Disallow bp 'build' includes to reference other dirs

Bug: 65683273
Test: add 'build = ["sub/nope.bp"]' to an Android.bp; notice the error

Change-Id: Ic0f171f283edda074f65a76029e660dfaab2504b

1 files changed, 8 insertions, 0 deletions

diff --git a/context.go b/context.go
index 30cc973..5a7e558 100644
--- a/context.go
+++ b/context.go
@@ -954,6 +954,14 @@ func (c *Context) parseOne(rootDir, filename string, reader io.Reader,
 	if err != nil {
 		errs = append(errs, err)
 	}
+	for _, buildEntry := range build {
+		if strings.Contains(buildEntry, "/") {
+			errs = append(errs, &BlueprintError{
+				Err: fmt.Errorf("illegal value %v. The '/' character is not permitted", buildEntry),
+				Pos: buildPos,
+			})
+		}
+	}
 
 	subBlueprintsName, _, err := getStringFromScope(scope, "subname")
 	if err != nil {