blob: 2722af35bcd79ad1d1c2ab755aad2848a86078d1 [file] [log] [blame]
From 7cedaa8bc2ca9e63369d0e2d4c4c23af9febb93a Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Sat, 2 Jul 2016 22:56:51 -0700
Subject: [PATCH] perl: fix CVE-2016-6185
MIME-Version: 1.0
Don't let XSLoader load relative paths
[rt.cpan.org #115808]
The logic in XSLoader for determining the library goes like this:
my $c = () = split(/::/,$caller,-1);
$modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
my $file = "$modlibname/auto/$modpname/$modfname.bundle";
(That last line varies by platform.)
$caller is the calling package. $modlibname is the calling file. It
removes as many path segments from $modlibname as there are segments
in $caller. So if you have Foo/Bar/XS.pm calling XSLoader from the
Foo::Bar package, the $modlibname will end up containing the path in
@INC where XS.pm was found, followed by "/Foo". Usually the fallback
to Dynaloader::bootstrap_inherit, which does an @INC search, makes
things Just Work.
But if our hypothetical Foo/Bar/XS.pm actually calls
XSLoader::load from inside a string eval, then path ends up being
"(eval 1)/auto/Foo/Bar/Bar.bundle".
So if someone creates a directory named '(eval 1)' with a naughty
binary file in it, it will be loaded if a script using Foo::Bar is run
in the parent directory.
This commit makes XSLoader fall back to Dynaloader's @INC search if
the calling file has a relative path that is not found in @INC.
Backport patch from http://perl5.git.perl.org/perl.git/commitdiff/08e3451d7
Upstream-Status: Backport
CVE: CVE-2016-6185
Signed-off-by: Mingli Yu <Mingli.Yu@windriver.com>
---
dist/XSLoader/XSLoader_pm.PL | 25 +++++++++++++++++++++++++
dist/XSLoader/t/XSLoader.t | 27 ++++++++++++++++++++++++++-
2 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/dist/XSLoader/XSLoader_pm.PL b/dist/XSLoader/XSLoader_pm.PL
index 668411d..778e46b 100644
--- a/dist/XSLoader/XSLoader_pm.PL
+++ b/dist/XSLoader/XSLoader_pm.PL
@@ -104,6 +104,31 @@ print OUT <<'EOT';
my $modpname = join('/',@modparts);
my $c = () = split(/::/,$caller,-1);
$modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
+ # Does this look like a relative path?
+ if ($modlibname !~ m|^[\\/]|) {
+ # Someone may have a #line directive that changes the file name, or
+ # may be calling XSLoader::load from inside a string eval. We cer-
+ # tainly do not want to go loading some code that is not in @INC,
+ # as it could be untrusted.
+ #
+ # We could just fall back to DynaLoader here, but then the rest of
+ # this function would go untested in the perl core, since all @INC
+ # paths are relative during testing. That would be a time bomb
+ # waiting to happen, since bugs could be introduced into the code.
+ #
+ # So look through @INC to see if $modlibname is in it. A rela-
+ # tive $modlibname is not a common occurrence, so this block is
+ # not hot code.
+ FOUND: {
+ for (@INC) {
+ if ($_ eq $modlibname) {
+ last FOUND;
+ }
+ }
+ # Not found. Fall back to DynaLoader.
+ goto \&XSLoader::bootstrap_inherit;
+ }
+ }
EOT
my $dl_dlext = quotemeta($Config::Config{'dlext'});
diff --git a/dist/XSLoader/t/XSLoader.t b/dist/XSLoader/t/XSLoader.t
index 2ff11fe..1e86faa 100644
--- a/dist/XSLoader/t/XSLoader.t
+++ b/dist/XSLoader/t/XSLoader.t
@@ -33,7 +33,7 @@ my %modules = (
'Time::HiRes'=> q| ::can_ok( 'Time::HiRes' => 'usleep' ) |, # 5.7.3
);
-plan tests => keys(%modules) * 3 + 9;
+plan tests => keys(%modules) * 3 + 10;
# Try to load the module
use_ok( 'XSLoader' );
@@ -125,3 +125,28 @@ XSLoader::load("Devel::Peek");
EOS
or ::diag $@;
}
+
+SKIP: {
+ skip "File::Path not available", 1
+ unless eval { require File::Path };
+ my $name = "phooo$$";
+ File::Path::make_path("$name/auto/Foo/Bar");
+ open my $fh,
+ ">$name/auto/Foo/Bar/Bar.$Config::Config{'dlext'}";
+ close $fh;
+ my $fell_back;
+ local *XSLoader::bootstrap_inherit = sub {
+ $fell_back++;
+ # Break out of the calling subs
+ goto the_test;
+ };
+ eval <<END;
+#line 1 $name
+package Foo::Bar;
+XSLoader::load("Foo::Bar");
+END
+ the_test:
+ ok $fell_back,
+ 'XSLoader will not load relative paths based on (caller)[1]';
+ File::Path::remove_tree($name);
+}
--
2.8.1