From 4cd58c2f2687fc5930a3da2581da09e2e96f69f5 Mon Sep 17 00:00:00 2001
From: Joe Tsai <joetsai@digital-static.net>
Date: Fri, 6 Oct 2017 01:40:58 -0700
Subject: [PATCH] archive/tar: improve handling of directory paths
The USTAR format says:
<<<
Implementors should be aware that the previous file format did not include
a mechanism to archive directory type files.
For this reason, the convention of using a filename ending with
<slash> was adopted to specify a directory on the archive.
>>>
In light of this suggestion, make the following changes:
* Writer.WriteHeader refuses to encode a header where a file that
is obviously a file-type has a trailing slash in the name.
* formatter.formatString avoids encoding a trailing slash in the event
that the string is truncated (the full string will be encoded elsewhere,
so stripping the slash is safe).
* Reader.Next treats a TypeRegA (which is the zero value of Typeflag)
as a TypeDir if the name has a trailing slash.
Change-Id: Ibf27aa8234cce2032d92e5e5b28546c2f2ae5ef6
Reviewed-on: https://go-review.googlesource.com/69293
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---
src/archive/tar/common.go | 5 +++++
src/archive/tar/reader.go | 3 +++
src/archive/tar/reader_test.go | 11 +++++++++++
src/archive/tar/strconv.go | 8 ++++++++
src/archive/tar/tar_test.go | 9 +++++++++
src/archive/tar/testdata/trailing-slash.tar | Bin 0 -> 2560 bytes
src/archive/tar/writer.go | 1 +
src/archive/tar/writer_test.go | 6 ++++++
8 files changed, 43 insertions(+)
create mode 100644 src/archive/tar/testdata/trailing-slash.tar
diff --git a/src/archive/tar/common.go b/src/archive/tar/common.go
index 5855b8e84f..7f8abdf989 100644
--- a/src/archive/tar/common.go
+++ b/src/archive/tar/common.go
@@ -444,6 +444,11 @@ func (h *Header) allowedFormats() (format Format, paxHdrs map[string]string, err
// Check for header-only types.
var whyOnlyPAX, whyOnlyGNU string
switch h.Typeflag {
+ case TypeReg, TypeChar, TypeBlock, TypeFifo, TypeGNUSparse:
+ // Exclude TypeLink and TypeSymlink, since they may reference directories.
+ if strings.HasSuffix(h.Name, "/") {
+ return FormatUnknown, nil, headerError{"filename may not have trailing slash"}
+ }
case TypeXHeader, TypeGNULongName, TypeGNULongLink:
return FormatUnknown, nil, headerError{"cannot manually encode TypeXHeader, TypeGNULongName, or TypeGNULongLink headers"}
case TypeXGlobalHeader:
diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
index bde6e1205c..6bb2c46e7b 100644
--- a/src/archive/tar/reader.go
+++ b/src/archive/tar/reader.go
@@ -130,6 +130,9 @@ loop:
if gnuLongLink != "" {
hdr.Linkname = gnuLongLink
}
+ if hdr.Typeflag == TypeRegA && strings.HasSuffix(hdr.Name, "/") {
+ hdr.Typeflag = TypeDir // Legacy archives use trailing slash for directories
+ }
// The extended headers may have updated the size.
// Thus, setup the regFileReader again after merging PAX headers.
diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
index bbabd96246..3ac81adb4d 100644
--- a/src/archive/tar/reader_test.go
+++ b/src/archive/tar/reader_test.go
@@ -675,6 +675,17 @@ func TestReader(t *testing.T) {
},
Format: FormatPAX,
}},
+ }, {
+ file: "testdata/trailing-slash.tar",
+ headers: []*Header{{
+ Typeflag: TypeDir,
+ Name: strings.Repeat("123456789/", 30),
+ ModTime: time.Unix(0, 0),
+ PAXRecords: map[string]string{
+ "path": strings.Repeat("123456789/", 30),
+ },
+ Format: FormatPAX,
+ }},
}}
for _, v := range vectors {
diff --git a/src/archive/tar/strconv.go b/src/archive/tar/strconv.go
index e02963b74b..8bbd65cd1a 100644
--- a/src/archive/tar/strconv.go
+++ b/src/archive/tar/strconv.go
@@ -68,6 +68,14 @@ func (f *formatter) formatString(b []byte, s string) {
if len(s) < len(b) {
b[len(s)] = 0
}
+
+ // Some buggy readers treat regular files with a trailing slash
+ // in the V7 path field as a directory even though the full path
+ // recorded elsewhere (e.g., via PAX record) contains no trailing slash.
+ if len(s) > len(b) && b[len(b)-1] == '/' {
+ n := len(strings.TrimRight(s[:len(b)], "/"))
+ b[n] = 0 // Replace trailing slash with NUL terminator
+ }
}
// fitsInBase256 reports whether x can be encoded into n bytes using base-256
diff --git a/src/archive/tar/tar_test.go b/src/archive/tar/tar_test.go
index 8d44f3bf65..61f52be31d 100644
--- a/src/archive/tar/tar_test.go
+++ b/src/archive/tar/tar_test.go
@@ -748,6 +748,15 @@ func TestHeaderAllowedFormats(t *testing.T) {
}, {
header: &Header{Name: "sparse.db", Size: 1000, SparseHoles: []SparseEntry{{0, 500}}, Format: FormatUSTAR},
formats: FormatUnknown,
+ }, {
+ header: &Header{Name: "foo/", Typeflag: TypeDir},
+ formats: FormatUSTAR | FormatPAX | FormatGNU,
+ }, {
+ header: &Header{Name: "foo/", Typeflag: TypeReg},
+ formats: FormatUnknown,
+ }, {
+ header: &Header{Name: "foo/", Typeflag: TypeSymlink},
+ formats: FormatUSTAR | FormatPAX | FormatGNU,
}}
for i, v := range vectors {
diff --git a/src/archive/tar/testdata/trailing-slash.tar b/src/archive/tar/testdata/trailing-slash.tar
new file mode 100644
index 0000000000000000000000000000000000000000..bf1b2ec426b4999b111c7f0914fb1f2d52b91728
GIT binary patch
literal 2560
zcmXpsGBz<aGq<qRH>4Gd!2kkq(FP`FW-vLBN(KWX14A<d289X+I)KvRlEfmQ^>nam
zFj`@3XrNG#Sdw8&v*@Q?!WuA>xdvlQlIJEmL^~{R<DwyX9#Td?^S_~yAu#`w=OYqz
bQ7ivL-4FL9iOv{RJ{kg}Aut*O^bP?4t`UQn
literal 0
HcmV?d00001
diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
index 1e5b76f58f..f938dfbfde 100644
--- a/src/archive/tar/writer.go
+++ b/src/archive/tar/writer.go
@@ -323,6 +323,7 @@ func (tw *Writer) writeRawFile(name, data string, flag byte, format Format) erro
if len(name) > nameSize {
name = name[:nameSize]
}
+ name = strings.TrimRight(name, "/")
var f formatter
v7 := tw.blk.V7()
diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
index ecac29a39e..e9bcad9374 100644
--- a/src/archive/tar/writer_test.go
+++ b/src/archive/tar/writer_test.go
@@ -451,6 +451,12 @@ func TestWriter(t *testing.T) {
}, 6e10, nil},
testClose{nil},
},
+ }, {
+ file: "testdata/trailing-slash.tar",
+ tests: []testFnc{
+ testHeader{Header{Name: strings.Repeat("123456789/", 30)}, nil},
+ testClose{nil},
+ },
}}
equalError := func(x, y error) bool {
--
2.30.9