Re: [PATCH bpf-next v2 3/5] selftests/bpf: Add tests for bpf_crypto_hash kfunc

Song Liu
2025-12-06T01:15:05Z

On Fri, Dec 5, 2025 at 9:39 AM Daniel Hodges <git@danielhodges.dev> wrote:
>
> Add selftests to validate the bpf_crypto_hash works properly. The tests
> verify both correct functionality and proper error handling.
>
> Test Data:
> All tests use the well-known NIST test vector input "abc" and validate
> against the standardized expected outputs for each algorithm. This ensures
> the BPF kfunc wrappers correctly delegate to the kernel crypto library.
>
> Signed-off-by: Daniel Hodges <git@danielhodges.dev>
> ---
> tools/testing/selftests/bpf/config | 2 +
> .../selftests/bpf/prog_tests/crypto_hash.c | 158 ++++++++++++++++++
> .../testing/selftests/bpf/progs/crypto_hash.c | 141 ++++++++++++++++
> 3 files changed, 301 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/crypto_hash.c
> create mode 100644 tools/testing/selftests/bpf/progs/crypto_hash.c
>
> diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
> index 558839e3c185..d168b3073cba 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -12,7 +12,9 @@ CONFIG_BPF_SYSCALL=y
> # CONFIG_BPF_UNPRIV_DEFAULT_OFF is not set
> CONFIG_CGROUP_BPF=y
> CONFIG_CRYPTO_HMAC=y
> +CONFIG_CRYPTO_HASH2=y
> CONFIG_CRYPTO_SHA256=y
> +CONFIG_CRYPTO_SHA512=y
> CONFIG_CRYPTO_USER_API=y
> CONFIG_CRYPTO_USER_API_HASH=y
> CONFIG_CRYPTO_USER_API_SKCIPHER=y
> diff --git a/tools/testing/selftests/bpf/prog_tests/crypto_hash.c b/tools/testing/selftests/bpf/prog_tests/crypto_hash.c
> new file mode 100644
> index 000000000000..f1495ea85aae
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/crypto_hash.c
> @@ -0,0 +1,158 @@
> +// SPDX-License-Identifier: GPL-2.0

Maybe add Copyright here?

> +
> +#include <test_progs.h>
> +#include <errno.h>
> +#include "crypto_hash.skel.h"
> +
> +/* NIST test vectors for SHA-256("abc") */
> +static const unsigned char expected_sha256[32] = {
> + 0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea,
> + 0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23,
> + 0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c,
> + 0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad
> +};
> +
> +/* NIST test vectors for SHA-384("abc") */
> +static const unsigned char expected_sha384[48] = {
> + 0xcb, 0x00, 0x75, 0x3f, 0x45, 0xa3, 0x5e, 0x8b,
> + 0xb5, 0xa0, 0x3d, 0x69, 0x9a, 0xc6, 0x50, 0x07,
> + 0x27, 0x2c, 0x32, 0xab, 0x0e, 0xde, 0xd1, 0x63,
> + 0x1a, 0x8b, 0x60, 0x5a, 0x43, 0xff, 0x5b, 0xed,
> + 0x80, 0x86, 0x07, 0x2b, 0xa1, 0xe7, 0xcc, 0x23,
> + 0x58, 0xba, 0xec, 0xa1, 0x34, 0xc8, 0x25, 0xa7
> +};
> +
> +/* NIST test vectors for SHA-512("abc") */
> +static const unsigned char expected_sha512[64] = {
> + 0xdd, 0xaf, 0x35, 0xa1, 0x93, 0x61, 0x7a, 0xba,
> + 0xcc, 0x41, 0x73, 0x49, 0xae, 0x20, 0x41, 0x31,
> + 0x12, 0xe6, 0xfa, 0x4e, 0x89, 0xa9, 0x7e, 0xa2,
> + 0x0a, 0x9e, 0xee, 0xe6, 0x4b, 0x55, 0xd3, 0x9a,
> + 0x21, 0x92, 0x99, 0x2a, 0x27, 0x4f, 0xc1, 0xa8,
> + 0x36, 0xba, 0x3c, 0x23, 0xa3, 0xfe, 0xeb, 0xbd,
> + 0x45, 0x4d, 0x44, 0x23, 0x64, 0x3c, 0xe8, 0x0e,
> + 0x2a, 0x9a, 0xc9, 0x4f, 0xa5, 0x4c, 0xa4, 0x9f
> +};
> +
> +static void test_sha256_basic(void)
> +{
> + struct crypto_hash *skel;
> + int err, prog_fd;
> +
> + LIBBPF_OPTS(bpf_test_run_opts, topts);
> +
> + skel = crypto_hash__open_and_load();
> + if (!skel) {
> + /* Skip if kfuncs not available (CONFIG_CRYPTO_HASH2 not set) */
> + if (errno == ENOENT || errno == EINVAL) {
> + test__skip();
> + return;
> + }
> + ASSERT_OK_PTR(skel, "crypto_hash__open_and_load");
> + return;
> + }
> +
> + prog_fd = bpf_program__fd(skel->progs.test_sha256);
> + err = bpf_prog_test_run_opts(prog_fd, &topts);
> + ASSERT_OK(err, "test_sha256");
> + ASSERT_EQ(skel->data->sha256_status, 0, "sha256_status");
> + ASSERT_EQ(memcmp(skel->bss->sha256_output, expected_sha256, 32), 0,
> + "sha256_output_match");
> +
> + crypto_hash__destroy(skel);
> +}

nit: We have quite some duplicated code here. Maybe try to reuse some of
the code?

Thanks,
Song