Imported Upstream version 1.3upstream/1.3

2 files changed, 46 insertions, 20 deletions

diff --git a/src/pkg/encoding/base64/base64.go b/src/pkg/encoding/base64/base64.go
index 85e398fd0..e38c26d0e 100644
--- a/src/pkg/encoding/base64/base64.go
+++ b/src/pkg/encoding/base64/base64.go
@@ -159,13 +159,11 @@ func (e *encoder) Write(p []byte) (n int, err error) {
 		nn := len(e.out) / 4 * 3
 		if nn > len(p) {
 			nn = len(p)
+			nn -= nn % 3
 		}
-		nn -= nn % 3
-		if nn > 0 {
-			e.enc.Encode(e.out[0:], p[0:nn])
-			if _, e.err = e.w.Write(e.out[0 : nn/3*4]); e.err != nil {
-				return n, e.err
-			}
+		e.enc.Encode(e.out[0:], p[0:nn])
+		if _, e.err = e.w.Write(e.out[0 : nn/3*4]); e.err != nil {
+			return n, e.err
 		}
 		n += nn
 		p = p[nn:]
@@ -226,21 +224,33 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		var dbuf [4]byte
 		dlen := 4
 
-		for j := 0; j < 4; {
+		for j := range dbuf {
 			if len(src) == 0 {
 				return n, false, CorruptInputError(olen - len(src) - j)
 			}
 			in := src[0]
 			src = src[1:]
-			if in == '=' && j >= 2 && len(src) < 4 {
+			if in == '=' {
 				// We've reached the end and there's padding
-				if len(src)+j < 4-1 {
-					// not enough padding
-					return n, false, CorruptInputError(olen)
-				}
-				if len(src) > 0 && src[0] != '=' {
+				switch j {
+				case 0, 1:
 					// incorrect padding
 					return n, false, CorruptInputError(olen - len(src) - 1)
+				case 2:
+					// "==" is expected, the first "=" is already consumed.
+					if len(src) == 0 {
+						// not enough padding
+						return n, false, CorruptInputError(olen)
+					}
+					if src[0] != '=' {
+						// incorrect padding
+						return n, false, CorruptInputError(olen - len(src) - 1)
+					}
+					src = src[1:]
+				}
+				if len(src) > 0 {
+					// trailing garbage
+					err = CorruptInputError(olen - len(src))
 				}
 				dlen, end = j, true
 				break
@@ -249,7 +259,6 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 			if dbuf[j] == 0xFF {
 				return n, false, CorruptInputError(olen - len(src) - 1)
 			}
-			j++
 		}
 
 		// Pack 4x 6-bit source blocks into 3 byte destination
@@ -268,7 +277,7 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		n += dlen - 1
 	}
 
-	return n, end, nil
+	return n, end, err
 }
 
 // Decode decodes src using the encoding enc.  It writes at most
diff --git a/src/pkg/encoding/base64/base64_test.go b/src/pkg/encoding/base64/base64_test.go
index 579591a88..a075194e0 100644
--- a/src/pkg/encoding/base64/base64_test.go
+++ b/src/pkg/encoding/base64/base64_test.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"io"
 	"io/ioutil"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -113,7 +114,7 @@ func TestDecode(t *testing.T) {
 
 func TestDecoder(t *testing.T) {
 	for _, p := range pairs {
-		decoder := NewDecoder(StdEncoding, bytes.NewBufferString(p.encoded))
+		decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
 		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
 		count, err := decoder.Read(dbuf)
 		if err != nil && err != io.EOF {
@@ -130,7 +131,7 @@ func TestDecoder(t *testing.T) {
 
 func TestDecoderBuffering(t *testing.T) {
 	for bs := 1; bs <= 12; bs++ {
-		decoder := NewDecoder(StdEncoding, bytes.NewBufferString(bigtest.encoded))
+		decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
 		buf := make([]byte, len(bigtest.decoded)+12)
 		var total int
 		for total = 0; total < len(bigtest.decoded); {
@@ -149,9 +150,13 @@ func TestDecodeCorrupt(t *testing.T) {
 	}{
 		{"", -1},
 		{"!!!!", 0},
+		{"====", 0},
 		{"x===", 1},
+		{"=AAA", 0},
+		{"A=AA", 1},
 		{"AA=A", 2},
-		{"AAA=AAAA", 3},
+		{"AA==A", 4},
+		{"AAA=AAAA", 4},
 		{"AAAAA", 4},
 		{"AAAAAA", 4},
 		{"A=", 1},
@@ -161,6 +166,7 @@ func TestDecodeCorrupt(t *testing.T) {
 		{"AAA=", -1},
 		{"AAAA", -1},
 		{"AAAAAA=", 7},
+		{"YWJjZA=====", 8},
 	}
 	for _, tc := range testCases {
 		dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
@@ -308,13 +314,13 @@ bqbPb06551Y4
 `
 	encodedShort := strings.Replace(encoded, "\n", "", -1)
 
-	dec := NewDecoder(StdEncoding, bytes.NewBufferString(encoded))
+	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
 	res1, err := ioutil.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}
 
-	dec = NewDecoder(StdEncoding, bytes.NewBufferString(encodedShort))
+	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
 	var res2 []byte
 	res2, err = ioutil.ReadAll(dec)
 	if err != nil {
@@ -325,3 +331,14 @@ bqbPb06551Y4
 		t.Error("Decoded results not equal")
 	}
 }
+
+func TestDecoderIssue7733(t *testing.T) {
+	s, err := StdEncoding.DecodeString("YWJjZA=====")
+	want := CorruptInputError(8)
+	if !reflect.DeepEqual(want, err) {
+		t.Errorf("Error = %v; want CorruptInputError(8)", err)
+	}
+	if string(s) != "abcd" {
+		t.Errorf("DecodeString = %q; want abcd", s)
+	}
+}