Sankasaurus » linux

Dependency Nightmare for Tomcat on Debian

Peter Sankauskas — Tue, 18 Aug 2009 17:34:01 +0000

I would love to not have to install the real Java and Tomcat manually on Debian, but I have little choice in the matter. Take a look at this:

$ apt-get install tomcat5.5 Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: ant ant-gcj ant-optional ant-optional-gcj antlr build-essential debhelper default-jdk default-jre default-jre-headless defoma dpkg-dev ecj ecj-gcj fastjar file fontconfig fontconfig-config g++ g++-4.3 gappletviewer-4.3 gcj-4.3 gcj-4.3-base gettext gettext-base gij-4.3 gjdoc hicolor-icon-theme html2text intltool-debian java-common java-gcj-compat java-gcj-compat-dev java-gcj-compat-headless jsvc libantlr-java libantlr-java-gcj libasound2 libatk1.0-0 libatk1.0-data libbcel-java libcairo2 libcommons-beanutils-java libcommons-collections-java libcommons-collections3-java libcommons-daemon-java libcommons-dbcp-java libcommons-digester-java libcommons-el-java libcommons-launcher-java libcommons-logging-java libcommons-modeler-java libcommons-pool-java libcompress-raw-zlib-perl libcompress-zlib-perl libcups2 libdatrie0 libdb4.5 libdigest-hmac-perl libdigest-sha1-perl libdirectfb-1.0-0 libecj-java libecj-java-gcj libexpat1 libfile-remove-perl libfontconfig1 libfontenc1 libfreetype6 libgcj-bc libgcj-common libgcj9-0 libgcj9-0-awt libgcj9-dev libgcj9-jar libgcj9-src libglib2.0-0 libglib2.0-data libgtk2.0-0 libgtk2.0-bin libgtk2.0-common libice6 libio-compress-base-perl libio-compress-zlib-perl libio-stringy-perl libjaxp1.3-java libjaxp1.3-java-gcj libjpeg62 liblog4j1.2-java liblog4j1.2-java-gcj libmagic1 libmail-box-perl libmail-sendmail-perl libmailtools-perl libmime-types-perl libmx4j-java libobject-realize-later-perl libpango1.0-0 libpango1.0-common libpixman-1-0 libpng12-0 libregexp-java libservlet2.3-java libservlet2.4-java libsm6 libsqlite3-0 libstdc++6-4.3-dev libsys-hostname-long-perl libthai-data libthai0 libtiff4 libtimedate-perl libtomcat5.5-java libts-0.0-0 liburi-perl libuser-identity-perl libxcb-render-util0 libxcb-render0 libxcomposite1 libxcursor1 libxdamage1 libxerces2-java libxerces2-java-gcj libxfixes3 libxfont1 libxft2 libxi6 libxinerama1 libxrandr2 libxrender1 libxtst6 make mime-support patch po-debconf python python-central python-minimal python2.5 python2.5-minimal ttf-dejavu ttf-dejavu-core ttf-dejavu-extra x-ttcidfont-conf xfonts-encodings xfonts-utils ... 0 upgraded, 146 newly installed, 0 to remove and 0 not upgraded. Need to get 101MB of archives. After this operation, 288MB of additional disk space will be used. Do you want to continue [Y/n]?

WTF? I understand that Tomcat needs some kind of Java, but this is ridiculous. It is installing ant, fonts, compilers and worst of all, the most evil Java ever.

Ubuntu has the sense to make Sun Java available, but even if you do have Sun Java installed, the above is true on Ubuntu.

For shame!

I’ll stick to downloading from java.sun.com and tomcat.apache.org.

Download Chrome OS now – it's called cl33n

Peter Sankauskas — Wed, 08 Jul 2009 23:06:19 +0000

For some strange reason, Chrome OS is getting a lot of press. Is it a slow news day?

They say that it is direct competition to Microsoft, that it makes Linux less relevant… are they serious? Chrome OS is a non-announcement. There is a project that has existed for over 2 years called “cl33n“. From the creator:

Chrome OS is “Google Chrome running within a new windowing system on top of a Linux kernel.”
cl33n is “Mozilla Firefox running in a little-used windowing system on top of a Linux kernel.”

This “OS” is due to the released mid 2010. Is that how slowly things move inside Google? Why would it take them 12 months to create nothing more than cl33n?

What I am trying to say, is that Chrome OS is nothing new. Cl33n is not alone in this space either – other project like Webconverger share my view.

While on the subject of Google’s non-annoucements, did you hear that Gmail, Doc, etc are out of beta. Big news huh? So what is their excuse now for daily “Server error” dialogs?

Fighting with SELinux and Nagios

Peter Sankauskas — Sat, 02 May 2009 17:25:55 +0000

I can’t believe it, but I won! I have been trying to set up Nagios on a RHEL5 machine running SELinux and have been loosing the fight for the last 3 days. But today, I win! This is such a win, it is worth sharing.

Now that I have won though, I believe this is not Nagios specific at all, and if I had bothered to learn about SELinux, this may have been obvious. Anyway, the error Nagios was giving me was:

Error: Could not stat() command file ‘/usr/local/nagios/var/rw/nagios.cmd’!
The external command file may be missing, Nagios may not be running, and/or Nagios may not be checking external commands.
An error occurred while attempting to commit your command for processing.
Return from whence you came

As you may have already guess, the solution has nothing to do with the location or permissions of the file, the file was not missing, Nagios was running, and Nagios was checking external commands. The final line of the message is great though, and I can only hope we start to see more old English in error messages.

The problem of course, was that SELinux was enabled and stopping this blatant security violation. You can check to see if SELinux is on by running:

$ /usr/sbin/getenforce

Enforcing

If you got “Permissive” or “Disabled”, then this post is not for you. To see SELinux’s side of things, check out /var/log/messages:

setroubleshoot: SELinux is preventing ping (ping_t) “read write” to /usr/local/nagios/var/spool/checkresults/checkrXH96b (usr_t). For complete SELinux messages. run sealert -l 1ffc2533-42b5-4e04-b7ab-a81bb7d02040

setroubleshoot: SELinux is preventing ping (ping_t) “read write” to /usr/local/nagios/var/spool/checkresults/checkrZxsA1 (usr_t). For complete SELinux messages. run sealert -l 178ba2d4-0822-47eb-9e32-bfaa19ee3c4b

setroubleshoot: SELinux is preventing cmd.cgi (httpd_sys_script_t) “getattr” to /usr/local/nagios/var/rw/nagios.cmd (httpd_sys_content_t). For complete SELinux messages. run sealert -l 4df0946e-8816-4b90-a7d1-37e743697b9c

As you can see, SELinux is trying to give you a hint with that sealert bit, so you should take it.

$ sealert -l 1ffc2533-42b5-4e04-b7ab-a81bb7d02040

Summary:
SELinux is preventing ping (ping_t) “read write” to

/usr/local/nagios/var/spool/checkresults/checkrXH96b (usr_t).
Detailed Description:
… (removed from post)
Raw Audit Messages
host=myhost.myisp.host type=AVC msg=audit(1241217029.141:125305): avc:  denied  { read write } for  pid=32379 comm=”ping” path=”/usr/local/nagios/var/spool/checkresults/checkrXH96b” dev=sda3 ino=52894945 scontext=user_u:system_r:ping_t:s0 tcontext=user_u:object_r:usr_t:s0 tclass=file
host=myhost.myisp.host type=SYSCALL msg=audit(1241217029.141:125305): arch=c000003e syscall=59 success=yes exit=0 a0=153952a0 a1=15395330 a2=7fff75c5eb40 a3=0 items=0 ppid=32378 pid=32379 auid=503 uid=508 gid=508 euid=0 suid=0 fsuid=0 egid=508 sgid=508 fsgid=508 tty=(none) ses=1392 comm=”ping” exe=”/bin/ping” subj=user_u:system_r:ping_t:s0 key=(null)

That raw audit message is GOLD! There is some other information in there, but nothing about what the next step should be to create a policy and make it permanent. Using chron I have heard is a temporary fix. The solution is copying that raw audit message into an empty file and running audit2allow to create a policy:

$ cat > /tmp/tmp-nagiosping

host=myhost.myisp.host type=AVC msg=audit(1241217029.141:125305): avc:  denied  { read write } for  pid=32379 comm=”ping” path=”/usr/local/nagios/var/spool/checkresults/checkrXH96b” dev=sda3 ino=52894945 scontext=user_u:system_r:ping_t:s0 tcontext=user_u:object_r:usr_t:s0 tclass=file
host=myhost.myisp.host type=SYSCALL msg=audit(1241217029.141:125305): arch=c000003e syscall=59 success=yes exit=0 a0=153952a0 a1=15395330 a2=7fff75c5eb40 a3=0 items=0 ppid=32378 pid=32379 auid=503 uid=508 gid=508 euid=0 suid=0 fsuid=0 egid=508 sgid=508 fsgid=508 tty=(none) ses=1392 comm=”ping” exe=”/bin/ping” subj=user_u:system_r:ping_t:s0 key=(null)

* Ctrl-D *
$ audit2allow -M NagiosPing < /tmp/tmp-nagiosping
******************** IMPORTANT ***********************

To make this policy package active, execute:
semodule -i NagiosPing.pp

This creates a file call NagiosPing.pp which contains the SELinux policy needed to make these errors go away. The only thing left to do is to install this policy:

$ semodule -i NagiosPing.pp

If your setup was like mine, SELinux was actually preventing 3 different actions, needing 3 different policies. HA! That is easy now – just repeat the steps until Nagios is doing your bidding.