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

[Thomas Huth <thuth@redhat.com>]

On 13/08/2026 04.27, Eric Biggers wrote:
> 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 As you probably know, SHA-1 is a bit outdated.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).
Yes, makes sense. I've got a patch for HMAC-SHA2 ready, too, but the patch 
that is using it on the calling site has a conflict with the smb patch that 
I already sent out, so I wanted to wait a little bit til that is merged:

  https://lore.kernel.org/lkml/20260812130152.2861834-2-thuth@redhat.com/

... but if you're fine with a series that introduces the zeroization 
functions first, without immediately introducing callers, I'm happy to 
assemble such a patch series first!

  Thomas