Re: [PATCH] powerpc/kernel: Fix potential spectre v1 in syscall

On Tue, Mar 12, 2024 at 08:17:42AM +0000, Christophe Leroy wrote:

+Nathan as this is RTAS related.

Le 21/08/2018 à 20:42, Breno Leitao a écrit :

quoted

The rtas syscall reads a value from a user-provided structure and uses it
to index an array, being a possible area for a potential spectre v1 attack.
This is the code that exposes this problem.

	args.rets = &args.args[nargs];

The nargs is an user provided value, and the below code is an example where
the 'nargs' value would be set to XX.

	struct rtas_args ra;
	ra.nargs = htobe32(XX);
	syscall(__NR_rtas, &ra);

This patch has been hanging around in patchwork since 2018 and doesn't 
apply anymore. Is it still relevant ? If so, can you rebase et resubmit ?

This seems to be important, since nargs is a user-provided value. I can
submit it if the maintainers are willing to accept. I do not want to
spend my time if no one is willing to review it.

Thanks for revamping this one.