[perl5.git] / pod / perl5283delta.pod

=encoding utf8

=head1 NAME

perl5283delta - what is new for perl v5.28.3

=head1 DESCRIPTION

This document describes differences between the 5.28.2 release and the 5.28.3
release.

If you are upgrading from an earlier release such as 5.28.1, first read
L<perl5282delta>, which describes differences between 5.28.1 and 5.28.2.

=head1 Security

=head2 [CVE-2020-10543] Buffer overflow caused by a crafted regular expression

A signed C<size_t> integer overflow in the storage space calculations for
nested regular expression quantifiers could cause a heap buffer overflow in
Perl's regular expression compiler that overwrites memory allocated after the
regular expression storage space with attacker supplied data.

The target system needs a sufficient amount of memory to allocate partial
expansions of the nested quantifiers prior to the overflow occurring.  This
requirement is unlikely to be met on 64-bit systems.

Discovered by: ManhND of The Tarantula Team, VinCSS (a member of Vingroup).

=head2 [CVE-2020-10878] Integer overflow via malformed bytecode produced by a crafted regular expression

Integer overflows in the calculation of offsets between instructions for the
regular expression engine could cause corruption of the intermediate language
state of a compiled regular expression.  An attacker could abuse this behaviour
to insert instructions into the compiled form of a Perl regular expression.

Discovered by: Hugo van der Sanden and Slaven Rezic.

=head2 [CVE-2020-12723] Buffer overflow caused by a crafted regular expression

Recursive calls to C<S_study_chunk()> by Perl's regular expression compiler to
optimize the intermediate language representation of a regular expression could
cause corruption of the intermediate language state of a compiled regular
expression.

Discovered by: Sergey Aleynikov.

=head2 Additional Note

An application written in Perl would only be vulnerable to any of the above
flaws if it evaluates regular expressions supplied by the attacker.  Evaluating
regular expressions in this fashion is known to be dangerous since the regular
expression engine does not protect against denial of service attacks in this
usage scenario.

=head1 Incompatible Changes

There are no changes intentionally incompatible with Perl 5.28.2.  If any
exist, they are bugs, and we request that you submit a report.  See
L</Reporting Bugs> below.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Module::CoreList> has been upgraded from version 5.20190419 to 5.20200601_28.

=back

=head1 Testing

Tests were added and changed to reflect the other additions and changes in this
release.

=head1 Acknowledgements

Perl 5.28.3 represents approximately 13 months of development since Perl 5.28.2
and contains approximately 3,100 lines of changes across 48 files from 16
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 1,700 lines of changes to 9 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant community
of users and developers.  The following people are known to have contributed
the improvements that became Perl 5.28.3:

Chris 'BinGOs' Williams, Dan Book, Hugo van der Sanden, James E Keenan, John
Lightsey, Karen Etheridge, Karl Williamson, Matthew Horsfall, Max Maischein,
Nicolas R., Renee Baecker, Sawyer X, Steve Hay, Tom Hukins, Tony Cook, Zak B.
Elep.

The list above is almost certainly incomplete as it is automatically generated
from version control history.  In particular, it does not include the names of
the (very much appreciated) contributors who reported issues to the Perl bug
tracker.

Many of the changes included in this version originated in the CPAN modules
included in Perl's core.  We're grateful to the entire CPAN community for
helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see
the F<AUTHORS> file in the Perl source distribution.

=head1 Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at
L<https://github.com/Perl/perl5/issues>.  There may also be information at
L<https://www.perl.org/>, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at
L<https://github.com/Perl/perl5/issues>.  Be sure to trim your bug down to a
tiny but sufficient test case.

If the bug you are reporting has security implications which make it
inappropriate to send to a public issue tracker, then see
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
report the issue.

=head1 Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you
can do so by running the C<perlthanks> program:

    perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

=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
Commit	Line	Data
189c2812 SH	1	=encoding utf8
	2
	3	=head1 NAME
	4
	5	perl5283delta - what is new for perl v5.28.3
	6
	7	=head1 DESCRIPTION
	8
	9	This document describes differences between the 5.28.2 release and the 5.28.3
	10	release.
	11
	12	If you are upgrading from an earlier release such as 5.28.1, first read
	13	L<perl5282delta>, which describes differences between 5.28.1 and 5.28.2.
	14
	15	=head1 Security
	16
	17	=head2 [CVE-2020-10543] Buffer overflow caused by a crafted regular expression
	18
	19	A signed C<size_t> integer overflow in the storage space calculations for
	20	nested regular expression quantifiers could cause a heap buffer overflow in
	21	Perl's regular expression compiler that overwrites memory allocated after the
	22	regular expression storage space with attacker supplied data.
	23
	24	The target system needs a sufficient amount of memory to allocate partial
	25	expansions of the nested quantifiers prior to the overflow occurring. This
	26	requirement is unlikely to be met on 64-bit systems.
	27
	28	Discovered by: ManhND of The Tarantula Team, VinCSS (a member of Vingroup).
	29
	30	=head2 [CVE-2020-10878] Integer overflow via malformed bytecode produced by a crafted regular expression
	31
	32	Integer overflows in the calculation of offsets between instructions for the
	33	regular expression engine could cause corruption of the intermediate language
	34	state of a compiled regular expression. An attacker could abuse this behaviour
	35	to insert instructions into the compiled form of a Perl regular expression.
	36
	37	Discovered by: Hugo van der Sanden and Slaven Rezic.
	38
	39	=head2 [CVE-2020-12723] Buffer overflow caused by a crafted regular expression
	40
	41	Recursive calls to C<S_study_chunk()> by Perl's regular expression compiler to
	42	optimize the intermediate language representation of a regular expression could
	43	cause corruption of the intermediate language state of a compiled regular
	44	expression.
	45
	46	Discovered by: Sergey Aleynikov.
	47
	48	=head2 Additional Note
	49
	50	An application written in Perl would only be vulnerable to any of the above
	51	flaws if it evaluates regular expressions supplied by the attacker. Evaluating
	52	regular expressions in this fashion is known to be dangerous since the regular
	53	expression engine does not protect against denial of service attacks in this
	54	usage scenario.
	55
	56	=head1 Incompatible Changes
	57
	58	There are no changes intentionally incompatible with Perl 5.28.2. If any
	59	exist, they are bugs, and we request that you submit a report. See
	60	L</Reporting Bugs> below.
	61
	62	=head1 Modules and Pragmata
	63
	64	=head2 Updated Modules and Pragmata
65
66	=over 4
67
68	=item *
69
70	L<Module::CoreList> has been upgraded from version 5.20190419 to 5.20200601_28.
71
72	=back
73
74	=head1 Testing
75
76	Tests were added and changed to reflect the other additions and changes in this
77	release.
78
79	=head1 Acknowledgements
80
81	Perl 5.28.3 represents approximately 13 months of development since Perl 5.28.2
82	and contains approximately 3,100 lines of changes across 48 files from 16
83	authors.
84
85	Excluding auto-generated files, documentation and release tools, there were
86	approximately 1,700 lines of changes to 9 .pm, .t, .c and .h files.
87
88	Perl continues to flourish into its fourth decade thanks to a vibrant community
89	of users and developers. The following people are known to have contributed
90	the improvements that became Perl 5.28.3:
91
92	Chris 'BinGOs' Williams, Dan Book, Hugo van der Sanden, James E Keenan, John
93	Lightsey, Karen Etheridge, Karl Williamson, Matthew Horsfall, Max Maischein,
94	Nicolas R., Renee Baecker, Sawyer X, Steve Hay, Tom Hukins, Tony Cook, Zak B.
95	Elep.
96
97	The list above is almost certainly incomplete as it is automatically generated
98	from version control history. In particular, it does not include the names of
99	the (very much appreciated) contributors who reported issues to the Perl bug
100	tracker.
101
102	Many of the changes included in this version originated in the CPAN modules
103	included in Perl's core. We're grateful to the entire CPAN community for
104	helping Perl to flourish.
105
106	For a more complete list of all of Perl's historical contributors, please see
107	the F<AUTHORS> file in the Perl source distribution.
108
109	=head1 Reporting Bugs
110
111	If you find what you think is a bug, you might check the perl bug database at
112	L<https://github.com/Perl/perl5/issues>. There may also be information at
113	L<https://www.perl.org/>, the Perl Home Page.
114
115	If you believe you have an unreported bug, please open an issue at
116	L<https://github.com/Perl/perl5/issues>. Be sure to trim your bug down to a
117	tiny but sufficient test case.
118
119	If the bug you are reporting has security implications which make it
120	inappropriate to send to a public issue tracker, then see
121	L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
122	report the issue.
123
124	=head1 Give Thanks
125
126	If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you
127	can do so by running the C<perlthanks> program:
128
129	perlthanks
130
131	This will send an email to the Perl 5 Porters list with your show of thanks.
132
133	=head1 SEE ALSO
134
135	The F<Changes> file for an explanation of how to view exhaustive details on
136	what changed.
137
138	The F<INSTALL> file for how to build Perl.
139
140	The F<README> file for general stuff.
141
142	The F<Artistic> and F<Copying> files for copyright information.
143
144	=cut