Older blog entries for senthilkumar (starting at number 15)

The work is going fine. Logu brought me a issue with capset() call in Linux. Intially he discover the issue with Squid code in which the the daemon dont have permission to open the file to log its pid. It happens only if TPROXY option is enabled. On further debugging Logu ends with capset() call and it needs much more investigation.

I'm falling prey to Monday sickness. It is about getting back to work after the week end. ;)

I mostly deal with chroot environments and today I put some of my time over it. The question that come to me is How to Break up chroot() jail? Sounds tricky to me initially. But its simple, root user cant be chrooted. If he does, he can break it. Simple logic.

1. Create a temp dir and chroot to it. 2. Change the current working dir by repeattedly running chdir(..). 3. Run chroot(.) and this makes you to move to root dir.

Going to home for this week end and hope the week end would be great.

The last Week had a mix of good and bads. But the bad things overshadows the good ones. I gave some Technical Training to people and the outcome was fantastic. In parallel, I lost a chance on work.

Nothing more to update on personal side of life. Just called some of my friends and enquired about their safety on possibility of riots in Bangalore,India over river water sharing.

Just thinking about my focus areas and thinking, think , think..............

I had a chance to attend marketing seminars from some big vendors. For a techie, it completely looks different as most of things are marketing and I vaded my time over there.

Why not dive in to bash code................ Thinking......

Mood: Bored

Again, Long delay in the post. The Trip is fine and by now I have completed one more Trip with almost same people. This Trip happens part of New Year 2007. Lots of things happened over 2006. To mention a few, I attended the FOSS.in 2006, one of the most respected Open Source conference in the world. Some the attendees included Suparna Bhattacharya, Rasmus, Harald etc...

Then the Year 2006 have lots os Ups and few downs. Looking forward for 2007 :)

The LCA 2007 is happening as of Now and should plan to attend next time................

Things going fine but i dislike that. Should there be some challenging things?. Yes it should be there to make life more FUN and lively. So some of us (me, Sekar, Logu and Jag) planned for a trip exactly its a trekking.

I'm overjoyed that till now plans are perfect and we hope to leave at exact time. We stay in the hill station for today night, refresh ourselves in the night :-) will start the trekking early morning. We plan to return from trekking by tomorrow evening and then return to our place.

From wednesday onwards, the day will be filled with more testing and hacking, debugging, blogging etc which are more FUN to add...... Update you on the trip later....

Its been nearly Six months since i touched my blog. Am I becoming lazy. This question is unnecessary as infrequent update answers it. There are some changes in my career. Things going fine. I have forget few things due to this long gap. Will do frequent updates.

Technically, I just started playing with sinfp, a finger printing tool. Its been claimed that it overcome some of disadvantages of nmap. Looks interesting :)

I think i should put my experience in a proprietary PAM-Kerberos module and the way i found a bug. The implementation way, the credential files are destroyed results in deletion of credentials of some other session done by same user. ie. it deletes the credential obtained by doing a kinit command in some other session. First I looked at OpenSSH code to find the cause of prolem and later it navigated to the PAM module. Its really cool and interesting.

The new year celebrations went away nicely. Back to work. Hope this year will be more adventurous.

Just checked how passwd command behaves when tried to change the passwd for a user who has two entries in /etc/passwd and the first one being commented. This I did in one of commercial distribution of unix and to my surprise it asks to change passwd for the commented user. I find tht somehow passwd command matches the first commented entry and prompts as below, Changing password for #senthil Old password:

Also at this juncture with the commercial version I checked the ownership of somefiles owned by user senthil. It displays as below, -rw------- 1 #senthil <grp> <file name>

But In Linux for same scenario, -rw------- 1 117 <grp> <file> (username replaced by uid)

In OpenBSD (its great and retains the username) -rw------- 1 senthil <grp> <file> (remain as it is)

So a common situation which give rise to 2 bugs.

I remember a quote, "Finding and fixing the bugs enhance the software". I think im not comfortable with PERL tht much and started making me good in that. This is the last working day of the Year 2005. Hey, Have FUN.

I did some fun with login shells, non-login shells subshell etc.. I came across a thing that only login shells are prefixed with "-". But i saw that even when we fork a subshell from login shell on execution of commands they too prefixed with "-". But normal creation of child shell from login shell doesn't have such a thing.

Also there exists an inconsistent behaviour if I fork few child shells in series from login shell and forcibly kill a middle one. The behaviour differs depending on terminal I send the kill signal. This I checked in korn and bash. Have to find out how well recent versions work.

2005 is leaving down and Im in great mood to Welcome 2006. Wish u all a Happy New Year. Have Fun.