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Notes from Apache HTTPD Source Code

thought I'd take a break from coding and post about how open-source is such a great tool for finding the best answers to the toughest questions,

/** is the status code informational */
#define ap_is_HTTP_INFO(x)         (((x) >= 100)&&((x) < 200))
/** is the status code OK ?*/

#define ap_is_HTTP_SUCCESS(x)      (((x) >= 200)&&((x) < 300))
/** is the status code a redirect */
#define ap_is_HTTP_REDIRECT(x)     (((x) >= 300)&&((x) < 400))

/** is the status code a error (client or server) */
#define ap_is_HTTP_ERROR(x)        (((x) >= 400)&&((x) < 600))
/** is the status code a client error  */

#define ap_is_HTTP_CLIENT_ERROR(x) (((x) >= 400)&&((x) < 500))
/** is the status code a server error  */
#define ap_is_HTTP_SERVER_ERROR(x) (((x) >= 500)&&((x) < 600))

/** is the status code a (potentially) valid response code?  */
#define ap_is_HTTP_VALID_RESPONSE(x) (((x) >= 100)&&((x) < 600))

Hacking

30x Faster Cache and Site Speed with TMPFS

NOT a typo.. 30x is measurable, well-documented, and easily tested. This is what open-source is about. I haven’t had time to post much the past year, I'm always working! So I wanted to make up for that by publishing an article on a topic that would blow your mind and be something that you could actually start using and really get some benefit out of it. This is one of those articles that the majority of web hosting companies would love to see in paperback, so they could burn it.

Optimization

DreamHost Server IP Address List

A list of all DreamHost Servers and corresponding IP address. The dreamhost.com DNS zone is currently having troubles, so most hostnames within this zone are not resolving.

Hosting

Optimizing Servers and Processes for Speed with ionice, nice, ulimit

To prepare for several upcoming articles on AskApache that are focused on optimizing Servers and Sites from a server admin level, here is an article to introduce the main tools that we will be using. These tools are used to optimize CPU time for each process using nice and renice, and other tools like ionice are used to optimize the Disk IO, or Disk speed / Disk traffic for each process. Then you can make sure your mysqld and httpd processes are always fast and prioritized.

Optimization

TMUX

penguin-tmuxarchlinux-on-macStop wasting your lives with Mac Terminals.. or Macs. Get a real machine and then get a real shell multiplexer! For many years we all loved GNU Screen, but tmux is by far a better option today. The only time I am in the shell and not using a multiplexer, is when I'm not on one of my machines. My Arch Linux machines all run URxvt and my .bash_profiles all start tmux automataically, whether in X or single-user mode, tmux is where it's at.

Hacking, Linux

Advanced WordPress wp-config.php Tweaks

The bottom line for this article is that I want to make WordPress as fast, secure, and easy to install, run, and manage because I am using it more and more for client production sites, I will work for days in order to solve an issue so that I never have to spend time on that issue again. Time is money in this industry and that is ultimately (time) what there is to gain by tweaking WordPress.

Note: I spent no time on readability, this is primarily a read the code and figure it out article.. This is for advanced users looking for a reference or discussion and for those of you looking to advance. Feedback would be great if you make it that far..

WordPress

Internet Census 2012 – Port scanning using insecure embedded devices – Carna Botnet

While playing around with the Nmap Scripting Engine (NSE) we discovered an amazing number of open embedded devices on the Internet. Many of them are based on Linux and allow login to standard BusyBox with empty or default credentials. We used these devices to build a distributed port scanner to scan all IPv4 addresses. These scans include service probes for the most common ports, ICMP ping, reverse DNS and SYN scans. We analyzed some of the data to get an estimation of the IP address usage.

Hacking

ASCII Chart

Wanted to stick this here for a reference, mostly for me. I use ASCII alot in bash, preg_matches, preg_replace, etc..

Linux

An AskApache Plugin Upgrade to Rule them All

apache-server-statusSo my blog as been rather quiet for almost a year now, and very few updates if any have been released for my Password Protection PLugin, my Google 404 Plugin, and definately not for my AskApache CrazyCache plugin, which I will be releasing last... So for all of you who've helped me out by sending me suggestions and notifying me of errors and sticking with it... Just wanted to say sorry about that, and thanks for all the great ideas.. Well, I've been sticking with it as well believe it our not. I manage to get free days once in a while, and then its time to jam.

WordPress

Crazy POWERFUL Bash Prompt

bash power prompt PS1This amazing bash linux prompt does more than meets the eye. If you want to know how to become really good with technology, linux is the secret sauce behind the AskApache articles. Open Source is elixir of the web. Thanks to everyone who helped me for the past 20 years. I use linux/bsd because homey don't play, so this is geared to be as productive a prompt as I can make it.

Don't have much time.. or just don't care? Not a problem, here are the 3 lines to copy and paste - you can just paste them right in your shell to test it, or add to a startup script.

export AA_P="export PVE=\"\\033[m\\033[38;5;2m\"\$(( \`sed -n \"s/MemFree:[\\t ]\\+\\([0-9]\\+\\) kB/\\1/p\" /proc/meminfo\` / 1024 ))\"\\033[38;5;22m/\"\$((\`sed -n \"s/MemTotal:[\\t ]\\+\\([0-9]\\+\\) kB/\\1/p\" /proc/meminfo\`/ 1024 ))MB\"\\t\\033[m\\033[38;5;55m\$(< /proc/loadavg)\\033[m\";echo -en \"\""
export PROMPT_COMMAND="history -a;((\$SECONDS % 10==0 ))&&eval \"\$AA_P\";echo -en \"\$PVE\";"
export PS1="\\[\\e[m\\n\\e[1;30m\\][\$\$:\$PPID \\j:\\!\\[\\e[1;30m\\]]\\[\\e[0;36m\\] \\T \\d \\[\\e[1;30m\\][\\[\\e[1;34m\\]\\u@\\H\\[\\e[1;30m\\]:\\[\\e[0;37m\\]\${SSH_TTY} \\[\\e[0;32m\\]+\${SHLVL}\\[\\e[1;30m\\]] \\[\\e[1;37m\\]\\w\\[\\e[0;37m\\] \\n(\$SHLVL:\\!)\\\$ " && eval $AA_P

Linux

DNS Round Robin Configuration using Rsync over SSH

The goal is to add the HostGator server to be an exact mirror of the s.askapache.net domain, then to add that server as a 2nd A record to my DNS zone. That way half the visitors to the size will be taking up resources and bandwidth on the HostGator server instead of mine.

Round Robin A records in DNS are intended to evenly distribute queries between each host of the same name. Using some tricks straight out of a hackers toolbox we can verify if the distribution is taking place. (It is.)

Optimization

Hacking VLAN switched networks

Bypassing VLAN security on networked switchesThere isn't much vlan info on the net in terms of specifics and I had to learn all about it because I needed to log in to a switch that was on a different vlan. With the help of the Ettercap developers NaGA and ALoR I figured it out.

Originally Posted: 3/30/2004

Hacking

PHP Session File Hacks

What they say about kung-fu is true..

It can be attained by anyone through hard work over time. You can become as good as the amount of work you put in. Here's a short look at a basic technique that I use. Simply reverse engineering the source code and taking notes along the way...

static void php_session_send_cookie(TSRMLS_D)
  if (SG(headers_sent)) {
          if (output_start_filename) {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent by (output started at %s:%d)",
                          output_start_filename, output_start_lineno);
          } else {
                  php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent");
          }
          return;
  }

  /* URL encode session_name and id because they might be user supplied */
  e_session_name = php_url_encode(PS(session_name), strlen(PS(session_name)), NULL);

PHP

Debugging Tools for Windows

I am almost ready to publish the final tutorial on using ssh tunnels from a truecrypt partition on a Windows machine. Of course I choose to go way overboard in my research and the tutorial is full of some pretty awesome windows tricks.. I will come back to this post soon and post all the other advanced tools I use for debugging windows, for now though you MUST know how to debug the kernel and use these basic debugging tools.

Windows

Mod_Security .htaccess tricks

Mod_Security rivals Mod_Rewrite in the amount of features it provides. I decided to go ahead and post what I learned about it today, even though its tough to give away such awesome htaccess and apache tricks.. Learn how to control spam once and for all, conditionally log/deny/allow/redirect requests based on IP, username, etc.. Mod_Security is so fine!

Htaccess

Introducing the Online Figlet ASCII Generator

Look at the text "askapache". That's pretty boring huh? It would be cool to have a nerdy textual representation of that for extra nerdy stuff like styling my /robots.txt file, email list signatures, forum sigs, etc. But who has time to create that by hand? If only there were an online tool to create it..

Bam.

askapache-figlet

Web Design

Securing php.ini and php.cgi with .htaccess

If you have a php.cgi or php.ini file in your /cgi-bin/ directory or other pub directory, try requesting them from your web browser. If your php.ini shows up or worse you are able to execute your php cgi, you'll need to secure it ASAP. This shows several ways to secure these files, and other interpreters like perl, fastCGI, bash, csh, etc.

Htaccess

Help the Free Software Foundation


Become a member of the Free Software Foundation today to help us reach our goal of $450,000 by January 31st.


Net

MariaDB with LZ4 Compression Howto for CentOS

I really really wanted to run the latest MariaDB with LZ4 Page Compression.. it is a game changer for many types of large databases I deal with. So I compiled it manually in a way that is repeatable and follows best-practices and it's now powering this site. Now I can use InnoDB Page Compression with lzo, lzma, bzip2, snappy, or my favorite algorithm: LZ4.

Thought this would be a good chance to post a howto, and show that there is a lot you can do by compiling software yourself and breaking the package management one-click install shackles.

Linux, MySQL

AskApache Debug Viewer Plugin for WordPress

screenshot-1The story behind this plugin is sorta wack, but in a good way :). While doing tons of security research on permissions, authorization, access, etc.. for the Password Protection plugin (still being worked on), I needed to have unheard of debugging capabilities while working on the plugin on the various websites, webhosts, and test servers that I use to test in different environments. So I hacked together a bunch of php code that helped me debug, actually I pretty much went overkill and tried to get as much debugging info as programmatically possible, and it ended up being so much code that I took it out of my Password Protection code and made it its own plugin.

WordPress

Install multiple OS Without Cds

Orig published 2006. I had a CD-RW drive but being a computer security researcher I had no money for blank cd-recordables. What follows is how I managed to install various operating systems on my computer (1 hard drive) without having to burn to a CD the ISO and then boot from that.

And also:

==Phrack Inc.==
 
              Volume 0x0b, Issue 0x3f, Phile #0x0a of 0x14
 
|=-----------------=[ Hacking Grub for fun and profit ]=-----------------=|

Linux

Getting flash to show up in front of content

Adobe Flash PositioningI used to have a problem of controlling flash elements on my sites.. On one site we have 6 different flash flv movies that are all the same size and are in the same position on the page. But only 1 is displayed at a time based on what the user wants to watch. So the selected flash movie needs to have the highest stacking order/zIndex.

CSS