[rt.cpan.org #45885] File::Spec: Don’t use tainted tmpdir in 5.6

Perl 5.6 doesn’t have ${^TAINT}, so the taint check in
File::Spec::Unix->_tmpdir was skipped.  This commit adds a taint check
using eval { eval $safe_substring } for 5.6.

2 files changed, 22 insertions, 2 deletions

diff --git a/dist/Cwd/lib/File/Spec/Unix.pm b/dist/Cwd/lib/File/Spec/Unix.pm
index 9f024e00be..b3481476a8 100644
--- a/dist/Cwd/lib/File/Spec/Unix.pm
+++ b/dist/Cwd/lib/File/Spec/Unix.pm
@@ -3,7 +3,7 @@ package File::Spec::Unix;
 use strict;
 use vars qw($VERSION);
 
-$VERSION = '3.34';
+$VERSION = '3.35';
 $VERSION = eval $VERSION;
 
 =head1 NAME
@@ -135,7 +135,7 @@ writable:
     $ENV{TMPDIR}
     /tmp
 
-Since perl 5.8.0, if running under taint mode, and if $ENV{TMPDIR}
+If running under taint mode, and if $ENV{TMPDIR}
 is tainted, it is not used.
 
 =cut
@@ -151,6 +151,9 @@ sub _tmpdir {
             require Scalar::Util;
 	    @dirlist = grep { ! Scalar::Util::tainted($_) } @dirlist;
 	}
+	elsif ($] < 5.007) { # No ${^TAINT} before 5.8
+	    @dirlist = grep { eval { eval('1'.substr $_,0,0) } } @dirlist;
+	}
     }
     foreach (@dirlist) {
 	next unless defined && -d && -w _;
diff --git a/dist/Cwd/t/Spec-taint.t b/dist/Cwd/t/Spec-taint.t
new file mode 100644
index 0000000000..ef4f1ee3f2
--- /dev/null
+++ b/dist/Cwd/t/Spec-taint.t
@@ -0,0 +1,17 @@
+#!./perl -Tw
+# Testing File::Spec under taint mode.
+
+use strict;
+
+chdir 't' unless $ENV{PERL_CORE};
+
+use File::Spec;
+use lib File::Spec->catdir('t', 'lib');
+use Test::More tests => 2;
+
+use Scalar::Util qw/tainted/;
+
+my $ret;
+eval { $ret = File::Spec->tmpdir };
+is( $@, '',		"tmpdir should not explode under taint mode" );
+ok( !tainted($ret),	"its return value should not be tainted" );