Puppy Linux Discussion Forum

[Lobster]

Hi Guys
Been keeping my eyes open so our warrior worriers
have something to get their energy into
http://www.theregister.co.uk/2009/07/17/linux_kernel_exploit/

Not sure if it is applicable
but may be of interest . . .

[prehistoric]

The null-pointer de-reference vulnerability has been around for ages. The compiler optimization which removes the code which checks for this illustrates the serious problem of preserving semantics during optimization.

If you look for errors in preserving semantics, you can find them. Many optimizations could be characterized as "I hope this makes things faster without breaking anything". The surprise is not that he found such, it is the size of the class of vulnerabilities exposed.

In addition to actual problems of preserving well-defined semantics, there is the problem that many people writing code do not understand the precise semantics of the constructs they are using. This leads to another class of vulnerabilities, which might be classed as psychological. (Here's an example: if an integer is equal to its negation, it must be zero. Right?)

Linus is right in saying that no one should be surprised about attackers gaining root privileges if you let them make arbitrary kernel calls. He is off in a dreamworld if he doesn't recognize that running a LAMP installation (Linux, Apache, MySql, PHP) is a very common practice which can allow malicious programs from the web to do exactly that.

I'm convinced that a series of attacks on Puppy-related sites gained entry through PHP vulnerabilities.

[abushcrafter]

This is a disaster! Is puppy at risk?

[prehistoric]

[abushcrafter]

Yes, your right I don't know much on this stuff at all .

[Sit Heel Speak]

@Lobster: thanks very much for posting this.

From the source code to Mr. Spengler's exploit.c:

[prehistoric]

This problem introduced by compiler optimization brings us closer to a nightmare possibility Ken Thompson described in his Reflections on Trusting Trust. N.B. At the time he wrote this, M$ was working for IBM. The famous 1984 Apple MacIntosh ad was aimed at IBM.

[SirDuncan]

I always knew pointers were evil. Sure, they act like they're your friend, building linked lists and passing variables without wasting time and space allocating new memory. As soon as your project deadline approaches, however, they start writing over some other program's memory space and getting accidentally set to NULL.

[tasmod]

If you read later post details on that site you will see that this bug and the wi-fi bug have been solved in the newer kernel.

[nooby]

which Puppies use that older kernel then? How does the newbie know about such?

[Sit Heel Speak]

[Kirby]

AAAArgh
I was feeling all smug this morning because I was thinking I was Mostly safe from Malware and such. Last night I downloaded a small "Free" piece of software on my Puppy to install on my Old XP box to try and network my new Ancient IBM Thinkpad running win95 to XP . I have to do this because it's now the only way to transfer files over to it via a Direct Cable Connection. Well Low and behold soon as I executed the file it installed a nasty Virus on the XP box. At least it had the decency to inform me right away! LOL I am reformatting it as I write this.

I came on here to see if there were any Puplets made just for Virus scanning and such when I saw the new thread on Rootkits in Puppy! I quickly ran to the kitchen for my colander and neatly wrapped it in tin foil to prepare for battle!

After much reading in here I guess it just comes down to playing it safe with some preparation and luck. If I had virgin hardware, plenty of software protection and never let my computer get on the net or swap files with another, perhaps I would be at very low risk. But Life is only fun when there is some risk involved so I guess it goes with the territory to some extent.

This exploit on the Kernel brings up another question for me now. Does the feature "Trim the Fat" when installing Pets also create this vulnerability as well?

PS. Would it be safer to use an IBM mainframe from the mid 60's using only a card reader to get on the net? Or would they use the Y2k Bug to "Poke Holes" in it too?

Kirby

[Lobster]