lib: Prevent using protocol method with native path (fixes #7557) (#7563)

lib/fs/casefs.go

@@ -11,7 +11,6 @@ import (
 	"errors"
 	"fmt"
 	"path/filepath"
-	"strings"
 	"sync"
 	"time"
 
@@ -400,7 +399,7 @@ func (r *defaultRealCaser) realCase(name string) (string, error) {
 		return realName, nil
 	}
 
-	for _, comp := range strings.Split(name, string(PathSeparator)) {
+	for _, comp := range PathComponents(name) {
 		node := r.cache.getExpireAdd(realName)
 
 		node.once.Do(func() {

lib/fs/util.go

@@ -15,6 +15,8 @@ import (
 	"unicode"
 )
 
+const pathSeparatorString = string(PathSeparator)
+
 func ExpandTilde(path string) (string, error) {
 	if path == "~" {
 		return getHomeDir()
@@ -164,7 +166,7 @@ func IsParent(path, parent string) bool {
 		return path != "/"
 	}
 	if parent[len(parent)-1] != PathSeparator {
-		parent += string(PathSeparator)
+		parent += pathSeparatorString
 	}
 	return strings.HasPrefix(path, parent)
 }
@@ -175,8 +177,8 @@ func CommonPrefix(first, second string) string {
 		return ""
 	}
 
-	firstParts := strings.Split(filepath.Clean(first), string(PathSeparator))
-	secondParts := strings.Split(filepath.Clean(second), string(PathSeparator))
+	firstParts := PathComponents(filepath.Clean(first))
+	secondParts := PathComponents(filepath.Clean(second))
 
 	isAbs := filepath.IsAbs(first) && filepath.IsAbs(second)
 
@@ -200,7 +202,7 @@ func CommonPrefix(first, second string) string {
 			common = append(common, "")
 		} else if len(common) == 1 {
 			// If isAbs on non Windows, first element in both first and second is "", hence joining that returns nothing.
-			return string(PathSeparator)
+			return pathSeparatorString
 		}
 	}
 
@@ -211,10 +213,16 @@ func CommonPrefix(first, second string) string {
 	}
 
 	// This has to be strings.Join, because filepath.Join([]string{"", "", "?", "C:", "Audrius"}...) returns garbage
-	result := strings.Join(common, string(PathSeparator))
+	result := strings.Join(common, pathSeparatorString)
 	return filepath.Clean(result)
 }
 
+// PathComponents returns a list of names of parent directories and the leaf
+// item for the given native (fs.PathSeparator delimited) and clean path.
+func PathComponents(path string) []string {
+	return strings.Split(path, pathSeparatorString)
+}
+
 func isVolumeNameOnly(parts []string) bool {
 	isNormalVolumeName := len(parts) == 1 && strings.HasSuffix(parts[0], ":")
 	isUNCVolumeName := len(parts) == 4 && strings.HasSuffix(parts[3], ":")

lib/model/folder.go

@@ -558,7 +558,7 @@ func (f *folder) scanSubdirsBatchAppendFunc(batch *fileInfoBatch) batchAppendFun
 			// This is a "virtual" parent directory of encrypted files.
 			// We don't track it, but check if anything still exists
 			// within and delete it otherwise.
-			if fi.IsDirectory() && protocol.IsEncryptedParent(fi.Name) {
+			if fi.IsDirectory() && protocol.IsEncryptedParent(fs.PathComponents(fi.Name)) {
 				if names, err := f.mtimefs.DirNames(fi.Name); err == nil && len(names) == 0 {
 					f.mtimefs.Remove(fi.Name)
 				}

lib/osutil/traversessymlink.go

@@ -9,7 +9,6 @@ package osutil
 import (
 	"fmt"
 	"path/filepath"
-	"strings"
 
 	"github.com/syncthing/syncthing/lib/fs"
 )
@@ -47,7 +46,7 @@ func TraversesSymlink(filesystem fs.Filesystem, name string) error {
 	}
 
 	var path string
-	for _, part := range strings.Split(name, string(fs.PathSeparator)) {
+	for _, part := range fs.PathComponents(name) {
 		path = filepath.Join(path, part)
 		info, err := filesystem.Lstat(path)
 		if err != nil {

lib/protocol/encryption.go

@@ -559,24 +559,10 @@ func (r rawResponse) Data() []byte {
 func (r rawResponse) Close() {}
 func (r rawResponse) Wait()  {}
 
-// IsEncryptedPath returns true if the path points at encrypted data. This is
-// determined by checking for a sentinel string in the path.
-func IsEncryptedPath(path string) bool {
-	pathComponents := strings.Split(path, "/")
-	if len(pathComponents) != 3 {
-		return false
-	}
-	return isEncryptedParentFromComponents(pathComponents[:2])
-}
-
 // IsEncryptedParent returns true if the path points at a parent directory of
 // encrypted data, i.e. is not a "real" directory. This is determined by
 // checking for a sentinel string in the path.
-func IsEncryptedParent(path string) bool {
-	return isEncryptedParentFromComponents(strings.Split(path, "/"))
-}
-
-func isEncryptedParentFromComponents(pathComponents []string) bool {
+func IsEncryptedParent(pathComponents []string) bool {
 	l := len(pathComponents)
 	if l == 2 && len(pathComponents[1]) != 2 {
 		return false

lib/protocol/encryption_test.go

@@ -196,7 +196,7 @@ func TestIsEncryptedParent(t *testing.T) {
 		{"1" + encryptedDirExtension + "/bc/" + comp + "/a/" + comp, false},
 	}
 	for _, tc := range cases {
-		if res := IsEncryptedParent(tc.path); res != tc.is {
+		if res := IsEncryptedParent(strings.Split(tc.path, "/")); res != tc.is {
 			t.Errorf("%v: got %v, expected %v", tc.path, res, tc.is)
 		}
 	}

lib/scanner/virtualfs_test.go

@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -43,7 +42,7 @@ func (i infiniteFS) DirNames(name string) ([]string, error) {
 	for j := 0; j < i.width; j++ {
 		names = append(names, fmt.Sprintf("aa-file-%d", j))
 	}
-	if len(strings.Split(name, string(os.PathSeparator))) < i.depth {
+	if len(fs.PathComponents(name)) < i.depth {
 		for j := 0; j < i.width; j++ {
 			names = append(names, fmt.Sprintf("zz-dir-%d", j))
 		}

lib/scanner/walk.go

@@ -311,7 +311,7 @@ func (w *walker) walkAndHashFiles(ctx context.Context, toHashChan chan<- protoco
 		// ignored path need to be handled as well.
 		// Prepend an empty string to handle ignoredParent without anything
 		// appended in the first iteration.
-		for _, name := range append([]string{""}, strings.Split(rel, string(fs.PathSeparator))...) {
+		for _, name := range append([]string{""}, fs.PathComponents(rel)...) {
 			ignoredParent = filepath.Join(ignoredParent, name)
 			info, err = w.Filesystem.Lstat(ignoredParent)
 			// An error here would be weird as we've already gotten to this point, but act on it nonetheless