Re: [PATCH bpf-next v4 3/6] bpf: Add hash kfunc for cryptographic hashing

Vadim Fedorenko
2026-01-06T22:12:33Z

On 05/01/2026 17:37, Daniel Hodges wrote:
> Extend bpf_crypto_type structure with hash operations:
> - hash(): Performs hashing operation
> - digestsize(): Returns hash output size

well, as I've already mentioned, none of them are actually introduced in
the patchset.

>
> Update bpf_crypto_ctx_create() to support keyless operations:
> - Hash algorithms don't require keys, unlike ciphers
> - Only validates key presence if type->setkey is defined
> - Conditionally sets IV/state length for cipher operations only
>
> Add bpf_crypto_hash() kfunc that works with any hash algorithm
> registered in the kernel's crypto API through the BPF crypto type
> system. This enables BPF programs to compute cryptographic hashes for
> use cases such as content verification, integrity checking, and data
> authentication.
>
> Signed-off-by: Daniel Hodges <git@danielhodges.dev>
> ---
> kernel/bpf/crypto.c | 78 ++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 70 insertions(+), 8 deletions(-)
>