path: root/pod/perl5125delta.pod

=encoding utf8

=head1 NAME

[ this is a template for a new perldelta file. Any text flagged as
XXX needs to be processed before release. ]

perldelta - what is new for perl v5.12.5

=head1 DESCRIPTION

This document describes differences between the 5.12.4 release and
the 5.12.5 release.

If you are upgrading from an earlier release such as 5.12.3, first read
L<perl5124delta>, which describes differences between 5.12.3 and
5.12.4.

=head1 Notice

XXX Any important notices here

=head1 Security

=head2 C<Encode> decode_xs n-byte heap-overflow (CVE-2011-2939)

A bug in C<Encode> could, on certain inputs, cause the heap to overflow.
This problem has been corrected.  Bug reported by Robert Zacek.

=head2 C<File::Glob::bsd_glob()> memory error with GLOB_ALTDIRFUNC (CVE-2011-2728).

Calling C<File::Glob::bsd_glob> with the unsupported flag GLOB_ALTDIRFUNC would 
cause an access violation / segfault.  A Perl program that accepts a flags value from
an external source could expose itself to denial of service or arbitrary code
execution attacks.  There are no known exploits in the wild.  The problem has been
corrected by explicitly disabling all unsupported flags and setting unused function
pointers to null.  Bug reported by Clément Lecigne.

=head2 Heap buffer overrun in 'x' string repeat operator (CVE-2012-5195)

Poorly written perl code that allows an attacker to specify the count to
perl's 'x' string repeat operator can already cause a memory exhaustion
denial-of-service attack. A flaw in versions of perl before 5.15.5 can
escalate that into a heap buffer overrun; coupled with versions of glibc
before 2.16, it possibly allows the execution of arbitrary code.

This problem has been fixed.

=head1 Incompatible Changes

XXX For a release on a stable branch, this section aspires to be:

    There are no changes intentionally incompatible with 5.XXX.XXX. If any
    exist, they are bugs and reports are welcome.


=head1 Core Enhancements

XXX New core language features go here. Summarise user-visible core language
enhancements. Particularly prominent performance optimisations could go
here, but most should go in the L</Performance Enhancements> section.

=head1 New Platforms

XXX List any platforms that this version of perl compiles on, that previous
versions did not. These will either be enabled by new files in the F<hints/>
directories, or new subdirectories and F<README> files at the top level of the
source tree.

=head1 Modules and Pragmata

XXX All changes to installed files in F<cpan/>, F<dist/>, F<ext/> and F<lib/>
go here.  If Module::CoreList is updated, generate an initial draft of the
following sections using F<Porting/corelist-perldelta.pl>, which prints stub
entries to STDOUT.  Results can be pasted in place of the '=head2' entries
below.  A paragraph summary for important changes should then be added by hand.
In an ideal world, dual-life modules would have a F<Changes> file that could be
cribbed.

=head2 New Modules and Pragmata

=head2 Pragmata Changes

=head2 Updated Modules

=head3 L<B::Concise>

L<B::Concise> no longer produces mangled output with the B<-tree> option
[perl #80632].

=head3 L<charnames>

A regression introduced in Perl 5.8.8 has been fixed, that caused
C<charnames::viacode(0)> to return C<undef> instead of the string "NULL"
[perl #72624].

=head3 L<Encode> has been upgraded from version 2.39 to version 2.39_01.

See L</Security>.

=head3 L<File::Glob> has been upgraded from version 1.07 to version 1.07_01.

See L</Security>.

=head3 L<Unicode::UCD>

The documentation for the C<upper> function now actually says "upper", not
"lower".

=head2 Removed Modules and Pragmata

=head1 Utility Changes

XXX Changes to installed programs such as F<perlbug> and F<xsubpp> go
here. Most of these are built within the directories F<utils> and F<x2p>.

=over 4

=item F<XXX>

XXX

=back

=head1 New Documentation

XXX Changes which create B<new> files in F<pod/> go here.

=over 4

=item L<XXX>

XXX

=back

=head1 Changes to Existing Documentation

XXX Changes which significantly change existing files in F<pod/> go here.
Any changes to F<pod/perldiag.pod> should go in L</New or Changed Diagnostics>.

=head2 L<perlebcdic>

The L<perlebcdic> document contains a helpful table to use in C<tr///> to
convert between EBCDIC and Latin1/ASCII.  Unfortunately, the table was the
inverse of the one it describes.  This has been corrected.

=head2 L<perlunicode>

The section on
L<User-Defined Case Mappings|perlunicode/User-Defined Case Mappings> had
some bad markup and unclear sentences, making parts of it unreadable.  This
has been rectified.

=head2 L<perluniprops>

This document has been corrected to take non-ASCII platforms into account.

=head1 Performance Enhancements

XXX Changes which enhance performance without changing behaviour go here. There
may well be none in a stable release.

=over 4

=item *

XXX

=back

=head1 Installation and Configuration Improvements

XXX Changes to F<Configure>, F<installperl>, F<installman>, and analogous tools
go here.

=head2 Configuration improvements

XXX

=head2 Compilation improvements

XXX

=head2 Platform Specific Changes

=over 4

=item Mac OS X

There have been configuration and test fixes to make Perl build cleanly on
Lion and Mountain Lion.

=back

=head1 Selected Bug Fixes

XXX Important bug fixes in the core language are summarised here.
Bug fixes in files in F<ext/> and F<lib/> are best summarised in
L</Modules and Pragmata>.

=over 4

=item *

C<chop> now correctly handles characters above "\x{7fffffff}"
[perl #73246].

=item *

C<< ($<,$>) = (...) >> stopped working properly in 5.12.0.  It is supposed
to make a single C<setreuid()> call, rather than calling C<setruid()> and
C<seteuid()> separately.  Consequently it did not work properly.  This has
been fixed [perl #75212].

=item *

Fixed a regression of kill() when a match variable is used for the
process ID to kill [perl #75812].

=item *

C<UNIVERSAL::VERSION> no longer leaks memory.  It started leaking in Perl
5.10.0.

=item *

The C-level C<my_strftime> functions no longer leaks memory.  This fixes a
memory leak in C<POSIX::strftime> [perl #73520].

=item *

C<caller> no longer leaks memory when called from the DB package if
C<@DB::args> was assigned to after the first call to C<caller>.  L<Carp>
was triggering this bug [perl #97010].

=item *

Passing to C<index> an offset beyond the end of the string when the string
is encoded internally in UTF8 no longer causes panics [perl #75898].

=item *

Syntax errors in C<< (?{...}) >> blocks in regular expressions no longer
cause panic messages [perl #2353].

=item *

Perl 5.10.0 introduced some faulty logic that made "U*" in the middle of
a pack template equivalent to "U0" if the input string was empty.  This has
been fixed [perl #90160].

=back

=head1 New or Changed Diagnostics

XXX New or changed warnings emitted by the core's C<C> code go here.

=over 4

=item C<XXX>

XXX

=back

=head1 Changed Internals

XXX Changes which affect the interface available to C<XS> code go here.

=over 4

=item *

XXX

=back

=head1 New Tests

XXX Changes which create B<new> files in F<t/> go here. Changes to
existing files in F<t/> aren't worth summarising, although the bugs that
they represent may be.

=over 4

=item F<XXX>

XXX

=back

=head1 Known Problems

XXX Descriptions of platform agnostic bugs we know we can't fix go here. Any
tests that had to be C<TODO>ed for the release would be noted here, unless
they were specific to a particular platform (see below).

This is a list of some significant unfixed bugs, which are regressions
from either 5.XXX.XXX or 5.XXX.XXX.

=over 4

=item *

XXX

=back

=head1 Deprecations

XXX Add any new known deprecations here.

The following items are now deprecated.

=over 4

=item *

XXX

=back

=head1 Platform Specific Notes

XXX Any changes specific to a particular platform. VMS and Win32 are the usual
stars here. It's probably best to group changes under the same section layout
as the main perldelta

=head1 Errata

=head2 split() and C<@_>

split() no longer modifies C<@_> when called in scalar or void context.
In void context it now produces a "Useless use of split" warning.
This is actually a change introduced in perl 5.12.0, but it was missed from
that release's L<perl5120delta>.

=head1 Obituary

XXX If any significant core contributor has died, we've added a short obituary
here.

=head1 Acknowledgements

XXX The list of people to thank goes here.


=head1 Reporting Bugs

If you find what you think is a bug, you might check the articles
recently posted to the comp.lang.perl.misc newsgroup and the perl
bug database at http://rt.perl.org/perlbug/ .  There may also be
information at http://www.perl.org/ , the Perl Home Page.

If you believe you have an unreported bug, please run the B<perlbug>
program included with your release.  Be sure to trim your bug down
to a tiny but sufficient test case.  Your bug report, along with the
output of C<perl -V>, will be sent off to perlbug@perl.org to be
analysed by the Perl porting team.

If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please send
it to perl5-security-report@perl.org. This points to a closed subscription
unarchived mailing list, which includes all the core committers, who be able
to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported. Please only use this address for
security issues in the Perl core, not for modules independently
distributed on CPAN.

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view exhaustive details
on what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=cut