Merge pull request #99 from Mygod/v2multiauth

Fix multiauth for caddy2

caddyfile.go

@@ -1,6 +1,7 @@
 package forwardproxy
 
 import (
+	"encoding/base64"
 	"log"
 	"strconv"
 	"strings"
@@ -21,6 +22,14 @@ func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error)
 	return &fp, err
 }
 
+// EncodeAuthCredentials base64-encode credentials
+func EncodeAuthCredentials(user, pass string) (result []byte) {
+	raw := []byte(user + ":" + pass)
+	result = make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
+	base64.StdEncoding.Encode(result, raw)
+	return
+}
+
 // UnmarshalCaddyfile unmarshals Caddyfile tokens into h.
 func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 	if !d.Next() {
@@ -45,13 +54,10 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			if strings.Contains(args[0], ":") {
 				return d.Err("character ':' in usernames is not allowed")
 			}
-			// TODO: Support multiple basicauths.
-			// TODO: Actually, just try to use Caddy 2's existing basicauth module.
-			if h.BasicauthUser != "" || h.BasicauthPass != "" {
-				return d.Err("Multi-user basicauth is not supported")
+			if h.AuthCredentials == nil {
+				h.AuthCredentials = [][]byte{}
 			}
-			h.BasicauthUser = args[0]
-			h.BasicauthPass = args[1]
+			h.AuthCredentials = append(h.AuthCredentials, EncodeAuthCredentials(args[0], args[1]))
 		case "hosts":
 			if len(args) == 0 {
 				return d.ArgErr()

common_test.go

@@ -201,21 +201,19 @@ func TestMain(m *testing.M) {
 		root: "./test/forwardproxy",
 		tls:  true,
 		proxyHandler: &Handler{
-			PACPath:       defaultPACPath,
-			ACL:           []ACLRule{{Subjects: []string{"all"}, Allow: true}},
-			BasicauthUser: "test",
-			BasicauthPass: "pass",
+			PACPath:         defaultPACPath,
+			ACL:             []ACLRule{{Subjects: []string{"all"}, Allow: true}},
+			AuthCredentials: [][]byte{EncodeAuthCredentials("test", "pass")},
 		},
 	}
 
 	caddyHTTPForwardProxyAuth = caddyTestServer{
 		addr: "127.0.69.73:6973",
 		root: "./test/forwardproxy",
 		proxyHandler: &Handler{
-			PACPath:       defaultPACPath,
-			ACL:           []ACLRule{{Subjects: []string{"all"}, Allow: true}},
-			BasicauthUser: "test",
-			BasicauthPass: "pass",
+			PACPath:         defaultPACPath,
+			ACL:             []ACLRule{{Subjects: []string{"all"}, Allow: true}},
+			AuthCredentials: [][]byte{EncodeAuthCredentials("test", "pass")},
 		},
 	}
 
@@ -227,8 +225,7 @@ func TestMain(m *testing.M) {
 			PACPath:         "/superhiddenfile.pac",
 			ACL:             []ACLRule{{Subjects: []string{"all"}, Allow: true}},
 			ProbeResistance: &ProbeResistance{Domain: "test.localhost"},
-			BasicauthUser:   "test",
-			BasicauthPass:   "pass",
+			AuthCredentials: [][]byte{EncodeAuthCredentials("test", "pass")},
 		},
 		httpRedirPort: "8880",
 	}
@@ -255,9 +252,8 @@ func TestMain(m *testing.M) {
 		root: "./test/upstreamingproxy",
 		tls:  true,
 		proxyHandler: &Handler{
-			Upstream:      "https://test:[email protected]:4891",
-			BasicauthUser: "upstreamtest",
-			BasicauthPass: "upstreampass",
+			Upstream:        "https://test:[email protected]:4891",
+			AuthCredentials: [][]byte{EncodeAuthCredentials("upstreamtest", "upstreampass")},
 		},
 	}
 

forwardproxy.go

@@ -35,6 +35,7 @@ import (
 	"strings"
 	"sync"
 	"time"
+	"unicode/utf8"
 
 	caddy "github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
@@ -91,10 +92,7 @@ type Handler struct {
 	aclRules []aclRule
 
 	// TODO: temporary/deprecated - we should try to reuse existing authentication modules instead!
-	BasicauthUser   string `json:"auth_user_deprecated,omitempty"`
-	BasicauthPass   string `json:"auth_pass_deprecated,omitempty"`
-	authRequired    bool
-	authCredentials [][]byte // slice with base64-encoded credentials
+	AuthCredentials [][]byte `json:"auth_credentials,omitempty"` // slice with base64-encoded credentials
 }
 
 // CaddyModule returns the Caddy module information.
@@ -120,14 +118,6 @@ func (h *Handler) Provision(ctx caddy.Context) error {
 		TLSHandshakeTimeout: 10 * time.Second,
 	}
 
-	// TODO: temporary, in an effort to get the tests to pass
-	if h.BasicauthUser != "" && h.BasicauthPass != "" {
-		basicAuthBuf := make([]byte, base64.StdEncoding.EncodedLen(len(h.BasicauthUser)+1+len(h.BasicauthPass)))
-		base64.StdEncoding.Encode(basicAuthBuf, []byte(h.BasicauthUser+":"+h.BasicauthPass))
-		h.authRequired = true
-		h.authCredentials = [][]byte{basicAuthBuf}
-	}
-
 	// access control lists
 	for _, rule := range h.ACL {
 		for _, subj := range rule.Subjects {
@@ -155,7 +145,7 @@ func (h *Handler) Provision(ctx caddy.Context) error {
 	h.aclRules = append(h.aclRules, &aclAllRule{allow: true})
 
 	if h.ProbeResistance != nil {
-		if !h.authRequired {
+		if h.AuthCredentials == nil {
 			return fmt.Errorf("probe resistance requires authentication")
 		}
 		if len(h.ProbeResistance.Domain) > 0 {
@@ -237,7 +227,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyht
 	}
 
 	var authErr error
-	if h.authRequired {
+	if h.AuthCredentials != nil {
 		authErr = h.checkCredentials(r)
 	}
 	if h.ProbeResistance != nil && len(h.ProbeResistance.Domain) > 0 && reqHost == h.ProbeResistance.Domain {
@@ -421,14 +411,37 @@ func (h Handler) checkCredentials(r *http.Request) error {
 	if strings.ToLower(pa[0]) != "basic" {
 		return errors.New("auth type is not supported")
 	}
-	for _, creds := range h.authCredentials {
+	for _, creds := range h.AuthCredentials {
 		if subtle.ConstantTimeCompare(creds, []byte(pa[1])) == 1 {
+			repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
+			buf := make([]byte, base64.StdEncoding.DecodedLen(len(creds)))
+			_, _ = base64.StdEncoding.Decode(buf, creds) // should not err ever since we are decoding a known good input
+			cred := string(buf)
+			repl.Set("http.auth.user.id", cred[:strings.IndexByte(cred, ':')])
 			// Please do not consider this to be timing-attack-safe code. Simple equality is almost
 			// mindlessly substituted with constant time algo and there ARE known issues with this code,
 			// e.g. size of smallest credentials is guessable. TODO: protect from all the attacks! Hash?
 			return nil
 		}
 	}
+	repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
+	buf := make([]byte, base64.StdEncoding.DecodedLen(len([]byte(pa[1]))))
+	n, err := base64.StdEncoding.Decode(buf, []byte(pa[1]))
+	if err != nil {
+		repl.Set("http.auth.user.id", "invalidbase64:"+err.Error())
+		return err
+	}
+	if utf8.Valid(buf[:n]) {
+		cred := string(buf[:n])
+		i := strings.IndexByte(cred, ':')
+		if i >= 0 {
+			repl.Set("http.auth.user.id", "invalid:"+cred[:i])
+		} else {
+			repl.Set("http.auth.user.id", "invalidformat:"+cred)
+		}
+	} else {
+		repl.Set("http.auth.user.id", "invalid::")
+	}
 	return errors.New("invalid credentials")
 }