Re: [PATCH] crypto: lib/sha1 - use __DISABLE_EXPORTS for SHA1 library

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Dec 17, 2025 at 03:38:26PM -0800, Ross Philipson wrote:
> Allow the SHA1 library code in lib/crypto/sha1.c to be used in a pre-boot
> environments. Use the __DISABLE_EXPORTS macro to disable function exports and
> define the proper values for that environment as was done earlier for SHA256.
> 
> This issue was brought up during the review of the Secure Launch v15 patches
> that use SHA1 in a pre-boot environment (link in tags below). This is being
> sent as a standalone patch to address this.
> 
> Link: https://lore.kernel.org/r/20251216002150.GA11579@quark
> Cc: Eric Biggers <ebiggers@kernel.org>
> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
> ---
>  lib/crypto/sha1.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/crypto/sha1.c b/lib/crypto/sha1.c
> index 52788278cd17..e5a9e1361058 100644
> --- a/lib/crypto/sha1.c
> +++ b/lib/crypto/sha1.c
> @@ -154,7 +154,7 @@ static void __maybe_unused sha1_blocks_generic(struct sha1_block_state *state,
>  	memzero_explicit(workspace, sizeof(workspace));
>  }
>  
> -#ifdef CONFIG_CRYPTO_LIB_SHA1_ARCH
> +#if defined(CONFIG_CRYPTO_LIB_SHA1_ARCH) && !defined(__DISABLE_EXPORTS)
>  #include "sha1.h" /* $(SRCARCH)/sha1.h */
>  #else
>  #define sha1_blocks sha1_blocks_generic

Shouldn't this be part of the patchset that needs this?

Also, when __DISABLE_EXPORTS is defined, only the functionality actually
used by pre-boot environments should be included.  HMAC support for
example probably isn't needed.

The commit title is also misleading.  How about:
"lib/crypto: sha1: Add support for pre-boot environments".

- Eric