[PATCH bpf-next v5 5/7] selftests/bpf: Add tests for bpf_crypto_hash kfunc

[Daniel Hodges <git@danielhodges.dev>]

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>
---
 MAINTAINERS                                   |   2 +
 tools/testing/selftests/bpf/config            |   2 +
 .../selftests/bpf/prog_tests/crypto_hash.c    | 210 ++++++++++++++++
 .../selftests/bpf/progs/crypto_common.h       |   2 +
 .../testing/selftests/bpf/progs/crypto_hash.c | 235 ++++++++++++++++++
 5 files changed, 451 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/MAINTAINERS b/MAINTAINERS
index 62d712a1f730..d23ea38b606f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4718,6 +4718,8 @@ F:	crypto/bpf_crypto_sig.c
 F:	crypto/bpf_crypto_skcipher.c
 F:	include/linux/bpf_crypto.h
 F:	kernel/bpf/crypto.c
+F:	tools/testing/selftests/bpf/prog_tests/crypto_hash.c
+F:	tools/testing/selftests/bpf/progs/crypto_hash.c
 
 BPF [DOCUMENTATION] (Related to Standardization)
 R:	David Vernet <void@manifault.com>
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 558839e3c185..814804f71780 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -13,6 +13,8 @@ CONFIG_BPF_SYSCALL=y
 CONFIG_CGROUP_BPF=y
 CONFIG_CRYPTO_HMAC=y
 CONFIG_CRYPTO_SHA256=y
+CONFIG_CRYPTO_SHA512=y
+CONFIG_CRYPTO_HASH2=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..0c78b5f46c9c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/crypto_hash.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#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 struct crypto_hash *setup_skel(void)
+{
+	struct crypto_hash *skel;
+
+	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 NULL;
+		}
+		ASSERT_OK_PTR(skel, "crypto_hash__open_and_load");
+		return NULL;
+	}
+
+	return skel;
+}
+
+static void test_sha256_basic(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		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);
+}
+
+static void test_sha384_basic(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+	prog_fd = bpf_program__fd(skel->progs.test_sha384);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_sha384");
+	ASSERT_EQ(skel->data->sha384_status, 0, "sha384_status");
+	ASSERT_EQ(memcmp(skel->bss->sha384_output, expected_sha384, 48), 0,
+		  "sha384_output_match");
+
+	crypto_hash__destroy(skel);
+}
+
+static void test_sha512_basic(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_sha512);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_sha512");
+	ASSERT_EQ(skel->data->sha512_status, 0, "sha512_status");
+	ASSERT_EQ(memcmp(skel->bss->sha512_output, expected_sha512, 64), 0,
+		  "sha512_output_match");
+
+	crypto_hash__destroy(skel);
+}
+
+static void test_sha256_invalid_params(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_sha256_zero_len);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_zero_len");
+	ASSERT_EQ(skel->data->sha256_status, 0, "zero_len_rejected");
+
+	crypto_hash__destroy(skel);
+}
+
+static void test_hash_with_key_rejected(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_hash_with_key_rejected);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_hash_with_key_rejected");
+	ASSERT_EQ(skel->data->hash_with_key_status, 0, "hash_with_key_rejected");
+
+	crypto_hash__destroy(skel);
+}
+
+static void test_hash_output_too_small(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_hash_output_too_small);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_hash_output_too_small");
+	ASSERT_EQ(skel->data->hash_output_too_small_status, 0, "hash_output_too_small");
+
+	crypto_hash__destroy(skel);
+}
+
+static void test_hash_on_skcipher_ctx(void)
+{
+	struct crypto_hash *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = setup_skel();
+	if (!skel)
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_hash_on_skcipher_ctx);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_hash_on_skcipher_ctx");
+	ASSERT_EQ(skel->data->hash_on_skcipher_status, 0, "hash_on_skcipher_rejected");
+
+	crypto_hash__destroy(skel);
+}
+
+void test_crypto_hash(void)
+{
+	if (test__start_subtest("sha256_basic"))
+		test_sha256_basic();
+	if (test__start_subtest("sha384_basic"))
+		test_sha384_basic();
+	if (test__start_subtest("sha512_basic"))
+		test_sha512_basic();
+	if (test__start_subtest("sha256_invalid_params"))
+		test_sha256_invalid_params();
+	if (test__start_subtest("hash_with_key_rejected"))
+		test_hash_with_key_rejected();
+	if (test__start_subtest("hash_output_too_small"))
+		test_hash_output_too_small();
+	if (test__start_subtest("hash_on_skcipher_ctx"))
+		test_hash_on_skcipher_ctx();
+}
diff --git a/tools/testing/selftests/bpf/progs/crypto_common.h b/tools/testing/selftests/bpf/progs/crypto_common.h
index 57dd7a68a8c3..2f04f08f890b 100644
--- a/tools/testing/selftests/bpf/progs/crypto_common.h
+++ b/tools/testing/selftests/bpf/progs/crypto_common.h
@@ -15,6 +15,8 @@ int bpf_crypto_encrypt(struct bpf_crypto_ctx *ctx, const struct bpf_dynptr *src,
 		       const struct bpf_dynptr *dst, const struct bpf_dynptr *iv) __ksym;
 int bpf_crypto_decrypt(struct bpf_crypto_ctx *ctx, const struct bpf_dynptr *src,
 		       const struct bpf_dynptr *dst, const struct bpf_dynptr *iv) __ksym;
+int bpf_crypto_hash(struct bpf_crypto_ctx *ctx, const struct bpf_dynptr *data,
+		    const struct bpf_dynptr *out) __ksym;
 
 struct __crypto_ctx_value {
 	struct bpf_crypto_ctx __kptr * ctx;
diff --git a/tools/testing/selftests/bpf/progs/crypto_hash.c b/tools/testing/selftests/bpf/progs/crypto_hash.c
new file mode 100644
index 000000000000..e6eacbc40607
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/crypto_hash.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "bpf_kfuncs.h"
+#include "crypto_common.h"
+
+unsigned char test_input[3] = "abc";
+
+/* Expected SHA-256 hash of "abc" */
+/* ba7816bf 8f01cfea 414140de 5dae2223 b00361a3 96177a9c b410ff61 f20015ad */
+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
+};
+
+/* Output buffers for test results */
+unsigned char sha256_output[32] = {};
+unsigned char sha384_output[48] = {};
+unsigned char sha512_output[64] = {};
+unsigned char small_output[16] = {}; /* Intentionally small for output_too_small test */
+
+int sha256_status = -1;
+int sha384_status = -1;
+int sha512_status = -1;
+int hash_with_key_status = -1;
+int hash_output_too_small_status = -1;
+int hash_on_skcipher_status = -1;
+
+SEC("syscall")
+int test_sha256(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha256",
+		.key_len = 0,
+	};
+	int err = 0;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		sha256_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, sizeof(test_input), 0, &input_ptr);
+	bpf_dynptr_from_mem(sha256_output, sizeof(sha256_output), 0, &output_ptr);
+
+	sha256_status = bpf_crypto_hash(hash_ctx, &input_ptr, &output_ptr);
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+SEC("syscall")
+int test_sha384(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha384",
+		.key_len = 0,
+	};
+	int err = 0;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		sha384_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, sizeof(test_input), 0, &input_ptr);
+	bpf_dynptr_from_mem(sha384_output, sizeof(sha384_output), 0, &output_ptr);
+
+	sha384_status = bpf_crypto_hash(hash_ctx, &input_ptr, &output_ptr);
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+SEC("syscall")
+int test_sha512(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha512",
+		.key_len = 0,
+	};
+	int err = 0;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		sha512_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, sizeof(test_input), 0, &input_ptr);
+	bpf_dynptr_from_mem(sha512_output, sizeof(sha512_output), 0, &output_ptr);
+
+	sha512_status = bpf_crypto_hash(hash_ctx, &input_ptr, &output_ptr);
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+SEC("syscall")
+int test_sha256_zero_len(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha256",
+		.key_len = 0,
+	};
+	int err = 0;
+	int ret;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		sha256_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, 0, 0, &input_ptr);
+	bpf_dynptr_from_mem(sha256_output, sizeof(sha256_output), 0, &output_ptr);
+
+	ret = bpf_crypto_hash(hash_ctx, &input_ptr, &output_ptr);
+	sha256_status = (ret == -22) ? 0 : ret;
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+/* Test that hash context creation with a key is rejected */
+SEC("syscall")
+int test_hash_with_key_rejected(void *ctx)
+{
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha256",
+		.key_len = 16, /* Hash algorithms don't support keys */
+	};
+	int err = 0;
+
+	/* Set some dummy key data */
+	params.key[0] = 0x01;
+	params.key[1] = 0x02;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		/* Expected: should fail with -EINVAL (-22) */
+		hash_with_key_status = (err == -22) ? 0 : err;
+		return 0;
+	}
+
+	/* Should not reach here - context creation should have failed */
+	hash_with_key_status = -1;
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+/* Test that hash with output buffer too small is rejected */
+SEC("syscall")
+int test_hash_output_too_small(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *hash_ctx;
+	struct bpf_crypto_params params = {
+		.type = "hash",
+		.algo = "sha256",
+		.key_len = 0,
+	};
+	int err = 0;
+	int ret;
+
+	hash_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!hash_ctx) {
+		hash_output_too_small_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, sizeof(test_input), 0, &input_ptr);
+	bpf_dynptr_from_mem(small_output, sizeof(small_output), 0, &output_ptr);
+
+	ret = bpf_crypto_hash(hash_ctx, &input_ptr, &output_ptr);
+	/* Expected: should fail with -EINVAL (-22) */
+	hash_output_too_small_status = (ret == -22) ? 0 : ret;
+	bpf_crypto_ctx_release(hash_ctx);
+	return 0;
+}
+
+/* Test that calling bpf_crypto_hash on skcipher context fails */
+SEC("syscall")
+int test_hash_on_skcipher_ctx(void *ctx)
+{
+	struct bpf_dynptr input_ptr, output_ptr;
+	struct bpf_crypto_ctx *cipher_ctx;
+	struct bpf_crypto_params params = {
+		.type = "skcipher",
+		.algo = "ecb(aes)",
+		.key_len = 16,
+	};
+	int err = 0;
+	int ret;
+
+	/* Set a valid AES-128 key */
+	params.key[0] = 0x00; params.key[1] = 0x01; params.key[2] = 0x02; params.key[3] = 0x03;
+	params.key[4] = 0x04; params.key[5] = 0x05; params.key[6] = 0x06; params.key[7] = 0x07;
+	params.key[8] = 0x08; params.key[9] = 0x09; params.key[10] = 0x0a; params.key[11] = 0x0b;
+	params.key[12] = 0x0c; params.key[13] = 0x0d; params.key[14] = 0x0e; params.key[15] = 0x0f;
+
+	cipher_ctx = bpf_crypto_ctx_create(&params, sizeof(params), &err);
+	if (!cipher_ctx) {
+		hash_on_skcipher_status = err;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(test_input, sizeof(test_input), 0, &input_ptr);
+	bpf_dynptr_from_mem(sha256_output, sizeof(sha256_output), 0, &output_ptr);
+
+	ret = bpf_crypto_hash(cipher_ctx, &input_ptr, &output_ptr);
+	/* Expected: should fail with -EINVAL (-22) due to type_id mismatch */
+	hash_on_skcipher_status = (ret == -22) ? 0 : ret;
+	bpf_crypto_ctx_release(cipher_ctx);
+	return 0;
+}
+
+char __license[] SEC("license") = "GPL";
-- 
2.52.0