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perl-5.42.2
⭐ Starred 2013 / Test2::Require::Fork
Security Advisories (3)
CVE-2026-13221 (2026-07-13)

Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk. When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error. A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.

CVE-2026-57432 (2026-07-13)

Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds. A template derived from untrusted input can read heap memory past the buffer and return it to the caller.

CVE-2026-8376 (2026-05-25)

Perl versions through 5.43.10 have a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds. Perl_study_chunk in regcomp_study.c checked the size of the joined substring buffer in characters rather than bytes. For a quantified fixed substring with a large minimum count, the byte length mincount * l could overflow SSize_t, producing an undersized SvGROW allocation; the subsequent copy writes past the end of the buffer. A caller that compiles an attacker-controlled regular expression on a 32-bit perl build triggers a heap buffer overflow at compile time.

NAME

Test2::Require::Fork - Skip a test file unless the system supports forking

DESCRIPTION

It is fairly common to write tests that need to fork. Not all systems support forking. This library does the hard work of checking if forking is supported on the current system. If forking is not supported then this will skip all tests and exit true.

SYNOPSIS

use Test2::Require::Fork;

... Code that forks ...

EXPLANATION

Checking if the current system supports forking is not simple. Here is an example of how to do it:

use Config;

sub CAN_FORK {
    return 1 if $Config{d_fork};

    # Some platforms use ithreads to mimic forking
    return 0 unless $^O eq 'MSWin32' || $^O eq 'NetWare';
    return 0 unless $Config{useithreads};
    return 0 unless $Config{ccflags} =~ /-DPERL_IMPLICIT_SYS/;

    # Threads are not reliable before 5.008001
    return 0 unless $] >= 5.008001;

    # Devel::Cover currently breaks with threads
    return 0 if $INC{'Devel/Cover.pm'};
    return 1;
}

Duplicating this non-trivial code in all tests that need to fork is error-prone. It is easy to forget bits, or get it wrong. On top of these checks, you also need to tell the harness that no tests should run and why.

SEE ALSO

Test2::Require::RealFork

Similar to this module, but will skip on any perl that only has fork emulation.

Test2::Require::Threads

Skip the test file if the system does not support threads.

SOURCE

The source code repository for Test2-Suite can be found at https://github.com/Test-More/test-more/.

MAINTAINERS

Chad Granum <exodist@cpan.org>

AUTHORS

Chad Granum <exodist@cpan.org>

COPYRIGHT

Copyright Chad Granum <exodist@cpan.org>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://dev.perl.org/licenses/