Shorewall 3.9.6 ---------------------------------------------------------------------------- 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 3.9.2, 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 3.9.6. 1) Placing 'ipp2p' in the PROTOCOL column of configuration files now works. 2) Previously, '!' in the TEST column of the tcrules file was not handled correctly. 3) The code generated for copying routing tables from provider file entries was previously incorrect, resulting in run-time errors. 4) Previously, using an ipset in a rule would generate invalid iptables-restore input. 5) Previously, use of CONTINUE in the tcrules file would cause generation of invalid iptables-restore input. Other changes in Shorewall 3.9.6. 1) Eariler generations of Shorewall Lite required that remote root login via ssh be enabled in order to use the 'load' and 'reload' commands. Beginning with this release, you may define an alternative means for accessing the remote firewall system. Two new options have been added to shorewall.conf: RSH_COMMAND RCP_COMMAND The default values for these are as follows: RSH_COMMAND: ssh ${root}@${system} ${command} RCP_COMMAND: scp ${files} ${root}@${system}:${destination} Shell variables that will be set when the commands are envoked are as follows: root - root user. Normally 'root' but may be overridden using the '-r' option. system - The name/IP address of the remote firewall system. command - For RSH_COMMAND, the command to be executed on the firewall system. files - For RCP_COMMAND, a space-separated list of files to be copied to the remote firewall system. destination - The directory on the remote system that the files are to be copied into. 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-3.9.2-1.noarch.rpm error: Failed dependencies: shorewall_compiler is needed by shorewall-3.9.2-1.noarch gateway:~ # You must either: rpm -U shorewall-3.9.2.noarch.rpm shorewall-shell-3.9.2.noarch.rpm or rpm -U shorewall-3.9.2.noarch.rpm shorewall-perl-3.9.2.noarch.rpm or rpm -i shorewall-shell-3.9.2.noarch.rpm rpm -U shorewall-3.9.2.noarch.rpm or rpm -i shorewall-perl-3.9.2.noarch.rpm rpm -U shorewall-3.9.2.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 ---------------------------------------------------------------------------- 1) Shorewall-perl 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. l) BLACKLISTNEWONLY=No is not permitted with FASTACCEPT=Yes. This combination doesn't work in previous versions of Shorewall so the Perl-based compiler simply rejects it. m) Shorewall-perl has a single rule generator that is used for all rule-oriented files. So it is important that the syntax is consistent between files. With shorewall-shell, there is a special syntax in the SOURCE column of /etc/shorewall/masq to designate "all traffic entering the firewall on this interface except...". Example: #INTERFACE SOURCE ADDRESSES eth0 eth1!192.168.4.9 ... Shorewall-perl uses syntax that is consistent with the rest of Shorewall: #INTERFACE SOURCE ADDRESSES eth0 eth1:!192.168.4.9 ... 2) An 'optional' option has been added to /etc/shorewall/interfaces. When 'optional' is specified for an interface, Shorewall will be silent when: - a /proc/sys/net/ipv4/conf/ entry for the interface cannot be modified (including for proxy ARP). - The first address of the interface cannot be obtained. I specify 'optional' on interfaces to Xen virtual machines that may or may not be running when Shorewall is [re]started. CAUTION: Use 'optional' at your own risk. If you [re]start Shorewall when an 'optional' interface is not available and then do a 'shorewall save', subsequent 'shorewall restore' and 'shorewall -f start' operations will instantiate a ruleset that does not support that interface, even if it is available at the time of the restore/start. 3) The treatment of the following interface options has changed under Shorewall-perl. - arp_filter - routefilter - logmartians - proxy_arp - sourceroute With the Shorewall-shell compiler, Shorewall resets these options on all interfaces then sets the option on those interfaces for which the option is defined in /etc/shorewall/interfaces. Under Shorewall-perl, these options can be specified with the value 0 or 1 (e.g., proxy_arp=0). If no value is specified, the value 1 is assumed. Shorewall will modify only the setting of those interfaces for which the option is specified and will set the option to the given value. A fatal compilation error is also generated if you specify one of these options with a wildcard interface (one ending with '+'). 4) Thanks to Paul Gear, an IPPServer macro has been added. Be sure to read the comments in the macro file before trying to use this macro. 5) The LOG_MARTIANS and ROUTE_FILTER options are now tri-valued. Yes - Same as before No - Same as before except that it applies regardless of whether any interfaces have the logmartians/routefilter option Keep - Shorewall ignores the option entirely. ---------------------------------------------------------------------------- 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=perl' 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. If you install Shorewall-perl under Shorewall 3.9.2 or later, you can select the compiler to use on the command line using the 'C option: '-C shell' means use the shell compiler '-C perl' means use the perl compiler The -C option overrides the setting in shorewall.conf. Example: shorewall restart -C perl 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. ---------------------------------------------------------------------------- C H A N G E H I S T O R Y ---------------------------------------------------------------------------- Problems corrected in Shorewall 3.9.3 1) If a rule specified a source or destination port of 0 for TCP or UDP it was ignored. The test for the presence of a source or destination port if the protocol is not specified also ignored port 0. Patch courtesy of Steven Springl. 2) An entry in the USER/GROUP column no longer generates a corrupted rule. 3) The value zero (0) is no longer ignored in the USER/GROUP column. 4) A number of problems associated with detected addresses and routed networks were corrected. These problems surfaced only when the same interface required more than one of the following to be detected: - First address - All addresses - Routed networks 5) The 'dropInvalid' built-in action now correctly generates a DROP rule rather than a REJECT rule. 6) The Shorewall-perl compiler was not treating 'none' in the SOURCE or DEST column of the rules file correctly. 7) The Shorewall-perl compiler did not accept 'tcp:syn' in the PROTO column. 8) The Shorewall-perl compiler generated an invalid rule when $FW was the SOURCE of a SAME rule (iptables/netfilter do not support SAME in the OUTPUT chain). 9) When 'all' appeared in the SOURCE column and there were any NONE policies, then a compilation error occurred. ERROR: Rules may not override a NONE policy 10) The reserved zone names 'all' and 'none' were not being flagged when used as the name of a zone. 11) The Shorewall-perl compiler now raises an error if there is no firewall zone declared. 12) If 'all' appeared in the SOURCE column and an undefined zone was specified in the DEST column of /etc/shorewall/rules, then a Perl run-time diagnostic was produced.