2009 Jun 28 - Sun
Blosxom Reinstall on Debian Lenny 5.0.1
It is almost time to retire my perl based bloging server software known as
blosxom. It has performed well. However, my page count is starting to get high,
and blosxom is taking longer and longer to process. For now, I've moved it to faster hardware while I work on a different
blog delivery mechanism (I hope to have Wt on C++ with PostgreSQL running the back-end soon).
Copying over the directory structure was no real problem. The only real thing needed was to put the mod_rewrite stuff
back in so the unsightly cgi-bin url portion is removed. By default, mod_rewrite is not enabled.
To enable it:
a2enmod rewrite
Here is what the rewrite stuff as it looks in sites-enabled/default file:
RewriteLogLevel 0
RewriteLog /var/log/apache2/rewrite.log
<Directory "/var/www/blog">
AddHandler cgi-script .cgi
Options +ExecCGI
RewriteEngine On
RewriteCond %{REQUEST_URI} !-f
RewriteCond %{REQUEST_URI} !-d
RewriteRule ^(.*)$ /cgi-bin/blosxom.cgi/$1 [L,QSA]
</Directory>
[/OpenSource/blosxom]
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Perl Mason Install
Installing mason v1.42 from Mason HQ
is quite straight-forward:
- apt-get install build-essential
- apt-get install libapache2-mod-apreq2
- apt-get install libapreq2-dev
- apt-get install libapache2-request-perl
- ln -s /etc/apache2/mods-available/apreq.load /etc/apache2/mods-enabled/apreq.load
- perl -MCPAN -eshell
- install HTML::Mason
[/OpenSource/Debian/Monitoring]
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VMWare Mouse Release on Debian Lenny Guest
A simple message to myself. When installing a Debian Lenny 5.0.1 KDE guest
in VMWare Workstation hosted on Windows XP, a few steps are required in order to
move into and out of the guest without the ctrl-alt mouse release sequence:
- apt-get install build-essential on the guest
- apt-get install linux-headers-...
- build and install the VMWare toolkit in the guest
- add 'Option "CorePointer"' to the mouse section of /etc/X11/xorg.conf
- add 'Option "CoreKeyBoard"' to the keyboard section of /etc/X11/xorg.conf
- restart KDE
A visit to a
VMWare Community
describes a couple of additional steps for getting the VMWare Shared Folders (HGFS) Share to
work inside of Lenny 5.0.1 as well. Basically, in the /etc/fstab file, which VMWare updates
when you perform a tool install, append ',uid=1000,gid=1000' to the 'ttl=5' portion
of the .host line, so it looks something like:
.host:/ /mnt/hgfs vmhgfs defaults,ttl=5,uid=1000,gid=1000 0 0
The actual value to be used in place of 1000 is what ever your uid,gid are for your
current window session. This an be determined at the command line by:
echo ${UID}
Without the uid/gid values in the fstab file, the share is made available for the root user. Anyway, after
the restart, by using the file explorer, go to /mnt/hgfs to see the volumes.
[/OpenSource/Debian]
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Web Statistics with awstats on Debian Lenny 5.0.1
On an old system, I used Webalizer to analyze Apache log files. On a newer system
I thought I'd give awstats a try. I had two options, install via the original source,
or install via apt-get. Considering the number of files and directories involved, I
decided to go with the Debian package manager to install awstats.
The package manager to get things into decent directories, but it appears to have
been built for an earlier flavour of Debian. A few things I had to fix up for working in
Debian Lenny 5.0.1 with Apache v2.0 include:
- In /etc/cron.d/awstats, changing one of the file checks from /var/log/apache/access.log to /var/log/apache2/access.log
- changing the ownership of the logs in /var/log/apache from root.adm to root.www-data (an alternative might be www-data.adm)
- changing the creation ownership in /etc/logrotate.d/apache2 from 'create 640 root adm' to 'create 640 root www-data'
- in /etc/awstats/awstats.conf.loal, added 'LogFormat=1' and 'DirIcons=/awstats/icon'
- in /etc/apache2/sites-enabled/000-default, added 'Alias /awstats/icon "/usr/share/awstats/icon"'
- the version of awstats installed was 6.5. I downloaded the awstats.pl file from awstats site and
placed it in the /usr/lib/cgi-bin directly as a simple upgrade to v6.9.
During package installation, the package manager suggested some additional packages: libnet-dns-perl libnet-ip-perl libgeo-ipfree-perl. Perhaps
when I get a chance, I'll install those and see what they add to the statistics management.
[/OpenSource/Debian]
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2009 Jun 27 - Sat
Network Broadcast Addresses
A customer was performing penetration testing on their network. Once the test results
were in, among other things, they had a couple questions about responses to certain addresses
on their external subnet range.
As a background, every subnet with a network mask of /30 or shorter has three address groups:
- first address: the zeros address aka network address
- middle addresses: usuable addresses
- last address: the ones address aka broadcast address
For explanation purposes, imagine a router with two interfaces:
- interface 1, the ingress interface, with address range of 10.0.0.0/30 and interface address of 10.0.0.1.
- interface 2, the egress interface, with address range of 10.0.0.4/30 and interface address of 10.0.0.5.
For some network devices, for a packet arriving on the ingress interface destined for the broadcast address
of the egress interface (10.0.0.7), the network device will forward the packet, effectively broadcasting to
all devices located in the subnet of the egress interfaces. When many packets arrive in this manner,
this is known as a
Smurf Attack.
Current Cisco devices, by default, no longer forward packets to broadcast addresses, but may respond to these
packets. The following command is applied by default to prevent forwarding of packets to broadcast addresses:
no ip directed-broadcast
At the other end of the subnet, for the network address, I originally thought this was a quiescent address. However,
I did find that the an ICMP echo request arriving on the ingress interface destined to the network address (10.0.0.4) of the
egress interface will generate an echo-reply with the ingress ip address (10.0.0.1) as the source address.
It appears that in days gone past, that for BSD Unix boxes and various other equipment, the network address was *the*
broadcast address. This is why some configurations allow one to configure the address of the broadcast address setting,
whether it be the high end or low end of a subnet. (thanx to Steinar Haug for this info).
rfc 1122 formalizes this broadcast address
configuration (thanx to an inciteful responder named Lee):
3.3.6 Broadcasts
There is a class of hosts* that use non-standard broadcast
address forms, substituting 0 for -1. All hosts SHOULD
recognize and accept any of these non-standard broadcast
addresses as the destination address of an incoming datagram.
A host MAY optionally have a configuration option to choose the
0 or the -1 form of broadcast address, for each physical
interface, but this option SHOULD default to the standard (-1)
form.
The host will respond with the echo-reply because of
rfc 791:
3.2.1.3 Addressing: RFC-791 Section 3.2
... An incoming datagram is destined
for the host if the datagram's destination address field is:
(1) (one of) the host's IP address(es); or
(2) an IP broadcast address valid for the connected
network; or
From a Cisco router perspective, the default use of the command 'no ip directed-broadcast', allows one
to use a /31 subnet (two ip addresses) for point to point links instead of the usual /30 subnet (four ip addresses).
One can effectively address twice as many links with the same number of addresses. This feature is mentioned in
Cisco's Feature Guide:
Using 31-Bit Prefixes on IPv4 Point-to-Point Links.
Coincidently, while I was writing this article, I received a note that there are a couple of TCP Security Assessment
documents available:
These documents go into the details of the bits and bytes making up the TCP protocol, analyzing the reasons for the bits,
how they can be misused, and suggesting counter-measures when used illegally. Theres is a detailed bibilography with
active links to related papers and documents.
An idea of the scope of the document can be seen through its first level table of content:
- The Transmission Control Protocol
- TCP Header Fields
- Common TCP Options
- Connection-Establishment Mechanism
- Connection-Termination Mechanism
- Buffer Management
- TCP Segment Reassembly Algorithm
- TCP Congestion Control
- TCP API
- Blind In-Window Attacks
- Information Leaking
- Covert Channels
- TCP Port Scanning
- Processing of ICMP Error Messages by TCP
- TCP Interaction with the Internet Protocol (IP>
- References
[/Networks]
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Securely Erasing Files
On a Linux system, there are a number of tools available for over-writing a file
with random data and then deleting the file and hiding the name of the name of the file as well.
Of course, there are certain caveats that go along with this. If you focus only on
securely deleting files, you will miss file content that may have been written to bad sectors,
file journals, sectors released when files have been relocated from one area to another
(as in when you edit or shorten files),
and various other disk dead areas.
On popular tool is a utility called shred, and is found natively on most distributions. In
the most basic form:
shred --remove filename
If you use the -v (verbose) option, you can see how many times it over-writes a file, and with
what patterns it uses. It also uses a descending 0 write in order to obliterate
a file name.
If you need to recurse sub-directories:
find * -depth -type f | xargs shred --remove
If you have created then moved or erased files and want to ensure that the released content
is overwritten, then you need to over-write drive free space and then release it. There are some
poeople who suggest using dd to fill the free space and then use shred to overwrite and delete the single
large file.
An alternative is to use
scrub, a tool built by the
Lawrence Livermore National Library folks. It uses various national standards for selecting suitable patterns
and over-writing strategies. Source can be found at
Sourceforge.
A quick way to apply all 0's to the free space of a drive:
dd if=/dev/zero of=zerofile bs=1M
sync
rm zerofile
If you can't get scrub to work, then the above command with the shred might be a good combination.
To ensure you have all the data, not just what was located in files or drive free space, one needs to
apply scrub/shred to whole partitions and/or drives. The Gentoo Wiki talks about ways of
securely deleting drives and partitions.
For near-absolute protection of data, I've known companies to specify that once a drive is no longer
useful, that it be crushed and sent to landfill.
[/OpenSource/Linux]
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2009 Jun 17 - Wed
New Release of WTL (Windows Template Library)
I've been able to start on a new project with a clean slate. For the portion residing on Microsoft
Windows, I'm going to give the latest version (v8.1, build 9127) of the WTL (Windows Template Library) for
crafting the GUI side of things. The latest version can be downloaded from
SourceForge,
which looks to have a release date of May 7, 2009.
The release notes don't indicate anything for running with the Visual Studio 2008 IDE. A blog entry at
Code Gem called
WTL Wizard for Visual Studio 2008 indicates that by changing a few references to registry entries in the
Visual Studio 2005 script, one can get the new WTL Wizard to install in the 2008 IDE. He supplies
downloadable source code in the blog entry. Another location for a patch file is located in the
Yahoo Forums.
WTL has in the past been underdocumented. Besides some websites linked from the wtl.sourceforge.net
web site, the WTL group on Yahoo has had a
WTL Developer's Guide posted in Doc and PDF forms.
[/OpenSource/Programming]
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2009 Jun 06 - Sat
The American Dream
In a recent issue of
Investment News,
former U.S. Comptroller General David Walker was quoted as saying:
"The American dream is not owning a house; it.s every individual having the opportunity
to achieve their full, God-given ability, and each generation having the responsibility to
leave the country better off and better-positioned than the next so that our children and
grandchildren can have a better way of life than we have."
In light of the trillion dollar budget deficits which Obama's government is attempting to
run up, Walker's warning is one of good reason.
[/Personal/Business]
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2009 Jun 04 - Thu
Installing PostgreSQL on Debian Lenny
Release 5.0.1 of Debian's Lenny GNU/Linux distribution includes version 8.3 of
PostgreSQL.
During the creation of a new Debian Lenny server, a list of software packages is
provided. To make a new PostgreSQL-only server, unselect everything, including the
'Standard system', then select 'SQL Database', and proceed with the installation.
Once installation has completed, and the new server has rebooted, the PostgreSQL service
is not auto-started. There are a couple of manual commands to be applied. In prior
versions, PostgreSQL was auto-started. I think I understand the reasoning, particularily
because it is useful for my situation.
During the server creation, I have a separate set of disks allocated for the database.
By manually finishing the PostgreSQL implementation, I am able to initialize the directory
location during service creation. If I have I've mounted my drives at /var/local/db, then
these two commands get the PostgreSQL 8.3 service started:
pg_createcluster -d /var/local/db 8.3 main
/etc/init.d/postgresql-8.3 start
[/OpenSource/Debian]
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2009 Jun 01 - Mon
Building WebGUI 7.7.8 on Debian Lenny
It is a couple of years since I built a
WebGUI server.
Last one I built was on a Fedora Linux box.
This article is about building the most recent beta WebGUI on a Debian Lenny Linux box.
The procedure is a bit long, but there is nothing complicated.
I start with a basic Debian build that has the 'Web Server' and 'Standard Build' options
selected.
There are a few packages to install first:
apt-get install ntpdate
ntpdate 0.pool.ntp.org
apt-get install ntp
apt-get install build-essential
apt-get install mysql-server-5.0
apt-get install imagemagick
apt-get install perlmagick
apt-get install exim4-daemon-light
apt-get install exim4-conf
apt-get install libcrypt-ssleay-perl libnet-ssleay-perl
apt-get install libxml-sax-perl
apt-get install libxml-sax-expat-perl
apt-get install libxml-simple-perl
apt-get install libsoap-lite-perl
apt-get install libtext-aspell-perl
apt-get install libapache2-mod-apreq2
apt-get install libapreq2-dev
apt-get install libapache2-request-perl
ln -s /etc/apache2/mods-available/apreq.load /etc/apache2/mods-enabled/apreq.load
Then using
perl -MCPAN -eshell
Install or confirm the installation of the following Perl packages:
install Bundle::CPAN
install Log::Log4perl
install Class::InsideOut
install Config::JSON
install Module::Find
install Tie::IxHash
install Net::Subnets
install Text::CSV_XS
install Tie::CPHash
install Net::LDAP
install Exception::Class
install POE::Component::IKC::ClientLite
install POE::Component::Client::HTTP
install Clone
install HTML::Packer
install Path::Class
install Scope::Guard
install HTML::TagFilter
install DateTime
install HTML::TagCloud
install DateTime::Format::Strptime
install DateTime::Format::Mail
install Class::C3
install MIME::Entity
install XML::FeedPP
install CSS::Minifier::XS
install Color::Calc
install Finance::Quote
install Net::DNS
install Crypt::SSLeay
install XML::Simple
install JavaScript::Packer
install JavaScript::Minifier::XS
install Archive::Any
install HTML::Template::Expr
install SOAP::Lite
install Weather::Com::Finder
install Image::Size
install Image::Info
install Template
install Image::ExifTool
install Business::Tax::VAT::Validation
install HTML::Highlight
install CSS::Packer
install Contextual::Return
force install Test::Class
install Test::MockObject
install Text::Aspell
Download and expand the current software from SourceForge:
cd /usr/src
wget http://voxel.dl.sourceforge.net/sourceforge/pbwebgui/webgui-7.7.8-beta.tar.gz
tar -zxvf webgui-7.7.8-beta.tar.gz
Move some files around:
mkdir /data
mv WebGUI /data/
cd /data/WebGUI/etc/
cp log.conf.original log.conf
touch /var/log/webgui.log
chown www-data.www-data /var/log/webgui.log
cp spectre.conf.original spectre.conf
mkdir -p /data/domains/www.example.com/public/extras
mkdir /data/domains/www.example.com/logs
cp WebGUI.conf.original www.example.com.conf
cp -R /data/WebGUI/www/uploads /data/domains/www.example.com/public/
chown -Rf www-data.www-data /data/domains/www.example.com/public/uploads
Append the following to /etc/rc.local:
cd /data/WebGUI/sbin
perl spectre.pl --daemon
Add the following to /etc/apache2/httpd.conf:
PerlSetVar WebguiRoot /data/WebGUI
PerlCleanupHandler Apache2::SizeLimit
PerlRequire /data/WebGUI/sbin/preload.perl
Add the following to /etc/apache2/sites-enabled/000-default:
ServerName www.example.com
ServerAlias www.example.com
DocumentRoot /data/domains/www.example.com/public
SetHandler perl-script
PerlInitHandler WebGUI
PerlSetVar webguiConfig www.example.com.conf
Alias /extras /data/WebGUI/www/extras
Alias /uploads /var/local/webgui/uploads
Check that all the Perl packages are loaded:
cd /data/WebGUI/sbin
./testEnvironment.pl
Create the MySQL Database:
cd /data/WebGUI/etc
mysql -e "create database www_example_com"
mysql -e "grant all privileges on www_example.com.* to webgui@localhost identified by 'password'"
mysql -e "flush privileges"
mysql -uwebgui -ppassword www_example_com < /data/WebGUI/docs/create.sql
The /data/WebGUI/etc/www.example.com.conf file may need updates:
"sitename" : ["www.example.com",example.com"],
"dsn" : "DBI:mysql:www_example_com",
"dbuser" : "webgui",
"dbpass" : "password",
"uploadsPath" : "/data/domains/www.example.com/public/uploads",
"spectreSubnets" : ["127.0.0.1/32", "123.123.123.123/32"],
Start up Spectre:
cd /data/WebGUI/sbin
perl spectre.pl --daemon
Restart the web server:
/etc/init.d/apache2 restart
Browse to www.example.com and get started!
If you would like a pre-configured WebGUI server capable of running on VMWare let me
know. I can even host Virtual Sessions.
Note: there is a problem with the "uploadsPath" thing.
Note: there is a problem with the "fileCacheRoot" thing.
[/OpenSource/Debian]
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