Shorewall 3.9.1 ---------------------------------------------------------------------------- R E L E A S E H I G H L I G H T S ---------------------------------------------------------------------------- 1) This is the first Shorewall release that fully integrates the new Shorewall-perl compiler. See the "New Features" section below. 2) You are now offered a choice as to which compiler(s) you install. In 3.9.1, there are the following packages: - Shorewall ( common files ) - Shorewall-shell ( the shell-based compiler ) - Shorewall-perl (the Perl-based compiler ) You must install Shorewall and at least one of the compiler packages (you may install them both). Problems corrected in Shorewall 3.9.1 Migration Considerations: 1) You cannot simply upgrade your existing Shorewall package. You must upgrade Shorewall *and* install one or both of the compilers. If you attempt to upgrade using the RPM, you get this result: gateway:~ # rpm -Uvh shorewall-3.9.1-1.noarch.rpm error: Failed dependencies: shorewall_compiler is needed by shorewall-3.9.1-1.noarch gateway:~ # You must either: rpm -U shorewall-3.9.1.noarch.rpm shorewall-shell-3.9.1.noarch.rpm or rpm -U shorewall-3.9.1.noarch.rpm shorewall-perl-3.9.1.noarch.rpm or rpm -i shorewall-shell-3.9.1.noarch.rpm rpm -U shorewall-3.9.1.noarch.rpm or rpm -i shorewall-perl-3.9.1.noarch.rpm rpm -U shorewall-3.9.1.noarch.rpm If you are upgrading using the tarball, you must install either shorewall-shell or shorewall-perl before you upgrade Shorewall. Otherwise, the install.sh script fails with: ERROR: No Shorewall compiler is installed The shorewall-shell and shorewall-perl packages are installed from the tarball in the expected way; untar the package, and run the install.sh script. ---------------------------------------------------------------------------- N E W F E A T U R E S ---------------------------------------------------------------------------- Shorewall-perl 3.9.1 ---------------------------------------------------------------------------- This companion product to Shorewall 3.4.2 and later includes a complete rewrite of the compiler in Perl. I decided to make Shorewall-perl a separate product for several reasons: a) Embedded applications are unlikely to adopt Shorewall-perl; even Mini-Perl has a substantial disk and Ram footprint. b) Because of the gross incompatibilities between the new compiler and the old (see below), migration to the new compiler must be voluntary. c) By allowing Shorewall-perl to co-exist with the current Shorewall stable release (3.4), I'm hoping that the new compiler will get more testing and validation than it would if I were to package it with a new development version of Shorewall itself. d) Along the same vein, I think that users will be more likely to experiment with the new compiler if they can easily fall back to the old one if things get sticky. ---------------------------------------------------------------------------- T H E G O O D N E W S: ---------------------------------------------------------------------------- a) The compiler has a small disk footprint. b) The compiler is very fast. c) The compiler generates a firewall script that uses iptables-restore; so the script is very fast. d) Use of the perl compiler is optional! The old slow clunky Bourne-shell compiler is still available. ---------------------------------------------------------------------------- T H E B A D N E W S: ---------------------------------------------------------------------------- There are a number of incompatibilities between the Perl-based compiler and the Bourne-shell one. Some of these will probably go away by first official release but most will not. a) The Perl-based compiler requires the following capabilities in your kernel and iptables. - addrtype match (may be relaxed later) - multiport match (will not be relaxed) These capabilities are in current distributions. b) Now that Netfilter has features to deal reasonably with port lists, I see no reason to duplicate those features in Shorewall. The Bourne-shell compiler goes to great pain (in some cases) to break very long port lists ( > 15 where port ranges in lists count as two ports) into individual rules. In the new compiler, I'm avoiding the ugliness required to do that. The new compiler just generates an error if your list is too long. It will also produce an error if you insert a port range into a port list and you don't have extended multiport support. c) BRIDGING=Yes is not supported. The kernel code necessary to support this option was removed in Linux kernel 2.6.20. d) The BROADCAST column in the interfaces file is essentially unused; if you enter anything in this column but '-' or 'detect', you will receive a warning. This will be relaxed if and when the addrtype match requirement is relaxed. e) Because the compiler is now written in Perl, your compile-time extension scripts from earlier versions will no longer work. Compile-time extension scripts are executed using the Perl 'eval `cat `' mechanism. Be sure that each script returns a 'true' value; otherwise, the compiler will assume that the script failed and will abort the compilation. When a script is invoked, the $chainref scalar variable will hold a reference to a chain table entry. $chainref->{name} contains the name of the chain $chainref->{table} holds the table name To add a rule to the chain: add_rule $chainref, Where is a scalar argument holding the rule text. Do not include "-A " Example: add_rule $chainref, '-j ACCEPT'; To insert a rule into the chain: insert_rule $chainref, , The log_rule_limit function works like it does in the shell compiler with two exceptions: - You pass the chain reference rather than the name of the chain. - The commands are 'add' and 'insert' rather than '-A' and '-I'. - There is only a single "pass as-is to iptables" argument (so you must quote that part). Example: log_rule_limit 'info' , $chainref , $chainref->{name}, 'DROP' , '', #Limit '' , #Log tag 'add'; f) The 'refresh' command is now synonymous with 'restart'. g) Some run-time scripts will need to be changed to write their iptables commands to file descriptor 3 in iptables-restore format rather than running those commands. maclog Details to follow. Some run-time scripts are simply eliminated because they no longer make any sense under Shorewall-perl: initdone - The these two scripts assumed a model where the continue chains were built in parallel. In the iptables-restore model, chains are built serially within tables and tables are build serially. refresh - The 'refresh' command is the same as 'restart' refreshed h) The /etc/shorewall/tos file now has zone-independent SOURCE and DEST columns as do all other files except the rules and policy files. The SOURCE column may be one of the following: [all:]
[,...] [all:][:
[,...]] $FW[:
[,...]] The DEST column may be one of the following: [all:]
[,...] [all:][:
[,...]] This is a permanent change. The old zone-based rules have never worked right and this is a good time to replace them. I've tried to make the new syntax cover the most common cases without requiring change to existing files. In particular, it will handle the tos file released with Shorewall 1.4 and earlier. i) Currently, support for ipsets is untested. That will change with future pre-releases but one thing is certain -- Shorewall is now out of the ipset load/reload business. With scripts generated by the Perl-based Compiler, the Netfilter ruleset is never cleared. That means that there is no opportunity for Shorewall to load/reload your ipsets since that cannot be done while there are any current rules using ipsets. So: i) Your ipsets must be loaded before Shorewall starts. You are free to try to do that with the following code in /etc/shorewall/start: if [ "$COMMAND" = start ]; then ipset -U :all: :all: ipset -F ipset -X ipset -R < /my/ipset/contents fi The file '/my/ipset/contents' (not its real name of course) will normally be produced using the ipset -S command. The above will work most of the time but will fail in a 'shorewall stop' - 'shorewall start' sequence if you use ipsets in your routestopped file (see below). ii) Your ipsets may not be reloaded until Shorewall is stopped or cleared. iii) If you specify ipsets in your routestopped file then Shorewall must be cleared in order to reload your ipsets. As a consequence, scripts generated by the Perl-based compiler will ignore /etc/shorewall/ipsets and will issue a warning if you set SAVE_IPSETS=Yes in shorewall.conf. j) Because the configuration files (with the exception of /etc/shorewall/params) are now processed by the Perl-based compiler rather than by the shell, only the basic forms of Shell expansion ($variable and ${variable}) are supported. The more exotic forms such as ${variable:=default} are not supported. Both variables defined in /etc/shorewall/params and environmental variables (exported by the shell) can be used in configuration files. h) USE_ACTIONS=No is not supported. That option is intended to minimize Shorewall's footprint in embedded applications. As a consequence, Default Macros are not supported. i) DELAYBLACKLISTLOAD=Yes is not supported. The entire ruleset is atomically loaded with one execution of iptables-restore. j) MAPOLDACTIONS=Yes is not supported. People should have converted to using macros by now. k) The pre Shorewall-3.0 format of the zones file is not supported; neither is the /etc/shorewall/ipsec file. ---------------------------------------------------------------------------- P R E R E Q U I S I T E S ---------------------------------------------------------------------------- - Perl (I use Perl 5.8.8 but other versions should work fine) - Perl Cwd Module - Perl File::Basename Module - Perl File::Temp Module ---------------------------------------------------------------------------- U S I N G T H E N E W C O M P I L E R ---------------------------------------------------------------------------- If you only install one compiler, then that compiler will be used. If you install both compilers, then the compiler actually used depends on the SHOREWALL_COMPILER setting in shorewall.conf. The value of this new option can be either 'perl' or 'shell'. If you add 'SHOREWALL_COMPILER=shell' to /etc/shorewall/shorewall.conf then by default, the new compiler will be used on the system. If you add it to shorewall.conf in a separate directory (such as a Shorewall-lite export directory) then the new compiler will only be used when you compile from that directory. If you only install one compiler, it is suggested that you do not set SHOREWALL_COMPILER. Regardless of the setting of SHOREWALL_COMPILER, there is one change in Shorewall operation that is triggered simply by installing shorewall-perl. Your params file will be processed during compilation with the shell's '-a' option which causes any variables that you set or create in that file to be automatically exported. Since the params file is processed before shorewall.conf, using -a insures that the settings of your params variables are available to the new compiler should it's use be specified in shorewall.conf.