path/filepath: handle ".." in normalizing a path on Windows

Current code assumes there are not ".." in the Clean(path).
That's not true. Clean doesn't handle leading "..", so we need to stop
normalization if we see "..".

Fixes #16793

Change-Id: I0a7901bedac17f1210b134d593ebd9f5e8483775
Reviewed-on: https://go-review.googlesource.com/27410
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 99 insertions, 2 deletions

diff --git a/src/path/filepath/path_windows_test.go b/src/path/filepath/path_windows_test.go
index 180c2e90af..2be200cb7d 100644
--- a/src/path/filepath/path_windows_test.go
+++ b/src/path/filepath/path_windows_test.go
@@ -309,9 +309,106 @@ func TestToNorm(t *testing.T) {
 	for _, test := range tests {
 		got, err := filepath.ToNorm(test.arg, stubBase)
 		if err != nil {
-			t.Errorf("unexpected toNorm error, arg: %s, err: %v\n", test.arg, err)
+			t.Errorf("toNorm(%s) failed: %v\n", test.arg, err)
 		} else if got != test.want {
-			t.Errorf("toNorm error, arg: %s, want: %s, got: %s\n", test.arg, test.want, got)
+			t.Errorf("toNorm(%s) returns %s, but %s expected\n", test.arg, got, test.want)
+		}
+	}
+
+	testPath := `{{tmp}}\test\foo\bar`
+
+	testsDir := []struct {
+		wd   string
+		arg  string
+		want string
+	}{
+		// test absolute paths
+		{".", `{{tmp}}\test\foo\bar`, `{{tmp}}\test\foo\bar`},
+		{".", `{{tmp}}\.\test/foo\bar`, `{{tmp}}\test\foo\bar`},
+		{".", `{{tmp}}\test\..\test\foo\bar`, `{{tmp}}\test\foo\bar`},
+		{".", `{{tmp}}\TEST\FOO\BAR`, `{{tmp}}\test\foo\bar`},
+
+		// test relative paths begin with drive letter
+		{`{{tmp}}\test`, `{{tmpvol}}.`, `{{tmpvol}}.`},
+		{`{{tmp}}\test`, `{{tmpvol}}..`, `{{tmpvol}}..`},
+		{`{{tmp}}\test`, `{{tmpvol}}foo\bar`, `{{tmpvol}}foo\bar`},
+		{`{{tmp}}\test`, `{{tmpvol}}.\foo\bar`, `{{tmpvol}}foo\bar`},
+		{`{{tmp}}\test`, `{{tmpvol}}foo\..\foo\bar`, `{{tmpvol}}foo\bar`},
+		{`{{tmp}}\test`, `{{tmpvol}}FOO\BAR`, `{{tmpvol}}foo\bar`},
+
+		// test relative paths begin with '\'
+		{".", `{{tmpnovol}}\test\foo\bar`, `{{tmpnovol}}\test\foo\bar`},
+		{".", `{{tmpnovol}}\.\test\foo\bar`, `{{tmpnovol}}\test\foo\bar`},
+		{".", `{{tmpnovol}}\test\..\test\foo\bar`, `{{tmpnovol}}\test\foo\bar`},
+		{".", `{{tmpnovol}}\TEST\FOO\BAR`, `{{tmpnovol}}\test\foo\bar`},
+
+		// test relative paths begin without '\'
+		{`{{tmp}}\test`, ".", `.`},
+		{`{{tmp}}\test`, "..", `..`},
+		{`{{tmp}}\test`, `foo\bar`, `foo\bar`},
+		{`{{tmp}}\test`, `.\foo\bar`, `foo\bar`},
+		{`{{tmp}}\test`, `foo\..\foo\bar`, `foo\bar`},
+		{`{{tmp}}\test`, `FOO\BAR`, `foo\bar`},
+	}
+
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() {
+		err := os.Chdir(cwd)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	tmp, err := ioutil.TempDir("", "testToNorm")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmp)
+
+	// ioutil.TempDir might return "non-canonical" name.
+	tmp, err = filepath.EvalSymlinks(tmp)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.MkdirAll(strings.Replace(testPath, "{{tmp}}", tmp, -1), 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tmpVol := filepath.VolumeName(tmp)
+	tmpNoVol := tmp[len(tmpVol):]
+
+	for _, test := range testsDir {
+		wd := strings.Replace(strings.Replace(strings.Replace(test.wd, "{{tmp}}", tmp, -1), "{{tmpvol}}", tmpVol, -1), "{{tmpnovol}}", tmpNoVol, -1)
+		arg := strings.Replace(strings.Replace(strings.Replace(test.arg, "{{tmp}}", tmp, -1), "{{tmpvol}}", tmpVol, -1), "{{tmpnovol}}", tmpNoVol, -1)
+		want := strings.Replace(strings.Replace(strings.Replace(test.want, "{{tmp}}", tmp, -1), "{{tmpvol}}", tmpVol, -1), "{{tmpnovol}}", tmpNoVol, -1)
+
+		if test.wd == "." {
+			err := os.Chdir(cwd)
+			if err != nil {
+				t.Error(err)
+
+				continue
+			}
+		} else {
+			err := os.Chdir(wd)
+			if err != nil {
+				t.Error(err)
+
+				continue
+			}
+		}
+
+		got, err := filepath.ToNorm(arg, filepath.NormBase)
+		if err != nil {
+			t.Errorf("toNorm(%s) failed: %v (wd=%s)\n", arg, err, wd)
+		} else if got != want {
+			t.Errorf("toNorm(%s) returns %s, but %s expected (wd=%s)\n", arg, got, want, wd)
 		}
 	}
 }