[OpenAFS] dirtyflag vulnerability and OpenAFS

[Jeffrey E Altman]

[Apologies for the duplicate transmission but some of the recipients 
only accept plain text[


Hello Matteo,


OpenAFS does not use the Linux rxrpc module for its network 
communications.  Instead it embeds its own Rx RPC implementation within 
the openafs.ko module.


Linux AFS (kafs) on the other hand relies upon the rxrpc.ko module for 
its network communications.


The mailing list for discussion of Linux AFS and Rx RPC is 
linux-afs at lists.infradead.org.


I've cc'd this message to that list as well as adding the rxrpc.ko 
maintainers.


Jeffrey Altman


On 5/8/2026 4:33 AM, Matteo Fois wrote:
> Good Morning,
> I'm a researcher at ENEA (Italy) and we use the OpenAFS filesystem 
> extensively in our facilities.
> This morning we discovered the dirtyflags vulnerability 
> (https://github.com/V4bel/dirtyfrag 
> <https://github.com/V4bel/dirtyfrag>) and quicky patched our machines.
>
> The patch works by blacklisting and removing the following kernel 
> modules: esp4 esp6 rxrpc
> The last module rxrpc we understand that it's used by OpenAFS 
> (https://docs.kernel.org/networking/rxrpc.html)
>
> We are able to use the filesystem and it seems to be working properly 
> after the patch, but we were wondering if there are more subtle side 
> effects, for example in performance.
> Also we were curious to know what happens if one uses the kafs kernel 
> module instead of the OpenAFS client, does the blacklisted module 
> create any problem?
>
> Thanks,
>
> Matteo
>
>
>
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