Add test for invalid tarball read

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)

archive/archive_test.go

@@ -137,3 +137,32 @@ func TestTypeXGlobalHeaderDoesNotFail(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+// Some tar have both GNU specific (huge uid) and Ustar specific (long name) things.
+// Not supposed to happen (should use PAX instead of Ustar for long name) but it does and it should still work.
+func TestUntarUstarGnuConflict(t *testing.T) {
+	f, err := os.Open("testdata/broken.tar")
+	if err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	tr := tar.NewReader(f)
+	// Iterate through the files in the archive.
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			// end of tar archive
+			break
+		}
+		if err != nil {
+			t.Fatal(err)
+		}
+		if hdr.Name == "root/.cpanm/work/1395823785.24209/Plack-1.0030/blib/man3/Plack::Middleware::LighttpdScriptNameFix.3pm" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatal("%s not found in the archive", "root/.cpanm/work/1395823785.24209/Plack-1.0030/blib/man3/Plack::Middleware::LighttpdScriptNameFix.3pm")
+	}
+}