From b1f12b72e5bdb58f4de2522607e3612c1742a536 Mon Sep 17 00:00:00 2001
From: Xavier <yadd@debian.org>
Date: Thu, 27 Jun 2019 20:48:01 +0200
Subject: [PATCH] Add MAC verification to crypto

---
 .../lib/Lemonldap/NG/Common/Crypto.pm         | 24 ++++++++++++-------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/lemonldap-ng-common/lib/Lemonldap/NG/Common/Crypto.pm b/lemonldap-ng-common/lib/Lemonldap/NG/Common/Crypto.pm
index 179c92036..70af44638 100644
--- a/lemonldap-ng-common/lib/Lemonldap/NG/Common/Crypto.pm
+++ b/lemonldap-ng-common/lib/Lemonldap/NG/Common/Crypto.pm
@@ -71,10 +71,11 @@ sub encrypt {
     $data .= "\0" x ( 16 - $l ) unless ( $l == 0 );
 
     my $iv = $low ? md5( rand() . time . {} ) : $newIv->();
+    my $hmac = md5($data);
     eval {
         $data =
-          encode_base64( $iv . $self->_getCipher->set_iv($iv)->encrypt($data),
-            '' );
+          encode_base64(
+            $iv . $hmac . $self->_getCipher->set_iv($iv)->encrypt($data), '' );
     };
     if ($@) {
         $msg = "Crypt::Rijndael error : $@";
@@ -100,13 +101,18 @@ sub decrypt {
     $data = decode_base64($data);
     my $iv;
     $iv = bytes::substr( $data, 0, 16 );
-    $data = bytes::substr( $data, 16 );
+    my $hmac = bytes::substr( $data, 16, 16 );
+    $data = bytes::substr( $data, 32 );
     eval { $data = $self->_getCipher->set_iv($iv)->decrypt($data); };
 
     if ($@) {
         $msg = "Crypt::Rijndael error : $@";
         return undef;
     }
+    if ( md5($data) ne $hmac ) {
+        $msg = "Bad MAC";
+        return undef;
+    }
     else {
         $msg = '';
 
@@ -163,21 +169,21 @@ sub _cryptHex {
         return undef;
     }
     my $iv;
-    if($sub eq 'encrypt') {
+    if ( $sub eq 'encrypt' ) {
         $iv = $newIv->();
     }
     $data = pack "H*", $data;
-    if($sub eq 'decrypt') {
-        $iv = bytes::substr($data,0,16);
-        $data = bytes::substr($data,16);
+    if ( $sub eq 'decrypt' ) {
+        $iv = bytes::substr( $data, 0, 16 );
+        $data = bytes::substr( $data, 16 );
     }
     eval { $data = $self->_getCipher($key)->set_iv($iv)->$sub($data); };
     if ($@) {
         $msg = "Crypt::Rijndael error : $@";
         return undef;
     }
-    if($sub eq 'encrypt') {
-        $data = $iv.$data;
+    if ( $sub eq 'encrypt' ) {
+        $data = $iv . $data;
     }
     $msg = "";
     $data = unpack "H*", $data;