Re: [PATCH] backports: crypto user - make NETLINK_CRYPTO work inside netns

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Apr 05, 2021 at 01:55:15PM +0000, Jianmin Wang wrote:
> There is same problem found in linux 4.19.y as upstream commit. The 
> changes of crypto_user_* and cryptouser.h files from upstream patch are merged into 
> crypto/crypto_user.c for backporting.
> 
> Upstream commit:
>     commit 91b05a7e7d8033a90a64f5fc0e3808db423e420a
>     Author: Ondrej Mosnacek <omosnace@redhat.com>
>     Date:   Tue,  9 Jul 2019 13:11:24 +0200
> 
>     Currently, NETLINK_CRYPTO works only in the init network namespace. It
>     doesn't make much sense to cut it out of the other network namespaces,
>     so do the minor plumbing work necessary to make it work in any network
>     namespace. Code inspired by net/core/sock_diag.c.
> 
>     Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
>     Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
> 
> Signed-off-by: Jianmin Wang <jianmin@iscas.ac.cn>
> ---
>  crypto/crypto_user.c        | 37 +++++++++++++++++++++++++------------
>  include/net/net_namespace.h |  3 +++
>  2 files changed, 28 insertions(+), 12 deletions(-)

How does this change fit with the stable kernel rules?  It looks to be a
new feature, if you need this, why not just use a newer kernel version?
What is preventing you from doing that?

thanks,

greg k-h