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Strip extended-timestap extra block in zip2zip.

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The extended-timestap extra block changes between Local File Header and
Central Directory. We have to strip it out to avoid mis-filling during
zip2zip.

Bug: b/65455145
Test: add unit-test.
Change-Id: I17e3f6c10fd6a068019620b4426f6042f6fac317
This commit is contained in:
Nan Zhang 2017-09-19 17:13:11 -07:00
parent 8eded0ac86
commit 10e8e93710
2 changed files with 21 additions and 11 deletions
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25
third_party/zip/android.go vendored
View file

@ -20,6 +20,7 @@ import (
) )
const DataDescriptorFlag = 0x8 const DataDescriptorFlag = 0x8
const ExtendedTimeStampTag = 0x5455
func (w *Writer) CopyFrom(orig *File, newName string) error { func (w *Writer) CopyFrom(orig *File, newName string) error {
if w.last != nil && !w.last.closed { if w.last != nil && !w.last.closed {
@ -33,11 +34,9 @@ func (w *Writer) CopyFrom(orig *File, newName string) error {
fileHeader.Name = newName fileHeader.Name = newName
fh := &fileHeader fh := &fileHeader
// The zip64 extras change between the Central Directory and Local File Header, while we use // In some cases, we need strip the extras if it change between Central Directory
// the same structure for both. The Local File Haeder is taken care of by us writing a data // and Local File Header.
// descriptor with the zip64 values. The Central Directory Entry is written by Close(), where fh.Extra = stripExtras(fh.Extra)
// the zip64 extra is automatically created and appended when necessary.
fh.Extra = stripZip64Extras(fh.Extra)
h := &header{ h := &header{
FileHeader: fh, FileHeader: fh,
@ -48,8 +47,6 @@ func (w *Writer) CopyFrom(orig *File, newName string) error {
if err := writeHeader(w.cw, fh); err != nil { if err := writeHeader(w.cw, fh); err != nil {
return err return err
} }
// Copy data
dataOffset, err := orig.DataOffset() dataOffset, err := orig.DataOffset()
if err != nil { if err != nil {
return err return err
@ -79,8 +76,16 @@ func (w *Writer) CopyFrom(orig *File, newName string) error {
return err return err
} }
// Strip any Zip64 extra fields // The zip64 extras change between the Central Directory and Local File Header, while we use
func stripZip64Extras(input []byte) []byte { // the same structure for both. The Local File Haeder is taken care of by us writing a data
// descriptor with the zip64 values. The Central Directory Entry is written by Close(), where
// the zip64 extra is automatically created and appended when necessary.
//
// The extended-timestamp extra block changes between the Central Directory Header and Local
// File Header.
// Extended-Timestamp extra(LFH): <tag-size-flag-modtime-actime-changetime>
// Extended-Timestamp extra(CDH): <tag-size-flag-modtime>
func stripExtras(input []byte) []byte {
ret := []byte{} ret := []byte{}
for len(input) >= 4 { for len(input) >= 4 {
@ -90,7 +95,7 @@ func stripZip64Extras(input []byte) []byte {
if int(size) > len(r) { if int(size) > len(r) {
break break
} }
if tag != zip64ExtraId { if tag != zip64ExtraId && tag != ExtendedTimeStampTag {
ret = append(ret, input[:4+size]...) ret = append(ret, input[:4+size]...)
} }
input = input[4+size:] input = input[4+size:]

7
third_party/zip/android_test.go vendored
View file

@ -59,11 +59,16 @@ var stripZip64Testcases = []struct {
in: []byte{0, 0, 8, 0, 0, 0}, in: []byte{0, 0, 8, 0, 0, 0},
out: []byte{0, 0, 8, 0, 0, 0}, out: []byte{0, 0, 8, 0, 0, 0},
}, },
{
name: "zip64 extra and extended-timestamp extra and valid non-zip64 extra",
in: []byte{1, 0, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 85, 84, 5, 0, 1, 1, 2, 3, 4, 2, 0, 0, 0},
out: []byte{2, 0, 0, 0},
},
} }
func TestStripZip64Extras(t *testing.T) { func TestStripZip64Extras(t *testing.T) {
for _, testcase := range stripZip64Testcases { for _, testcase := range stripZip64Testcases {
got := stripZip64Extras(testcase.in) got := stripExtras(testcase.in)
if !bytes.Equal(got, testcase.out) { if !bytes.Equal(got, testcase.out) {
t.Errorf("Failed testcase %s\ninput: %v\n want: %v\n got: %v\n", testcase.name, testcase.in, testcase.out, got) t.Errorf("Failed testcase %s\ninput: %v\n want: %v\n got: %v\n", testcase.name, testcase.in, testcase.out, got)
} }