One true regexp for untainting windows filenames?

jaldhar has asked for the wisdom of the Perl Monks concerning the following question:

Heres another problem in the module I wrote when built under Windows. My tests run in taint mode. They share some common code; the relevant bits look like this...

use English qw/-no_match_vars/;
...
our $filespec;
if ($OSNAME =~ /win/i) {
    $filespec =
        qr{ (\A(?:[[:alpha:]]:)?[ \\ \. \- [:space:] [:word:] ]+)\z }m
+sx;
}
else {
    $filespec = qr{ (\A[- + @ [:word:] . / ]+)\z }msx;
}
...
our $perl = untaint_path( $EXECUTABLE_NAME, '$perl' );
...

sub untaint_path {
    my ( $path, $description ) = @_;

    if ( !( $path =~ $filespec ) ) {
         die "$description is tainted.\n";
    }

    return $1;
}
[download]

A tester using strawberry perl 5.10.0 on Windows XP is reporting this...

t\01-load.................1/1 # Testing Module::Starter::Plugin::CGIAp
+p
0.07, Perl 5.010000, C:\STRAWB~1\perl\bin\perl.exe
t\01-load.................ok
t\extutils-makemaker......$perl is tainted.
Compilation failed in require at t\extutils-makemaker.t line 12.
BEGIN failed--compilation aborted at t\extutils-makemaker.t line 12.
t\extutils-makemaker...... Dubious, test returned 2 (wstat 512, 0x200)
 No subtests run
[download]

the reason it is failing I believe is the ~ in STRAWB~1 which I didn't realize was legal in a Windows file name.

So all this background leads me to my question. What is the canonical regexp for untainting windows file names? Based on the code shown above, are there any other situations where untaint_path could fail?

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