/ 
perl-5.41.8
⭐ Starred 2013 / Errno
Security Advisories (2)
CVE-2024-56406 (2025-04-13)

A heap buffer overflow vulnerability was discovered in Perl. Release branches 5.34, 5.36, 5.38 and 5.40 are affected, including development versions from 5.33.1 through 5.41.10. When there are non-ASCII bytes in the left-hand-side of the `tr` operator, `S_do_trans_invmap` can overflow the destination pointer `d`.    $ perl -e '$_ = "\x{FF}" x 1000000; tr/\xFF/\x{100}/;'    Segmentation fault (core dumped) It is believed that this vulnerability can enable Denial of Service and possibly Code Execution attacks on platforms that lack sufficient defenses.

CVE-2025-40909 (2025-05-30)

Perl threads have a working directory race condition where file operations may target unintended paths. If a directory handle is open at thread creation, the process-wide current working directory is temporarily changed in order to clone that handle for the new thread, which is visible from any third (or more) thread already running. This may lead to unintended operations such as loading code or accessing files from unexpected locations, which a local attacker may be able to exploit. The bug was introduced in commit 11a11ecf4bea72b17d250cfb43c897be1341861e and released in Perl version 5.13.6

NAME

Errno - System errno constants

SYNOPSIS

use Errno qw(EINTR EIO :POSIX);

DESCRIPTION

Errno defines and conditionally exports all the error constants defined in your system errno.h include file. It has a single export tag, :POSIX, which will export all POSIX defined error numbers.

On Windows, Errno also defines and conditionally exports all the Winsock error constants defined in your system WinError.h include file. These are included in a second export tag, :WINSOCK.

Errno also makes %! magic such that each element of %! has a non-zero value only if $! is set to that value. For example:

my $fh;
unless (open($fh, "<", "/fangorn/spouse")) {
    if ($!{ENOENT}) {
        warn "Get a wife!\n";
    } else {
        warn "This path is barred: $!";
    } 
}

If a specified constant EFOO does not exist on the system, $!{EFOO} returns "". You may use exists $!{EFOO} to check whether the constant is available on the system.

Perl automatically loads Errno the first time you use %!, so you don't need an explicit use.

CAVEATS

Importing a particular constant may not be very portable, because the import will fail on platforms that do not have that constant. A more portable way to set $! to a valid value is to use:

if (exists &Errno::EFOO) {
    $! = &Errno::EFOO;
}

AUTHOR

Graham Barr <gbarr@pobox.com>

COPYRIGHT

Copyright (c) 1997-8 Graham Barr. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.