Re: [PATCH 0/3] lib/crypto: Provide a function for zeroizing hmac_sha1_ctx

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Aug 12, 2026 at 06:33:33PM +0200, Thomas Huth wrote:
> It's maybe not worth the effort for hmac_sha1_ctx right now (since there
> is only one spot that forgot to zeroize the structure in case of errors),
> but offering a function for zeroizing the data via __cleanup might help to
> get future code into the proper shape right from the start. Thus let's
> introduce a hmac_sha1_zeroize_ctx() function now and use it in the
> appropriate spots.
> 
> Thomas Huth (3):
>   crypto: Provide a wrapper for zeroizing hmac_sha1_ctx

Subject prefix should be "lib/crypto: sha1:"

>   security: keys: trusted: always clear the hmac_sha1_ctx before
>     returning
>   lib/crypto: sha1: Use hmac_sha1_zeroize_ctx() instead of
>     memzero_explicit()
> 
>  include/crypto/sha1.h                     | 17 +++++++++++++++++
>  lib/crypto/sha1.c                         |  2 +-
>  security/keys/trusted-keys/trusted_tpm1.c |  2 +-
>  3 files changed, 19 insertions(+), 2 deletions(-)

As you probably know, SHA-1 is a bit outdated.  Will these be coming for
SHA-2 as well?  It would be nice to introduce all the APIs at the same
time so that we can make sure they're consistent.  I would actually
prioritize that over introducing callers of them right now, as that can
be done later and often requires acks from other maintainers (and they
can go through other trees as well).

- Eric