Prevent using symlinks to starlark files
Symlinks are frequently confusing / a source of bugs. They also don't
provide much utility over just loading the other file and re-exporting
its symbols, so recommend doing that instead.
Test: Presubmits
Change-Id: Ie3052ebc0add77f1746d6321fbdf7bc15df9819b
diff --git a/tools/rbcrun/host.go b/tools/rbcrun/host.go
index 7f5e332..f36553e 100644
--- a/tools/rbcrun/host.go
+++ b/tools/rbcrun/host.go
@@ -63,6 +63,14 @@
"json": starlarkjson.Module,
}
+func isSymlink(filepath string) (bool, error) {
+ if info, err := os.Lstat(filepath); err == nil {
+ return info.Mode() & os.ModeSymlink != 0, nil
+ } else {
+ return false, err
+ }
+}
+
// Takes a module name (the first argument to the load() function) and returns the path
// it's trying to load, stripping out leading //, and handling leading :s.
func cleanModuleName(moduleName string, callerDir string, allowExternalPaths bool) (string, error) {
@@ -158,6 +166,13 @@
if strings.HasSuffix(modulePath, ".scl") {
mode = ExecutionModeScl
}
+
+ if sym, err := isSymlink(modulePath); sym && err == nil {
+ return nil, fmt.Errorf("symlinks to starlark files are not allowed. Instead, load the target file and re-export its symbols: %s", modulePath)
+ } else if err != nil {
+ return nil, err
+ }
+
childThread := &starlark.Thread{Name: "exec " + module, Load: thread.Load}
// Cheating for the sake of testing:
// propagate starlarktest's Reporter key, otherwise testing
@@ -368,6 +383,12 @@
return nil, nil, err
}
+ if sym, err := isSymlink(filename); sym && err == nil {
+ return nil, nil, fmt.Errorf("symlinks to starlark files are not allowed. Instead, load the target file and re-export its symbols: %s", filename)
+ } else if err != nil {
+ return nil, nil, err
+ }
+
// Add top-level file to cache for cycle detection purposes
moduleCache[filename] = nil
diff --git a/tools/rbcrun/host_test.go b/tools/rbcrun/host_test.go
index 468a620..7cfeb14 100644
--- a/tools/rbcrun/host_test.go
+++ b/tools/rbcrun/host_test.go
@@ -186,6 +186,21 @@
}
}
+func TestCantLoadSymlink(t *testing.T) {
+ moduleCache = make(map[string]*modentry)
+ dir := dataDir()
+ if err := os.Chdir(filepath.Dir(dir)); err != nil {
+ t.Fatal(err)
+ }
+ _, _, err := Run("testdata/test_scl_symlink.scl", nil, ExecutionModeScl, false)
+ if err == nil {
+ t.Fatal("Expected failure")
+ }
+ if !strings.Contains(err.Error(), "symlinks to starlark files are not allowed") {
+ t.Fatalf("Expected error to contain \"symlinks to starlark files are not allowed\": %q", err.Error())
+ }
+}
+
func TestShell(t *testing.T) {
exerciseStarlarkTestFile(t, "testdata/shell.star")
}
diff --git a/tools/rbcrun/testdata/test_scl_symlink.scl b/tools/rbcrun/testdata/test_scl_symlink.scl
new file mode 120000
index 0000000..3f5aef4
--- /dev/null
+++ b/tools/rbcrun/testdata/test_scl_symlink.scl
@@ -0,0 +1 @@
+test_scl.scl
\ No newline at end of file