archive/tar: reapply Header.Size to regFileReader after merging

The use of PAX headers can modify the overall file size, thus the
formerly created regFileReader may be stale.

The relevant PAX specification for this behavior is:
<<<
Any fields in the preceding optional extended header shall override
the associated fields in this header block for this file.
>>>
Where "optional extended header" refers to the preceding PAX header.
Where "this header block" refers to the subsequent USTAR header.

Fixes #15573
Fixes #15564

Change-Id: I83b1c3f05a9ca2d3be38647425ad21a9fe450ee2
Reviewed-on: https://go-review.googlesource.com/28418
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
index b8b1652b2b450545b4bf390c57e227dd2aa1a9af..fa1c48adeb610ebb66b552f46638edafddaf0d81 100644 (file)
--- a/src/archive/tar/reader.go
+++ b/src/archive/tar/reader.go
@@ -175,11 +175,14 @@ loop:
                                return nil, err
                        }
 
-                       // TODO(dsnet): The extended headers may have updated the size.
-                       // Thus, we must setup the regFileReader again here.
-                       //
-                       // See golang.org/issue/15573
+                       // The extended headers may have updated the size.
+                       // Thus, setup the regFileReader again after merging PAX headers.
+                       if err := tr.handleRegularFile(hdr); err != nil {
+                               return nil, err
+                       }
 
+                       // Sparse formats rely on being able to read from the logical data
+                       // section; there must be a preceding call to handleRegularFile.
                        if err := tr.handleSparseFile(hdr, rawHdr, extHdrs); err != nil {
                                return nil, err
                        }

diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
index 3de5299bacfc16916a42da3ee910de54cf74cdfa..9ffc8d6459b46e2153355c8b4b4df39c0d50d9f8 100644 (file)
--- a/src/archive/tar/reader_test.go
+++ b/src/archive/tar/reader_test.go
@@ -237,6 +237,23 @@ var untarTests = []*untarTest{
                file: "testdata/pax-bad-mtime-file.tar",
                err:  ErrHeader,
        },
+       {
+               file: "testdata/pax-pos-size-file.tar",
+               headers: []*Header{{
+                       Name:     "foo",
+                       Mode:     0640,
+                       Uid:      319973,
+                       Gid:      5000,
+                       Size:     999,
+                       ModTime:  time.Unix(1442282516, 0),
+                       Typeflag: '0',
+                       Uname:    "joetsai",
+                       Gname:    "eng",
+               }},
+               chksums: []string{
+                       "0afb597b283fe61b5d4879669a350556",
+               },
+       },
        {
                file: "testdata/nil-uid.tar", // golang.org/issue/5290
                headers: []*Header{

diff --git a/src/archive/tar/testdata/pax-pos-size-file.tar b/src/archive/tar/testdata/pax-pos-size-file.tar
new file mode 100644 (file)
index 0000000..aed9a8a
Binary files /dev/null and b/src/archive/tar/testdata/pax-pos-size-file.tar differ