| Subject: | CVE-2016-1238: App::Cpan may load an optional module from the current directory |
This can be used by another user on the system to attack the current user if
this code is run from a globally writable directory such as /tmp.
The attached patch temporarily removes . from @INC when attemptting to load
optional modules.
The patch is also available as a pull request at:
https://github.com/andk/cpanpm/pull/101
This change is in maint-5.22, maint-5.24 and blead perl.
Tony
| Subject: | 0001-CVE-2016-1238-don-t-load-optional-modules-from-defau.patch |
From 394ac06dc5e9e94a81c39c43135d1635f516422e Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Wed, 27 Jul 2016 12:14:13 +1000
Subject: [PATCH] CVE-2016-1238: don't load optional modules from default .
App::Cpan attempts to load several optional modules, which an attacker
can use if cpan is run from a directory writable by other users, such
as /tmp.
---
lib/App/Cpan.pm | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/lib/App/Cpan.pm b/lib/App/Cpan.pm
index f43dea9..c654c2c 100644
--- a/lib/App/Cpan.pm
+++ b/lib/App/Cpan.pm
@@ -549,9 +549,20 @@ sub AUTOLOAD { 1 }
sub DESTROY { 1 }
}
+# load a module without searching the default entry for the current
+# directory
+sub _safe_load_module {
+ my $name = shift;
+
+ local @INC = @INC;
+ pop @INC if $INC[-1] eq '.';
+
+ eval "require $name; 1";
+}
+
sub _init_logger
{
- my $log4perl_loaded = eval "require Log::Log4perl; 1";
+ my $log4perl_loaded = _safe_load_module("Log::Log4perl");
unless( $log4perl_loaded )
{
@@ -1020,7 +1031,7 @@ sub _load_local_lib # -I
{
$logger->debug( "Loading local::lib" );
- my $rc = eval { require local::lib; 1; };
+ my $rc = _safe_load_module("local::lib");
unless( $rc ) {
$logger->die( "Could not load local::lib" );
}
@@ -1160,7 +1171,7 @@ sub _get_file
{
my $path = shift;
- my $loaded = eval "require LWP::Simple; 1;";
+ my $loaded = _safe_load_module("LWP::Simple");
croak "You need LWP::Simple to use features that fetch files from CPAN\n"
unless $loaded;
@@ -1182,7 +1193,7 @@ sub _gitify
{
my $args = shift;
- my $loaded = eval "require Archive::Extract; 1;";
+ my $loaded = _safe_load_module("Archive::Extract");
croak "You need Archive::Extract to use features that gitify distributions\n"
unless $loaded;
@@ -1245,7 +1256,7 @@ sub _show_Changes
sub _get_changes_file
{
croak "Reading Changes files requires LWP::Simple and URI\n"
- unless eval "require LWP::Simple; require URI; 1";
+ unless _safe_load_module("LWP::Simple") && _safe_load_module("URI");
my $url = shift;
--
2.1.4