The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Tuesday, January 27, 2004

Hello world! Care to read your email?

Yes, this really is the classic program that prints “Hello, world!” when you run it. Unlike the elementary version often presented in books like K&R, GNU hello processes its argument list to modify its behavior, supports internationalization, and includes a mail reader.

hello - GNU Project - Free Software Foundation

Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can.

Law of Software Envelopment

I didn't even realize GNU had a “Hello world” program available for downloading, much less one that succumbed to the Law of Software Envelopment. Granted, GNU then goes on to say:

The primary purpose of this program is to demonstrate how to write other programs that do these things; it serves as a model for all of the GNU coding standards.

It's quite amusing that GNU can turn this:

#include <stdio.h>

main()
{
	printf("hello, world\n");
}

into a 400k compressed download, complete with its own configuration script, m4 macros (who uses m4 anymore?), man pages (and here I thought GNU was big on info pages) along with documentation in TeX, plus the various language files for Russian, Slovanian, Japanese and I even think English is included in there somewhere.

Quite amusing.

Note: technically, the code should be written as:

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	printf("hello, world\n");
	return(EXIT_SUCCESS);
}

to be fully ANSI compliant, but hey, who am I to argue with the authors of C?

Then again, if you really want to be anal retentive about it, then:

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	(void)printf("hello, world\n");
	return(EXIT_SUCCESS);
}

But that's just being silly …


Oops

Yet another SYN flood to contend with, and yet again, it's the same extortionists that took this company last year for quite a bit of money (and I have to wonder—how do they note this in their financials? “Unexpected hiring of Russian Security Consultants”?) that “promised” protection for (I think) a year or so against such attacks. One it was brought to their attention, the attack subsided.

But in the mean time, I was tasked to move several of the larger sites still on the Boca Raton servers to the ones down in Miami. The intent of the Miami servers is for each to act as a backup of the other (and the Boca Raton servers will eventually act as a backup for the Miami servers) so in the process of creating the accounts needed on the two servers I made a slight mistake. Nothing bad, like an errant rm -rf * or attempting to restart the network remotely. Nope. Just a simple overwriting of /etc/passwd with the wrong file.

Nothing major. It just meant that no one could log into the system. I didn't notice until I attempted to copy over some more files and they failed. Or rather, I think scp or rsync started asking for passwords when I explicitely set up a trust mechanism between the two servers on their private network interfaces. I started poking around on the server with the munged /etc/passwd file and it came quite apparent what happened.

Fortunately, I still logged into the server with the munged /etc/passwd file.

Unfortunately, I was not root. Nor could I become root. This was not good.

Can't ssh since the authentication was blown. Which meant that scp wouldn't work either. I thought maybe rsync would work, but then I realized I set up rsync to use ssh and since authentication didn't work … (not that I realized until after trying rsync).

That's when I realized that a trip down to Miami might be required. Several hours worth of driving for less than a minutes worth of work to restore /etc/passwd. It was then I had a brainstorm … why not hack my way back to root? Wasn't illegal—I was, after all, the administrator for the system, and I had local access, which would make it easier than a remote exploit.

One Google search later, and I'm perusing 0day-exploits. Downloaded a few, got the code to the borked server, compile, run and nothing. Download another one, get it on the server, compile, run, and nothing.

Damn you, Gentoo, I thought, and your custom compiliation installs! I can't even hack my way back into the system!

I supposed I could have kept at it, but at there comes a time of diminishing returns, which would be the time it would take me to drive to Miami, reboot the server into single user mode, restore the file, reboot and drive back home. The drive and reboot is the simpler solution in this case (if a bit tedious); had the server been on the other side of the country, then yes, maybe I would have stuck with the hacking attempt a bit longer …

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