fix: refactoring previous fix in attempt to address ongoing issues

See #211 and #215

lib/handler.go

@@ -2,7 +2,6 @@ package lib
 
 import (
 	"net/http"
-	"net/url"
 	"os"
 	"strings"
 
@@ -19,7 +18,6 @@ type handlerUser struct {
 type Handler struct {
 	noPassword  bool
 	behindProxy bool
-	prefix      string
 	user        *handlerUser
 	users       map[string]*handlerUser
 }
@@ -28,12 +26,12 @@ func NewHandler(c *Config) (http.Handler, error) {
 	h := &Handler{
 		noPassword:  c.NoPassword,
 		behindProxy: c.BehindProxy,
-		prefix:      c.Prefix,
 		user: &handlerUser{
 			User: User{
 				UserPermissions: c.UserPermissions,
 			},
 			Handler: webdav.Handler{
+				Prefix: c.Prefix,
 				FileSystem: Dir{
 					Dir:     webdav.Dir(c.Directory),
 					noSniff: c.NoSniff,
@@ -48,6 +46,7 @@ func NewHandler(c *Config) (http.Handler, error) {
 		h.users[u.Username] = &handlerUser{
 			User: u,
 			Handler: webdav.Handler{
+				Prefix: c.Prefix,
 				FileSystem: Dir{
 					Dir:     webdav.Dir(u.Directory),
 					noSniff: c.NoSniff,
@@ -116,51 +115,16 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		zap.L().Info("user authorized", zap.String("username", username), zap.String("remote_address", remoteAddr))
 	}
 
-	// Validate and clean destination header if it exists, by stripping out the
+	// Convert the HTTP request into an internal request type
-	// prefix and only keeping the actual destination path, always prefixed by
+	req, err := newRequest(r, h.user.Prefix)
-	// a forward slash to ensure that the rules can successful match the path.
+	if err != nil {
-	if destination := r.Header.Get("Destination"); destination != "" {
+		zap.L().Info("invalid request path or destination", zap.Error(err))
-		u, err := url.Parse(destination)
+		http.Error(w, "Invalid request path or destination", http.StatusBadRequest)
-		if err != nil {
+		return
-			http.Error(w, "Invalid Destination header", http.StatusBadRequest)
-			return
-		}
-
-		if h.prefix != "" {
-			destination = strings.TrimPrefix(u.Path, h.prefix)
-			if len(destination) >= len(u.Path) {
-				http.Error(w, "Invalid URL prefix", http.StatusBadRequest)
-				return
-			}
-		}
-
-		if !strings.HasPrefix(destination, "/") {
-			destination = "/" + destination
-		}
-
-		r.Header.Set("Destination", destination)
 	}
 
-	// Clean up URL path by stripping out the prefix, and ensuring it always begins
-	// with a forward slash, so that it can match against the rules.
-	path := r.URL.Path
-
-	if h.prefix != "" {
-		path = strings.TrimPrefix(r.URL.Path, h.prefix)
-		if len(path) >= len(r.URL.Path) {
-			http.Error(w, "Invalid URL prefix", http.StatusBadRequest)
-			return
-		}
-	}
-
-	if !strings.HasPrefix(path, "/") {
-		path = "/" + path
-	}
-
-	r.URL.Path = path
-
 	// Checks for user permissions relatively to this PATH.
-	allowed := user.Allowed(r, func(filename string) bool {
+	allowed := user.Allowed(req, func(filename string) bool {
 		_, err := user.FileSystem.Stat(r.Context(), filename)
 		return !os.IsNotExist(err)
 	})

lib/handler_test.go

@@ -292,82 +292,6 @@ users:
 	require.ErrorContains(t, err, "403")
 }
 
-func TestServerRulesPrefix(t *testing.T) {
-	t.Parallel()
-
-	dir := makeTestDirectory(t, map[string][]byte{
-		"foo.txt":   []byte("foo"),
-		"bar.js":    []byte("foo js"),
-		"a/foo.js":  []byte("foo js"),
-		"a/foo.txt": []byte("foo txt"),
-		"b/foo.txt": []byte("foo b"),
-		"c/a.txt":   []byte("b"),
-		"c/b.txt":   []byte("b"),
-		"c/c.txt":   []byte("b"),
-	})
-
-	srv := makeTestServer(t, fmt.Sprintf(`
-directory: %s
-permissions: CRUD
-prefix: /prefix
-
-users:
-  - username: basic
-    password: basic
-    rules:
-    - regex: "^.+.js$"
-      permissions: R
-    - path: "/b/"
-      permissions: R
-    - path: "/a/foo.txt"
-      permissions: none
-    - path: "/c/"
-      permissions: none
-`, dir))
-
-	client := gowebdav.NewClient(srv.URL, "basic", "basic")
-
-	files, err := client.ReadDir("/prefix")
-	require.NoError(t, err)
-	require.Len(t, files, 5)
-
-	err = client.Write("/prefix/foo.txt", []byte("new"), 0666)
-	require.NoError(t, err)
-
-	err = client.Write("/prefix/new.txt", []byte("new"), 0666)
-	require.NoError(t, err)
-
-	err = client.Copy("/prefix/bar.js", "/prefix/b/bar.js", false)
-	require.ErrorContains(t, err, "403")
-
-	err = client.Copy("/prefix/bar.js", "/prefix/bar.jsx", false)
-	require.NoError(t, err)
-
-	err = client.Copy("/prefix/b/foo.txt", "/prefix/foo1.txt", false)
-	require.NoError(t, err)
-
-	err = client.Rename("/prefix/b/foo.txt", "/prefix/foo2.txt", false)
-	require.ErrorContains(t, err, "403")
-
-	_, err = client.Read("/prefix/a/foo.txt")
-	require.ErrorContains(t, err, "403")
-
-	err = client.Write("/prefix/a/foo.js", []byte("new"), 0666)
-	require.ErrorContains(t, err, "403")
-
-	err = client.Write("/prefix/b/foo.txt", []byte("new"), 0666)
-	require.ErrorContains(t, err, "403")
-
-	_, err = client.ReadDir("/prefix/c")
-	require.ErrorContains(t, err, "403")
-
-	_, err = client.Read("/prefix/c/a.txt")
-	require.ErrorContains(t, err, "403")
-
-	err = client.Write("/prefix/c/b.txt", []byte("new"), 0666)
-	require.ErrorContains(t, err, "403")
-}
-
 func TestServerPermissions(t *testing.T) {
 	t.Parallel()
 

lib/permissions.go

@@ -3,7 +3,6 @@ package lib
 import (
 	"errors"
 	"fmt"
-	"net/http"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -51,12 +50,12 @@ type UserPermissions struct {
 }
 
 // Allowed checks if the user has permission to access a directory/file
-func (p UserPermissions) Allowed(r *http.Request, fileExists func(string) bool) bool {
+func (p UserPermissions) Allowed(r *request, fileExists func(string) bool) bool {
 	// For COPY and MOVE requests, we first check the permissions for the destination
 	// path. As soon as a rule matches and does not allow the operation at the destination,
 	// we fail immediately. If no rule matches, we check the global permissions.
-	if r.Method == "COPY" || r.Method == "MOVE" {
+	if r.method == "COPY" || r.method == "MOVE" {
-		dst := r.Header.Get("Destination")
+		dst := r.destination
 
 		for i := len(p.Rules) - 1; i >= 0; i-- {
 			if p.Rules[i].Matches(dst) {
@@ -77,7 +76,7 @@ func (p UserPermissions) Allowed(r *http.Request, fileExists func(string) bool)
 	// Go through rules beginning from the last one, and check the permissions at
 	// the source. The first matched rule returns.
 	for i := len(p.Rules) - 1; i >= 0; i-- {
-		if p.Rules[i].Matches(r.URL.Path) {
+		if p.Rules[i].Matches(r.path) {
 			return p.Rules[i].Permissions.Allowed(r, fileExists)
 		}
 	}
@@ -142,8 +141,8 @@ func (p *Permissions) UnmarshalText(data []byte) error {
 
 // Allowed returns whether this permission set has permissions to execute this
 // request in the source directory. This applies to all requests with all methods.
-func (p Permissions) Allowed(r *http.Request, fileExists func(string) bool) bool {
+func (p Permissions) Allowed(r *request, fileExists func(string) bool) bool {
-	switch r.Method {
+	switch r.method {
 	case "GET", "HEAD", "OPTIONS", "POST", "PROPFIND":
 		// Note: POST backend implementation just returns the same thing as GET.
 		return p.Read
@@ -152,7 +151,7 @@ func (p Permissions) Allowed(r *http.Request, fileExists func(string) bool) bool
 	case "PROPPATCH":
 		return p.Update
 	case "PUT":
-		if fileExists(r.URL.Path) {
+		if fileExists(r.path) {
 			return p.Update
 		} else {
 			return p.Create
@@ -172,10 +171,10 @@ func (p Permissions) Allowed(r *http.Request, fileExists func(string) bool) bool
 
 // AllowedDestination returns whether this permissions set has permissions to execute this
 // request in the destination directory. This only applies for COPY and MOVE requests.
-func (p Permissions) AllowedDestination(r *http.Request, fileExists func(string) bool) bool {
+func (p Permissions) AllowedDestination(r *request, fileExists func(string) bool) bool {
-	switch r.Method {
+	switch r.method {
 	case "COPY", "MOVE":
-		if fileExists(r.Header.Get("Destination")) {
+		if fileExists(r.destination) {
 			return p.Update
 		} else {
 			return p.Create

lib/request.go

@@ -0,0 +1,57 @@
+package lib
+
+import (
+	"errors"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+type request struct {
+	method      string
+	path        string
+	destination string
+}
+
+func newRequest(r *http.Request, prefix string) (*request, error) {
+	ctx := &request{
+		method: r.Method,
+	}
+
+	if destination := r.Header.Get("Destination"); destination != "" {
+		u, err := url.Parse(destination)
+		if err != nil {
+			return nil, errors.New("invalid destination header")
+		}
+
+		if prefix != "" {
+			destination = strings.TrimPrefix(u.Path, prefix)
+			if len(destination) >= len(u.Path) {
+				return nil, errors.New("invalid url prefix")
+			}
+		}
+
+		if !strings.HasPrefix(destination, "/") {
+			destination = "/" + destination
+		}
+
+		ctx.destination = destination
+	}
+
+	path := r.URL.Path
+
+	if prefix != "" {
+		path = strings.TrimPrefix(r.URL.Path, prefix)
+		if len(path) >= len(r.URL.Path) {
+			return nil, errors.New("invalid url prefix")
+		}
+	}
+
+	if !strings.HasPrefix(path, "/") {
+		path = "/" + path
+	}
+
+	ctx.path = path
+
+	return ctx, nil
+}