blog.sdamm.de

On one server I have a slightly complicated setup. I share this server with other people, we run Xen hosts on it. The physical server has two hard disks in it. So you might think of using RAID to secure your data. Well, but for some portions one might want RAID0 just to have more space, some of it should be safer, so one would use a RAID1 for it. We split up both hard drives in physical partitions, every party got a chunk of it to do whatever he wants with it. To be a flexible, I used LVM2 at first. I setup some logical volumes on both drives, and then I joined them the way I want it iwth software RAID.

Now the home partition got pretty full. So, what to do? Enlarge it. Because of a kernel update I had to reboot the Xen DomU anyway, so just do it. But how? This is the way I found to be working:

One evening last month I noticed, that when closing the lid on my laptop it switched to Suspend to Ram Mode. I never knew that behavior before, it must have come with the update to XfCE 4.4.

Since that point I have been using that "feature" quite often and my Linux always did wake up again when opening the lid. And all that "out of the box", without the usual work before (in German I would call it "frickeln", but I don't know a good translation for that term ).

To a RedmondOS user this probably is no big deal, but to me it has been a quite pleasant surprise.

What if you have more than one number ending up at the same VoIP account, but you want to route each number to a different phone? If you are lucky, your sip provider still has the originally dialed number in the To: field of the SIP message. Then a snippet like the following might help you:

exten => _X.,1,Set(CALLEDNUM=${SIP_HEADER(To)})
exten => _X.,n,Set(CALLEDNUM=${CALLEDNUM:5})
exten => _X.,n,Set(CALLEDNUM=${CUT(CALLEDNUM,@,1)})
exten => _X.,n,NoOp(${CALLEDNUM})
exten => _X.,n,Goto(${CALLEDNUM},1)

You need to have the module app_cut.so loaded for this to work.

Only about two weeks after the last huge DoS vulnerability in Asterisk, I just stumbled across this bug on the Gentoo bugtracker:

Impact:

• A remote individual can remotely crash and perform a Denial of Service(DoS) attack in all the services provided by the software by sending one crafted SIP INVITE message. This is conceptually similar to the "ping of death".

Affected Versions:

• Asterisk 1.2.14, 1.2.15, 1.2.16
• Asterisk 1.4.1
• probably previous versions also

Right now I can't find anything on Securityfocus yet, but I'm pretty sure it will be there tomorrow morning. An immediate update is highly recommended.

Update[20/02/07]: Today I had some time to play around with the patch suggested in the patch. The patch mentioned in comment#1 did not work. So I dug into it a little deeper and found the correct patch. I posted working patches on the Gentoo bug. The svn version of asterisk is already patched, new releases 1.2.17 and 1.4.2 are already available for download, but there is no announcement at the moment.

Last week I've been playing around with an Asterisk VoIP server on a live system. Actually, I just wanted to improve the behavior in the dialplan. On my test system it worked well, but on the live system I saw an effect, which I had not foreseen.