feat(acp): ResolveSafePath helper (3-fold check: abs/prefix/symlink)

internal/acp/permission_test.go

@@ -0,0 +1,105 @@
+package acp_test
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/yan1h/agent-coding-workflow/internal/acp"
+	"github.com/yan1h/agent-coding-workflow/internal/infra/errs"
+)
+
+func TestResolveSafePath_InsideWorktree(t *testing.T) {
+	t.Parallel()
+	tmp := t.TempDir()
+
+	target := filepath.Join(tmp, "sub", "a.txt")
+	require.NoError(t, os.MkdirAll(filepath.Dir(target), 0o755))
+	require.NoError(t, os.WriteFile(target, []byte("x"), 0o644))
+
+	got, err := acp.ResolveSafePath(tmp, target)
+	require.NoError(t, err)
+	// EvalSymlinks may resolve macOS / temp paths via /private prefix; on
+	// Windows the path may be returned as-is. Compare via filepath.Clean.
+	assert.Equal(t, filepath.Clean(target), got)
+
+	got, err = acp.ResolveSafePath(tmp, "sub/a.txt")
+	require.NoError(t, err)
+	assert.Equal(t, filepath.Clean(target), got)
+}
+
+func TestResolveSafePath_AbsoluteOutside(t *testing.T) {
+	t.Parallel()
+	tmp := t.TempDir()
+
+	// On Windows /etc/passwd is interpreted relative to the current drive;
+	// use a guaranteed-outside path.
+	outsideAbs := filepath.Join(filepath.VolumeName(tmp)+string(filepath.Separator), "etc", "passwd")
+
+	_, err := acp.ResolveSafePath(tmp, outsideAbs)
+	ae, ok := errs.As(err)
+	require.True(t, ok)
+	assert.Equal(t, errs.CodeAcpFsPathOutsideWorktree, ae.Code)
+}
+
+func TestResolveSafePath_RelativeWithDotDot(t *testing.T) {
+	t.Parallel()
+	tmp := t.TempDir()
+
+	_, err := acp.ResolveSafePath(tmp, "../etc/passwd")
+	ae, ok := errs.As(err)
+	require.True(t, ok)
+	assert.Equal(t, errs.CodeAcpFsPathOutsideWorktree, ae.Code)
+}
+
+func TestResolveSafePath_PrefixSiblingTrap(t *testing.T) {
+	t.Parallel()
+	tmp := t.TempDir()
+	sibling := tmp + "_sibling"
+	require.NoError(t, os.MkdirAll(sibling, 0o755))
+	t.Cleanup(func() { _ = os.RemoveAll(sibling) })
+
+	_, err := acp.ResolveSafePath(tmp, sibling+string(filepath.Separator)+"file")
+	ae, ok := errs.As(err)
+	require.True(t, ok)
+	assert.Equal(t, errs.CodeAcpFsPathOutsideWorktree, ae.Code)
+}
+
+func TestResolveSafePath_SymlinkEscape(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("symlink test requires admin on Windows")
+	}
+	t.Parallel()
+	tmp := t.TempDir()
+	outside := t.TempDir()
+	require.NoError(t, os.WriteFile(filepath.Join(outside, "secret"), []byte("s"), 0o644))
+
+	link := filepath.Join(tmp, "link-to-secret")
+	require.NoError(t, os.Symlink(filepath.Join(outside, "secret"), link))
+
+	_, err := acp.ResolveSafePath(tmp, link)
+	ae, ok := errs.As(err)
+	require.True(t, ok)
+	assert.Equal(t, errs.CodeAcpFsPathOutsideWorktree, ae.Code)
+}
+
+func TestResolveSafePath_NonexistentInsideOK(t *testing.T) {
+	t.Parallel()
+	tmp := t.TempDir()
+	want := filepath.Join(tmp, "newfile.txt")
+	got, err := acp.ResolveSafePath(tmp, want)
+	require.NoError(t, err)
+	assert.Equal(t, want, got)
+}
+
+func TestResolveSafePath_RelativeCwdRejected(t *testing.T) {
+	t.Parallel()
+	_, err := acp.ResolveSafePath("relative-cwd", "x")
+	ae, ok := errs.As(err)
+	require.True(t, ok)
+	assert.Equal(t, errs.CodeAcpFsPathOutsideWorktree, ae.Code)
+}