Re: [PATCH iproute2-next v2] lib/bpf_legacy: Use userspace SHA-1 code instead of AF_ALG

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Nov 12, 2025 at 12:12:12PM -0800, Stephen Hemminger wrote:
> On Mon, 29 Sep 2025 12:46:48 -0700
> Eric Biggers <ebiggers@kernel.org> wrote:
> 
> > diff --git a/lib/sha1.c b/lib/sha1.c
> > new file mode 100644
> > index 00000000..1aa8fd83
> > --- /dev/null
> > +++ b/lib/sha1.c
> > @@ -0,0 +1,108 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * SHA-1 message digest algorithm
> > + *
> > + * Copyright 2025 Google LLC
> > + */
> 
> Not a big fan of having actual crypto in iproute2.
> It creates even more technical debt.
> Is there another crypto library that could be used?

Currently iproute2 doesn't depend on OpenSSL.  You can make it do that,
if you want, and then you could use SHA-1 from there.  I suspect that
doing that would be much more trouble than just adding this SHA-1 code.

If you happen to be planning to pull in OpenSSL as a dependency for
other reasons, it might make sense then.

> Better yet, is there a reason legacy BPF code needs to still exist
> in current iproute2? When was the cut over.

No idea.  That's a question for the BPF folks.

- Eric