shorewall_code/Shorewall/releasenotes.txt
2009-04-18 16:28:25 +00:00

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Shorewall 4.3.9
Shorewall 4.3 is the development thread for Shorewall 4.4 which will be
released late in 2009.
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R E L E A S E 4 . 3 H I G H L I G H T S
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1) Support for Shorewall-shell has been discontinued. Shorewall-perl
has been combined with Shorewall-common to produce a single
Shorewall package.
2) The Shorewall documentation and man pages have been purged of
information about earlier Shorewall releases. The documentation
describes only the behavior of Shorewall 4.3 and later versions.
3) The interfaces file OPTIONs have been extended to largely remove the
need for the hosts file.
4) It is now possible to define PREROUTING and OUTPUT marking rules
that cause new connections to use the same provider as an existing
connection of the same kind.
5) Dynamic Zone support is once again available for IPv4; ipset support is
required in your kernel and in iptables.
6) A new AUTOMAKE option has been added to shorewall.conf and
shorewall6.conf. Setting this option will allow Shorewall to skip
the compilation phase during start/restart if no configuration
changes have occurred since the last start/restart.
7) The LIMIT:BURST column in /etc/shorewall/policy
(/etc/shorewall6/policy) and the RATE LIMIT column in
/etc/shorewall/rules (/etc/shorewall6/rules) may now be used to
limit on a per source IP or per destination IP basis.
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M I G R A T I O N I S S U E S
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1) The 'shorewall stop', 'shorewall clear', 'shorewall6 stop' and
'shorewall6 clear' commands no longer read the 'routestopped'
file. The 'routestopped' file used is the one that was present at
the last 'start', 'restart' or 'restore' command.
2) The old macro parameter syntax (e.g., SSH/ACCEPT) is now deprecated
in favor of the new syntax (e.g., SSH(ACCEPT)). The 4.3 documentation
uses the new syntax exclusively, although the old syntax
continues to be supported.
3) Support for the SAME target in /etc/shorewall/masq and
/etc/shorewall/rules has been removed, following the removal of the
underlying support in the Linux kernel.
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P R O B L E M S C O R R E C T E D I N 4 . 3 . 9
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1) If an interface name was specified in a PREROUTING rule (tcrules or
notrack) then an invalid iptables rule would be generated.
2) When a network address appeared in the SOURCE or DEST column of
/etc/shorewall/tcfilters, an incorrect netmask was being generated in
the resulting 'tc' rule.
3) Placing an IP address in the BROADCAST column of
/etc/shorewall/interfaces caused Shorewall-perl to generate an
erroneous 'Invalid BROADCAST address' error.
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K N O W N P R O B L E M S R E M A I N I N G
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None.
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N E W F E A T U R E S I N 4 . 3 . 9
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1) Rules that specify a log level with a target other than LOG or NFLOG
are now implemented through a separate chain. While this may increase
the processing cost slightly for packets that match these rules, it
is expected to reduce the overall cost of such rules because each
packet that doesn't match the rules only has to be processed once
per rule rather than twice.
Example:
/etc/shorewall/rules:
REJECT:info loc net tcp 25
This previously generated these two rules (long rules folded):
-A loc2net -p 6 --dport 25 -j LOG --log-level 6
--log-prefix "Shorewall:loc2net:reject:"
-A loc2net -p 6 --dport 25 -j reject
It now generates these rules:
:log0 - [0:0]
...
-A loc2net -p 6 --dport 25 -g log0
...
-A log0 -j LOG --log-level 6
--log-prefix "Shorewall:loc2net:REJECT:"
-A log0 -p 6 --dport 25 -j reject
Notice that now there is only a single rule generated in the
'loc2net' chain where before there were two. Packets for other than
TCP port 25 had to be processed by both rules.
Notice also that the new LOG rule reflects the original action
("REJECT") rather than what Shorewall maps that to ("reject").
2) Shorewall6 has now been tested on kernel 2.6.24 (Ubuntu Hardy) and
hence will now start successfully when running on that kernel.
3) Three new options (IP, TC and IPSET) have been added to
shorewall.conf and shorwall6.conf. These options specify the name
of the executable for the 'ip', 'tc' and 'ipset' utilities
respectively.
If not specified, the default values are:
IP=ip
TC=tc
IPSET=ipset
In other words, the utilities will be located via the current PATH
setting.
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N E W F E A T U R E S IN 4 . 3
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1) The Shorewall packaging has been completely revamped in Shorewall
4.3.
The new packages are:
- Shorewall. Includes the former Shorewall-common and
Shorewall-perl packages. Includes everything needed
to create an IPv4 firewall.
- Shorewall6. Requires Shorewall. Adds the components necessary to
create an IPv6 firewall.
- Shorewall-lite
May be installed on a firewall system to run
IPv4 firewall scripts generated by Shorewall.
- Shorewall6-lite
May be installed on a firewall system to run
IPv6 firewall scripts generated by Shorewall6.
2) The interfaces file supports a new 'nets=' option. This option
allows users to restrict a zone's definition to particular networks
through an interface without having to use the hosts file.
Example interfaces file:
#ZONE INTERFACE BROADCAST OPTIONS
loc eth3 detect dhcp,logmartians=1,routefilter=1,nets=172.20.1.0/24
dmz eth4 detect logmartians=1,routefilter=1,nets=206.124.146.177
net eth0 detect dhcp,blacklist,tcpflags,optional,routefilter=0,nets=(!172.20.0.0/24,206.124.146.177)
net eth2 detect dhcp,blacklist,tcpflags,optional,upnp,routefilter=0,nets=(!172.20.0.0/24,206.124.146.177)
loc tun+ detect nets=172.20.0.0/24
#LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE
Note that when more than one network address is listed, the list
must be enclosed in parentheses. Notice also that exclusion may be
used.
The first entry in the above interfaces file is equivalent to the
following:
interfaces:
#ZONE INTERFACE BROADCAST OPTIONS
- eth0 detect dhcp,logmartians=1,routefilter=1
hosts:
#ZONE HOST(S) OPTIONS
loc $INT_IF:192.20.1.0/24 broadcast
Note that the 'broadcast' option is automatically assumed and need
not be explicitly specified.
3) Some websites run applications that require multiple connections
from a client browser. Where multiple 'balanced' providers are
configured, this can lead to problems when some of the connections
are routed through one provider and some through another.
To work around this issue, the SAME target has been added to
/etc/shorewall/tcrules. SAME may be used in the PREROUTING and
OUTPUT chains. When used in PREROUTING, it causes matching
connections from an individual local system to all use the same
provider.
For example:
SAME:P 192.168.1.0/24 - tcp 80,443
If a host in 192.168.1.0/24 attempts a connection on TCP port 80 or
443 and it has sent a packet on either of those ports in the last
five minutes then the new connection will use the same provider as
the connection over which that last packet was sent.
When used in the OUTPUT chain, it causes all matching connections
to an individual remote system to all use the same provider.
For example:
SAME $FW - tcp 80,443
If the firewall attempts a connection on TCP port 80 or
443 and it has sent a packet on either of those ports in the last
five minutes to the same remote system then the new connection will
use the same provider as the connection over which that last packet
was sent.
Important note: SAME only works with providers that have the
'track' option specified in /etc/shorewall/providers.
4) The file /var/lib/shorewall/.restore has been renamed to
/var/lib/shorewall/firewall. A similar change has been made in
Shorewall6.
When a successful start or restart is completed, the script that
executed the command copies itself to to
/var/lib/shorewall[6]/firewall.
5) Dynamic zone support is once again available for IPv4. This support
is built on top of ipsets so you must have the xtables-addons
installed on the firewall system.
Dynamic zones are available when Shorewall-lite is used as well.
Note that the dynamic zone support built into Shorewall provides no
additional functionality over what is provided by simply defining a
zone in terms of an ipset (see
http://www1.shorewall.net/ipsets.html#Dynamic).
You define a zone as having dynamic content in one of two ways:
- By specifying nets=dynamic in the OPTIONS column of an entry for
the zone in /etc/shorewall/interfaces; or
- By specifying <interface>:dynamic in the HOST(S) column of an
entry for the zone in /etc/shorewall/hosts.
When there are any dynamic zones present in your configuration,
Shorewall (Shorewall-lite) will:
a) Execute the following commands during 'shorewall start' or
'shorewall-lite start'.
ipset -U :all: :all:
ipset -U :all: :default:
ipset -F
ipset -X
ipset -R < ${VARDIR}/ipsets.save
where $VARDIR normally contains /var/lib/shorewall
(/var/lib/shorewall-lite) but may be modified by
/etc/shorewall/vardir (/etc/shorewall-lite/vardir).
b) During 'start', 'restart' and 'restore' processing, Shorewall
will then attempt to create an ipset named <zone>_<interface>
for each zone/interface pair that has been specified as
dynamic. The type of ipset created is 'iphash' so that only
individual IPv4 addresses may be added to the set.
c) Execute the following commands during 'shorewall stop' or
'shorewall-lite stop':
if ipset -S > ${VARDIR}/ipsets.tmp; then
mv -f ${VARDIR}/ipsets.tmp ${VARDIR}/ipsets.save
fi
The 'shorewall add' and 'shorewall delete' commands are supported
with their original syntax:
add <interface>[:<host-list>] ... <zone>
delete <interface>[:<host-list>] ... <zone>
In addition, the 'show dynamic' command is added that lists the dynamic
content of a zone.
show dynamic <zone>
These commands are supported by shorewall-lite as well.
6) The generated program now attempts to detect all dynamic
information when it first starts. If any of those steps fail, an
error message is generated and the state of the firewall is not
changed.
7) Shorewall will now attempt to detect a dynamic gateway by reading
the dhclient lease file for the interface
(/var/run/dhcp/dhclient-<if>.lease).
8) To improve readability of the configuration files, Shorewall now
allows leading white space in continuation lines when the continued
line ends in ":" or ",".
Example (/etc/shorewall/rules):
#ACTION SOURCE DEST PROTO DEST
# PORT(S)
ACCEPT net:\
206.124.146.177,\
206.124.146.178,\
206.124.146.180\
dmz tcp 873
The leading white space on the lines that contain just an IP
address is ignored so the SOURCE column effectively contains
"net:206.124.146.177,206.124.147.178,206.124.146.180".
9) The generated script now uses iptables[6]-restore to instantiate
the Netfilter ruleset during processing of the 'stop' command. As a
consequence, the 'critical' option in /etc/shorewall/route_stopped
is no longer needed and will result in a warning.
10) A new AUTOMAKE option has been added to shorewall.conf and
shorewall6.conf. When set to 'Yes', this option causes new behavior
during processing of the 'start' and 'restart' commands; if no
files in /etc/shorewall/ (/etc/shorewall6) have changed since the last
'start' or 'restart', then the compilation step is skipped and the
script used during the last 'start' or 'restart' is used to
start/restart the firewall.
Note that if a <directory> is specified in the start/restart
command (e.g., "shorewall restart /etc/shorewall.new") then the
setting of AUTOMAKE is ignored.
Note that the 'make' utility must be installed on the firewall
system in order for AUTOMAKE=Yes to work correctly.
11) The 'compile' command now allows you to omit the <pathname>. When
you do that, the <pathname> defaults to /var/lib/shorewall/firewall
(/var/lib/shorewall6/firewall) unless you have overridden VARDIR
using /etc/shorewall/vardir (/etc/shorewall6/vardir).
When combined with AUTOMAKE=Yes, it allows the following:
gateway:~ # shorewall compile
Compiling...
Shorewall configuration compiled to /root/shorewall/firewall
gateway:~ #
...
gateway:~ # shorewall restart
Restarting Shorewall....
done.
gateway:~ #
In other words, you can compile the current configuration then
install it at a later time.
12) Thanks to I. Buijs, it is now possible to rate-limit connections by
source IP or destination IP. The LIMIT:BURST column in
/etc/shorewall/policy (/etc/shorewall6/policy) and the RATE LIMIT
column /etc/shorewall/rules (/etc/shorewall6/rules) have been
extended as follows:
[{s|d}:[[<name>]:]]<rate>/{sec|min}[:<burst>]
When s: is specified, the rate is per source IP address.
When d: is specified, the rate is per destination IP address.
The <name> specifies the name of a hash table -- you get to choose
the name. If you don't specify a name, the name 'shorewall' is
assumed. Rules with the same name have their connection counts
aggregated and the individual rates are applied to the aggregate.
Example:
ACCEPT net fw tcp 22 - - s:ssh:3/min
This will limit SSH connections from net->fw to 3 per minute.
ACCEPT net fw tcp 25 - - s:mail:3/min
ACCEPT net fw tcp 587 - - s:mail:3/min
Since the same hash table name is used in both rules, the above is
equivalent to this single rule:
ACCEPT net fw tcp 25,587 - - s:mail:3/min