sysfault's kernelpanic

added a public repo on github, kernelpanic.
for now it just hosts a gist with a kernel patch that helps sysadmins do blindfolded remote linux kernel upgrades

snip:

description:
this patch allows you to automatically start the softdog on linux kernel at module initialization time. read this page 'til the end to see why in the name of god you need this.

console autologin

have you ever been woke up in the mid of the night by a phone call, booted your computer and spent the next 20 minutes trying to type your 16 chars beautifully randomized password so you can get console access? cry no more. here's the malfunctioning mind's login program. with some more infos on launchpad

google appengine python sdk startup problems

if you have any google eggs in your system (like protobuf for example) and you are trying to start the google appengine sdk you will get a "could not find version file" error. this is mainly caused by coding outside python peps guidelines (more exactly, package namespaces) and some more bad coding style.

I reported this bug just after last year's christmas but I guess the appengine has so many bugs they are busy with something else more important :-P

I gave detailed infos on the appengine bugtracker. The patch that fixes the problem is also available here.

if the live appengine is written the same way ...
i wish you happy hacking.

openssh random local port forwarding

you can't forward a random local port with openssh. forwarding a local random port with -L is useful when you use the option within some batched maintenance tasks (and not only, for some pure randomness just makes geeks feel secure). the  "random local port forwarding" job seems to be half done in the openssh original source tree (openbsd). ubuntu dudes added one more unneeded test (dummy?) in mux.c. I wrote a patch to solve this problem.

the original ssh client:


ssh -L 127.0.0.1:0:127.0.0.1:3000 mailgw
Bad local forwarding specification '127.0.0.1:0:127.0.0.1:3000'

the patched ssh client:

./ssh -L 127.0.0.1:0:127.0.0.1:3000 mailgw

Last login: Wed Jan 19 16:00:40 2011 from 

Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994

the result:

tcp        0      0 127.0.0.1:38412         0.0.0.0:*               LISTEN      15010/ssh       

note the "0" port specification in the fwd arg.

here is a link to the patch generated against ubuntu openssh 5.5p1 source package. the same patch can be easily rewritten for the openssh original source tree (openbsd) if the mux.c diff is ignored (no unneeded test from bsd guys)

few notess
1. getting the next available port with a script and feed the ssh args with it immediately after does not guarantee you at all the port will still be available when ssh binds to it
2. how are you going to dig what port was used? see above
3. I failed to understand this:
if (fwd->listen_port < 0 || (!remotefwd && fwd->listen_port == 0))
why should random listen ports should be allowed for remote forwards (-R) and not for local forwards / dynamic forwards? it just doesn't make any sense.