Re: [PATCH] crypto: af_alg - Add af_alg_restrict sysctl, defaulting to 1

Hi,

On 7/1/26 12:54 AM, Demi Marie Obenour wrote:

> That said, if the crypto_rng support is to remain, should it have a
> non-empty allowlist for privileged processes?  Otherwise, it's dead code
> with the default sysctl value.

For desktop users, it is indeed dead, but only if we can guarantee that 
they will never change the sysctl value to allow all algorithms.

So I'd probably do an enabled-by-default configuration option that takes 
away the option to enable all algorithms, and the RNG code in AF_ALG 
becomes conditional on that option.

I think that embedded systems will still use this code until a better 
alternative exists, so it's not entirely dead, and the best way to get 
rid of it is to build something better.

I'd love to see a vDSO based interface for all crypto operations that 
allows reusing the code in the kernel from userspace, avoids the system 
call overhead in the likely case that the CPU based implementation is 
also the most efficient, and allows for more flexibility with hardware 
interfaces (quite a few allow submission directly from unprivileged 
processes).

    Simon