Prevent from some stack-not-ref-counted crashes in Carp

Carp-1.42-Fix-RT-52610-Carp-Do-not-crash-when-reading-DB-args.patch

@@ -0,0 +1,82 @@
+From b5ad485cc167b3b6aa43f83aa92bbf8b8811cb42 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
+Date: Fri, 20 Apr 2018 10:20:55 +0200
+Subject: [PATCH] Fix RT #52610: Carp: Do not crash when reading @DB::args
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Petr Pisar: Ported from perl after 5.27.8. The unreliable test was
+later deleted in a77eff3c and the comments rephrased in 02c84d7:
+
+commit 4764858cb80e76fdba33cc1b3be8fcdef26df754
+Author: Pali <pali@cpan.org>
+Date:   Wed Jan 31 22:43:46 2018 +0100
+
+    Fix RT #52610: Carp: Do not crash when reading @DB::args
+
+    Trying to read values from array @DB::args can lead to perl fatal error
+    "Bizarre copy of ARRAY in scalar assignment". But missing, incomplete or
+    possible incorrect value in @DB::args is not a fatal error for Carp.
+
+    Carp is primary used for reporting warnings and errors from other
+    modules, so it should not crash perl when trying to print error message.
+
+    This patch safely iterates all elements of @DB::args array via eval { }
+    block and replace already freed scalars for Carp usage by string
+    "** argument not available anymore **".
+
+    This prevent crashing perl and allows to use Carp module. It it not a
+    proper fix but rather workaround for Carp module. At least it allows to
+    safely use Carp.
+
+    Patch amended by Yves Orton
+
+Signed-off-by: Petr Písař <ppisar@redhat.com>
+---
+ lib/Carp.pm | 22 ++++++++++++++++------
+ 1 file changed, 16 insertions(+), 6 deletions(-)
+
+diff --git a/lib/Carp.pm b/lib/Carp.pm
+index 05052b9..60b2469 100644
+--- a/lib/Carp.pm
++++ b/lib/Carp.pm
+@@ -203,11 +203,22 @@ sub caller_info {
+ 
+     my $sub_name = Carp::get_subname( \%call_info );
+     if ( $call_info{has_args} ) {
+-        my @args;
+-        if (CALLER_OVERRIDE_CHECK_OK && @DB::args == 1
+-            && ref $DB::args[0] eq ref \$i
+-            && $DB::args[0] == \$i ) {
+-            @DB::args = ();    # Don't let anyone see the address of $i
++        # guard our serialization of the stack from stack refcounting bugs
++        my @args = map {
++                my $arg;
++                local $@= $@;
++                eval {
++                    $arg = $_;
++                    1;
++                } or do {
++                    $arg = '** argument not available anymore **';
++                };
++                $arg;
++            } @DB::args;
++        if (CALLER_OVERRIDE_CHECK_OK && @args == 1
++            && ref $args[0] eq ref \$i
++            && $args[0] == \$i ) {
++            @args = ();    # Don't let anyone see the address of $i
+             local $@;
+             my $where = eval {
+                 my $func    = $cgc or return '';
+@@ -226,7 +237,6 @@ sub caller_info {
+                 = "** Incomplete caller override detected$where; \@DB::args were not set **";
+         }
+         else {
+-            @args = @DB::args;
+             my $overflow;
+             if ( $MaxArgNums and @args > $MaxArgNums )
+             {    # More than we want to show?
+-- 
+2.14.3
+

perl-Carp.spec

@@ -2,7 +2,7 @@
 
 Name:           perl-Carp
 Version:        1.42
-Release:        395%{?dist}
+Release:        396%{?dist}
 Summary:        Alternative warn and die for modules
 License:        GPL+ or Artistic
 URL:            http://search.cpan.org/dist/Carp/
@@ -11,10 +11,13 @@ Source0:        http://www.cpan.org/authors/id/R/RJ/RJBS/Carp-%{cpan_version}.ta
 Patch0:         Carp-1.38-Upgrade-to-1.40.patch
 # Unbundled from perl 5.25.12
 Patch1:         Carp-1.40-Upgrade-to-1.42.patch
+# Prevent from some stack-not-ref-counted crashes in Carp, RT#52610,
+# in perl upstream after 5.27.8
+Patch2:         Carp-1.42-Fix-RT-52610-Carp-Do-not-crash-when-reading-DB-args.patch
 BuildArch:      noarch
 BuildRequires:  make
-BuildRequires:  perl-interpreter
 BuildRequires:  perl-generators
+BuildRequires:  perl-interpreter
 BuildRequires:  perl(ExtUtils::MakeMaker) >= 6.76
 BuildRequires:  perl(warnings)
 BuildRequires:  perl(strict)
@@ -46,6 +49,7 @@ but it is a good educated guess.
 %setup -q -n Carp-%{cpan_version}
 %patch0 -p1
 %patch1 -p1
+%patch2 -p1
 
 %build
 perl Makefile.PL INSTALLDIRS=vendor NO_PACKLIST=1
@@ -64,6 +68,9 @@ make test
 %{_mandir}/man3/*
 
 %changelog
+* Fri Apr 20 2018 Petr Pisar <ppisar@redhat.com> - 1.42-396
+- Prevent from some stack-not-ref-counted crashes in Carp (RT#52610)
+
 * Thu Feb 08 2018 Fedora Release Engineering <releng@fedoraproject.org> - 1.42-395
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild