175 lines
6.0 KiB
Diff
175 lines
6.0 KiB
Diff
From e4fb3394d935b68ddb36cc6c543cbecd8e9875b5 Mon Sep 17 00:00:00 2001
|
|
From: Stig Palmquist <stig@stig.io>
|
|
Date: Thu, 21 May 2026 19:59:21 +0100
|
|
Subject: [PATCH 1/2] Validate symlink and hardlink linkname in SECURE MODE
|
|
|
|
Signed-off-by: Chris 'BinGOs' Williams <chris@bingosnet.co.uk>
|
|
---
|
|
lib/Archive/Tar.pm | 30 ++++++++++++++++++++++++++++++
|
|
t/04_resolved_issues.t | 2 ++
|
|
2 files changed, 32 insertions(+)
|
|
|
|
diff --git a/lib/Archive/Tar.pm b/lib/Archive/Tar.pm
|
|
index e08b5e5..d4a6d56 100644
|
|
--- a/lib/Archive/Tar.pm
|
|
+++ b/lib/Archive/Tar.pm
|
|
@@ -918,6 +918,19 @@ sub _make_special_file {
|
|
my $err;
|
|
|
|
if( $entry->is_symlink ) {
|
|
+ if( !$INSECURE_EXTRACT_MODE ) {
|
|
+ my $linkname = $entry->linkname;
|
|
+ if( File::Spec->file_name_is_absolute($linkname) ) {
|
|
+ $self->_error( qq[Symlink '] . $entry->full_path .
|
|
+ qq[' has absolute target. Not extracting under SECURE EXTRACT MODE] );
|
|
+ return;
|
|
+ }
|
|
+ if( grep { $_ eq '..' } File::Spec->splitdir($linkname) ) {
|
|
+ $self->_error( qq[Symlink '] . $entry->full_path .
|
|
+ qq[' target attempts traversal. Not extracting under SECURE EXTRACT MODE] );
|
|
+ return;
|
|
+ }
|
|
+ }
|
|
my $fail;
|
|
if( ON_UNIX ) {
|
|
symlink( $entry->linkname, $file ) or $fail++;
|
|
@@ -931,6 +944,23 @@ sub _make_special_file {
|
|
$entry->linkname .q[' failed] if $fail;
|
|
|
|
} elsif ( $entry->is_hardlink ) {
|
|
+ if( !$INSECURE_EXTRACT_MODE ) {
|
|
+ my $linkname = $entry->linkname;
|
|
+ if( File::Spec->file_name_is_absolute($linkname) ) {
|
|
+ $self->_error( qq[Hardlink '] . $entry->full_path .
|
|
+ qq[' has absolute target '$linkname'. Not extracting ] .
|
|
+ qq[under SECURE EXTRACT MODE: extraction itself chmods ] .
|
|
+ qq[the shared inode.] );
|
|
+ return;
|
|
+ }
|
|
+ if( grep { $_ eq '..' } File::Spec->splitdir($linkname) ) {
|
|
+ $self->_error( qq[Hardlink '] . $entry->full_path .
|
|
+ qq[' target '$linkname' attempts traversal. Not ] .
|
|
+ qq[extracting under SECURE EXTRACT MODE: extraction ] .
|
|
+ qq[itself chmods the shared inode.] );
|
|
+ return;
|
|
+ }
|
|
+ }
|
|
my $fail;
|
|
if( ON_UNIX ) {
|
|
link( $entry->linkname, $file ) or $fail++;
|
|
diff --git a/t/04_resolved_issues.t b/t/04_resolved_issues.t
|
|
index 4991d9a..c7dc0f8 100644
|
|
--- a/t/04_resolved_issues.t
|
|
+++ b/t/04_resolved_issues.t
|
|
@@ -216,6 +216,7 @@ use_ok( $FileClass );
|
|
}
|
|
|
|
{ #use case 1 - in memory extraction
|
|
+ local $Archive::Tar::INSECURE_EXTRACT_MODE=1;
|
|
my $t=Archive::Tar->new;
|
|
$t->read( $archname );
|
|
my $r = eval{ $t->extract };
|
|
@@ -227,6 +228,7 @@ use_ok( $FileClass );
|
|
|
|
{ #use case 2 - iter extraction
|
|
#$DB::single = 2;
|
|
+ local $Archive::Tar::INSECURE_EXTRACT_MODE=1;
|
|
my $next=Archive::Tar->iter( $archname, 1 );
|
|
my $failed = 0;
|
|
#use Data::Dumper;
|
|
--
|
|
2.52.0
|
|
|
|
|
|
From 9ab74ba586a2328207da232f390968057a9a0ef6 Mon Sep 17 00:00:00 2001
|
|
From: Stig Palmquist <git@stig.io>
|
|
Date: Tue, 2 Jun 2026 16:09:03 +0200
|
|
Subject: [PATCH 2/2] Allow `..` links in secure extract in parent path
|
|
|
|
Assisted-by: OpenAI Codex
|
|
Signed-off-by: Stig Palmquist <git@stig.io>
|
|
---
|
|
lib/Archive/Tar.pm | 7 ++++---
|
|
t/90_symlink.t | 26 ++++++++++++++++++++++++++
|
|
2 files changed, 30 insertions(+), 3 deletions(-)
|
|
|
|
diff --git a/lib/Archive/Tar.pm b/lib/Archive/Tar.pm
|
|
index d4a6d56..5b968c8 100644
|
|
--- a/lib/Archive/Tar.pm
|
|
+++ b/lib/Archive/Tar.pm
|
|
@@ -925,7 +925,7 @@ sub _make_special_file {
|
|
qq[' has absolute target. Not extracting under SECURE EXTRACT MODE] );
|
|
return;
|
|
}
|
|
- if( grep { $_ eq '..' } File::Spec->splitdir($linkname) ) {
|
|
+ if( !defined _symlinks_resolver( $entry->full_path, $linkname, 1 ) ) {
|
|
$self->_error( qq[Symlink '] . $entry->full_path .
|
|
qq[' target attempts traversal. Not extracting under SECURE EXTRACT MODE] );
|
|
return;
|
|
@@ -953,7 +953,7 @@ sub _make_special_file {
|
|
qq[the shared inode.] );
|
|
return;
|
|
}
|
|
- if( grep { $_ eq '..' } File::Spec->splitdir($linkname) ) {
|
|
+ if( !defined _symlinks_resolver( $entry->full_path, $linkname, 1 ) ) {
|
|
$self->_error( qq[Hardlink '] . $entry->full_path .
|
|
qq[' target '$linkname' attempts traversal. Not ] .
|
|
qq[extracting under SECURE EXTRACT MODE: extraction ] .
|
|
@@ -1964,7 +1964,7 @@ sub no_string_support {
|
|
}
|
|
|
|
sub _symlinks_resolver{
|
|
- my ($src, $trg) = @_;
|
|
+ my ($src, $trg, $strict) = @_;
|
|
my @src = split /[\/\\]/, $src;
|
|
my @trg = split /[\/\\]/, $trg;
|
|
pop @src; #strip out current object name
|
|
@@ -1977,6 +1977,7 @@ sub _symlinks_resolver{
|
|
next if $part eq '.'; #ignore current
|
|
if($part eq '..'){
|
|
#got to parent
|
|
+ return if $strict && !@src;
|
|
pop @src;
|
|
}
|
|
else{
|
|
diff --git a/t/90_symlink.t b/t/90_symlink.t
|
|
index 3d7b406..db7a3bd 100644
|
|
--- a/t/90_symlink.t
|
|
+++ b/t/90_symlink.t
|
|
@@ -26,6 +26,32 @@ my %Map = (
|
|
|
|
use_ok( $Class );
|
|
|
|
+{
|
|
+ my $tar = $Class->new;
|
|
+ $tar->add_data( '.github/README.md', '',
|
|
+ { type => 2, linkname => '../README' } );
|
|
+
|
|
+ local $Archive::Tar::INSECURE_EXTRACT_MODE = 0;
|
|
+ ok( $tar->extract_file( '.github/README.md' ),
|
|
+ "Extracted symlink target that stays under cwd" );
|
|
+
|
|
+ unlink File::Spec->catfile( qw[.github README.md] );
|
|
+ rmtree( '.github' );
|
|
+}
|
|
+
|
|
+{
|
|
+ my $tar = $Class->new;
|
|
+ $tar->add_data( 'safe/link', '',
|
|
+ { type => 2, linkname => '../../outside' } );
|
|
+
|
|
+ local $Archive::Tar::INSECURE_EXTRACT_MODE = 0;
|
|
+ local $Archive::Tar::WARN = 0;
|
|
+ ok( !$tar->extract_file( 'safe/link' ),
|
|
+ "Refused symlink target escaping cwd" );
|
|
+
|
|
+ rmtree( 'safe' );
|
|
+}
|
|
+
|
|
{ while( my($file, $aref) = each %Map ) {
|
|
|
|
for my $mode ( 0, 1 ) {
|
|
--
|
|
2.52.0
|
|
|