Start working on ACLs

cmd/simpleauth/main.go

@@ -7,6 +7,7 @@ import (
 	"io/ioutil"
 	"log"
 	"net/http"
+	"net/url"
 	"os"
 	"path"
 	"strings"
@@ -23,6 +24,19 @@ var secret []byte = make([]byte, 256)
 var lifespan time.Duration
 var cryptedPasswords map[string]string
 var loginHtml []byte
+var verbose bool
+
+func debugln(v ...any) {
+	if verbose {
+		log.Println(v...)
+	}
+}
+
+func debugf(fmt string, v ...any) {
+	if verbose {
+		log.Printf(fmt, v...)
+	}
+}
 
 func authenticationValid(username, password string) bool {
 	c := crypt.SHA256.New()
@@ -35,18 +49,31 @@ func authenticationValid(username, password string) bool {
 }
 
 func usernameIfAuthenticated(req *http.Request) string {
-	if cookie, err := req.Cookie(CookieName); err == nil {
-		t, _ := token.ParseString(cookie.Value)
-		if t.Valid(secret) {
-			return t.Username
-		}
-	}
-
-	authUsername, authPassword, ok := req.BasicAuth()
-	if ok {
-		if authenticationValid(authUsername, authPassword) {
+	if authUsername, authPassword, ok := req.BasicAuth(); ok {
+		valid := authenticationValid(authUsername, authPassword)
+		debugf("basic auth valid:%v username:%v", valid, authUsername)
+		if valid {
 			return authUsername
 		}
+	} else {
+    debugf("no basic auth")
+  }
+
+  ncookies := 0
+	for i, cookie := range req.Cookies() {
+		if cookie.Name != CookieName {
+			continue
+		}
+		t, _ := token.ParseString(cookie.Value)
+		valid := t.Valid(secret)
+		debugf("cookie %d valid:%v username:%v", i, valid, t.Username)
+		if valid {
+			return t.Username
+		}
+    ncookies += 1
+	}
+  if ncookies == 0 {
+    debugf("no cookies")
   }
 
 	return ""
@@ -79,12 +106,23 @@ func rootHandler(w http.ResponseWriter, req *http.Request) {
 		// which needs these headers to set the cookie and try again.
 	}
 
-	// Log the request
 	clientIP := req.Header.Get("X-Real-IP")
 	if clientIP == "" {
 		clientIP = req.RemoteAddr
 	}
-	log.Println(clientIP, req.Method, req.URL, status, username)
+	forwardedMethod := req.Header.Get("X-Forwarded-Method")
+	forwardedURL := url.URL{
+		Scheme: req.Header.Get("X-Forwarded-Proto"),
+		Host:  req.Header.Get("X-Forwarded-Host"),
+		Path:  req.Header.Get("X-Forwarded-Uri"),
+		User:  url.UserPassword(username, ""),
+	}
+
+	// Log the request
+	log.Printf("%s %s %s login:%v %s",
+		clientIP, forwardedMethod, forwardedURL.String(),
+		login, status,
+	)
 
 	w.Header().Set("Content-Type", "text/html")
 	w.Header().Set("X-Simpleauth-Authentication", status)
@@ -124,6 +162,12 @@ func main() {
 		"web",
 		"Path to HTML files",
 	)
+	flag.BoolVar(
+		&verbose,
+		"verbose",
+		false,
+		"Print verbose logs, for debugging",
+	)
 	flag.Parse()
 
 	cryptedPasswords = make(map[string]string, 10)

go.mod

@@ -1,9 +1,13 @@
 module git.woozle.org/neale/simpleauth
 
-go 1.13
+go 1.18
 
 require (
 	github.com/GehirnInc/crypt v0.0.0-20200316065508-bb7000b8a962
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/stretchr/testify v1.8.1 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect

pkg/acl/acl.go

@@ -0,0 +1,46 @@
+package acl
+
+import (
+	"io"
+	"log"
+	"net/http"
+
+	"gopkg.in/yaml.v3"
+)
+
+type ACL struct {
+	Rules []Rule
+}
+
+func Read(r io.Reader) (*ACL, error) {
+	acl := ACL{}
+	ydec := yaml.NewDecoder(r)
+	if err := ydec.Decode(&acl); err != nil {
+		return nil, err
+	}
+	if err := acl.CompileURLs(); err != nil {
+		return nil, err
+	}
+	return &acl, nil
+}
+
+// CompileURLs compiles regular expressions for all URLs.
+func (acl *ACL) CompileURLs() error {
+	for i := range acl.Rules {
+		rule := &acl.Rules[i]
+		if err := rule.CompileURL(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (acl *ACL) Match(req *http.Request) Action {
+	for _, rule := range acl.Rules {
+		log.Println(rule)
+		if rule.Match(req) {
+			return rule.Action
+		}
+	}
+	return Deny
+}

pkg/acl/acl_test.go

@@ -0,0 +1,89 @@
+package acl
+
+import (
+	"net/http"
+	"net/url"
+	"os"
+	"testing"
+)
+
+type testAcl struct {
+	t   *testing.T
+	acl *ACL
+}
+
+func readAcl(filename string) (*ACL, error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	acl, err := Read(f)
+	if err != nil {
+		return nil, err
+	}
+	return acl, nil
+}
+
+func (ta *testAcl) try(method string, URL string, expected Action) {
+	u, err := url.Parse(URL)
+	if err != nil {
+		ta.t.Errorf("Parsing %s: %v", URL, err)
+	}
+	req := &http.Request{
+		Method: method,
+		URL:    u,
+	}
+	action := ta.acl.Match(req)
+	if action != expected {
+		ta.t.Errorf("%s %s expected %v but got %v", method, URL, expected, action)
+	}
+}
+
+func TestRegexen(t *testing.T) {
+	acl, err := readAcl("testdata/acl.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, rule := range acl.Rules {
+		if rule.urlRegexp == nil {
+			t.Errorf("Regexp not precompiled on rule %d", i)
+		}
+	}
+}
+
+func TestUsers(t *testing.T) {
+	acl, err := readAcl("testdata/acl.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if acl.Rules[0].Users != nil {
+		t.Errorf("Rules[0].Users != nil")
+	}
+	if acl.Rules[1].Users == nil {
+		t.Errorf("Rules[0].Users == nil")
+	}
+}
+
+func TestAclMatching(t *testing.T) {
+	acl, err := readAcl("testdata/acl.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	ta := testAcl{
+		t:   t,
+		acl: acl,
+	}
+
+	ta.try("GET", "https://example.com/moo", Deny)
+	ta.try("GET", "https://example.com/blargh", Deny)
+	ta.try("GET", "https://example.com/public/moo", Public)
+	ta.try("BLARGH", "https://example.com/blargh", Public)
+	ta.try("GET", "https://example.com/only-alice/boog", Deny)
+	ta.try("GET", "https://alice:@example.com/only-alice/boog", Auth)
+	ta.try("GET", "https://alice:@example.com/bob/", Deny)
+	ta.try("GET", "https://bob:@example.com/bob/", Auth)
+}

pkg/acl/action.go

@@ -0,0 +1,40 @@
+package acl
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Action int
+
+const (
+	Deny Action = iota
+	Auth
+	Public
+)
+
+var actions = [...]string{
+	"deny",
+	"auth",
+	"public",
+}
+
+func (a Action) String() string {
+	return actions[a]
+}
+
+func (a *Action) UnmarshalYAML(unmarshal func(any) error) error {
+	var val string
+	if err := unmarshal(&val); err != nil {
+		return err
+	}
+	val = strings.ToLower(val)
+
+	for i, s := range actions {
+		if val == s {
+			*a = (Action)(i)
+			return nil
+		}
+	}
+	return fmt.Errorf("Unknown action type: %s", val)
+}

pkg/acl/action_test.go

@@ -0,0 +1,38 @@
+package acl
+
+import (
+	"testing"
+
+	"gopkg.in/yaml.v3"
+)
+
+func TestActions(t *testing.T) {
+	if Deny.String() != "deny" {
+		t.Error("Deny string wrong")
+	}
+	if Auth.String() != "auth" {
+		t.Error("Auth string wrong")
+	}
+	if Public.String() != "public" {
+		t.Error("Public string wrong")
+	}
+}
+
+func TestYamlActions(t *testing.T) {
+	var out []Action
+	yamlDoc := "[Deny, Auth, Public, dEnY, pUBLiC]"
+	expected := []Action{Deny, Auth, Public, Deny, Public}
+	if err := yaml.Unmarshal([]byte(yamlDoc), &out); err != nil {
+		t.Fatal(err)
+	}
+
+	if len(out) != len(expected) {
+		t.Error("Wrong length of unmarshalled yaml")
+	}
+
+	for i, a := range out {
+		if expected[i] != a {
+			t.Errorf("Wrong value at position %d. Wanted %v, got %v", i, expected[i], a)
+		}
+	}
+}

pkg/acl/rule.go

@@ -0,0 +1,73 @@
+package acl
+
+import (
+	"net/http"
+	"net/url"
+	"regexp"
+)
+
+type Rule struct {
+	URL       string
+	urlRegexp *regexp.Regexp
+	Users     []string
+	Methods   []string
+	Action    Action
+}
+
+// CompileURL compiles regular expressions for the URL.
+// This is an startup optimization that speeds up rule processing.
+func (r *Rule) CompileURL() error {
+	if re, err := regexp.Compile(r.URL); err != nil {
+		return err
+	} else {
+		r.urlRegexp = re
+	}
+	return nil
+}
+
+// Match returns true if req is matched by the rule
+func (r *Rule) Match(req *http.Request) bool {
+	if r.urlRegexp == nil {
+		// Womp womp. Things will be slow, because the compiled regex won't get cached.
+		r.CompileURL()
+	}
+	requestUser := req.URL.User.Username()
+	anonURL := url.URL(*req.URL)
+	anonURL.User = nil
+	found := r.urlRegexp.FindStringSubmatch(anonURL.String())
+	if len(found) == 0 {
+		return false
+	}
+
+	// Match any listed method
+	methodMatch := (len(r.Methods) == 0)
+	for _, method := range r.Methods {
+		if method == req.Method {
+			methodMatch = true
+		}
+	}
+	if !methodMatch {
+		return false
+	}
+
+	// If they used (?P<user>),
+	// make sure that matches the username in the request URL
+	userIndex := r.urlRegexp.SubexpIndex("user")
+	if (userIndex != -1) && (found[userIndex] != requestUser) {
+		return false
+	}
+
+	// Match any listed user
+	userMatch := (len(r.Users) == 0)
+	for _, user := range r.Users {
+		if user == requestUser {
+			userMatch = true
+		}
+	}
+	if !userMatch {
+		// If no user match
+		return false
+	}
+
+	return true
+}

pkg/acl/testdata/acl.yaml

@@ -0,0 +1,22 @@
+groups:
+  - &any [.]
+  - &all
+    - alice
+    - bob
+    - carol
+rules:
+  - url: ^https://example.org/public/
+    action: public
+  - url: ^https://example.com/private/
+    users: *any
+    action: auth
+  - url: ^https://example.com/blargh
+    methods:
+      - BLARGH
+    action: public
+  - url: ^https://example.com/only-alice/
+    users:
+      - alice
+    action: auth
+  - url: ^https://example.com/(?P<user>)/
+    action: auth

pkg/acl/url.go

@@ -0,0 +1,17 @@
+package acl
+
+import "net/url"
+
+type URL struct {
+	*url.URL
+}
+
+func (u *URL) UnmarshalYAML(unmarshal func(any) error) error {
+	var s string
+	if err := unmarshal(&s); err != nil {
+		return err
+	}
+	nu, err := url.Parse(s)
+	u.URL = nu
+	return err
+}

pkg/token/token_test.go

@@ -34,4 +34,3 @@ func TestExpired(t *testing.T) {
 		t.Error("Expired token still valid")
 	}
 }
-