Re: [PATCH v2] lib/mpi: call cond_resched() from mpi_powm() loop

[Eric Biggers]

On Wed, Nov 08, 2017 at 08:17:12PM +0000, David Howells wrote:
> Eric Biggers <ebiggers3@xxxxxxxxx> wrote:
> 
> > This probably should be grouped with my series "crypto: dh - input validation
> > fixes", as this is also a fix for Diffie-Hellman.  I was actually expecting
> > Herbert Xu to take these patches, as Diffie-Hellman is now part of the crypto
> > API (crypto/dh.c); none of the patches actually touch security/keys/.
> 
> Fine by me.
> 
> > If you'd like to maintain the Diffie-Hellman implementation(s) you should
> > get yourself added to MAINTAINERS for the relevant files.
> 
> It touches the MPI lib, though, so it also potentially affects RSA and stuff,
> which is why I introduced it to the kernel originally.
> 

True, mpi_powm() might also be reachable by adding a key of type "asymmetric",
in which case this fix would need to go to older kernels than v4.12.  If I have
a chance I'll see if I can find a reproducer.

Eric