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GdkPixbuf Suffers Image Decoding Vulnerabilities
DNAspark99 writes "It seems Multiple vulnerabilities have been reported in GdkPixbuf, which can be exploited by malicious people to DoS (Denial of Service), and potentially compromise a vulnerable system. Personally, I wasn't concerned about this until I ran 'ldd firefox-bin | grep libgdk_pixbuf'" There's no official patch yet, but the article notes several Linux vendors have issued updates. Worth keeping an eye for those who use libgdk_pixbuf under other Unix-style operating systems as well.
Who says the parent poster is complaining?
The parent poster was just making an observation... he/she was not passing judgement.
The one who found this vuln is Chris Evans, as known
as the vsftpd author (http://vsftpd.beasts.org/), and
here (http://scary.beasts.org/security/) are other bugs he found.
The only places using gdk-pixbuf in Firefox for loading images are all for loading images from your local machine. No from-the-network code paths use gdk-pixbuf.
Now your GNU/Hippie software is vulnverable what are you going to do about it?!
...patch it before the vulnerability is even announced... not six months later.
There's a particular comment which we'll see about a thousand times on this thread alone, the gist of which will be, "See? Even open source has bugs/security holes! It's no better than Microsoft!"
The reason we bash Microsoft for its bugs and security holes is not because they have bugs and holes; the reason is that Microsoft paints itself as the savior of computing, as software that will make your life infallibly better and easier, and along the way has made quite a lot of unethical business decisions. They basically brag about how uber they are, and then they release crappy software and frequently take forever to fix certain bugs (or simply never fix them -- e.g. PNG transparency in IE. What's it at, 3 years and counting? 4?).
The guys who write open source stuff like GdkPixBuf, on the other hand, have not (to my knowledge) done these things. They are thus not deserving of scorn; they write software, release it, and say, "I wrote this because I needed it. If you want to try it out, here you go. Have fun; I don't promise anything."
That's why we mock Microsoft for its bugs and not the GDK team.
(To be fair, I'm certain that there are some OS projects whose developers are as arrogant as Microsoft, but they at least do not have the unethical business history Microsoft does, nor do they (still!) have a monopoly on desktop OSes that they continue to abuse to the detriment of everyone except themselves. It's one thing to be an asshole when you're nobody important; it's quite another when you have a great deal of power.)
"Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
I don't read replies by ACs.
Firefox doesn't use gdk-pixbuf for drawing it's images. The only places using gdk-pixbuf in Firefox are loading a couple of images from your hard drive into the browser UI -- like the little Windows desktop icon that shows up in the download manager UI. This isn't remotely exploitable in Firefox.
--Asa
it's always uncool to run unknown commands that you've seen on slashdot ;-)
Son of a BITCH, I was just about to post that! GAH!
(Dear Slashdotters: The command shown above will not harm your computer, but will probably require a reboot to recover from it)
You need to write exploits in order to test whether you've actually fixed the bugs, and in order to determine whether the code is actually correct for some reason you're not seeing.
It is often the case that support for some functionality which is buggy in one implementation will be buggy in other implementations as well, so it is pretty common in general for a lot of similar bugs to turn up at the same time.
ldd searches for dynamic dependancies, hence no need for a new packages. Mozilla's gdk_pixbuf will be updated by the updated gdk_pixbuf containg package.
It's called a "fork bomb." Search for that term on Google, and you should get a better idea of what you shouldn't be pasting into your terminal. :>
Thanks YaST!
It makes more sense when you format it differently. It's a shell script (sorry to post as text, can't get the indentation to work otherwise):
:|: &
:()
{
}
:
Basically, it defines a function called ":" which, when executed, calls itself recursively twice and puts itself into the background. The last ":" actually executes the function. Thus, one shell forks into two shells, those two shells fork into four shells, those four into eight, etc etc etc.
There is no algorithm to do what you are describing (google for "halting problem")
You could run something like lint to catch common C errors.
Better than that though is to profile your code actually running, to see buffer overflows and leaks that actually occur (google for valgrind).
But most of these exploits are specially crafted input that produce buffer overflows. Typical input won't. So it is very hard to test for buffer overflows.
The only 100% way to work these kinds of problems out is to write code in higher level languages, so at least you'll get an exception and fail closed in the case of a buffer overflow.
But in C, the only way to resolve these problems is
1) Don't write code with buffer overflows (hard)
2) Find and fix buffer overflows in code review (harder)
3) Write good enough negative test cases that you find the buffer overflows (really hard for even a good tester).
I tried "apt-get --dry-run --purge remove libgdk-pixbuf2 libgdk-pixbuf-gnome2" and the list of packages was _long_. I do not have a gnome-heavy system, either. Some choice selections:
bonobo
galeon
gdm
gnome-control-center
gnome-help
gnome-panel
gnome-session
gnome-utils
libgnomeprint-bin
nautilus
rep-gtk-gnome
sawfish-gnome
xchat-gnome
It's a biggie, all right.
If opportunity came disguised as temptation, one knock would be enough.
3^2 * 67^1 * 977^1
Now it seems this is universal, or at the very least universal outside the macintosh world.
Wtf, what does that mean? It's in the mac world too. Have you seen all the mac vulns that have come out? Just last week they had a few moderately bad ones. And yes they had had remote exploits etc. in the past. There is no OS distribution in existence today that's over five years old that has not had remote exploits in the default install.
In a language without pointers, array-bounds checks impose a 1-3% performance hit. This is because advanced optimizers can usually remove most of the array-bounds checks. In practice, safe natively compiled languages (Ocaml, Lisp) can get within 10% - 20% the performance of C. 10% - 20% for the sake of security is a trade-off I'm willing to make. Obviously, the current C recommendation of "learn to write secure code in a language that encourages you not to" isn't working, because buffer-overflow vulnerabilities are rampant. It's time to throw that idea out the window.
A deep unwavering belief is a sure sign you're missing something...
I tried "apt-get --dry-run --purge remove libgdk-pixbuf2 libgdk-pixbuf-gnome2" and the list of packages was _long_. I do not have a gnome-heavy system, either.
Well yeah, the library is part of Gtk+ - anything using Gtk+ 2.x uses it. Nothing to do with Gnome specifically.
A more general prevention method is to use an environment that doesn't allow buffer overflows; as Java proponents never tire of pointing out, Java guards against this type of attack. There are C libraries which do similar things, IIRC; StackGuard was one such method, though it seems to haved faded into obscurity.
As to your suggestion of a static source code check for unsafe programming practices, there are programs that do that too. GCC itself includes a number of warnings that pop up if you use inherently unsafe C library functions, like gets() (which is buffer overflow in a can...).
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
I just woke up, red this, and checked the SuSe update.
And guess what, the patch was allready there.
Gotta love the OSS usually-same-day-patch-cycle.
Thumbs up, SuSe!