On Fri, Dec 5, 2025 at 9:40 AM Daniel Hodges git@danielhodges.dev 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
crypto/Makefile | 3 ++ crypto/bpf_crypto_shash.c | 94 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 97 insertions(+) create mode 100644 crypto/bpf_crypto_shash.c
diff --git a/crypto/Makefile b/crypto/Makefile index 16a35649dd91..853dff375906 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -30,6 +30,9 @@ obj-$(CONFIG_CRYPTO_ECHAINIV) += echainiv.o crypto_hash-y += ahash.o crypto_hash-y += shash.o obj-$(CONFIG_CRYPTO_HASH2) += crypto_hash.o +ifeq ($(CONFIG_BPF_SYSCALL),y) +obj-$(CONFIG_CRYPTO_HASH2) += bpf_crypto_shash.o +endif
obj-$(CONFIG_CRYPTO_AKCIPHER2) += akcipher.o obj-$(CONFIG_CRYPTO_SIG2) += sig.o diff --git a/crypto/bpf_crypto_shash.c b/crypto/bpf_crypto_shash.c new file mode 100644 index 000000000000..39032e7dd602 --- /dev/null +++ b/crypto/bpf_crypto_shash.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/types.h> +#include <linux/module.h> +#include <linux/bpf_crypto.h> +#include <crypto/hash.h>
+struct bpf_shash_ctx {
struct crypto_shash *tfm;struct shash_desc desc;+};
Instead of adding bpf_shash_ctx and bpf_ecdsa_ctx, can we extend bpf_crypto_ctx to cover all hash and ECDSA? bpf_crypto_ctx has a const pointer to bpf_crypto_type, so this should be possible?
Thanks, Song