archive/zip: handle files with data descriptors

Fixes #1471.

R=rsc
CC=golang-dev
https://golang.org/cl/4183048

diff --git a/src/pkg/archive/zip/reader.go b/src/pkg/archive/zip/reader.go
index 579ba16029494a35aff3ec3bede977e08b5b112f..d8d9bba60bc56e977c43213a236af5732360d0e4 100644 (file)
--- a/src/pkg/archive/zip/reader.go
+++ b/src/pkg/archive/zip/reader.go
@@ -42,6 +42,10 @@ type File struct {
        bodyOffset   int64
 }
 
+func (f *File) hasDataDescriptor() bool {
+       return f.Flags&0x8 != 0
+}
+
 // OpenReader will open the Zip file specified by name and return a Reader.
 func OpenReader(name string) (*Reader, os.Error) {
        f, err := os.Open(name, os.O_RDONLY, 0644)
@@ -93,7 +97,16 @@ func (f *File) Open() (rc io.ReadCloser, err os.Error) {
                        return
                }
        }
-       r := io.NewSectionReader(f.zipr, off+f.bodyOffset, int64(f.CompressedSize))
+       size := int64(f.CompressedSize)
+       if f.hasDataDescriptor() {
+               if size == 0 {
+                       // permit SectionReader to see the rest of the file
+                       size = f.zipsize - (off + f.bodyOffset)
+               } else {
+                       size += dataDescriptorLen
+               }
+       }
+       r := io.NewSectionReader(f.zipr, off+f.bodyOffset, size)
        switch f.Method {
        case 0: // store (no compression)
                rc = nopCloser{r}
@@ -103,7 +116,7 @@ func (f *File) Open() (rc io.ReadCloser, err os.Error) {
                err = UnsupportedMethod
        }
        if rc != nil {
-               rc = &checksumReader{rc, crc32.NewIEEE(), f.CRC32}
+               rc = &checksumReader{rc, crc32.NewIEEE(), f, r}
        }
        return
 }
@@ -111,7 +124,8 @@ func (f *File) Open() (rc io.ReadCloser, err os.Error) {
 type checksumReader struct {
        rc   io.ReadCloser
        hash hash.Hash32
-       sum  uint32
+       f    *File
+       zipr io.Reader // for reading the data descriptor
 }
 
 func (r *checksumReader) Read(b []byte) (n int, err os.Error) {
@@ -120,7 +134,12 @@ func (r *checksumReader) Read(b []byte) (n int, err os.Error) {
        if err != os.EOF {
                return
        }
-       if r.hash.Sum32() != r.sum {
+       if r.f.hasDataDescriptor() {
+               if err = readDataDescriptor(r.zipr, r.f); err != nil {
+                       return
+               }
+       }
+       if r.hash.Sum32() != r.f.CRC32 {
                err = ChecksumError
        }
        return
@@ -205,6 +224,18 @@ func readDirectoryHeader(f *File, r io.Reader) (err os.Error) {
        return
 }
 
+func readDataDescriptor(r io.Reader, f *File) (err os.Error) {
+       defer func() {
+               if rerr, ok := recover().(os.Error); ok {
+                       err = rerr
+               }
+       }()
+       read(r, &f.CRC32)
+       read(r, &f.CompressedSize)
+       read(r, &f.UncompressedSize)
+       return
+}
+
 func readDirectoryEnd(r io.ReaderAt, size int64) (d *directoryEnd, err os.Error) {
        // look for directoryEndSignature in the last 1k, then in the last 65k
        var b []byte

diff --git a/src/pkg/archive/zip/reader_test.go b/src/pkg/archive/zip/reader_test.go
index 3c24f1467cf8e71b5775a9c40a54954d958ba8d3..72e8cccfd47dc58c5e33e449cf13772d01cf0b43 100644 (file)
--- a/src/pkg/archive/zip/reader_test.go
+++ b/src/pkg/archive/zip/reader_test.go
@@ -52,6 +52,15 @@ var tests = []ZipTest{
        },
        {Name: "readme.zip"},
        {Name: "readme.notzip", Error: FormatError},
+       {
+               Name: "dd.zip",
+               File: []ZipTestFile{
+                       {
+                               Name:    "filename",
+                               Content: []byte("This is a test textfile.\n"),
+                       },
+               },
+       },
 }
 
 func TestReader(t *testing.T) {
@@ -102,16 +111,18 @@ func readTestZip(t *testing.T, zt ZipTest) {
        }
 
        // test invalid checksum
-       z.File[0].CRC32++ // invalidate
-       r, err := z.File[0].Open()
-       if err != nil {
-               t.Error(err)
-               return
-       }
-       var b bytes.Buffer
-       _, err = io.Copy(&b, r)
-       if err != ChecksumError {
-               t.Errorf("%s: copy error=%v, want %v", z.File[0].Name, err, ChecksumError)
+       if !z.File[0].hasDataDescriptor() { // skip test when crc32 in dd
+               z.File[0].CRC32++ // invalidate
+               r, err := z.File[0].Open()
+               if err != nil {
+                       t.Error(err)
+                       return
+               }
+               var b bytes.Buffer
+               _, err = io.Copy(&b, r)
+               if err != ChecksumError {
+                       t.Errorf("%s: copy error=%v, want %v", z.File[0].Name, err, ChecksumError)
+               }
        }
 }
 

diff --git a/src/pkg/archive/zip/struct.go b/src/pkg/archive/zip/struct.go
index 8a8c727d474068ed6962bc35d94738be469b64e5..bfe0aae2e9a2ac8ac8fefdc0a242fd59fb4aea6f 100644 (file)
--- a/src/pkg/archive/zip/struct.go
+++ b/src/pkg/archive/zip/struct.go
@@ -4,6 +4,7 @@ const (
        fileHeaderSignature      = 0x04034b50
        directoryHeaderSignature = 0x02014b50
        directoryEndSignature    = 0x06054b50
+       dataDescriptorLen        = 12
 )
 
 type FileHeader struct {

diff --git a/src/pkg/archive/zip/testdata/dd.zip b/src/pkg/archive/zip/testdata/dd.zip
new file mode 100644 (file)
index 0000000..e53378b
Binary files /dev/null and b/src/pkg/archive/zip/testdata/dd.zip differ