Re: [PATCH] crypto: pcrypt - Remove pcrypt

[Herbert Xu <herbert@gondor.apana.org.au>]

On Sun, Jul 12, 2026 at 11:26:00PM -0400, Eric Biggers wrote:
> pcrypt was originally intended to improve IPsec performance.  However,
> it's no longer useful for that.  Reports from the rare cases that anyone
> has actually tried to use it over the years indicate that it actually
> reduces IPsec performance, e.g.:
> 
> * https://github.com/libreswan/libreswan/wiki/Internals:-Cryptographic-Acceleration#obsoleted-ipsec-accelerations
> * https://users.strongswan.narkive.com/liqTaTq8/strongswan-problem-with-pcrypt
> * https://unix.stackexchange.com/questions/594336/ipsec-multithreading-via-pcrypt-worse-than-single-thread
> 
> It's also undocumented and quite difficult to actually use.  Its design
> is also broken, in that any unprivileged program can enable pcrypt
> systemwide at any time (by instantiating it using AF_ALG).
> 
> Meanwhile, pcrypt has been a regular source of bugs, including at least
> four that have received CVEs.
> 
> Let's just remove it.  No one seems to care about it anymore other than
> people looking for vulnerabilities.
> 
> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Looks good to me.

More than half of kernel/padata.c is only used by pcrypt and can
also be removed if pcrypt is removed.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt