Re: Various Squashfs Issues

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Richard,

On 16.07.24 17:49, Richard Weinberger wrote:
> Hi!
> 
> While inspecting the squashfs implementation of Barebox I noticed
> some issues and was able trigger heap corruptions using crafted filesystems.

Thanks for sharing your results. By the way I had started a libfuzzer integration
for barebox a while back that I just pushed here:

  https://github.com/a3f/barebox/tree/libfuzzer

It still needs some love to make it upstream, but it's already usable and can find
issues, but it still suffers from depleting memory after a while. I need to fix
those memory leaks and clean it up when I find the time, so we can start more heavily
fuzzing a base set of functionality that's needed for secure boot (mainly partition
tables, file type detection and FIT image parser).

> e.g.

[snip]

> While implementing fixes for them I realized that these are all known
> and fixed in Linux.
> 
> I suggest backporting at least these Linux fixes for squashfs:
> 
> 01cfb7937a9af ("squashfs: be more careful about metadata corruption")
> d512584780d3e ("squashfs: more metadata hardening")
> cdbb65c4c7ead ("squashfs metadata 2: electric boogaloo")
> 71755ee5350b6 ("squashfs: more metadata hardening")
> a3f94cb99a854 ("Squashfs: Compute expected length from inode size rather than block length")

Backported in https://lore.barebox.org/barebox/20240717063328.2810835-1-a.fatoum@pengutronix.de/

Cheers,
Ahmad


> 
> Thanks,
> //richard
> 

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