Re: Backport of 67c37756898a ("tty: n_gsm: require CAP_NET_ADMIN to attach N_GSM0710 ldisc") to older stable series? (at least 6.1.y)

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Apr 10, 2024 at 09:02:50PM +0200, Salvatore Bonaccorso wrote:
> Hi Greg, Sasha, Thadeu,
> 
> Today there was mentioning of 
> 
> https://www.jmpeax.dev/The-tale-of-a-GSM-Kernel-LPE.html
> 
> a LPE from the n_gsm module. I do realize, Thadeu mentioned the
> possible attack surface already back in
> 
> https://lore.kernel.org/all/ZMuRoDbMcQrsCs3m@quatroqueijos.cascardo.eti.br/#t
> 
> Published exploits are referenced as well through the potential
> initial finder in https://github.com/YuriiCrimson/ExploitGSM .
> 
> While 67c37756898a ("tty: n_gsm: require CAP_NET_ADMIN to attach
> N_GSM0710 ldisc") is not the fix itself, it helps mitigating against
> this issue.
> 
> Thus can you consider applying this still to the stable series as
> needed? I think it should go at least back to 5.15.y but if
> Iunderstood Thadeu correctly then even further back to the still
> supported stable branches.
> 
> What do you think?

Sure, I'll queue it up.  I think the "real" bugs there are already
resolved in the various older kernel trees, but adding this is "defense
in depth" and makes sense.

thanks,

greg k-h