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Posted by larusso 1 day ago

Copy Fail 2: Electric Boogaloo(github.com)
37 points | 13 comments
cassianoleal 1 day ago|
How is this different from Dirty Frag [0]?

It seems to use the same vector.

[0] https://github.com/V4bel/dirtyfrag

auscompgeek 1 day ago|
From what I can gather it is the exact same vulnerability.
alecco 1 day ago||
People are blaming the wrong guy for breaking the embargo but via this blog post [1]:

> on 2026-05-05 Steffen Klassert pushed f4c50a4034 to netdev/net.git with Cc: stable@vger.kernel.org.

Once the fix is out it's usual for researchers to race to make the first exploit out of it.

[1] https://afflicted.sh/blog/posts/copy-fail-2.html

cpach 1 day ago||
Does anyone know how to mitigate this one? Is it sufficient to disable the esp4/esp6/rxrpc modules?
nonamesleft 1 day ago||
sysctl kernel.unprivileged_userns_clone=1 keeps on giving.
sickthecat 1 day ago|
Yes. Giving me a massive... Well.. Dopamine rush.
Mindless2112 1 day ago|
How much pain must there be until people realize we actually do need memory safety?
delamon 1 day ago|
How would've memory safety helped here?
Mindless2112 1 day ago|||
In CHERI, for example, pointers have permissions. The pointer to the COW memory would not have the "write" permission.

I could be misunderstanding the bug, of course.

delamon 1 day ago||
If you "forget" to mark COW memory pointer as no-write, the net effect would be same, would it not? If I'm reading the diff correctly, the problem was that code missed to mark some pages as shared (aka no-write).
Mindless2112 1 day ago||
A fair point...

I thought the bug was a missing check for the COW flag, but looking at it again it seems it was missing both setting and checking the flag.

delamon 1 day ago||
Apparently it is both...
tatersolid 1 day ago|||
Because “Page-cache write into any readable file” is a memory safety bug? All of these recent Linux LPEs are memory safety issues.