Re: [PATCH 1/2] crypto: pcrypt - Remove pcrypt

[Thomas Huth <thuth@redhat.com>]

On 14/07/2026 00.32, 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>
> ---
>   MAINTAINERS                                 |   7 -
>   arch/loongarch/configs/loongson32_defconfig |   1 -
>   arch/loongarch/configs/loongson64_defconfig |   1 -
>   arch/s390/configs/debug_defconfig           |   1 -
>   arch/s390/configs/defconfig                 |   1 -
>   crypto/Kconfig                              |  10 -
>   crypto/Makefile                             |   1 -
>   crypto/pcrypt.c                             | 394 --------------------
>   include/crypto/pcrypt.h                     |  39 --
>   tools/crypto/tcrypt/tcrypt_speed_compare.py |   7 +-
>   10 files changed, 2 insertions(+), 460 deletions(-)
>   delete mode 100644 crypto/pcrypt.c
>   delete mode 100644 include/crypto/pcrypt.h

Thanks!

Reviewed-by: Thomas Huth <thuth@redhat.com>