Syndicate content

Unix

An Operating System that works. All the specifications are free and Linux, AIX, HP-UX, SunOS, Solaris, IRIX are examples of a Unix implementation.

Attack by ZmEu

Who is ZmEu?

An image showing ZmeuThe name Zmeu (no capital E) is the name of a fantastic creature of Romania. There are so many stories that there isn't a clear understanding of what it is... but it is human like, can spit fire and wants to marry young women.

If you're wondering, it is generally a bad guy.

ZmEu Attack

Today, I noticed a lot of traffic on one of my servers. Looking into what was happening, I immediately found out that an attacker was looking for a loophole in that system. That attack was being performed from China.

Turning sites and modules on and off in Apache2

I always have to looks for the command line option to turn sites and modules on and off (really it is said to be enabled or disabled.)

The commands are as follow:

  • a2ensite -- enable one site
  • a2dissite -- disable one site
  • a2enmod -- enable one module
  • a2dismod -- disable one module

When you use one of the commands in the command line terminal without specifying which site or module to enable, then you are given a list of the sites or modules you can enable or disable. Note that the configuration files have to end with .conf for this mechanism to work as expected.

Solaris virtual consoles are password protected, how to remove the protection?

Solaris 11.2 (Open SunOS really) has virtual console a la Linux. This works great. You can use the Alt-F1 to Alt-F6 keys to instantly switch between 6 different consoles. I use that to have one console with an editor and another with my make and runtime tests.

Unfortunately, Solaris includes a lock which manes that each time you switch between a console, it hides the content and ask you for your password to unlock the console (that way you could have multiple users on the same computer, each using a different console and the system remains safe since people cannot just go to someone's ...

How do you get micro-seconds from the Linux stat(2) call?

A little while ago I noticed that I couldn't find documentation on how to get the modification time of a file in micro-seconds. The notorious stat() call returns st_mtime defined as a time_t in the documentation.

Well... The fact is that the structure is really composed of a timeval structure and not a time_t (that applies to all 3 time values: modification, last access, and last status change.) So in fact you can use the name of the field without the last letter and a sub-timeval field as in:

struct stat s;
seconds = s.st_mtim.tv_sec; // == s.st_mtime
microseconds = ...

Make Firefox NOT close when I close the last tab

I found it a pain to see the Firefox window gets closed when I click the close button of the last tab.

When I use that same feature in SeaMonkey, it does not close the main window, instead it makes the tab empty.

Today I thought that maybe they had a flag in there to decide whether the main window should be closed or not and indeed they have:

browser.tabs.closeWindowWithLastTab

So all you have to do is change this flag to 'false' (the default in FF being true now) and closing the last tab won't close the window!

To change your Firefox configuration use:  about:config

To ...

Lost SSH key graphical prompt and auto-add to SSH agent

At some point in the past, my system somehow lost the ability to avoid asking me for my key every time I connect to one of my servers. It generally okay, I don't do so much work on that server that I'd have to connect all the time...

However, it is annoying when, once in while, I end up doing a lot of work, back and forth.

The ssh-agent was installed and working. I could add the key manually:

ssh-add ~/.ssh/my-secret-key
ssh-add -l

The ssh-add command allows you to add and remove keys from the ssh-agent. The -l command line option lists the keys currently held by the agent.

...

Supermicro X9SCI/X9SCA, video is gone!

As I am still trying to get my computers to work with a dual seat (or multiseat), I did an attempt in using the onboard video (a relatively decent Matrox card.) So I went in the BIOS and changed the setup for the video from Offboard to Onboard. Big mistake!

The video stopped working. On reboot the computer beeped 8 times and booted the OS normally (I have SSH setup so I could access the computer, but absolutely no video on either port: on board and off board.)

I have a Supermicro X9SCI/X9SCA. Searching for "no video" or "missing video on boot"... returned nothing ...

X11 starts, but nothing appears on the screen...

Today I finally resolved a problem I had for a while on one of my computers.

When logging in using the normal lightdm X11 login screen, directly on the computer, I would get an error and absolutely no menu, no icons, no keyboard functionality, no unity, no nautilus... The only thing I had working was the background which gave me access to the settings, but nothing else. More or less, nothing useful.

I just had an idea and then I found a comment form a user on a forum who said that he just deleted his .config and .compiz directories and rebooted. After that it worked for him. It worked for me ...

How to only upgrade packages with a security requirement in Ubuntu/Debian?

Today I wanted to upgrade some packages that had security issues. Ubuntu (like Debian) provides the apt-get tool that allows you to do upgrades the easy way:

sudo apt-get upgrade

However, that upgrades all the packages present. In some cases, you may want to skip on some packages because you know they are not ready (i.e. your own packages).

In order to only upgrade security issues, you want to get a list of packages that are to be upgraded for security issues:

apt-get -s dist-upgrade | grep "^Inst" | grep -i securi

That apt-get command line lists all the packages ready for ...

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

As I upgrade to 14.04, I started seeing this error in my console:

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

Quite cryptic if you ask me, but the "leaking memory" did sound bad.

The error would in particular appear when I used sudo for whatever reason, for example:

sudo iptables -L -nvx

So... something to do with sudo?

I found the answer on the Ubuntu forum. The solution is to turn off a feature of samba. Run the samba setup tool in your console:

sudo pam-auth-update

That opens a curses window in your console. You should then see an option ...

Syndicate content Syndicate content