		if Config.remoteAuthFile != "" {
-			remoteAuthKeys = readAuthKeys(Config.remoteAuthFile)
+			remoteAuthKeys = apikeys.ReadAuthKeys(Config.remoteAuthFile)
 		}
 	}
 
-	if Config.basicAuth {
-		options := AuthOptions{
-			AuthFile:      Config.authFile,
-			UnauthMethods: []string{},
-		}
-		okFunc := func(w http.ResponseWriter, r *http.Request) {
-			w.Header().Set("Location", Config.sitePath)
-			w.WriteHeader(http.StatusFound)
-		}
-		authHandler := auth{
-			successHandler: http.HandlerFunc(okFunc),
-			failureHandler: http.HandlerFunc(badAuthorizationHandler),
-			authKeys:       readAuthKeys(Config.authFile),
-			o:              options,
-		}
-		mux.Head(Config.sitePath+"auth", authHandler)
-		mux.Get(Config.sitePath+"auth", authHandler)
-	}
-
 	mux.Post(Config.sitePath+"upload", uploadPostHandler)
 	mux.Post(Config.sitePath+"upload/", uploadPostHandler)
 	mux.Put(Config.sitePath+"upload", uploadPutHandler)

upload.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/andreimarcu/linx-server/auth/apikeys"
 	"github.com/andreimarcu/linx-server/backends"
 	"github.com/andreimarcu/linx-server/expiry"
 	"github.com/dchest/uniuri"
@@ -166,13 +167,16 @@ func uploadRemote(c web.C, w http.ResponseWriter, r *http.Request) {
 				key = password
 			}
 		}
-		result, err := checkAuth(remoteAuthKeys, key)
+		result, err := apikeys.CheckAuth(remoteAuthKeys, key)
 		if err != nil || !result {
 			if Config.basicAuth {
-				badAuthorizationHandler(w, r)
-			} else {
-				unauthorizedHandler(c, w, r)
+				rs := ""
+				if Config.siteName != "" {
+					rs = fmt.Sprintf(` realm="%s"`, Config.siteName)
+				}
+				w.Header().Set("WWW-Authenticate", `Basic`+rs)
 			}
+			unauthorizedHandler(c, w, r)
 			return
 		}
 	}