1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package base64
6
7import (
8	"bytes"
9	"errors"
10	"fmt"
11	"io"
12	"math"
13	"reflect"
14	"runtime/debug"
15	"strconv"
16	"strings"
17	"testing"
18	"time"
19)
20
21type testpair struct {
22	decoded, encoded string
23}
24
25var pairs = []testpair{
26	// RFC 3548 examples
27	{"\x14\xfb\x9c\x03\xd9\x7e", "FPucA9l+"},
28	{"\x14\xfb\x9c\x03\xd9", "FPucA9k="},
29	{"\x14\xfb\x9c\x03", "FPucAw=="},
30
31	// RFC 4648 examples
32	{"", ""},
33	{"f", "Zg=="},
34	{"fo", "Zm8="},
35	{"foo", "Zm9v"},
36	{"foob", "Zm9vYg=="},
37	{"fooba", "Zm9vYmE="},
38	{"foobar", "Zm9vYmFy"},
39
40	// Wikipedia examples
41	{"sure.", "c3VyZS4="},
42	{"sure", "c3VyZQ=="},
43	{"sur", "c3Vy"},
44	{"su", "c3U="},
45	{"leasure.", "bGVhc3VyZS4="},
46	{"easure.", "ZWFzdXJlLg=="},
47	{"asure.", "YXN1cmUu"},
48	{"sure.", "c3VyZS4="},
49}
50
51// Do nothing to a reference base64 string (leave in standard format)
52func stdRef(ref string) string {
53	return ref
54}
55
56// Convert a reference string to URL-encoding
57func urlRef(ref string) string {
58	ref = strings.ReplaceAll(ref, "+", "-")
59	ref = strings.ReplaceAll(ref, "/", "_")
60	return ref
61}
62
63// Convert a reference string to raw, unpadded format
64func rawRef(ref string) string {
65	return strings.TrimRight(ref, "=")
66}
67
68// Both URL and unpadding conversions
69func rawURLRef(ref string) string {
70	return rawRef(urlRef(ref))
71}
72
73const encodeStd = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
74
75// A nonstandard encoding with a funny padding character, for testing
76var funnyEncoding = NewEncoding(encodeStd).WithPadding(rune('@'))
77
78func funnyRef(ref string) string {
79	return strings.ReplaceAll(ref, "=", "@")
80}
81
82type encodingTest struct {
83	enc  *Encoding           // Encoding to test
84	conv func(string) string // Reference string converter
85}
86
87var encodingTests = []encodingTest{
88	{StdEncoding, stdRef},
89	{URLEncoding, urlRef},
90	{RawStdEncoding, rawRef},
91	{RawURLEncoding, rawURLRef},
92	{funnyEncoding, funnyRef},
93	{StdEncoding.Strict(), stdRef},
94	{URLEncoding.Strict(), urlRef},
95	{RawStdEncoding.Strict(), rawRef},
96	{RawURLEncoding.Strict(), rawURLRef},
97	{funnyEncoding.Strict(), funnyRef},
98}
99
100var bigtest = testpair{
101	"Twas brillig, and the slithy toves",
102	"VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==",
103}
104
105func testEqual(t *testing.T, msg string, args ...any) bool {
106	t.Helper()
107	if args[len(args)-2] != args[len(args)-1] {
108		t.Errorf(msg, args...)
109		return false
110	}
111	return true
112}
113
114func TestEncode(t *testing.T) {
115	for _, p := range pairs {
116		for _, tt := range encodingTests {
117			got := tt.enc.EncodeToString([]byte(p.decoded))
118			testEqual(t, "Encode(%q) = %q, want %q", p.decoded, got, tt.conv(p.encoded))
119			dst := tt.enc.AppendEncode([]byte("lead"), []byte(p.decoded))
120			testEqual(t, `AppendEncode("lead", %q) = %q, want %q`, p.decoded, string(dst), "lead"+tt.conv(p.encoded))
121		}
122	}
123}
124
125func TestEncoder(t *testing.T) {
126	for _, p := range pairs {
127		bb := &strings.Builder{}
128		encoder := NewEncoder(StdEncoding, bb)
129		encoder.Write([]byte(p.decoded))
130		encoder.Close()
131		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
132	}
133}
134
135func TestEncoderBuffering(t *testing.T) {
136	input := []byte(bigtest.decoded)
137	for bs := 1; bs <= 12; bs++ {
138		bb := &strings.Builder{}
139		encoder := NewEncoder(StdEncoding, bb)
140		for pos := 0; pos < len(input); pos += bs {
141			end := pos + bs
142			if end > len(input) {
143				end = len(input)
144			}
145			n, err := encoder.Write(input[pos:end])
146			testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
147			testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
148		}
149		err := encoder.Close()
150		testEqual(t, "Close gave error %v, want %v", err, error(nil))
151		testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
152	}
153}
154
155func TestDecode(t *testing.T) {
156	for _, p := range pairs {
157		for _, tt := range encodingTests {
158			encoded := tt.conv(p.encoded)
159			dbuf := make([]byte, tt.enc.DecodedLen(len(encoded)))
160			count, err := tt.enc.Decode(dbuf, []byte(encoded))
161			testEqual(t, "Decode(%q) = error %v, want %v", encoded, err, error(nil))
162			testEqual(t, "Decode(%q) = length %v, want %v", encoded, count, len(p.decoded))
163			testEqual(t, "Decode(%q) = %q, want %q", encoded, string(dbuf[0:count]), p.decoded)
164
165			dbuf, err = tt.enc.DecodeString(encoded)
166			testEqual(t, "DecodeString(%q) = error %v, want %v", encoded, err, error(nil))
167			testEqual(t, "DecodeString(%q) = %q, want %q", encoded, string(dbuf), p.decoded)
168
169			dst, err := tt.enc.AppendDecode([]byte("lead"), []byte(encoded))
170			testEqual(t, "AppendDecode(%q) = error %v, want %v", p.encoded, err, error(nil))
171			testEqual(t, `AppendDecode("lead", %q) = %q, want %q`, p.encoded, string(dst), "lead"+p.decoded)
172
173			dst2, err := tt.enc.AppendDecode(dst[:0:len(p.decoded)], []byte(encoded))
174			testEqual(t, "AppendDecode(%q) = error %v, want %v", p.encoded, err, error(nil))
175			testEqual(t, `AppendDecode("", %q) = %q, want %q`, p.encoded, string(dst2), p.decoded)
176			if len(dst) > 0 && len(dst2) > 0 && &dst[0] != &dst2[0] {
177				t.Errorf("unexpected capacity growth: got %d, want %d", cap(dst2), cap(dst))
178			}
179		}
180	}
181}
182
183func TestDecoder(t *testing.T) {
184	for _, p := range pairs {
185		decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
186		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
187		count, err := decoder.Read(dbuf)
188		if err != nil && err != io.EOF {
189			t.Fatal("Read failed", err)
190		}
191		testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
192		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
193		if err != io.EOF {
194			_, err = decoder.Read(dbuf)
195		}
196		testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
197	}
198}
199
200func TestDecoderBuffering(t *testing.T) {
201	for bs := 1; bs <= 12; bs++ {
202		decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
203		buf := make([]byte, len(bigtest.decoded)+12)
204		var total int
205		var n int
206		var err error
207		for total = 0; total < len(bigtest.decoded) && err == nil; {
208			n, err = decoder.Read(buf[total : total+bs])
209			total += n
210		}
211		if err != nil && err != io.EOF {
212			t.Errorf("Read from %q at pos %d = %d, unexpected error %v", bigtest.encoded, total, n, err)
213		}
214		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
215	}
216}
217
218func TestDecodeCorrupt(t *testing.T) {
219	testCases := []struct {
220		input  string
221		offset int // -1 means no corruption.
222	}{
223		{"", -1},
224		{"\n", -1},
225		{"AAA=\n", -1},
226		{"AAAA\n", -1},
227		{"!!!!", 0},
228		{"====", 0},
229		{"x===", 1},
230		{"=AAA", 0},
231		{"A=AA", 1},
232		{"AA=A", 2},
233		{"AA==A", 4},
234		{"AAA=AAAA", 4},
235		{"AAAAA", 4},
236		{"AAAAAA", 4},
237		{"A=", 1},
238		{"A==", 1},
239		{"AA=", 3},
240		{"AA==", -1},
241		{"AAA=", -1},
242		{"AAAA", -1},
243		{"AAAAAA=", 7},
244		{"YWJjZA=====", 8},
245		{"A!\n", 1},
246		{"A=\n", 1},
247	}
248	for _, tc := range testCases {
249		dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
250		_, err := StdEncoding.Decode(dbuf, []byte(tc.input))
251		if tc.offset == -1 {
252			if err != nil {
253				t.Error("Decoder wrongly detected corruption in", tc.input)
254			}
255			continue
256		}
257		switch err := err.(type) {
258		case CorruptInputError:
259			testEqual(t, "Corruption in %q at offset %v, want %v", tc.input, int(err), tc.offset)
260		default:
261			t.Error("Decoder failed to detect corruption in", tc)
262		}
263	}
264}
265
266func TestDecodeBounds(t *testing.T) {
267	var buf [32]byte
268	s := StdEncoding.EncodeToString(buf[:])
269	defer func() {
270		if err := recover(); err != nil {
271			t.Fatalf("Decode panicked unexpectedly: %v\n%s", err, debug.Stack())
272		}
273	}()
274	n, err := StdEncoding.Decode(buf[:], []byte(s))
275	if n != len(buf) || err != nil {
276		t.Fatalf("StdEncoding.Decode = %d, %v, want %d, nil", n, err, len(buf))
277	}
278}
279
280func TestEncodedLen(t *testing.T) {
281	type test struct {
282		enc  *Encoding
283		n    int
284		want int64
285	}
286	tests := []test{
287		{RawStdEncoding, 0, 0},
288		{RawStdEncoding, 1, 2},
289		{RawStdEncoding, 2, 3},
290		{RawStdEncoding, 3, 4},
291		{RawStdEncoding, 7, 10},
292		{StdEncoding, 0, 0},
293		{StdEncoding, 1, 4},
294		{StdEncoding, 2, 4},
295		{StdEncoding, 3, 4},
296		{StdEncoding, 4, 8},
297		{StdEncoding, 7, 12},
298	}
299	// check overflow
300	switch strconv.IntSize {
301	case 32:
302		tests = append(tests, test{RawStdEncoding, (math.MaxInt-5)/8 + 1, 357913942})
303		tests = append(tests, test{RawStdEncoding, math.MaxInt/4*3 + 2, math.MaxInt})
304	case 64:
305		tests = append(tests, test{RawStdEncoding, (math.MaxInt-5)/8 + 1, 1537228672809129302})
306		tests = append(tests, test{RawStdEncoding, math.MaxInt/4*3 + 2, math.MaxInt})
307	}
308	for _, tt := range tests {
309		if got := tt.enc.EncodedLen(tt.n); int64(got) != tt.want {
310			t.Errorf("EncodedLen(%d): got %d, want %d", tt.n, got, tt.want)
311		}
312	}
313}
314
315func TestDecodedLen(t *testing.T) {
316	type test struct {
317		enc  *Encoding
318		n    int
319		want int64
320	}
321	tests := []test{
322		{RawStdEncoding, 0, 0},
323		{RawStdEncoding, 2, 1},
324		{RawStdEncoding, 3, 2},
325		{RawStdEncoding, 4, 3},
326		{RawStdEncoding, 10, 7},
327		{StdEncoding, 0, 0},
328		{StdEncoding, 4, 3},
329		{StdEncoding, 8, 6},
330	}
331	// check overflow
332	switch strconv.IntSize {
333	case 32:
334		tests = append(tests, test{RawStdEncoding, math.MaxInt/6 + 1, 268435456})
335		tests = append(tests, test{RawStdEncoding, math.MaxInt, 1610612735})
336	case 64:
337		tests = append(tests, test{RawStdEncoding, math.MaxInt/6 + 1, 1152921504606846976})
338		tests = append(tests, test{RawStdEncoding, math.MaxInt, 6917529027641081855})
339	}
340	for _, tt := range tests {
341		if got := tt.enc.DecodedLen(tt.n); int64(got) != tt.want {
342			t.Errorf("DecodedLen(%d): got %d, want %d", tt.n, got, tt.want)
343		}
344	}
345}
346
347func TestBig(t *testing.T) {
348	n := 3*1000 + 1
349	raw := make([]byte, n)
350	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
351	for i := 0; i < n; i++ {
352		raw[i] = alpha[i%len(alpha)]
353	}
354	encoded := new(bytes.Buffer)
355	w := NewEncoder(StdEncoding, encoded)
356	nn, err := w.Write(raw)
357	if nn != n || err != nil {
358		t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
359	}
360	err = w.Close()
361	if err != nil {
362		t.Fatalf("Encoder.Close() = %v want nil", err)
363	}
364	decoded, err := io.ReadAll(NewDecoder(StdEncoding, encoded))
365	if err != nil {
366		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
367	}
368
369	if !bytes.Equal(raw, decoded) {
370		var i int
371		for i = 0; i < len(decoded) && i < len(raw); i++ {
372			if decoded[i] != raw[i] {
373				break
374			}
375		}
376		t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
377	}
378}
379
380func TestNewLineCharacters(t *testing.T) {
381	// Each of these should decode to the string "sure", without errors.
382	const expected = "sure"
383	examples := []string{
384		"c3VyZQ==",
385		"c3VyZQ==\r",
386		"c3VyZQ==\n",
387		"c3VyZQ==\r\n",
388		"c3VyZ\r\nQ==",
389		"c3V\ryZ\nQ==",
390		"c3V\nyZ\rQ==",
391		"c3VyZ\nQ==",
392		"c3VyZQ\n==",
393		"c3VyZQ=\n=",
394		"c3VyZQ=\r\n\r\n=",
395	}
396	for _, e := range examples {
397		buf, err := StdEncoding.DecodeString(e)
398		if err != nil {
399			t.Errorf("Decode(%q) failed: %v", e, err)
400			continue
401		}
402		if s := string(buf); s != expected {
403			t.Errorf("Decode(%q) = %q, want %q", e, s, expected)
404		}
405	}
406}
407
408type nextRead struct {
409	n   int   // bytes to return
410	err error // error to return
411}
412
413// faultInjectReader returns data from source, rate-limited
414// and with the errors as written to nextc.
415type faultInjectReader struct {
416	source string
417	nextc  <-chan nextRead
418}
419
420func (r *faultInjectReader) Read(p []byte) (int, error) {
421	nr := <-r.nextc
422	if len(p) > nr.n {
423		p = p[:nr.n]
424	}
425	n := copy(p, r.source)
426	r.source = r.source[n:]
427	return n, nr.err
428}
429
430// tests that we don't ignore errors from our underlying reader
431func TestDecoderIssue3577(t *testing.T) {
432	next := make(chan nextRead, 10)
433	wantErr := errors.New("my error")
434	next <- nextRead{5, nil}
435	next <- nextRead{10, wantErr}
436	next <- nextRead{0, wantErr}
437	d := NewDecoder(StdEncoding, &faultInjectReader{
438		source: "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==", // twas brillig...
439		nextc:  next,
440	})
441	errc := make(chan error, 1)
442	go func() {
443		_, err := io.ReadAll(d)
444		errc <- err
445	}()
446	select {
447	case err := <-errc:
448		if err != wantErr {
449			t.Errorf("got error %v; want %v", err, wantErr)
450		}
451	case <-time.After(5 * time.Second):
452		t.Errorf("timeout; Decoder blocked without returning an error")
453	}
454}
455
456func TestDecoderIssue4779(t *testing.T) {
457	encoded := `CP/EAT8AAAEF
458AQEBAQEBAAAAAAAAAAMAAQIEBQYHCAkKCwEAAQUBAQEBAQEAAAAAAAAAAQACAwQFBgcICQoLEAAB
459BAEDAgQCBQcGCAUDDDMBAAIRAwQhEjEFQVFhEyJxgTIGFJGhsUIjJBVSwWIzNHKC0UMHJZJT8OHx
460Y3M1FqKygyZEk1RkRcKjdDYX0lXiZfKzhMPTdePzRieUpIW0lcTU5PSltcXV5fVWZnaGlqa2xtbm
4619jdHV2d3h5ent8fX5/cRAAICAQIEBAMEBQYHBwYFNQEAAhEDITESBEFRYXEiEwUygZEUobFCI8FS
4620fAzJGLhcoKSQ1MVY3M08SUGFqKygwcmNcLSRJNUoxdkRVU2dGXi8rOEw9N14/NGlKSFtJXE1OT0
463pbXF1eX1VmZ2hpamtsbW5vYnN0dXZ3eHl6e3x//aAAwDAQACEQMRAD8A9VSSSSUpJJJJSkkkJ+Tj
4641kiy1jCJJDnAcCTykpKkuQ6p/jN6FgmxlNduXawwAzaGH+V6jn/R/wCt71zdn+N/qL3kVYFNYB4N
465ji6PDVjWpKp9TSXnvTf8bFNjg3qOEa2n6VlLpj/rT/pf567DpX1i6L1hs9Py67X8mqdtg/rUWbbf
466+gkp0kkkklKSSSSUpJJJJT//0PVUkkklKVLq3WMDpGI7KzrNjADtYNXvI/Mqr/Pd/q9W3vaxjnvM
467NaCXE9gNSvGPrf8AWS3qmba5jjsJhoB0DAf0NDf6sevf+/lf8Hj0JJATfWT6/dV6oXU1uOLQeKKn
468EQP+Hubtfe/+R7Mf/g7f5xcocp++Z11JMCJPgFBxOg7/AOuqDx8I/ikpkXkmSdU8mJIJA/O8EMAy
469j+mSARB/17pKVXYWHXjsj7yIex0PadzXMO1zT5KHoNA3HT8ietoGhgjsfA+CSnvvqh/jJtqsrwOv
4702b6NGNzXfTYexzJ+nU7/ALkf4P8Awv6P9KvTQQ4AgyDqCF85Pho3CTB7eHwXoH+LT65uZbX9X+o2
471bqbPb06551Y4
472`
473	encodedShort := strings.ReplaceAll(encoded, "\n", "")
474
475	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
476	res1, err := io.ReadAll(dec)
477	if err != nil {
478		t.Errorf("ReadAll failed: %v", err)
479	}
480
481	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
482	var res2 []byte
483	res2, err = io.ReadAll(dec)
484	if err != nil {
485		t.Errorf("ReadAll failed: %v", err)
486	}
487
488	if !bytes.Equal(res1, res2) {
489		t.Error("Decoded results not equal")
490	}
491}
492
493func TestDecoderIssue7733(t *testing.T) {
494	s, err := StdEncoding.DecodeString("YWJjZA=====")
495	want := CorruptInputError(8)
496	if !reflect.DeepEqual(want, err) {
497		t.Errorf("Error = %v; want CorruptInputError(8)", err)
498	}
499	if string(s) != "abcd" {
500		t.Errorf("DecodeString = %q; want abcd", s)
501	}
502}
503
504func TestDecoderIssue15656(t *testing.T) {
505	_, err := StdEncoding.Strict().DecodeString("WvLTlMrX9NpYDQlEIFlnDB==")
506	want := CorruptInputError(22)
507	if !reflect.DeepEqual(want, err) {
508		t.Errorf("Error = %v; want CorruptInputError(22)", err)
509	}
510	_, err = StdEncoding.Strict().DecodeString("WvLTlMrX9NpYDQlEIFlnDA==")
511	if err != nil {
512		t.Errorf("Error = %v; want nil", err)
513	}
514	_, err = StdEncoding.DecodeString("WvLTlMrX9NpYDQlEIFlnDB==")
515	if err != nil {
516		t.Errorf("Error = %v; want nil", err)
517	}
518}
519
520func BenchmarkEncodeToString(b *testing.B) {
521	data := make([]byte, 8192)
522	b.SetBytes(int64(len(data)))
523	for i := 0; i < b.N; i++ {
524		StdEncoding.EncodeToString(data)
525	}
526}
527
528func BenchmarkDecodeString(b *testing.B) {
529	sizes := []int{2, 4, 8, 64, 8192}
530	benchFunc := func(b *testing.B, benchSize int) {
531		data := StdEncoding.EncodeToString(make([]byte, benchSize))
532		b.SetBytes(int64(len(data)))
533		b.ResetTimer()
534		for i := 0; i < b.N; i++ {
535			StdEncoding.DecodeString(data)
536		}
537	}
538	for _, size := range sizes {
539		b.Run(fmt.Sprintf("%d", size), func(b *testing.B) {
540			benchFunc(b, size)
541		})
542	}
543}
544
545func BenchmarkNewEncoding(b *testing.B) {
546	b.SetBytes(int64(len(Encoding{}.decodeMap)))
547	for i := 0; i < b.N; i++ {
548		e := NewEncoding(encodeStd)
549		for _, v := range e.decodeMap {
550			_ = v
551		}
552	}
553}
554
555func TestDecoderRaw(t *testing.T) {
556	source := "AAAAAA"
557	want := []byte{0, 0, 0, 0}
558
559	// Direct.
560	dec1, err := RawURLEncoding.DecodeString(source)
561	if err != nil || !bytes.Equal(dec1, want) {
562		t.Errorf("RawURLEncoding.DecodeString(%q) = %x, %v, want %x, nil", source, dec1, err, want)
563	}
564
565	// Through reader. Used to fail.
566	r := NewDecoder(RawURLEncoding, bytes.NewReader([]byte(source)))
567	dec2, err := io.ReadAll(io.LimitReader(r, 100))
568	if err != nil || !bytes.Equal(dec2, want) {
569		t.Errorf("reading NewDecoder(RawURLEncoding, %q) = %x, %v, want %x, nil", source, dec2, err, want)
570	}
571
572	// Should work with padding.
573	r = NewDecoder(URLEncoding, bytes.NewReader([]byte(source+"==")))
574	dec3, err := io.ReadAll(r)
575	if err != nil || !bytes.Equal(dec3, want) {
576		t.Errorf("reading NewDecoder(URLEncoding, %q) = %x, %v, want %x, nil", source+"==", dec3, err, want)
577	}
578}
579