mptcp: move crypto test to KUNIT

currently MPTCP uses a custom hook to executed unit tests at
boot time. Let's use the KUNIT framework instead.
Additionally move the relevant code to a separate file and
export the function needed by the test when self-tests
are build as a module.
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/Kconfig

@@ -18,12 +18,20 @@ config MPTCP_IPV6
 	select IPV6
 	default y
 
-config MPTCP_HMAC_TEST
-	bool "Tests for MPTCP HMAC implementation"
+endif
+
+config MPTCP_KUNIT_TESTS
+	tristate "This builds the MPTCP KUnit tests" if !KUNIT_ALL_TESTS
+	select MPTCP
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
 	help
-	  This option enable boot time self-test for the HMAC implementation
-	  used by the MPTCP code
+	  Currently covers the MPTCP crypto helpers.
+	  Only useful for kernel devs running KUnit test harness and are not
+	  for inclusion into a production build.
 
-	  Say N if you are unsure.
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
 
-endif

net/mptcp/Makefile

@@ -3,3 +3,6 @@ obj-$(CONFIG_MPTCP) += mptcp.o
 
 mptcp-y := protocol.o subflow.o options.o token.o crypto.o ctrl.o pm.o diag.o \
 	   mib.o pm_netlink.o
+
+mptcp_crypto_test-objs := crypto_test.o
+obj-$(CONFIG_MPTCP_KUNIT_TESTS) += mptcp_crypto_test.o
\ No newline at end of file

net/mptcp/crypto.c

@@ -87,65 +87,6 @@ void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac)
 	sha256_final(&state, (u8 *)hmac);
 }
 
-#ifdef CONFIG_MPTCP_HMAC_TEST
-struct test_cast {
-	char *key;
-	char *msg;
-	char *result;
-};
-
-/* we can't reuse RFC 4231 test vectors, as we have constraint on the
- * input and key size.
- */
-static struct test_cast tests[] = {
-	{
-		.key = "0b0b0b0b0b0b0b0b",
-		.msg = "48692054",
-		.result = "8385e24fb4235ac37556b6b886db106284a1da671699f46db1f235ec622dcafa",
-	},
-	{
-		.key = "aaaaaaaaaaaaaaaa",
-		.msg = "dddddddd",
-		.result = "2c5e219164ff1dca1c4a92318d847bb6b9d44492984e1eb71aff9022f71046e9",
-	},
-	{
-		.key = "0102030405060708",
-		.msg = "cdcdcdcd",
-		.result = "e73b9ba9969969cefb04aa0d6df18ec2fcc075b6f23b4d8c4da736a5dbbc6e7d",
-	},
-};
-
-static int __init test_mptcp_crypto(void)
-{
-	char hmac[32], hmac_hex[65];
-	u32 nonce1, nonce2;
-	u64 key1, key2;
-	u8 msg[8];
-	int i, j;
-
-	for (i = 0; i < ARRAY_SIZE(tests); ++i) {
-		/* mptcp hmap will convert to be before computing the hmac */
-		key1 = be64_to_cpu(*((__be64 *)&tests[i].key[0]));
-		key2 = be64_to_cpu(*((__be64 *)&tests[i].key[8]));
-		nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));
-		nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));
-
-		put_unaligned_be32(nonce1, &msg[0]);
-		put_unaligned_be32(nonce2, &msg[4]);
-
-		mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
-		for (j = 0; j < 32; ++j)
-			sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);
-		hmac_hex[64] = 0;
-
-		if (memcmp(hmac_hex, tests[i].result, 64))
-			pr_err("test %d failed, got %s expected %s", i,
-			       hmac_hex, tests[i].result);
-		else
-			pr_info("test %d [ ok ]", i);
-	}
-	return 0;
-}
-
-late_initcall(test_mptcp_crypto);
+#if IS_MODULE(CONFIG_MPTCP_KUNIT_TESTS)
+EXPORT_SYMBOL_GPL(mptcp_crypto_hmac_sha);
 #endif

net/mptcp/crypto_test.c

+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+
+#include "protocol.h"
+
+struct test_case {
+	char *key;
+	char *msg;
+	char *result;
+};
+
+/* we can't reuse RFC 4231 test vectors, as we have constraint on the
+ * input and key size.
+ */
+static struct test_case tests[] = {
+	{
+		.key = "0b0b0b0b0b0b0b0b",
+		.msg = "48692054",
+		.result = "8385e24fb4235ac37556b6b886db106284a1da671699f46db1f235ec622dcafa",
+	},
+	{
+		.key = "aaaaaaaaaaaaaaaa",
+		.msg = "dddddddd",
+		.result = "2c5e219164ff1dca1c4a92318d847bb6b9d44492984e1eb71aff9022f71046e9",
+	},
+	{
+		.key = "0102030405060708",
+		.msg = "cdcdcdcd",
+		.result = "e73b9ba9969969cefb04aa0d6df18ec2fcc075b6f23b4d8c4da736a5dbbc6e7d",
+	},
+};
+
+static void mptcp_crypto_test_basic(struct kunit *test)
+{
+	char hmac[32], hmac_hex[65];
+	u32 nonce1, nonce2;
+	u64 key1, key2;
+	u8 msg[8];
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+		/* mptcp hmap will convert to be before computing the hmac */
+		key1 = be64_to_cpu(*((__be64 *)&tests[i].key[0]));
+		key2 = be64_to_cpu(*((__be64 *)&tests[i].key[8]));
+		nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));
+		nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));
+
+		put_unaligned_be32(nonce1, &msg[0]);
+		put_unaligned_be32(nonce2, &msg[4]);
+
+		mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
+		for (j = 0; j < 32; ++j)
+			sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);
+		hmac_hex[64] = 0;
+
+		KUNIT_EXPECT_STREQ(test, &hmac_hex[0], tests[i].result);
+	}
+}
+
+static struct kunit_case mptcp_crypto_test_cases[] = {
+	KUNIT_CASE(mptcp_crypto_test_basic),
+	{}
+};
+
+static struct kunit_suite mptcp_crypto_suite = {
+	.name = "mptcp-crypto",
+	.test_cases = mptcp_crypto_test_cases,
+};
+
+kunit_test_suite(mptcp_crypto_suite);
+
+MODULE_LICENSE("GPL");