Re: [PATCH bpf-next v4 1/6] crypto: Add BPF hash algorithm type registration module

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 05/01/2026 17:37, Daniel Hodges wrote:
> Add bpf_crypto_shash module that registers a hash type with the BPF
> crypto infrastructure, enabling BPF programs to access kernel hash
> algorithms through a unified interface.
> 
> Update the bpf_crypto_type interface with hash-specific callbacks:
>     - alloc_tfm: Allocates crypto_shash context with proper descriptor size
>     - free_tfm: Releases hash transform and context memory
>     - has_algo: Checks algorithm availability via crypto_has_shash()
>     - hash: Performs single-shot hashing via crypto_shash_digest()
>     - digestsize: Returns the output size for the hash algorithm
>     - get_flags: Exposes transform flags to BPF programs
> 
> Update bpf_shash_ctx to contain crypto_shash transform and shash_desc
> descriptor to accommodate algorithm-specific descriptor requirements.
> 
> Signed-off-by: Daniel Hodges <git@danielhodges.dev>
> ---
>   MAINTAINERS               |  1 +
>   crypto/Makefile           |  3 ++
>   crypto/bpf_crypto_shash.c | 95 +++++++++++++++++++++++++++++++++++++++
>   3 files changed, 99 insertions(+)
>   create mode 100644 crypto/bpf_crypto_shash.c

[...]

> +static const struct bpf_crypto_type bpf_crypto_shash_type = {
> +	.alloc_tfm	= bpf_crypto_shash_alloc_tfm,
> +	.free_tfm	= bpf_crypto_shash_free_tfm,
> +	.has_algo	= bpf_crypto_shash_has_algo,
> +	.hash		= bpf_crypto_shash_hash,

I don't see a definition of hash() callback in struct bpf_crypto_type

> +	.digestsize	= bpf_crypto_shash_digestsize,
> +	.get_flags	= bpf_crypto_shash_get_flags,
> +	.owner		= THIS_MODULE,
> +	.name		= "hash",
> +};