From 24d0c56350e10b09d1bedc40b678ed4b2dc279cb Mon Sep 17 00:00:00 2001
From: Jingwen Chen <jingwen@google.com>
Date: Tue, 7 Feb 2023 09:29:36 +0000
Subject: [PATCH] Remove unnecessary pass in validatePath.

Perform a single pass over pathComponents in both validatePath and
validateSafePath instead.

Test: presubmits
Change-Id: I1499183e345ca180900c54a18f9dc8bd534f2588
---
 android/paths.go | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/android/paths.go b/android/paths.go
index 0fc39df6c..2c5010473 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -1868,10 +1868,14 @@ func (p InstallPaths) Strings() []string {
 	return ret
 }
 
-// validateSafePath validates a path that we trust (may contain ninja variables).
-// Ensures that each path component does not attempt to leave its component.
-func validateSafePath(pathComponents ...string) (string, error) {
+// validatePathInternal ensures that a path does not leave its component, and
+// optionally doesn't contain Ninja variables.
+func validatePathInternal(allowNinjaVariables bool, pathComponents ...string) (string, error) {
 	for _, path := range pathComponents {
+		if !allowNinjaVariables && strings.Contains(path, "$") {
+			return "", fmt.Errorf("Path contains invalid character($): %s", path)
+		}
+
 		path := filepath.Clean(path)
 		if path == ".." || strings.HasPrefix(path, "../") || strings.HasPrefix(path, "/") {
 			return "", fmt.Errorf("Path is outside directory: %s", path)
@@ -1883,16 +1887,18 @@ func validateSafePath(pathComponents ...string) (string, error) {
 	return filepath.Join(pathComponents...), nil
 }
 
+// validateSafePath validates a path that we trust (may contain ninja
+// variables).  Ensures that each path component does not attempt to leave its
+// component. Returns a joined version of each path component.
+func validateSafePath(pathComponents ...string) (string, error) {
+	return validatePathInternal(true, pathComponents...)
+}
+
 // validatePath validates that a path does not include ninja variables, and that
 // each path component does not attempt to leave its component. Returns a joined
 // version of each path component.
 func validatePath(pathComponents ...string) (string, error) {
-	for _, path := range pathComponents {
-		if strings.Contains(path, "$") {
-			return "", fmt.Errorf("Path contains invalid character($): %s", path)
-		}
-	}
-	return validateSafePath(pathComponents...)
+	return validatePathInternal(false, pathComponents...)
 }
 
 func PathForPhony(ctx PathContext, phony string) WritablePath {