xref: /openbsd/gnu/usr.bin/perl/t/op/taint.t (revision 3bef86f7)

#!./perl -T
#
# Taint tests by Tom Phoenix <rootbeer@teleport.com>.
#
# I don't claim to know all about tainting. If anyone sees
# tests that I've missed here, please add them. But this is
# better than having no tests at all, right?
#

BEGIN {
    chdir 't' if -d 't';
    require './test.pl';
    set_up_inc('../lib');
    require './loc_tools.pl';
}

use strict;
use warnings;
use Config;

my $NoTaintSupport = exists($Config{taint_support}) && !$Config{taint_support};

if ($NoTaintSupport) {
    skip_all("your perl was built without taint support");
    exit 0;
}

plan tests => 1058;

$| = 1;

my $ipcsysv; # did we manage to load IPC::SysV?

my ($old_env_path, $old_env_dcl_path, $old_env_term);
BEGIN {
   $old_env_path = $ENV{'PATH'};
   $old_env_dcl_path = $ENV{'DCL$PATH'};
   $old_env_term = $ENV{'TERM'};
  if ($^O eq 'VMS' && !defined($Config{d_setenv})) {
      $ENV{PATH} = $ENV{PATH};
      $ENV{TERM} = $ENV{TERM} ne ''? $ENV{TERM} : 'dummy';
  }
  if ($Config{'extensions'} =~ /\bIPC\/SysV\b/
      && ($Config{d_shm} || $Config{d_msg})) {
      eval { require IPC::SysV };
      unless ($@) {
	  $ipcsysv++;
	  IPC::SysV->import(qw(IPC_PRIVATE IPC_RMID IPC_CREAT S_IRWXU IPC_NOWAIT));
      }
  }
}

my $Is_VMS      = $^O eq 'VMS';
my $Is_MSWin32  = $^O eq 'MSWin32';
my $Is_Cygwin   = $^O eq 'cygwin';
my $Is_OpenBSD  = $^O eq 'openbsd';
my $Is_MirBSD   = $^O eq 'mirbsd';
my $Invoke_Perl = $Is_VMS      ? 'MCR Sys$Disk:[]Perl.exe' :
                  $Is_MSWin32  ? '.\perl'               :
                                 './perl'               ;
my @MoreEnv = qw/IFS CDPATH ENV BASH_ENV/;

if ($Is_VMS) {
    my (%old, $x);
    for $x ('DCL$PATH', @MoreEnv) {
	($old{$x}) = $ENV{$x} =~ /^(.*)$/ if exists $ENV{$x};
    }
    # VMS note:  PATH and TERM are automatically created by the C
    # library in VMS on reference to the their keys in %ENV.
    # There is currently no way to determine if they did not exist
    # before this test was run.
    eval <<EndOfCleanup;
	END {
	    \$ENV{PATH} = \$old_env_path;
	    warn "# Note: logical name 'PATH' may have been created\n";
	    \$ENV{'TERM'} = \$old_env_term;
	    warn "# Note: logical name 'TERM' may have been created\n";
	    \@ENV{keys %old} = values %old;
	    if (defined \$old_env_dcl_path) {
		\$ENV{'DCL\$PATH'} = \$old_env_dcl_path;
	    } else {
		delete \$ENV{'DCL\$PATH'};
	    }
	}
EndOfCleanup
}

# Sources of taint:
#   The empty tainted value, for tainting strings
my $TAINT = substr($^X, 0, 0);
#   A tainted non-empty string
my $TAINTXYZ = "xyz".$TAINT;
#   A tainted zero, useful for tainting numbers
my $TAINT0;
{
    no warnings;
    $TAINT0 = 0 + $TAINT;
}

# This taints each argument passed. All must be lvalues.
# Side effect: It also stringifies them. :-(
sub taint_these :prototype(@) {
    for (@_) { $_ .= $TAINT }
}

# How to identify taint when you see it
sub tainted :prototype($) {
    local $@;   # Don't pollute caller's value.
    not eval { no warnings; join("", @_), kill 0; 1 };
}

sub is_tainted {
    my $thing = shift;
    local $::Level = $::Level + 1;
    ok(tainted($thing), @_);
}

sub isnt_tainted {
    my $thing = shift;
    local $::Level = $::Level + 1;
    ok(!tainted($thing), @_);
}

sub violates_taint {
    my ($code, $what, $desc) = @_;
    $desc //= $what;
    local $::Level = $::Level + 1;
    is(eval { $code->(); }, undef, $desc);
    like($@, qr/^Insecure dependency in $what while running with -T switch/);
}

# We need an external program to call.
my $ECHO = ($Is_MSWin32 ? ".\\tmpecho$$" : "./tmpecho$$");
END { unlink $ECHO unless $NoTaintSupport }
open my $fh, '>', $ECHO or die "Can't create $ECHO: $!";
print $fh 'print "@ARGV\n"', "\n";
close $fh;
my $echo = "$Invoke_Perl $ECHO";

my $TEST = 'TEST';

# First, let's make sure that Perl is checking the dangerous
# environment variables. Maybe they aren't set yet, so we'll
# taint them ourselves.
{
    $ENV{'DCL$PATH'} = '' if $Is_VMS;

    $ENV{PATH} = ($Is_Cygwin) ? '/usr/bin' : '';
    delete @ENV{@MoreEnv};
    $ENV{TERM} = 'dumb';

    is(eval { `$echo 1` }, "1\n");

    SKIP: {
        skip "Environment tainting tests skipped", 4
          if $Is_MSWin32 || $Is_VMS;

	my @vars = ('PATH', @MoreEnv);
	while (my $v = $vars[0]) {
	    local $ENV{$v} = $TAINT;
	    last if eval { `$echo 1` };
	    last unless $@ =~ /^Insecure \$ENV\{$v\}/;
	    shift @vars;
	}
	is("@vars", "");

	# tainted $TERM is unsafe only if it contains metachars
	local $ENV{TERM};
	$ENV{TERM} = 'e=mc2';
	is(eval { `$echo 1` }, "1\n");
	$ENV{TERM} = 'e=mc2' . $TAINT;
	is(eval { `$echo 1` }, undef);
	like($@, qr/^Insecure \$ENV\{TERM\}/);
    }

    my $tmp;
    if ($^O eq 'os2' || $^O eq 'amigaos' || $Is_MSWin32) {
	print "# all directories are writeable\n";
    }
    else {
	$tmp = (grep { defined and -d and (stat _)[2] & 2 }
		     qw(sys$scratch /tmp /var/tmp /usr/tmp),
		     @ENV{qw(TMP TEMP)})[0]
	    or print "# can't find world-writeable directory to test PATH\n";
    }

    SKIP: {
        skip "all directories are writeable", 2 unless $tmp;

	local $ENV{PATH} = $tmp;
	is(eval { `$echo 1` }, undef);
	# Message can be different depending on whether echo
	# is a builtin or not
	like($@, qr/^Insecure (?:directory in )?\$ENV\{PATH\}/);
    }

    # Relative paths in $ENV{PATH} are always implicitly tainted.
    SKIP: {
        skip "Do these work on VMS?", 4 if $Is_VMS;
        skip "Not applicable to DOSish systems", 4 if! $tmp;

        local $ENV{PATH} = '.';
        is(eval { `$echo 1` }, undef);
        like($@, qr/^Insecure (?:directory in )?\$ENV\{PATH\}/);

        # Backslash should not fool perl into thinking that this is one
        # path.
        local $ENV{PATH} = '/\:.';
        is(eval { `$echo 1` }, undef);
        like($@, qr/^Insecure (?:directory in )?\$ENV\{PATH\}/);
    }

    SKIP: {
        skip "This is not VMS", 4 unless $Is_VMS;

	$ENV{'DCL$PATH'} = $TAINT;
	is(eval { `$echo 1` }, undef);
	like($@, qr/^Insecure \$ENV\{DCL\$PATH\}/);
	SKIP: {
            skip q[can't find world-writeable directory to test DCL$PATH], 2
              unless $tmp;

	    $ENV{'DCL$PATH'} = $tmp;
	    is(eval { `$echo 1` }, undef);
	    like($@, qr/^Insecure directory in \$ENV\{DCL\$PATH\}/);
	}
	$ENV{'DCL$PATH'} = '';
    }
}

# Let's see that we can taint and untaint as needed.
{
    my $foo = $TAINT;
    is_tainted($foo);

    # That was a sanity check. If it failed, stop the insanity!
    die "Taint checks don't seem to be enabled" unless tainted $foo;

    $foo = "foo";
    isnt_tainted($foo);

    taint_these($foo);
    is_tainted($foo);

    my @list = 1..10;
    isnt_tainted($_) foreach @list;
    taint_these @list[1,3,5,7,9];
    is_tainted($_) foreach @list[1,3,5,7,9];
    isnt_tainted($_) foreach @list[0,2,4,6,8];

    ($foo) = $foo =~ /(.+)/;
    isnt_tainted($foo);

    my ($desc, $s, $res, $res2, $one);

    $desc = "match with string tainted";

    $s = 'abcd' . $TAINT;
    $res = $s =~ /(.+)/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "match /g with string tainted";

    $s = 'abcd' . $TAINT;
    $res = $s =~ /(.)/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($res, 1,        "$desc: res value");
    is($one, 'a',      "$desc: \$1 value");

    $desc = "match with string tainted, list cxt";

    $s = 'abcd' . $TAINT;
    ($res) = $s =~ /(.+)/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($res, 'abcd',   "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "match /g with string tainted, list cxt";

    $s = 'abcd' . $TAINT;
    ($res, $res2) = $s =~ /(.)/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($res2,"$desc: res2 not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($res, 'a',      "$desc: res value");
    is($res2,'b',      "$desc: res2 value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "match with pattern tainted";

    $s = 'abcd';
    $res = $s =~ /$TAINT(.+)/;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "match /g with pattern tainted";

    $s = 'abcd';
    $res = $s =~ /$TAINT(.)/g;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($res, 1,        "$desc: res value");
    is($one, 'a',      "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 10 unless locales_enabled('LC_CTYPE');

        $desc = "match with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ /(\w+)/; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 1,        "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "match /g with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ /(\w)/g; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 1,        "$desc: res value");
        is($one, 'a',      "$desc: \$1 value");
    }

    $desc = "match with pattern tainted, list cxt";

    $s = 'abcd';
    ($res) = $s =~ /$TAINT(.+)/;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($res, 'abcd',   "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "match /g with pattern tainted, list cxt";

    $s = 'abcd';
    ($res, $res2) = $s =~ /$TAINT(.)/g;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($res, 'a',      "$desc: res value");
    is($res2,'b',      "$desc: res2 value");
    is($one, 'd',      "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 12 unless locales_enabled('LC_CTYPE');

        $desc = "match with pattern tainted via locale, list cxt";

        $s = 'abcd';
        {
            use locale;
            ($res) = $s =~ /(\w+)/; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 'abcd',   "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "match /g with pattern tainted via locale, list cxt";

        $s = 'abcd';
        {
            use locale;
            ($res, $res2) = $s =~ /(\w)/g; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($res2,  "$desc: res2 tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 'a',      "$desc: res value");
        is($res2,'b',      "$desc: res2 value");
        is($one, 'd',      "$desc: \$1 value");
    }

    $desc = "substitution with string tainted";

    $s = 'abcd' . $TAINT;
    $res = $s =~ s/(.+)/xyz/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'xyz',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /g with string tainted";

    $s = 'abcd' . $TAINT;
    $res = $s =~ s/(.)/x/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'xxxx',   "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /r with string tainted";

    $s = 'abcd' . $TAINT;
    $res = $s =~ s/(.+)/xyz/r;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'abcd',   "$desc: s value");
    is($res, 'xyz',    "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with string tainted";

    $s = 'abcd' . $TAINT;
    $one = '';
    $res = $s =~ s{(.+)}{
		$one = $one . "x"; # make sure code not tainted
		isnt_tainted($one, "$desc: code not tainted within /e");
		$one = $1;
		isnt_tainted($one, "$desc: \$1 not tainted within /e");
		"xyz";
	    }e;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'xyz',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution with pattern tainted";

    $s = 'abcd';
    $res = $s =~ s/$TAINT(.+)/xyz/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($s,  'xyz',     "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /g with pattern tainted";

    $s = 'abcd';
    $res = $s =~ s/$TAINT(.)/x/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    is_tainted($res,   "$desc: res tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($s,  'xxxx',    "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with pattern tainted";

    $s = 'abc';
    {
	my $i = 0;
	my $j;
	$res = $s =~ s{(.)$TAINT}{
		    $j = $i; # make sure code not tainted
		    $one = $1;
		    isnt_tainted($j, "$desc: code not tainted within /e");
		    $i++;
		    if ($i == 1) {
			isnt_tainted($s,   "$desc: s not tainted loop 1");
		    }
		    else {
			is_tainted($s,     "$desc: s tainted loop $i");
		    }
		    is_tainted($one,   "$desc: \$1 tainted loop $i");
		    $i.$TAINT;
		}ge;
	$one = $1;
    }
    is_tainted($s,     "$desc: s tainted");
    is_tainted($res,   "$desc: res tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($s,  '123',     "$desc: s value");
    is($res, 3,        "$desc: res value");
    is($one, 'c',      "$desc: \$1 value");

    $desc = "substitution /r with pattern tainted";

    $s = 'abcd';
    $res = $s =~ s/$TAINT(.+)/xyz/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    is_tainted($one,   "$desc: \$1 tainted");
    is($s,  'abcd',    "$desc: s value");
    is($res, 'xyz',    "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 18 unless locales_enabled('LC_CTYPE');

        $desc = "substitution with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w+)/xyz/; $one = $1;
        }
        is_tainted($s,     "$desc: s tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'xyz',     "$desc: s value");
        is($res, 1,        "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "substitution /g with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w)/x/g; $one = $1;
        }
        is_tainted($s,     "$desc: s tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'xxxx',    "$desc: s value");
        is($res, 4,        "$desc: res value");
        is($one, 'd',      "$desc: \$1 value");

        $desc = "substitution /r with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w+)/xyz/r; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'abcd',    "$desc: s value");
        is($res, 'xyz',    "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");
    }

    $desc = "substitution with partial replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$TAINT/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  'xyz',     "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /g with partial replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.)/x$TAINT/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  'xxxx',    "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with partial replacement tainted";

    $s = 'abc';
    {
	my $i = 0;
	my $j;
	$res = $s =~ s{(.)}{
		    $j = $i; # make sure code not tainted
		    $one = $1;
		    isnt_tainted($j, "$desc: code not tainted within /e");
		    $i++;
		    if ($i == 1) {
			isnt_tainted($s,   "$desc: s not tainted loop 1");
		    }
		    else {
			is_tainted($s,     "$desc: s tainted loop $i");
		    }
		    isnt_tainted($one, "$desc: \$1 not tainted within /e");
		    $i.$TAINT;
		}ge;
	$one = $1;
    }
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  '123',     "$desc: s value");
    is($res, 3,        "$desc: res value");
    is($one, 'c',      "$desc: \$1 value");

    $desc = "substitution /r with partial replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$TAINT/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'abcd',   "$desc: s value");
    is($res, 'xyz',    "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution with whole replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.+)/$TAINTXYZ/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  'xyz',     "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /g with whole replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.)/$TAINTXYZ/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  'xyz' x 4, "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with whole replacement tainted";

    $s = 'abc';
    {
	my $i = 0;
	my $j;
	$res = $s =~ s{(.)}{
		    $j = $i; # make sure code not tainted
		    $one = $1;
		    isnt_tainted($j, "$desc: code not tainted within /e");
		    $i++;
		    if ($i == 1) {
			isnt_tainted($s,   "$desc: s not tainted loop 1");
		    }
		    else {
			is_tainted($s,     "$desc: s tainted loop $i");
		    }
		    isnt_tainted($one, "$desc: \$1 not tainted within /e");
		    $TAINTXYZ;
		}ge;
	$one = $1;
    }
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,  'xyz' x 3, "$desc: s value");
    is($res, 3,        "$desc: res value");
    is($one, 'c',      "$desc: \$1 value");

    $desc = "substitution /r with whole replacement tainted";

    $s = 'abcd';
    $res = $s =~ s/(.+)/$TAINTXYZ/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s,   'abcd',   "$desc: s value");
    is($res, 'xyz',    "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    {
	# now do them all again with "use re 'taint"

	use re 'taint';

	$desc = "use re 'taint': match with string tainted";

	$s = 'abcd' . $TAINT;
	$res = $s =~ /(.+)/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': match /g with string tainted";

	$s = 'abcd' . $TAINT;
	$res = $s =~ /(.)/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 1,        "$desc: res value");
	is($one, 'a',      "$desc: \$1 value");

	$desc = "use re 'taint': match with string tainted, list cxt";

	$s = 'abcd' . $TAINT;
	($res) = $s =~ /(.+)/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 'abcd',   "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': match /g with string tainted, list cxt";

	$s = 'abcd' . $TAINT;
	($res, $res2) = $s =~ /(.)/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($res2,  "$desc: res2 tainted");
	is_tainted($one,   "$desc: \$1 not tainted");
	is($res, 'a',      "$desc: res value");
	is($res2,'b',      "$desc: res2 value");
	is($one, 'd',      "$desc: \$1 value");

	$desc = "use re 'taint': match with pattern tainted";

	$s = 'abcd';
	$res = $s =~ /$TAINT(.+)/;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': match /g with pattern tainted";

	$s = 'abcd';
	$res = $s =~ /$TAINT(.)/g;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 1,        "$desc: res value");
	is($one, 'a',      "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 10 unless locales_enabled('LC_CTYPE');

        $desc = "use re 'taint': match with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ /(\w+)/; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 1,        "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "use re 'taint': match /g with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ /(\w)/g; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 1,        "$desc: res value");
        is($one, 'a',      "$desc: \$1 value");
    }

	$desc = "use re 'taint': match with pattern tainted, list cxt";

	$s = 'abcd';
	($res) = $s =~ /$TAINT(.+)/;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 'abcd',   "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': match /g with pattern tainted, list cxt";

	$s = 'abcd';
	($res, $res2) = $s =~ /$TAINT(.)/g;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($res, 'a',      "$desc: res value");
	is($res2,'b',      "$desc: res2 value");
	is($one, 'd',      "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 12 unless locales_enabled('LC_CTYPE');

        $desc = "use re 'taint': match with pattern tainted via locale, list cxt";

        $s = 'abcd';
        {
            use locale;
            ($res) = $s =~ /(\w+)/; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 'abcd',   "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "use re 'taint': match /g with pattern tainted via locale, list cxt";

        $s = 'abcd';
        {
            use locale;
            ($res, $res2) = $s =~ /(\w)/g; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($res2,  "$desc: res2 tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($res, 'a',      "$desc: res value");
        is($res2,'b',      "$desc: res2 value");
        is($one, 'd',      "$desc: \$1 value");
    }

	$desc = "use re 'taint': substitution with string tainted";

	$s = 'abcd' . $TAINT;
	$res = $s =~ s/(.+)/xyz/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,   'xyz',    "$desc: s value");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution /g with string tainted";

	$s = 'abcd' . $TAINT;
	$res = $s =~ s/(.)/x/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,   'xxxx',   "$desc: s value");
	is($res, 4,        "$desc: res value");
	is($one, 'd',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /r with string tainted";

	$s = 'abcd' . $TAINT;
	$res = $s =~ s/(.+)/xyz/r;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,   'abcd',   "$desc: s value");
	is($res, 'xyz',    "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution /e with string tainted";

	$s = 'abcd' . $TAINT;
	$one = '';
	$res = $s =~ s{(.+)}{
		    $one = $one . "x"; # make sure code not tainted
		    isnt_tainted($one, "$desc: code not tainted within /e");
		    $one = $1;
		    is_tainted($one, "$desc: $1 tainted within /e");
		    "xyz";
		}e;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,   'xyz',    "$desc: s value");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution with pattern tainted";

	$s = 'abcd';
	$res = $s =~ s/$TAINT(.+)/xyz/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,  'xyz',     "$desc: s value");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution /g with pattern tainted";

	$s = 'abcd';
	$res = $s =~ s/$TAINT(.)/x/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,  'xxxx',    "$desc: s value");
	is($res, 4,        "$desc: res value");
	is($one, 'd',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /ge with pattern tainted";

	$s = 'abc';
	{
	    my $i = 0;
	    my $j;
	    $res = $s =~ s{(.)$TAINT}{
			$j = $i; # make sure code not tainted
			$one = $1;
			isnt_tainted($j, "$desc: code not tainted within /e");
			$i++;
			if ($i == 1) {
			    isnt_tainted($s,   "$desc: s not tainted loop 1");
			}
			else {
			    is_tainted($s,     "$desc: s tainted loop $i");
			}
			is_tainted($one,   "$desc: \$1 tainted loop $i");
			$i.$TAINT;
		    }ge;
	    $one = $1;
	}
	is_tainted($s,     "$desc: s tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,  '123',     "$desc: s value");
	is($res, 3,        "$desc: res value");
	is($one, 'c',      "$desc: \$1 value");


	$desc = "use re 'taint': substitution /r with pattern tainted";

	$s = 'abcd';
	$res = $s =~ s/$TAINT(.+)/xyz/r;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	is_tainted($res,   "$desc: res tainted");
	is_tainted($one,   "$desc: \$1 tainted");
	is($s,  'abcd',    "$desc: s value");
	is($res, 'xyz',    "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

  SKIP: {
        skip 'Locales not available', 18 unless locales_enabled('LC_CTYPE');

        $desc = "use re 'taint': substitution with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w+)/xyz/; $one = $1;
        }
        is_tainted($s,     "$desc: s tainted");
        isnt_tainted($res, "$desc: res not tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'xyz',     "$desc: s value");
        is($res, 1,        "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");

        $desc = "use re 'taint': substitution /g with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w)/x/g; $one = $1;
        }
        is_tainted($s,     "$desc: s tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'xxxx',    "$desc: s value");
        is($res, 4,        "$desc: res value");
        is($one, 'd',      "$desc: \$1 value");

        $desc = "use re 'taint': substitution /r with pattern tainted via locale";

        $s = 'abcd';
        {
            use locale;
            $res = $s =~ s/(\w+)/xyz/r; $one = $1;
        }
        isnt_tainted($s,   "$desc: s not tainted");
        is_tainted($res,   "$desc: res tainted");
        is_tainted($one,   "$desc: \$1 tainted");
        is($s,  'abcd',    "$desc: s value");
        is($res, 'xyz',    "$desc: res value");
        is($one, 'abcd',   "$desc: \$1 value");
    }

	$desc = "use re 'taint': substitution with partial replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.+)/xyz$TAINT/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  'xyz',     "$desc: s value");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution /g with partial replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.)/x$TAINT/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  'xxxx',    "$desc: s value");
	is($res, 4,        "$desc: res value");
	is($one, 'd',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /ge with partial replacement tainted";

	$s = 'abc';
	{
	    my $i = 0;
	    my $j;
	    $res = $s =~ s{(.)}{
			$j = $i; # make sure code not tainted
			$one = $1;
			isnt_tainted($j, "$desc: code not tainted within /e");
			$i++;
			if ($i == 1) {
			    isnt_tainted($s,   "$desc: s not tainted loop 1");
			}
			else {
			    is_tainted($s,     "$desc: s tainted loop $i");
			}
			    isnt_tainted($one, "$desc: \$1 not tainted");
			$i.$TAINT;
		    }ge;
	    $one = $1;
	}
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  '123',     "$desc: s value");
	is($res, 3,        "$desc: res value");
	is($one, 'c',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /r with partial replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.+)/xyz$TAINT/r;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	is_tainted($res,   "$desc: res tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,   'abcd',   "$desc: s value");
	is($res, 'xyz',    "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution with whole replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.+)/$TAINTXYZ/;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  'xyz',     "$desc: s value");
	is($res, 1,        "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

	$desc = "use re 'taint': substitution /g with whole replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.)/$TAINTXYZ/g;
	$one = $1;
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res not tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  'xyz' x 4, "$desc: s value");
	is($res, 4,        "$desc: res value");
	is($one, 'd',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /ge with whole replacement tainted";

	$s = 'abc';
	{
	    my $i = 0;
	    my $j;
	    $res = $s =~ s{(.)}{
			$j = $i; # make sure code not tainted
			$one = $1;
			isnt_tainted($j, "$desc: code not tainted within /e");
			$i++;
			if ($i == 1) {
			    isnt_tainted($s,   "$desc: s not tainted loop 1");
			}
			else {
			    is_tainted($s,     "$desc: s tainted loop $i");
			}
			    isnt_tainted($one, "$desc: \$1 not tainted");
			$TAINTXYZ;
		    }ge;
	    $one = $1;
	}
	is_tainted($s,     "$desc: s tainted");
	isnt_tainted($res, "$desc: res tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,  'xyz' x 3, "$desc: s value");
	is($res, 3,        "$desc: res value");
	is($one, 'c',      "$desc: \$1 value");

	$desc = "use re 'taint': substitution /r with whole replacement tainted";

	$s = 'abcd';
	$res = $s =~ s/(.+)/$TAINTXYZ/r;
	$one = $1;
	isnt_tainted($s,   "$desc: s not tainted");
	is_tainted($res,   "$desc: res tainted");
	isnt_tainted($one, "$desc: \$1 not tainted");
	is($s,   'abcd',   "$desc: s value");
	is($res, 'xyz',    "$desc: res value");
	is($one, 'abcd',   "$desc: \$1 value");

        # [perl #121854] match taintedness became sticky
        # when one match has a taintess result, subseqent matches
        # using the same pattern shouldn't necessarily be tainted

        {
            my $f = sub { $_[0] =~ /(.*)/ or die; $1 };
            $res = $f->($TAINT);
            is_tainted($res,   "121854: res tainted");
            $res = $f->("abc");
            isnt_tainted($res,   "121854: res not tainted");
        }
    }

    $foo = $1 if 'bar' =~ /(.+)$TAINT/;
    is_tainted($foo);
    is($foo, 'bar');

    my $pi = 4 * atan2(1,1) + $TAINT0;
    is_tainted($pi);

    ($pi) = $pi =~ /(\d+\.\d+)/;
    isnt_tainted($pi);
    is(sprintf("%.5f", $pi), '3.14159');
}

# How about command-line arguments? The problem is that we don't
# always get some, so we'll run another process with some.
SKIP: {
    my $arg = tempfile();
    open $fh, '>', $arg or die "Can't create $arg: $!";
    print $fh q{
	eval { my $x = join('', @ARGV), kill 0 };
	exit 0 if $@ =~ /^Insecure dependency/;
	print "# Oops: \$@ was [$@]\n";
	exit 1;
    };
    close $fh or die "Can't close $arg: $!";
    print `$Invoke_Perl "-T" $arg and some suspect arguments`;
    is($?, 0, "Exited with status $?");
    unlink $arg;
}

# Reading from a file should be tainted
{
    ok(open my $fh, '<', $TEST) or diag("Couldn't open '$TEST': $!");
    binmode $fh;
    my $block;
    sysread($fh, $block, 100);
    my $line = <$fh>;
    close $fh;
    is_tainted($block);
    is_tainted($line);
}

# Output of commands should be tainted
{
    my $foo = `$echo abc`;
    is_tainted($foo);
}

# Certain system variables should be tainted
{
    is_tainted($^X);
    is_tainted($0);
}

# Results of matching should all be untainted
{
    my $foo = "abcdefghi" . $TAINT;
    is_tainted($foo);

    $foo =~ /def/;
    isnt_tainted($`);
    isnt_tainted($&);
    isnt_tainted($');

    $foo =~ /(...)(...)(...)/;
    isnt_tainted($1);
    isnt_tainted($2);
    isnt_tainted($3);
    isnt_tainted($+);

    my @bar = $foo =~ /(...)(...)(...)/;
    isnt_tainted($_) foreach @bar;

    is_tainted($foo);	# $foo should still be tainted!
    is($foo, "abcdefghi");
}

# Operations which affect files can't use tainted data.
{
    violates_taint(sub { chmod 0, $TAINT }, 'chmod');

    SKIP: {
        skip "truncate() is not available", 2 unless $Config{d_truncate};

	violates_taint(sub { truncate 'NoSuChFiLe', $TAINT0 }, 'truncate');
    }

    violates_taint(sub { rename '', $TAINT }, 'rename');
    violates_taint(sub { unlink $TAINT }, 'unlink');
    violates_taint(sub { utime $TAINT }, 'utime');

    SKIP: {
        skip "chown() is not available", 2 unless $Config{d_chown};

	violates_taint(sub { chown -1, -1, $TAINT }, 'chown');
    }

    SKIP: {
        skip "link() is not available", 2 unless $Config{d_link};

violates_taint(sub { link $TAINT, '' }, 'link');
    }

    SKIP: {
        skip "symlink() is not available", 2 unless $Config{d_symlink};

	violates_taint(sub { symlink $TAINT, '' }, 'symlink');
    }
}

# Operations which affect directories can't use tainted data.
{
    violates_taint(sub { mkdir "foo".$TAINT, 0755 . $TAINT0 }, 'mkdir');
    violates_taint(sub { rmdir $TAINT }, 'rmdir');
    violates_taint(sub { chdir "foo".$TAINT }, 'chdir');

    SKIP: {
        skip "chroot() is not available", 2 unless $Config{d_chroot};

	violates_taint(sub { chroot $TAINT }, 'chroot');
    }
}

# Some operations using files can't use tainted data.
{
    my $foo = "imaginary library" . $TAINT;
    violates_taint(sub { require $foo }, 'require');
    violates_taint(sub { do $foo }, 'do');

    my $filename = tempfile();	# NB: $filename isn't tainted!
    $foo = $filename . $TAINT;
    unlink $filename;	# in any case

    is(eval { open FOO, $foo }, undef, 'open for read');
    is($@, '');                # NB: This should be allowed
    is(eval { open my $fh, , '<', $foo }, undef, 'open for read');
    is($@, '');                # NB: This should be allowed

    # Try first new style but allow also old style.
    # We do not want the whole taint.t to fail
    # just because Errno possibly failing.
    ok(eval('$!{ENOENT}') ||
	$! == 2); # File not found

    violates_taint(sub { open FOO, "> $foo" }, 'open', 'open for write');
    violates_taint(sub { open my $fh, '>', $foo }, 'open', 'open for write');
}

# Commands to the system can't use tainted data
{
    my $foo = $TAINT;

    SKIP: {
        skip "open('|') is not available", 8 if $^O eq 'amigaos';

        violates_taint(sub { open FOO, "| x$foo" }, 'piped open', 'popen to');
        violates_taint(sub { open FOO, "x$foo |" }, 'piped open', 'popen from');
        violates_taint(sub { open my $fh, '|-', "x$foo" }, 'piped open', 'popen to');
        violates_taint(sub { open my $fh, '-|', "x$foo" }, 'piped open', 'popen from');
    }

    violates_taint(sub { exec $TAINT }, 'exec');
    violates_taint(sub { system $TAINT }, 'system');

    $foo = "*";
    taint_these $foo;

    violates_taint(sub { `$echo 1$foo` }, '``', 'backticks');

    SKIP: {
        # wildcard expansion doesn't invoke shell on VMS, so is safe
        skip "This is not VMS", 2 unless $Is_VMS;

	isnt(join('', eval { glob $foo } ), '', 'globbing');
	is($@, '');
    }
}

# Operations which affect processes can't use tainted data.
{
    violates_taint(sub { kill 0, $TAINT }, 'kill');

    SKIP: {
        skip "setpgrp() is not available", 2 unless $Config{d_setpgrp};

	violates_taint(sub { setpgrp 0, $TAINT0 }, 'setpgrp');
    }

    SKIP: {
        skip "setpriority() is not available", 2 unless $Config{d_setprior};

	violates_taint(sub { setpriority 0, $TAINT0, $TAINT0 }, 'setpriority');
    }
}

# Some miscellaneous operations can't use tainted data.
{
    SKIP: {
        skip "syscall() is not available", 2 unless $Config{d_syscall};

	violates_taint(sub { syscall $TAINT }, 'syscall');
    }

    {
	my $foo = "x" x 979;
	taint_these $foo;
	local *FOO;
	my $temp = tempfile();
	ok(open FOO, "> $temp") or diag("Couldn't open $temp for write: $!");
	violates_taint(sub { ioctl FOO, $TAINT0, $foo }, 'ioctl');

	my $temp2 = tempfile();
	ok(open my $fh, '>', $temp2) or diag("Couldn't open $temp2 for write: $!");
	violates_taint(sub { ioctl $fh, $TAINT0, $foo }, 'ioctl');

        SKIP: {
            skip "fcntl() is not available", 4 unless $Config{d_fcntl};

	    violates_taint(sub { fcntl FOO, $TAINT0, $foo }, 'fcntl');
	    violates_taint(sub { fcntl $fh, $TAINT0, $foo }, 'fcntl');
	}

	close FOO;
    }
}

# Some tests involving references
{
    my $foo = 'abc' . $TAINT;
    my $fooref = \$foo;
    isnt_tainted($fooref);
    is_tainted($$fooref);
    is_tainted($foo);
}

# Some tests involving assignment
{
    my $foo = $TAINT0;
    my $bar = $foo;
    is_tainted($foo);
    is_tainted($bar);
    is_tainted($foo = $bar);
    is_tainted($bar = $bar);
    is_tainted($bar += $bar);
    is_tainted($bar -= $bar);
    is_tainted($bar *= $bar);
    is_tainted($bar++);
    is_tainted($bar /= $bar);
    is_tainted($bar += 0);
    is_tainted($bar -= 2);
    is_tainted($bar *= -1);
    is_tainted($bar /= 1);
    is_tainted($bar--);
    is($bar, 0);
}

# Test assignment and return of lists
{
    my @foo = ("A", "tainted" . $TAINT, "B");
    isnt_tainted($foo[0]);
    is_tainted(    $foo[1]);
    isnt_tainted($foo[2]);
    my @bar = @foo;
    isnt_tainted($bar[0]);
    is_tainted(    $bar[1]);
    isnt_tainted($bar[2]);
    my @baz = eval { "A", "tainted" . $TAINT, "B" };
    isnt_tainted($baz[0]);
    is_tainted(    $baz[1]);
    isnt_tainted($baz[2]);
    my @plugh = eval q[ "A", "tainted" . $TAINT, "B" ];
    isnt_tainted($plugh[0]);
    is_tainted(    $plugh[1]);
    isnt_tainted($plugh[2]);
    my $nautilus = sub { "A", "tainted" . $TAINT, "B" };
    isnt_tainted(((&$nautilus)[0]));
    is_tainted(    ((&$nautilus)[1]));
    isnt_tainted(((&$nautilus)[2]));
    my @xyzzy = &$nautilus;
    isnt_tainted($xyzzy[0]);
    is_tainted(    $xyzzy[1]);
    isnt_tainted($xyzzy[2]);
    my $red_october = sub { return "A", "tainted" . $TAINT, "B" };
    isnt_tainted(((&$red_october)[0]));
    is_tainted(    ((&$red_october)[1]));
    isnt_tainted(((&$red_october)[2]));
    my @corge = &$red_october;
    isnt_tainted($corge[0]);
    is_tainted(    $corge[1]);
    isnt_tainted($corge[2]);
}

# Test for system/library calls returning string data of dubious origin.
{
    # No reliable %Config check for getpw*
    SKIP: {
        skip "getpwent() is not available", 9 unless
          eval { setpwent(); getpwent() };

	setpwent();
	my @getpwent = getpwent();
	die "getpwent: $!\n" unless (@getpwent);
	isnt_tainted($getpwent[0]);
	is_tainted($getpwent[1]);
	isnt_tainted($getpwent[2]);
	isnt_tainted($getpwent[3]);
	isnt_tainted($getpwent[4]);
	isnt_tainted($getpwent[5]);
	is_tainted($getpwent[6], 'ge?cos');
	isnt_tainted($getpwent[7]);
	is_tainted($getpwent[8], 'shell');
	endpwent();
    }

    SKIP: {
        # pretty hard to imagine not
        skip "readdir() is not available", 1 unless $Config{d_readdir};

	opendir my $dh, "op" or die "opendir: $!\n";
	my $readdir = readdir $dh;
	is_tainted($readdir);
	closedir $dh;
    }

    SKIP: {
        skip "readlink() or symlink() is not available" unless
          $Config{d_readlink} && $Config{d_symlink};

	my $symlink = "sl$$";
	unlink($symlink);
	my $sl = "/something/naughty";
	# it has to be a real path on Mac OS
	unless (symlink($sl, $symlink)) {
            skip "symlink not available or no priviliges", 1,
                if $^O eq "MSWin32";
            die "symlink: $!\n";
        }
	my $readlink = readlink($symlink);
	is_tainted($readlink);
	unlink($symlink);
    }
}

# test bitwise ops (regression bug)
{
    no warnings 'numeric';
    my $why = "y";
    my $j = "x" | $why;
    isnt_tainted($j);
    $why = $TAINT."y";
    $j = "x" | $why;
    is_tainted(    $j);
}

# test target of substitution (regression bug)
{
    my $why = $TAINT."y";
    $why =~ s/y/z/;
    is_tainted(    $why);

    my $z = "[z]";
    $why =~ s/$z/zee/;
    is_tainted(    $why);

    $why =~ s/e/'-'.$$/ge;
    is_tainted(    $why);
}


SKIP: {
    skip "no IPC::SysV", 2 unless $ipcsysv;

    # test shmread
    SKIP: {
        skip "shm*() not available", 1 unless $Config{d_shm};

        no strict 'subs';
        my $sent = "foobar";
        my $rcvd;
        my $size = 2000;
        my $id;
        eval {
            local $SIG{SYS} = sub { die "SIGSYS caught\n" };
            $id = shmget(IPC_PRIVATE, $size, S_IRWXU);
            1;
        } or do { chomp(my $msg = $@); skip "shmget: $msg", 1; };

        if (defined $id) {
            if (shmwrite($id, $sent, 0, 60)) {
                if (shmread($id, $rcvd, 0, 60)) {
                    substr($rcvd, index($rcvd, "\0")) = '';
                } else {
                    warn "# shmread failed: $!\n";
                }
            } else {
                warn "# shmwrite failed: $!\n";
            }
            shmctl($id, IPC_RMID, 0) or warn "# shmctl failed: $!\n";
        } else {
            warn "# shmget failed: $!\n";
        }

        skip "SysV shared memory operation failed", 1
            unless defined $rcvd and $rcvd eq $sent;

        is_tainted($rcvd, "shmread");
    }


    # test msgrcv
    SKIP: {
        skip "msg*() not available", 1 unless $Config{d_msg};

	no strict 'subs';
        my $id;
        eval {
            local $SIG{SYS} = sub { die "SIGSYS caught\n" };
            $id = msgget(IPC_PRIVATE, IPC_CREAT | S_IRWXU);
            1;
        } or do { chomp(my $msg = $@); skip "msgget: $msg", 1; };

	my $sent      = "message";
	my $type_sent = 1234;
	my $rcvd;
	my $type_rcvd;

	if (defined $id) {
	    if (msgsnd($id, pack("l! a*", $type_sent, $sent), IPC_NOWAIT)) {
		if (msgrcv($id, $rcvd, 60, 0, IPC_NOWAIT)) {
		    ($type_rcvd, $rcvd) = unpack("l! a*", $rcvd);
		} else {
		    warn "# msgrcv failed: $!\n";
		}
	    } else {
		warn "# msgsnd failed: $!\n";
	    }
	    msgctl($id, IPC_RMID, 0) or warn "# msgctl failed: $!\n";
	} else {
	    warn "# msgget failed\n";
	}

        SKIP: {
            skip "SysV message queue operation failed", 1
              unless $rcvd eq $sent && $type_sent == $type_rcvd;

	    is_tainted($rcvd, "msgrcv");
	}
    }
}

{
    # bug id 20001004.006 (#4380)

    open my $fh, '<', $TEST or warn "$0: cannot read $TEST: $!" ;
    local $/;
    my $a = <$fh>;
    my $b = <$fh>;

    is_tainted($a);
    is_tainted($b);
    is($b, undef);
}

{
    # bug id 20001004.007 (#4381)

    open my $fh, '<', $TEST or warn "$0: cannot read $TEST: $!" ;
    my $a = <$fh>;

    my $c = { a => 42,
	      b => $a };

    isnt_tainted($c->{a});
    is_tainted($c->{b});


    my $d = { a => $a,
	      b => 42 };
    is_tainted($d->{a});
    isnt_tainted($d->{b});


    my $e = { a => 42,
	      b => { c => $a, d => 42 } };
    isnt_tainted($e->{a});
    isnt_tainted($e->{b});
    is_tainted($e->{b}->{c});
    isnt_tainted($e->{b}->{d});
}

{
    # bug id 20010519.003 (#7015)

    our $has_fcntl;
    BEGIN {
	eval { require Fcntl; Fcntl->import; };
	unless ($@) {
	    $has_fcntl = 1;
	}
    }

    SKIP: {
        skip "no Fcntl", 36 unless $has_fcntl;

	my $foo = tempfile();
	my $evil = $foo . $TAINT;

	is(eval { sysopen(my $ro, $evil, &O_RDONLY) }, undef);
	is($@, '');

	violates_taint(sub { sysopen(my $wo, $evil, &O_WRONLY) }, 'sysopen');
	violates_taint(sub { sysopen(my $rw, $evil, &O_RDWR) }, 'sysopen');
	violates_taint(sub { sysopen(my $ap, $evil, &O_APPEND) }, 'sysopen');
	violates_taint(sub { sysopen(my $cr, $evil, &O_CREAT) }, 'sysopen');
	violates_taint(sub { sysopen(my $tr, $evil, &O_TRUNC) }, 'sysopen');

	is(eval { sysopen(my $ro, $foo, &O_RDONLY | $TAINT0) }, undef);
	is($@, '');

	violates_taint(sub { sysopen(my $wo, $foo, &O_WRONLY | $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $rw, $foo, &O_RDWR | $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $ap, $foo, &O_APPEND | $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $cr, $foo, &O_CREAT | $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $tr, $foo, &O_TRUNC | $TAINT0) }, 'sysopen');
	is(eval { sysopen(my $ro, $foo, &O_RDONLY, $TAINT0) }, undef);
	is($@, '');

	violates_taint(sub { sysopen(my $wo, $foo, &O_WRONLY, $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $rw, $foo, &O_RDWR, $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $ap, $foo, &O_APPEND, $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $cr, $foo, &O_CREAT, $TAINT0) }, 'sysopen');
	violates_taint(sub { sysopen(my $tr, $foo, &O_TRUNC, $TAINT0) }, 'sysopen');
    }
}

{
    # bug 20010526.004 (#7041)

    use warnings;

    my $saw_warning = 0;
    local $SIG{__WARN__} = sub { ++$saw_warning };

    sub fmi {
	my $divnum = shift()/1;
	sprintf("%1.1f\n", $divnum);
    }

    fmi(21 . $TAINT);
    fmi(37);
    fmi(248);

    is($saw_warning, 0);
}


{
    # Bug ID 20010730.010 (#7387)

    my $i = 0;

    sub Tie::TIESCALAR {
        my $class =  shift;
        my $arg   =  shift;

        bless \$arg => $class;
    }

    sub Tie::FETCH {
        $i ++;
        ${$_ [0]}
    }


    package main;

    my $bar = "The Big Bright Green Pleasure Machine";
    taint_these $bar;
    tie my ($foo), Tie => $bar;

    my $baz = $foo;

    ok $i == 1;
}

{
    # Check that all environment variables are tainted.
    my @untainted;
    while (my ($k, $v) = each %ENV) {
	if (!tainted($v) &&
	    # These we have explicitly untainted or set earlier.
	    $k !~ /^(BASH_ENV|CDPATH|ENV|IFS|PATH|PERL_CORE|TEMP|TERM|TMP|PERL5LIB)$/) {
	    push @untainted, "# '$k' = '$v'\n";
	}
    }
    is("@untainted", "", "untainted");
}


is(${^TAINT}, 1, '$^TAINT is on');

eval { ${^TAINT} = 0 };
is(${^TAINT}, 1, '$^TAINT is not assignable');
like($@, qr/^Modification of a read-only value attempted/,
     'Assigning to ${^TAINT} fails');

{
    # bug 20011111.105 (#7897)

    my $re1 = qr/x$TAINT/;
    is_tainted($re1);

    my $re2 = qr/^$re1\z/;
    is_tainted($re2);

    my $re3 = "$re2";
    is_tainted($re3);
}

SKIP: {
    skip "system {} has different semantics on Win32", 1 if $Is_MSWin32;

    # bug 20010221.005 (#5882)
    local $ENV{PATH} .= $TAINT;
    eval { system { "echo" } "/arg0", "arg1" };
    like($@, qr/^Insecure \$ENV/);
}

TODO: {
    todo_skip 'tainted %ENV warning occludes tainted arguments warning', 22
      if $Is_VMS;

    # bug 20020208.005 (#8465) plus some single arg exec/system extras
    violates_taint(sub { exec $TAINT, $TAINT }, 'exec');
    violates_taint(sub { exec $TAINT $TAINT }, 'exec');
    violates_taint(sub { exec $TAINT $TAINT, $TAINT }, 'exec');
    violates_taint(sub { exec $TAINT 'notaint' }, 'exec');
    violates_taint(sub { exec {'notaint'} $TAINT }, 'exec');

    violates_taint(sub { system $TAINT, $TAINT }, 'system');
    violates_taint(sub { system $TAINT $TAINT }, 'system');
    violates_taint(sub { system $TAINT $TAINT, $TAINT }, 'system');
    violates_taint(sub { system $TAINT 'notaint' }, 'system');
    violates_taint(sub { system {'notaint'} $TAINT }, 'system');

    eval {
        no warnings;
        system("lskdfj does not exist","with","args");
    };
    is($@, "");

    eval {
	no warnings;
	exec("lskdfj does not exist","with","args");
    };
    is($@, "");

    # If you add tests here update also the above skip block for VMS.
}

{
    # [ID 20020704.001 (#10026)] taint propagation failure
    use re 'taint';
    $TAINT =~ /(.*)/;
    is_tainted(my $foo = $1);
}

{
    # [perl #24291] this used to dump core
    our %nonmagicalenv = ( PATH => "util" );
    local *ENV = \%nonmagicalenv;
    eval { system("lskdfj"); };
    like($@, qr/^%ENV is aliased to another variable while running with -T switch/);
    local *ENV = *nonmagicalenv;
    eval { system("lskdfj"); };
    like($@, qr/^%ENV is aliased to %nonmagicalenv while running with -T switch/);
}
{
    # [perl #24248]
    $TAINT =~ /(.*)/;
    isnt_tainted($1);
    my $notaint = $1;
    isnt_tainted($notaint);

    my $l;
    $notaint =~ /($notaint)/;
    $l = $1;
    isnt_tainted($1);
    isnt_tainted($l);
    $notaint =~ /($TAINT)/;
    $l = $1;
    is_tainted($1);
    is_tainted($l);

    $TAINT =~ /($notaint)/;
    $l = $1;
    isnt_tainted($1);
    isnt_tainted($l);
    $TAINT =~ /($TAINT)/;
    $l = $1;
    is_tainted($1);
    is_tainted($l);

    my $r;
    ($r = $TAINT) =~ /($notaint)/;
    isnt_tainted($1);
    ($r = $TAINT) =~ /($TAINT)/;
    is_tainted($1);

    {
	use re 'eval'; # this shouldn't make any difference
	($r = $TAINT) =~ /($notaint)/;
	isnt_tainted($1);
	($r = $TAINT) =~ /($TAINT)/;
	is_tainted($1);
    }

    #  [perl #24674]
    # accessing $^O  shoudn't taint it as a side-effect;
    # assigning tainted data to it is now an error

    isnt_tainted($^O);
    if (!$^X) { } elsif ($^O eq 'bar') { }
    isnt_tainted($^O);
    local $^O;  # We're going to clobber something test infrastructure depends on.
    eval '$^O = $^X';
    like($@, qr/Insecure dependency in/);
}

EFFECTIVELY_CONSTANTS: {
    my $tainted_number = 12 + $TAINT0;
    is_tainted( $tainted_number );

    # Even though it's always 0, it's still tainted
    my $tainted_product = $tainted_number * 0;
    is_tainted( $tainted_product );
    is($tainted_product, 0);
}

TERNARY_CONDITIONALS: {
    my $tainted_true  = $TAINT . "blah blah blah";
    my $tainted_false = $TAINT0;
    is_tainted( $tainted_true );
    is_tainted( $tainted_false );

    my $result = $tainted_true ? "True" : "False";
    is($result, "True");
    isnt_tainted( $result );

    $result = $tainted_false ? "True" : "False";
    is($result, "False");
    isnt_tainted( $result );

    my $untainted_whatever = "The Fabulous Johnny Cash";
    my $tainted_whatever = "Soft Cell" . $TAINT;

    $result = $tainted_true ? $tainted_whatever : $untainted_whatever;
    is($result, "Soft Cell");
    is_tainted( $result );

    $result = $tainted_false ? $tainted_whatever : $untainted_whatever;
    is($result, "The Fabulous Johnny Cash");
    isnt_tainted( $result );
}

{
    # rt.perl.org 5900  $1 remains tainted if...
    # 1) The regular expression contains a scalar variable AND
    # 2) The regular expression appears in an elsif clause

    my $foo = "abcdefghi" . $TAINT;

    my $valid_chars = 'a-z';
    if ( $foo eq '' ) {
    }
    elsif ( $foo =~ /([$valid_chars]+)/o ) {
	isnt_tainted($1);
	isnt($1, undef);
    }

    if ( $foo eq '' ) {
    }
    elsif ( my @bar = $foo =~ /([$valid_chars]+)/o ) {
	isnt_tainted($bar[0]);
	is(scalar @bar, 1);
    }
}

# at scope exit, a restored localised value should have its old
# taint status, not the taint status of the current statement

{
    our $x99 = $^X;
    is_tainted($x99);

    $x99 = '';
    isnt_tainted($x99);

    my $c = do { local $x99; $^X };
    isnt_tainted($x99);
}
{
    our $x99 = $^X;
    is_tainted($x99);

    my $c = do { local $x99; '' };
    is_tainted($x99);
}

# an mg_get of a tainted value during localization shouldn't taint the
# statement

{
    eval { local $0, eval '1' };
    is($@, '');
}

# [perl #8262] //g loops infinitely on tainted data

{
    my @a;
    $a[0] = $^X . '-';
    $a[0]=~ m/(.)/g;
    cmp_ok pos($a[0]), '>', 0, "infinite m//g on arrays (aelemfast)";

    my $i = 1;
    $a[$i] = $^X . '-';
    $a[$i]=~ m/(.)/g;
    cmp_ok pos($a[$i]), '>', 0, "infinite m//g on arrays (aelem)";

    my %h;
    $h{a} = $^X . '-';
    $h{a}=~ m/(.)/g;
    cmp_ok pos($h{a}), '>', 0, "infinite m//g on hashes (helem)";
}

SKIP:
{
    my $got_dualvar;
    eval 'use Scalar::Util "dualvar"; $got_dualvar++';
    skip "No Scalar::Util::dualvar" unless $got_dualvar;
    my $a = Scalar::Util::dualvar(3, $^X);
    my $b = $a + 5;
    is ($b, 8, "Arithmetic on tainted dualvars works");
}

# opening '|-' should not trigger $ENV{PATH} check

{
    SKIP: {
	skip "fork() is not available", 3 unless $Config{'d_fork'};
	skip "opening |- is not stable on threaded Open/MirBSD with taint", 3
            if $Config{useithreads} and $Is_OpenBSD || $Is_MirBSD;

	$ENV{'PATH'} = $TAINT;
	local $SIG{'PIPE'} = 'IGNORE';
	eval {
	    my $pid = open my $pipe, '|-';
	    if (!defined $pid) {
		die "open failed: $!";
	    }
	    if (!$pid) {
		kill 'KILL', $$;	# child suicide
	    }
	    close $pipe;
	};
	unlike($@, qr/Insecure \$ENV/, 'fork triggers %ENV check');
	is($@, '',               'pipe/fork/open/close failed');
	eval {
	    open my $pipe, "|$Invoke_Perl -e 1";
	    close $pipe;
	};
	like($@, qr/Insecure \$ENV/, 'popen neglects %ENV check');
    }
}

{
    package AUTOLOAD_TAINT;
    sub AUTOLOAD {
        our $AUTOLOAD;
        return if $AUTOLOAD =~ /DESTROY/;
        if ($AUTOLOAD =~ /untainted/) {
            main::isnt_tainted($AUTOLOAD, '$AUTOLOAD can be untainted');
            my $copy = $AUTOLOAD;
            main::isnt_tainted($copy, '$AUTOLOAD can be untainted');
        } else {
            main::is_tainted($AUTOLOAD, '$AUTOLOAD can be tainted');
            my $copy = $AUTOLOAD;
            main::is_tainted($copy, '$AUTOLOAD can be tainted');
        }
    }

    package main;
    my $o = bless [], 'AUTOLOAD_TAINT';
    $o->untainted;
    $o->$TAINT;
    $o->untainted;
}

{
    # tests for tainted format in s?printf
    my $fmt = $TAINT . "# %s\n";
    violates_taint(sub { printf($fmt, "foo") }, 'printf',
		   q/printf doesn't like tainted formats/);
    violates_taint(sub { printf($TAINT . "# %s\n", "foo") }, 'printf',
		   q/printf doesn't like tainted format expressions/);
    eval { printf("# %s\n", $TAINT . "foo") };
    is($@, '', q/printf accepts other tainted args/);
    violates_taint(sub { sprintf($fmt, "foo") }, 'sprintf',
		   q/sprintf doesn't like tainted formats/);
    violates_taint(sub { sprintf($TAINT . "# %s\n", "foo") }, 'sprintf',
		   q/sprintf doesn't like tainted format expressions/);
    eval { my $str = sprintf("# %s\n", $TAINT . "foo") };
    is($@, '', q/sprintf accepts other tainted args/);
}

{
    # 40708
    my $n  = 7e9;
    my $sub = 8e9 - $n;
    is ( $sub, 1000000000, '8e9 - 7e9' );

    my $val = $n;
    is ($val, '7000000000', 'Assignment to untainted variable');
    $val = $TAINT;
    $val = $n;
    is ($val, '7000000000', 'Assignment to tainted variable');
}

{
    my $val = 0;
    my $tainted = '1' . $TAINT;
    eval '$val = eval $tainted;';
    is ($val, 0, "eval doesn't like tainted strings");
    like ($@, qr/^Insecure dependency in eval/);

    # Rather nice code to get a tainted undef by from Rick Delaney
    open my $fh, "test.pl" or die $!;
    seek $fh, 0, 2 or die $!;
    $tainted = <$fh>;

    no warnings 'uninitialized';
    eval 'eval $tainted';
    like ($@, qr/^Insecure dependency in eval/);
}

foreach my $ord (78, 163, 256) {
    # 47195
    my $line = 'A1' . $TAINT . chr $ord;
    chop $line;
    is($line, 'A1');
    $line =~ /(A\S*)/;
    isnt_tainted($1, "\\S match with chr $ord");
}

{
  SKIP: {
      skip 'No crypt function, skipping crypt tests', 4 if(!$Config{d_crypt});
      # 59998
      sub cr {
          # On platforms implementing FIPS mode, using a weak algorithm
          # (including the default triple-DES algorithm) causes crypt(3) to
          # return a null pointer, which Perl converts into undef. We assume
          # for now that all such platforms support glibc-style selection of
          # a different hashing algorithm.
          # glibc supports MD5, but OpenBSD only supports Blowfish.
          my $alg = '';       # Use default algorithm
          if ( !defined(crypt("ab", $alg."cd")) ) {
              $alg = '$5$';   # Try SHA-256
          }
          if ( !defined(crypt("ab", $alg."cd")) ) {
              $alg = '$2b$12$FPWWO2RJ3CK4FINTw0Hi';  # Try Blowfish
          }
          if ( !defined(crypt("ab", $alg."cd")) ) {
              $alg = ''; # Nothing worked.  Back to default
          }
          my $x = crypt($_[0], $alg . $_[1]);
          $x
      }
      sub co { no warnings 'numeric'; my $x = ~$_[0]; $x }
      my ($a, $b);
      $a = cr('hello', 'foo' . $TAINT);
      $b = cr('hello', 'foo');
      is_tainted($a,  "tainted crypt");
      isnt_tainted($b, "untainted crypt");
      $a = co('foo' . $TAINT);
      $b = co('foo');
      is_tainted($a,  "tainted complement");
      isnt_tainted($b, "untainted complement");
    }
}

{
    my @data = qw(bonk zam zlonk qunckkk);
    # Clearly some sort of usenet bang-path
    my $string = $TAINT . join "!", @data;

    is_tainted($string, "tainted data");

    my @got = split /!|,/, $string;

    # each @got would be useful here, but I want the test for earlier perls
    for my $i (0 .. $#data) {
	is_tainted($got[$i], "tainted result $i");
	is($got[$i], $data[$i], "correct content $i");
    }

    is_tainted($string, "still tainted data");

    @got = split /[!,]/, $string;

    # each @got would be useful here, but I want the test for earlier perls
    for my $i (0 .. $#data) {
	is_tainted($got[$i], "tainted result $i");
	is($got[$i], $data[$i], "correct content $i");
    }

    is_tainted($string, "still tainted data");

    @got = split /!/, $string;

    # each @got would be useful here, but I want the test for earlier perls
    for my $i (0 .. $#data) {
	is_tainted($got[$i], "tainted result $i");
	is($got[$i], $data[$i], "correct content $i");
    }
}

# Bug RT #52552 - broken by change at git commit id f337b08
{
    my $x = $TAINT. q{print "Hello world\n"};
    my $y = pack "a*", $x;
    is_tainted($y, "pack a* preserves tainting");

    my $z = pack "A*", q{print "Hello world\n"}.$TAINT;
    is_tainted($z, "pack A* preserves tainting");

    my $zz = pack "a*a*", q{print "Hello world\n"}, $TAINT;
    is_tainted($zz, "pack a*a* preserves tainting");
}

# Bug RT #61976 tainted $! would show numeric rather than string value

{
    my $tainted_path = substr($^X,0,0) . "/no/such/file";
    my $err;
    # $! is used in a tainted expression, so gets tainted
    open my $fh, $tainted_path or $err= "$!";
    unlike($err, qr/^\d+$/, 'tainted $!');
}

{
    # #6758: tainted values become untainted in tied hashes
    #         (also applies to other value magic such as pos)


    package P6758;

    sub TIEHASH { bless {} }
    sub TIEARRAY { bless {} }

    my $i = 0;

    sub STORE {
	main::is_tainted($_[1], "tied arg1 tainted");
	main::is_tainted($_[2], "tied arg2 tainted");
        $i++;
    }

    package main;

    my ($k,$v) = qw(1111 val);
    taint_these($k,$v);
    tie my @array, 'P6758';
    tie my %hash , 'P6758';
    $array[$k] = $v;
    $hash{$k} = $v;
    ok $i == 2, "tied STORE called correct number of times";
}

# Bug RT #45167 the return value of sprintf sometimes wasn't tainted
# when the args were tainted. This only occurred on the first use of
# sprintf; after that, its TARG has taint magic attached, so setmagic
# at the end works.  That's why there are multiple sprintf's below, rather
# than just one wrapped in an inner loop. Also, any plaintext between
# format entries would correctly cause tainting to get set. so test with
# "%s%s" rather than eg "%s %s".

{
    for my $var1 ($TAINT, "123") {
	for my $var2 ($TAINT0, "456") {
        no warnings q(redundant);
	    is( tainted(sprintf '%s', $var1, $var2), tainted($var1),
		"sprintf '%s', '$var1', '$var2'" );
	    is( tainted(sprintf ' %s', $var1, $var2), tainted($var1),
		"sprintf ' %s', '$var1', '$var2'" );
	    is( tainted(sprintf '%s%s', $var1, $var2),
		tainted($var1) || tainted($var2),
		"sprintf '%s%s', '$var1', '$var2'" );
	}
    }
}


# Bug RT #67962: old tainted $1 gets treated as tainted
# in next untainted # match

{
    use re 'taint';
    my $x = "abc".$TAINT =~ /(.*)/; # make $1 tainted
    is_tainted($1, '$1 should be tainted');

    my $untainted = "abcdef";
    isnt_tainted($untainted, '$untainted should be untainted');
    $untainted =~ s/(abc)/$1/;
    isnt_tainted($untainted, '$untainted should still be untainted');
    $untainted =~ s/(abc)/x$1/;
    isnt_tainted($untainted, '$untainted should yet still be untainted');
}

{
    # On Windows we can't spawn a fresh Perl interpreter unless at
    # least the Windows system directory (usually C:\Windows\System32)
    # is still on the PATH.  There is however no way to determine the
    # actual path on the current system without loading the Win32
    # module, so we just restore the original $ENV{PATH} here.
    local $ENV{PATH} = $ENV{PATH};
    $ENV{PATH} = $old_env_path if $Is_MSWin32;

    fresh_perl_is(<<'end', "ok", { switches => [ '-T' ] },
    $TAINT = substr($^X, 0, 0);
    formline('@'.('<'x("2000".$TAINT)).' | @*', 'hallo', 'welt');
    print "ok";
end
    "formline survives a tainted dynamic picture");
}

{
    isnt_tainted($^A, "format accumulator not tainted yet");
    formline('@ | @*', 'hallo' . $TAINT, 'welt');
    is_tainted($^A, "tainted formline argument makes a tainted accumulator");
    $^A = "";
    isnt_tainted($^A, "accumulator can be explicitly untainted");
    formline('@' .('<'x5) . ' | @*', 'hallo', 'welt');
    isnt_tainted($^A, "accumulator still untainted");
    $^A = "" . $TAINT;
    is_tainted($^A, "accumulator can be explicitly tainted");
    formline('@' .('<'x5) . ' | @*', 'hallo', 'welt');
    is_tainted($^A, "accumulator still tainted");
    $^A = "";
    isnt_tainted($^A, "accumulator untainted again");
    formline('@' .('<'x5) . ' | @*', 'hallo', 'welt');
    isnt_tainted($^A, "accumulator still untainted");
    formline('@' .('<'x(5+$TAINT0)) . ' | @*', 'hallo', 'welt');
    is_tainted($^A, "the accumulator should be tainted already");
    is_tainted($^A, "tainted formline picture makes a tainted accumulator");
}

{   # Bug #80610
    "Constant(1)" =~ / ^ ([a-z_]\w*) (?: [(] (.*) [)] )? $ /xi;
    my $a = $1;
    my $b = $2;
    isnt_tainted($a, "regex optimization of single char /[]/i doesn't taint");
    isnt_tainted($b, "regex optimization of single char /[]/i doesn't taint");
}

{
    # RT 81230: tainted value during FETCH created extra ref to tied obj

    package P81230;
    use warnings;

    my %h;

    sub TIEHASH {
	my $x = $^X; # tainted
	bless  \$x;
    }
    sub FETCH { my $x = $_[0]; $$x . "" }

    tie %h, 'P81230';

    my $w = "";
    local $SIG{__WARN__} = sub { $w .= "@_" };

    untie %h if $h{"k"};

    ::is($w, "", "RT 81230");
}

{
    # Compiling a subroutine inside a tainted expression does not make the
    # constant folded values tainted.
    my $x = sub { "x" . "y" };
    my $y = $ENV{PATH} . $x->(); # Compile $x inside a tainted expression
    my $z = $x->();
    isnt_tainted($z, "Constants folded value not tainted");
}

{
    # now that regexes are first class SVs, make sure that they themselves
    # as well as references to them are tainted

    my $rr = qr/(.)$TAINT/;
    my $r = $$rr; # bare REGEX
    my $s ="abc";
    ok($s =~ s/$r/x/, "match bare regex");
    is_tainted($s, "match bare regex taint");
    is($s, 'xbc', "match bare regex taint value");
}

{
    # [perl #82616] security Issues with user-defined \p{} properties
    # A using a tainted user-defined property should croak

    sub IsA { sprintf "%02x", ord("A") }

    my $prop = "IsA";
    ok("A" =~ /\p{$prop}/, "user-defined property: non-tainted case");
    $prop = "IsA$TAINT";
    eval { "A" =~ /\p{$prop}/};
    like($@, qr/Insecure user-defined property "IsA" in regex/,
	    "user-defined property: tainted case");

}

{
    SKIP: {
        skip "Environment tainting tests skipped", 1
          if $Is_MSWin32 || $Is_VMS;

        local $ENV{XX} = '\p{IsB}';   # Making it an environment variable taints it

        fresh_perl_like(<<'EOF',
            BEGIN { $re = qr/$ENV{XX}/; }

            sub IsB { "42" };
            "B" =~ $re
EOF
        qr/Insecure user-defined property \\p\{main::IsB\}/,
        { switches => [ "-T" ] },
        "user-defined property; defn not known until runtime, tainted case");
    }
}

{
    # [perl #87336] lc/uc(first) failing to taint the returned string
    my $source = "foo$TAINT";
    my $dest = lc $source;
    is_tainted $dest, "lc(tainted) taints its return value";
    $dest = lcfirst $source;
    is_tainted $dest, "lcfirst(tainted) taints its return value";
    $dest = uc $source;
    is_tainted $dest, "uc(tainted) taints its return value";
    $dest = ucfirst $source;
    is_tainted $dest, "ucfirst(tainted) taints its return value";
}

{
    # Taintedness of values returned from given()
    use feature 'switch';
    no warnings 'experimental::smartmatch';

    my @descriptions = ('when', 'given end', 'default');

    for (qw<x y z>) {
	my $letter = "$_$TAINT";

	my $desc = "tainted value returned from " . shift(@descriptions);

	my $res = do {
	    given ($_) {
		when ('x') { $letter }
		when ('y') { goto leavegiven }
		default    { $letter }
		leavegiven:  $letter
	    }
	};
	is         $res, $letter, "$desc is correct";
	is_tainted $res,          "$desc stays tainted";
    }
}


# tainted constants and index()
#  RT 64804; http://bugs.debian.org/291450
{
    ok(tainted $old_env_path, "initial taintedness");
    BEGIN { no strict 'refs'; my $v = $old_env_path; *{"::C"} = sub () { $v }; }
    ok(tainted C, "constant is tainted properly");
    ok(!tainted "", "tainting not broken yet");
    no warnings 'uninitialized';
    my $ix = index(undef, C);
    is( $ix, -1, q[index(undef, C)] );
    ok(!tainted "", "tainting still works after index() of the constant");
}

# Tainted values with smartmatch
# [perl #93590] S_do_smartmatch stealing its own string buffers
{
no warnings 'experimental::smartmatch';
ok "M$TAINT" ~~ ['m', 'M'], '$tainted ~~ ["whatever", "match"]';
ok !("M$TAINT" ~~ ['m', undef]), '$tainted ~~ ["whatever", undef]';
}

# Tainted values and ref()
for(1,2) {
  my $x = bless \"M$TAINT", ref(bless[], "main");
}
pass("no death when TARG of ref is tainted");

# $$ should not be tainted by being read in a tainted expression.
{
    isnt_tainted $$, "PID not tainted initially";
    my $x = $ENV{PATH}.$$;
    isnt_tainted $$, "PID not tainted when read in tainted expression";
}

SKIP: {
    skip 'Locales not available', 4 unless locales_enabled('LC_CTYPE');

    use feature 'fc';
    use locale;
    my ($latin1, $utf8) = ("\xDF") x 2;
    utf8::downgrade($latin1);
    utf8::upgrade($utf8);

    is_tainted fc($latin1), "under locale, lc(latin1) taints the result";
    is_tainted fc($utf8), "under locale, lc(utf8) taints the result";

    is_tainted "\F$latin1", "under locale, \\Flatin1 taints the result";
    is_tainted "\F$utf8", "under locale, \\Futf8 taints the result";
}

{ # 111654
  eval {
    eval { die "Test\n".substr($ENV{PATH}, 0, 0); };
    die;
  };
  like($@, qr/^Test\n\t\.\.\.propagated at /, "error should be propagated");
}

# tainted run-time (?{}) should die

{
    my $code = '(?{})' . $TAINT;
    use re 'eval';
    eval { "a" =~ /$code/ };
    like($@, qr/Eval-group in insecure regular expression/, "tainted (?{})");
}

# reset() and tainted undef (?!)
$::x = "foo";
$_ = "$TAINT".reset "x";
is eval { no warnings; eval $::x.1 }, 1, 'reset does not taint undef';

# [perl #122669]
{
    # See the comment above the first formline test.
    local $ENV{PATH} = $ENV{PATH};
    $ENV{PATH} = $old_env_path if $Is_MSWin32;
    is runperl(
       switches => [ '-T' ],
       prog => 'use constant K=>$^X; 0 if K; BEGIN{} use strict; '
              .'print 122669, qq-\n-',
       stderr => 1,
     ), "122669\n",
        'tainted constant as logop condition should not prevent "use"';
}

# optimised SETi etc need to handle tainting

{
    my ($i1, $i2, $i3) = (1, 1, 1);
    my ($n1, $n2, $n3) = (1.1, 1.1, 1.1);
    my $tn = $TAINT0 + 1.1;

    $i1 = $TAINT0 + 2;
    is_tainted $i1, "+ SETi";
    $i2 = $TAINT0 - 2;
    is_tainted $i2, "- SETi";
    $i3 = $TAINT0 * 2;
    is_tainted $i3, "* SETi";

    $n1 = $tn + 2.2;
    is_tainted $n1, "+ SETn";
    $n2 = $tn - 2.2;
    is_tainted $n2, "- SETn";
    $n3 = $tn * 2.2;
    is_tainted $n3, "* SETn";
}

# check that localizing something with get magic (e.g. taint) doesn't
# upgrade pIOK to IOK

{
    local our $x = 1.1 + $TAINT0;  # $x should be NOK
    my $ix = int($x);          #          now NOK, pIOK
    {
        local $x = 0;
    }
    my $x1 = $x * 1;
    isnt($x, 1); # it should be 1.1, not 1
}

# RT #129996
# every item in a list assignment is independent, even if the lvalue
# has taint magic already
{
    my ($a, $b, $c, $d);
    $d = "";
    $b = $TAINT;
    ($a, $b, $c) = ($TAINT, 0, 0);
    is_tainted   $a, "list assign tainted a";
    isnt_tainted $b, "list assign tainted b";
    isnt_tainted $c, "list assign tainted c";

    $b = $TAINT;
    $b = ""; # untaint;
    ($a, $b, $c) = ($TAINT, 0, 0);
    is_tainted   $a, "list assign detainted a";
    isnt_tainted $b, "list assign detainted b";
    isnt_tainted $c, "list assign detainted c";

    $b = $TAINT;
    $b = ""; # untaint;
    ($a, $b, $c) = ($TAINT);
    is_tainted   $a, "list assign empty rhs a";
    isnt_tainted $b, "list assign empty rhs b";
    isnt_tainted $c, "list assign empty rhs c";

    $b = $TAINT;
    $b = ""; # untaint;
    ($a = ($TAINT. "x")), (($b, $c) = (0));
    is_tainted   $a, "list assign already tainted expression a";
    isnt_tainted $b, "list assign already tainted expression b";
    isnt_tainted $c, "list assign already tainted expression c";

    $b = $TAINT;
    $b = ""; # untaint;
    (($a) = ($TAINT. "x")), ($b = $b . "x");
    is_tainted   $a, "list assign post tainted expression a";
    isnt_tainted $b, "list assign post tainted expression b";
}

# Module::Runtime was temporarily broken between 5.27.0 and 5.27.1 because
# ref() would fail an assertion in a tainted statement.  (No ok() neces-
# sary since it aborts when it fails.)
() = defined $^X && ref \$^X;

# taint passing through overloading
package OvTaint {
    sub new { bless({ t => $_[1] }, $_[0]) }
    use overload '""' => sub { $_[0]->{t} ? "hi".$TAINT : "hello" };
}
my $ovclean = OvTaint->new(0);
my $ovtaint = OvTaint->new(1);
isnt_tainted("$ovclean", "overload preserves cleanliness");
is_tainted("$ovtaint", "overload preserves taint");

# substitutions with overloaded replacement
{
    my ($desc, $s, $res, $one);

    $desc = "substitution with partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$ovclean/;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhello', "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution with partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$ovtaint/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhi',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution with whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovclean/;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hello',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution with whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovtaint/;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hi',       "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/"xyz".$ovclean/e;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhello', "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/"xyz".$ovtaint/e;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhi',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovclean/e;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hello',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovtaint/e;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hi',       "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with extra code and partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/(my $z++), "xyz".$ovclean/e;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhello', "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with extra code and partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/(my $z++), "xyz".$ovtaint/e;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xyzhi',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with extra code and whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/(my $z++), $ovclean/e;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hello',    "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /e with extra code and whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/(my $z++), $ovtaint/e;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hi',       "$desc: s value");
    is($res, 1,        "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /r with partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$ovclean/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'abcd',     "$desc: s value");
    is($res, 'xyzhello', "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /r with partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/xyz$ovtaint/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'abcd',     "$desc: s value");
    is($res, 'xyzhi',  "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /r with whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovclean/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'abcd',     "$desc: s value");
    is($res, 'hello',  "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /r with whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.+)/$ovtaint/r;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    is_tainted($res,   "$desc: res tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'abcd',     "$desc: s value");
    is($res, 'hi',     "$desc: res value");
    is($one, 'abcd',   "$desc: \$1 value");

    $desc = "substitution /g with partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.)/x$ovclean/g;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xhello' x 4, "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /g with partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.)/x$ovtaint/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xhi' x 4,  "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /g with whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.)/$ovclean/g;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hello' x 4, "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /g with whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.)/$ovtaint/g;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hi' x 4,   "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with partial replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.)/"x".$ovclean/ge;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xhello' x 4, "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with partial replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.)/"x".$ovtaint/ge;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'xhi' x 4,  "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with whole replacement overloaded and clean";
    $s = 'abcd';
    $res = $s =~ s/(.)/$ovclean/ge;
    $one = $1;
    isnt_tainted($s,   "$desc: s not tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hello' x 4, "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");

    $desc = "substitution /ge with whole replacement overloaded and tainted";
    $s = 'abcd';
    $res = $s =~ s/(.)/$ovtaint/ge;
    $one = $1;
    is_tainted($s,     "$desc: s tainted");
    isnt_tainted($res, "$desc: res not tainted");
    isnt_tainted($one, "$desc: \$1 not tainted");
    is($s, 'hi' x 4,   "$desc: s value");
    is($res, 4,        "$desc: res value");
    is($one, 'd',      "$desc: \$1 value");
}

# RT #132385
# It was trying to taint a boolean return from s/// (e.g. PL_sv_yes)
# and was thus crashing with 'Modification of a read-only value'.

{
    my $s = "abcd" . $TAINT;
    ok(!!($s =~ s/a/x/g), "RT #132385");
}

# RT #134409
# When the last substitution added both taint and utf8, adding taint
# magic to the result also triggered a byte-to-utf8 recalulation of the
# existing pos() magic, which had not yet been reset, resulting in a panic
# about pos() being off the end of the string.
{
    my $utf8_taint = substr($^X,0,0);
    utf8::upgrade($utf8_taint);

    my %map = (
        'UTF8'    => "$utf8_taint",
        'PLAIN' => '',
    );


    my $v = "PLAIN UTF8";
    my $c = eval { $v =~ s/(\w+)/$map{$1}/g; };
    is($c, 2, "RT #134409")
        or diag("\$@ = [$@]");
}

{
    # check that each param is independent taint-wise.
    use feature 'signatures';
    use experimental 'signatures';

    sub taint_sig1($a, $b, $c) {
        isnt_tainted($a, 'taint_sig1: $a');
        is_tainted  ($b, 'taint_sig1: $b');
        isnt_tainted($c, 'taint_sig1: $c');
    }
    taint_sig1(1, $TAINT, 3);

    sub taint_sig2($a, $b = $TAINT, $c = 3) {
        isnt_tainted($a, 'taint_sig2: $a');
        is_tainted  ($b, 'taint_sig2: $b');
        isnt_tainted($c, 'taint_sig2: $c');
    }
    taint_sig2(1);

    sub taint_sig3($a, $b = 2, $c = $TAINT) {
        is_tainted  ($a, 'taint_sig3: $a');
        isnt_tainted($b, 'taint_sig3: $b');
        is_tainted  ($c, 'taint_sig3: $c');
    }
    taint_sig3($TAINT);
}

{
	# GH 19478: panic on s///gre with tainted utf8 strings
	my $u = "\x{10469}";
	my $r1 = ("foo$TAINT" =~ s/./"$u"/gre);
	is($r1, "$u$u$u", 'tainted string with utf8 s/.//gre');
	my $r2 = ("foo$TAINT" =~ s/.*/"${u}"/gre);
	is($r2, "$u$u", 'tainted string with utf8 s/.*//gre');
	my $r3 = ("foo$TAINT" =~ s/.+/"${u}"/gre);
	is($r3, $u, 'tainted string with utf8 s/.+//gre');
	my $r4 = ("$u$TAINT" =~ s/./""/gre);
	is($r4, '', 'tainted utf8 string with s///gre');
}

# This may bomb out with the alarm signal so keep it last
SKIP: {
    skip "No alarm()"  unless $Config{d_alarm};
    # Test from RT #41831]
    # [PATCH] Bug & fix: hang when using study + taint mode (perl 5.6.1, 5.8.x)

    my $DATA = <<'END' . $TAINT;
line1 is here
line2 is here
line3 is here
line4 is here

END

    #study $DATA;

    ## don't set $SIG{ALRM}, since we'd never get to a user-level handler as
    ## perl is stuck in a regexp infinite loop!

    alarm(10);

    if ($DATA =~ /^line2.*line4/m) {
	fail("Should not be a match")
    } else {
	pass("Match on tainted multiline data should fail promptly");
    }

    alarm(0);
}
__END__
# Keep the previous test last