Message-ID: <20251117211413.1394-5-git@danielhodges.dev>
Date: Mon, 17 Nov 2025 16:14:01 -0500
From: Daniel Hodges <git@...ielhodges.dev>
To: Andrii Nakryiko <andrii@...nel.org>,
	Eduard Zingerman <eddyz87@...il.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Daniel Hodges <git@...ielhodges.dev>,
	linux-kernel@...r.kernel.org (open list),
	bpf@...r.kernel.org (open list:BPF [SELFTESTS] (Test Runners & Infrastructure)),
	linux-kselftest@...r.kernel.org (open list:KERNEL SELFTEST FRAMEWORK)
Subject: [PATCH bpf-next 4/4] selftests/bpf: Add tests for ECDSA signature verification kfuncs

Add selftests to validate the ECDSA signature verification kfuncs
introduced in the BPF crypto subsystem. The tests verify both valid
signature acceptance and invalid signature rejection using the
context-based ECDSA API.

The tests use RFC 6979 test vectors for NIST P-256 (secp256r1) with
well-known valid signatures. The algorithm "p1363(ecdsa-nist-p256)"
is used to handle standard r||s signature format.

Signed-off-by: Daniel Hodges <git@...ielhodges.dev>
---
 .../selftests/bpf/prog_tests/ecdsa_verify.c   |  96 ++++++++
 .../selftests/bpf/progs/ecdsa_verify.c        | 228 ++++++++++++++++++
 2 files changed, 324 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/ecdsa_verify.c
 create mode 100644 tools/testing/selftests/bpf/progs/ecdsa_verify.c

diff --git a/tools/testing/selftests/bpf/prog_tests/ecdsa_verify.c b/tools/testing/selftests/bpf/prog_tests/ecdsa_verify.c
new file mode 100644
index 000000000000..d1f83ce08ad6
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ecdsa_verify.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "ecdsa_verify.skel.h"
+
+static void test_ecdsa_verify_valid_signature(void)
+{
+	struct ecdsa_verify *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = ecdsa_verify__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "ecdsa_verify__open_and_load"))
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_ecdsa_verify_valid);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_ecdsa_verify_valid");
+	ASSERT_EQ(skel->data->ctx_create_status, 0, "ctx_create_status");
+	ASSERT_EQ(skel->data->verify_result, 0, "verify_valid_signature");
+
+	ecdsa_verify__destroy(skel);
+}
+
+static void test_ecdsa_verify_invalid_signature(void)
+{
+	struct ecdsa_verify *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = ecdsa_verify__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "ecdsa_verify__open_and_load"))
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_ecdsa_verify_invalid);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_ecdsa_verify_invalid");
+	ASSERT_NEQ(skel->data->verify_invalid_result, 0, "verify_invalid_signature_rejected");
+
+	ecdsa_verify__destroy(skel);
+}
+
+static void test_ecdsa_sign_and_verify(void)
+{
+	struct ecdsa_verify *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = ecdsa_verify__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "ecdsa_verify__open_and_load"))
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_ecdsa_sign_verify);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_ecdsa_sign_verify");
+	ASSERT_GT(skel->data->sign_result, 0, "sign_returns_signature_size");
+	ASSERT_EQ(skel->data->sign_verify_result, 0, "verify_generated_signature");
+
+	ecdsa_verify__destroy(skel);
+}
+
+static void test_ecdsa_size_queries(void)
+{
+	struct ecdsa_verify *skel;
+	int err, prog_fd;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	skel = ecdsa_verify__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "ecdsa_verify__open_and_load"))
+		return;
+
+	prog_fd = bpf_program__fd(skel->progs.test_ecdsa_size_queries);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_ecdsa_size_queries");
+	ASSERT_EQ(skel->data->keysize_result, 256, "keysize_p256");
+	ASSERT_EQ(skel->data->digestsize_result, 64, "digestsize_p256");
+	ASSERT_EQ(skel->data->maxsize_result, 64, "maxsize_p256");
+
+	ecdsa_verify__destroy(skel);
+}
+
+void test_ecdsa_verify(void)
+{
+	if (test__start_subtest("verify_valid_signature"))
+		test_ecdsa_verify_valid_signature();
+	if (test__start_subtest("verify_invalid_signature"))
+		test_ecdsa_verify_invalid_signature();
+	if (test__start_subtest("sign_and_verify"))
+		test_ecdsa_sign_and_verify();
+	if (test__start_subtest("size_queries"))
+		test_ecdsa_size_queries();
+}
diff --git a/tools/testing/selftests/bpf/progs/ecdsa_verify.c b/tools/testing/selftests/bpf/progs/ecdsa_verify.c
new file mode 100644
index 000000000000..fb24baf6c437
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/ecdsa_verify.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct bpf_ecdsa_ctx;
+extern struct bpf_ecdsa_ctx *
+bpf_ecdsa_ctx_create(const struct bpf_dynptr *algo_name,
+		     const struct bpf_dynptr *public_key, int *err) __ksym;
+extern struct bpf_ecdsa_ctx *
+bpf_ecdsa_ctx_create_with_privkey(const struct bpf_dynptr *algo_name,
+				   const struct bpf_dynptr *private_key, int *err) __ksym;
+extern int bpf_ecdsa_verify(struct bpf_ecdsa_ctx *ctx,
+			    const struct bpf_dynptr *message,
+			    const struct bpf_dynptr *signature) __ksym;
+extern int bpf_ecdsa_sign(struct bpf_ecdsa_ctx *ctx,
+			  const struct bpf_dynptr *message,
+			  const struct bpf_dynptr *signature) __ksym;
+extern int bpf_ecdsa_keysize(struct bpf_ecdsa_ctx *ctx) __ksym;
+extern int bpf_ecdsa_digestsize(struct bpf_ecdsa_ctx *ctx) __ksym;
+extern int bpf_ecdsa_maxsize(struct bpf_ecdsa_ctx *ctx) __ksym;
+extern void bpf_ecdsa_ctx_release(struct bpf_ecdsa_ctx *ctx) __ksym;
+
+/* NIST P-256 test vector
+ * This is a known valid ECDSA signature for testing purposes
+ */
+
+/* Algorithm name for P-256 with p1363 format (standard r||s signature) */
+char algo_p256[] = "p1363(ecdsa-nist-p256)";
+
+/* Public key in uncompressed format: 0x04 || x || y (65 bytes) */
+unsigned char pubkey_p256[65] = {
+	0x04, /* Uncompressed point indicator */
+	/* X coordinate (32 bytes) */
+	0x60, 0xfe, 0xd4, 0xba, 0x25, 0x5a, 0x9d, 0x31,
+	0xc9, 0x61, 0xeb, 0x74, 0xc6, 0x35, 0x6d, 0x68,
+	0xc0, 0x49, 0xb8, 0x92, 0x3b, 0x61, 0xfa, 0x6c,
+	0xe6, 0x69, 0x62, 0x2e, 0x60, 0xf2, 0x9f, 0xb6,
+	/* Y coordinate (32 bytes) */
+	0x79, 0x03, 0xfe, 0x10, 0x08, 0xb8, 0xbc, 0x99,
+	0xa4, 0x1a, 0xe9, 0xe9, 0x56, 0x28, 0xbc, 0x64,
+	0xf2, 0xf1, 0xb2, 0x0c, 0x2d, 0x7e, 0x9f, 0x51,
+	0x77, 0xa3, 0xc2, 0x94, 0xd4, 0x46, 0x22, 0x99
+};
+
+/* Message hash (32 bytes) - SHA-256 of "sample" */
+unsigned char message_hash[32] = {
+	0xaf, 0x2b, 0xdb, 0xe1, 0xaa, 0x9b, 0x6e, 0xc1,
+	0xe2, 0xad, 0xe1, 0xd6, 0x94, 0xf4, 0x1f, 0xc7,
+	0x1a, 0x83, 0x1d, 0x02, 0x68, 0xe9, 0x89, 0x15,
+	0x62, 0x11, 0x3d, 0x8a, 0x62, 0xad, 0xd1, 0xbf
+};
+
+/* Valid signature r || s (64 bytes) */
+unsigned char valid_signature[64] = {
+	/* r component (32 bytes) */
+	0xef, 0xd4, 0x8b, 0x2a, 0xac, 0xb6, 0xa8, 0xfd,
+	0x11, 0x40, 0xdd, 0x9c, 0xd4, 0x5e, 0x81, 0xd6,
+	0x9d, 0x2c, 0x87, 0x7b, 0x56, 0xaa, 0xf9, 0x91,
+	0xc3, 0x4d, 0x0e, 0xa8, 0x4e, 0xaf, 0x37, 0x16,
+	/* s component (32 bytes) */
+	0xf7, 0xcb, 0x1c, 0x94, 0x2d, 0x65, 0x7c, 0x41,
+	0xd4, 0x36, 0xc7, 0xa1, 0xb6, 0xe2, 0x9f, 0x65,
+	0xf3, 0xe9, 0x00, 0xdb, 0xb9, 0xaf, 0xf4, 0x06,
+	0x4d, 0xc4, 0xab, 0x2f, 0x84, 0x3a, 0xcd, 0xa8
+};
+
+/* Invalid signature (modified r component) for negative test */
+unsigned char invalid_signature[64] = {
+	/* r component (32 bytes) - first byte modified */
+	0xff, 0xd4, 0x8b, 0x2a, 0xac, 0xb6, 0xa8, 0xfd,
+	0x11, 0x40, 0xdd, 0x9c, 0xd4, 0x5e, 0x81, 0xd6,
+	0x9d, 0x2c, 0x87, 0x7b, 0x56, 0xaa, 0xf9, 0x91,
+	0xc3, 0x4d, 0x0e, 0xa8, 0x4e, 0xaf, 0x37, 0x16,
+	/* s component (32 bytes) */
+	0xf7, 0xcb, 0x1c, 0x94, 0x2d, 0x65, 0x7c, 0x41,
+	0xd4, 0x36, 0xc7, 0xa1, 0xb6, 0xe2, 0x9f, 0x65,
+	0xf3, 0xe9, 0x00, 0xdb, 0xb9, 0xaf, 0xf4, 0x06,
+	0x4d, 0xc4, 0xab, 0x2f, 0x84, 0x3a, 0xcd, 0xa8
+};
+
+/* Private key for signing (32 bytes) - matches the public key above */
+unsigned char privkey_p256[32] = {
+	0xc9, 0xaf, 0xa9, 0xd8, 0x45, 0xba, 0x75, 0x16,
+	0x6b, 0x5c, 0x21, 0x57, 0x67, 0xb1, 0xd6, 0x93,
+	0x4e, 0x50, 0xc3, 0xdb, 0x36, 0xe8, 0x9b, 0x12,
+	0x7b, 0x8a, 0x62, 0x2b, 0x12, 0x0f, 0x67, 0x21
+};
+
+/* Test results */
+int verify_result = -1;
+int verify_invalid_result = -1;
+int ctx_create_status = -1;
+int sign_result = -1;
+int sign_verify_result = -1;
+int keysize_result = -1;
+int digestsize_result = -1;
+int maxsize_result = -1;
+unsigned char generated_signature[64] = {0};
+
+SEC("syscall")
+int test_ecdsa_verify_valid(void *ctx)
+{
+	struct bpf_ecdsa_ctx *ecdsa_ctx;
+	struct bpf_dynptr algo_ptr, key_ptr, msg_ptr, sig_ptr;
+	int err = 0;
+
+	bpf_dynptr_from_mem(algo_p256, sizeof(algo_p256) - 1, 0, &algo_ptr);
+	bpf_dynptr_from_mem(pubkey_p256, sizeof(pubkey_p256), 0, &key_ptr);
+
+	ecdsa_ctx = bpf_ecdsa_ctx_create(&algo_ptr, &key_ptr, &err);
+	if (!ecdsa_ctx) {
+		ctx_create_status = err;
+		return 0;
+	}
+	ctx_create_status = 0;
+
+	bpf_dynptr_from_mem(message_hash, sizeof(message_hash), 0, &msg_ptr);
+	bpf_dynptr_from_mem(valid_signature, sizeof(valid_signature), 0, &sig_ptr);
+
+	verify_result = bpf_ecdsa_verify(ecdsa_ctx, &msg_ptr, &sig_ptr);
+
+	bpf_ecdsa_ctx_release(ecdsa_ctx);
+
+	return 0;
+}
+
+SEC("syscall")
+int test_ecdsa_verify_invalid(void *ctx)
+{
+	struct bpf_ecdsa_ctx *ecdsa_ctx;
+	struct bpf_dynptr algo_ptr, key_ptr, msg_ptr, sig_ptr;
+	int err = 0;
+
+	bpf_dynptr_from_mem(algo_p256, sizeof(algo_p256) - 1, 0, &algo_ptr);
+	bpf_dynptr_from_mem(pubkey_p256, sizeof(pubkey_p256), 0, &key_ptr);
+
+	ecdsa_ctx = bpf_ecdsa_ctx_create(&algo_ptr, &key_ptr, &err);
+	if (!ecdsa_ctx)
+		return 0;
+
+	bpf_dynptr_from_mem(message_hash, sizeof(message_hash), 0, &msg_ptr);
+	bpf_dynptr_from_mem(invalid_signature, sizeof(invalid_signature), 0, &sig_ptr);
+
+	verify_invalid_result = bpf_ecdsa_verify(ecdsa_ctx, &msg_ptr, &sig_ptr);
+
+	bpf_ecdsa_ctx_release(ecdsa_ctx);
+
+	return 0;
+}
+
+SEC("syscall")
+int test_ecdsa_sign_verify(void *ctx)
+{
+	struct bpf_ecdsa_ctx *sign_ctx, *verify_ctx;
+	struct bpf_dynptr algo_ptr, privkey_ptr, pubkey_ptr, msg_ptr, sig_ptr;
+	int err = 0;
+
+	/* Create signing context with private key */
+	bpf_dynptr_from_mem(algo_p256, sizeof(algo_p256) - 1, 0, &algo_ptr);
+	bpf_dynptr_from_mem(privkey_p256, sizeof(privkey_p256), 0, &privkey_ptr);
+
+	sign_ctx = bpf_ecdsa_ctx_create_with_privkey(&algo_ptr, &privkey_ptr, &err);
+	if (!sign_ctx) {
+		sign_result = err;
+		return 0;
+	}
+
+	/* Sign the message */
+	bpf_dynptr_from_mem(message_hash, sizeof(message_hash), 0, &msg_ptr);
+	bpf_dynptr_from_mem(generated_signature, sizeof(generated_signature), 0, &sig_ptr);
+
+	sign_result = bpf_ecdsa_sign(sign_ctx, &msg_ptr, &sig_ptr);
+
+	bpf_ecdsa_ctx_release(sign_ctx);
+
+	/* If signing succeeded, verify the generated signature */
+	if (sign_result > 0 && sign_result <= (int)sizeof(generated_signature)) {
+		unsigned int sig_size;
+
+		/* Explicitly bound the value for the verifier */
+		sig_size = sign_result & 0x3F; /* Max 64 bytes */
+
+		bpf_dynptr_from_mem(algo_p256, sizeof(algo_p256) - 1, 0, &algo_ptr);
+		bpf_dynptr_from_mem(pubkey_p256, sizeof(pubkey_p256), 0, &pubkey_ptr);
+
+		verify_ctx = bpf_ecdsa_ctx_create(&algo_ptr, &pubkey_ptr, &err);
+		if (!verify_ctx) {
+			sign_verify_result = err;
+			return 0;
+		}
+
+		bpf_dynptr_from_mem(message_hash, sizeof(message_hash), 0, &msg_ptr);
+		bpf_dynptr_from_mem(generated_signature, sig_size, 0, &sig_ptr);
+
+		sign_verify_result = bpf_ecdsa_verify(verify_ctx, &msg_ptr, &sig_ptr);
+
+		bpf_ecdsa_ctx_release(verify_ctx);
+	}
+
+	return 0;
+}
+
+SEC("syscall")
+int test_ecdsa_size_queries(void *ctx)
+{
+	struct bpf_ecdsa_ctx *ecdsa_ctx;
+	struct bpf_dynptr algo_ptr, key_ptr;
+	int err = 0;
+
+	bpf_dynptr_from_mem(algo_p256, sizeof(algo_p256) - 1, 0, &algo_ptr);
+	bpf_dynptr_from_mem(pubkey_p256, sizeof(pubkey_p256), 0, &key_ptr);
+
+	ecdsa_ctx = bpf_ecdsa_ctx_create(&algo_ptr, &key_ptr, &err);
+	if (!ecdsa_ctx)
+		return 0;
+
+	keysize_result = bpf_ecdsa_keysize(ecdsa_ctx);
+	digestsize_result = bpf_ecdsa_digestsize(ecdsa_ctx);
+	maxsize_result = bpf_ecdsa_maxsize(ecdsa_ctx);
+
+	bpf_ecdsa_ctx_release(ecdsa_ctx);
+
+	return 0;
+}
+
+char __license[] SEC("license") = "GPL";
-- 
2.51.0

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