[linux-next:master 11333/13846] lib/crypto/tests/aes_ccm_kunit.c:317 test_aes_ccm_data_len_too_large() warn: always true condition '(max_data_len + 1 <= (~0)) => (0-u64max <= u64max)'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   6b8c8af514d739d0335f5579b585e02babe8a727
commit: 78c1bc21eb055681672da1de139d27865b67d1b2 [11333/13846] lib/crypto: tests: Add KUnit test suite for AES-CCM
config: s390-randconfig-r072-20260807 (https://download.01.org/0day-ci/archive/20260808/[email protected]/config)
compiler: s390-linux-gcc (GCC) 8.5.0
smatch: v0.5.0-9187-g5189e3fb

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

smatch warnings:
lib/crypto/tests/aes_ccm_kunit.c:317 test_aes_ccm_data_len_too_large() warn: always true condition '(max_data_len + 1 <= (~0)) => (0-u64max <= u64max)'

vim +317 lib/crypto/tests/aes_ccm_kunit.c

   261	
   262	/*
   263	 * Test that for each AES-CCM nonce length, the message length is validated
   264	 * against the correct corresponding maximum message length.
   265	 */
   266	static void test_aes_ccm_data_len_too_large(struct kunit *test)
   267	{
   268		static const struct {
   269			size_t nonce_len;
   270			u64 max_data_len;
   271		} lens[] = {
   272			/* clang-format off */
   273			{ 7, 0xffffffffffffffff }, /* U64_MAX */
   274			{ 8, 0xffffffffffffff },
   275			{ 9, 0xffffffffffff },
   276			{ 10, 0xffffffffff },
   277			{ 11, 0xffffffff },
   278			{ 12, 0xffffff },
   279			{ 13, 0xffff },
   280			/* clang-format on */
   281		};
   282		u8 nonce[13] = {};
   283		u8 raw_key[AES_KEYSIZE_256] = {};
   284		int err;
   285		struct aes_ccm_key *key = alloc_buf(test, sizeof(*key));
   286		struct aes_ccm_ctx ctx;
   287	
   288		err = aes_ccm_preparekey(key, raw_key, sizeof(raw_key), 16);
   289		KUNIT_ASSERT_EQ(test, 0, err);
   290	
   291		for (size_t i = 0; i < ARRAY_SIZE(lens); i++) {
   292			size_t nonce_len = lens[i].nonce_len;
   293			u64 max_data_len = lens[i].max_data_len;
   294	
   295			/* data_len <= max_data_len should be accepted. */
   296			err = aes_ccm_init(&ctx, 0, 0, nonce, nonce_len, key);
   297			KUNIT_ASSERT_EQ_MSG(
   298				test, 0, err,
   299				"data_len=0 wasn't accepted with nonce_len=%zu",
   300				nonce_len);
   301			err = aes_ccm_init(&ctx, max_data_len, 0, nonce, nonce_len,
   302					   key);
   303			KUNIT_ASSERT_EQ_MSG(
   304				test, 0, err,
   305				"data_len=%llu wasn't accepted with nonce_len=%zu",
   306				max_data_len, nonce_len);
   307	
   308			/* data_len > max_data_len should be rejected. */
   309			if (max_data_len == U64_MAX)
   310				continue;
   311			err = aes_ccm_init(&ctx, max_data_len + 1, 0, nonce, nonce_len,
   312					   key);
   313			KUNIT_ASSERT_EQ_MSG(
   314				test, -EOVERFLOW, err,
   315				"data_len=%llu wasn't rejected with -EOVERFLOW with nonce_len=%zu (aes_ccm_init)",
   316				max_data_len + 1, nonce_len);
 > 317			if (max_data_len + 1 <= SIZE_MAX) {
   318				err = aes_ccm_encrypt(NULL, NULL, max_data_len + 1,
   319						      NULL, NULL, 0, nonce, nonce_len,
   320						      key);
   321				KUNIT_ASSERT_EQ_MSG(
   322					test, -EOVERFLOW, err,
   323					"data_len=%llu wasn't rejected with -EOVERFLOW with nonce_len=%zu (aes_ccm_encrypt)",
   324					max_data_len + 1, nonce_len);
   325				err = aes_ccm_decrypt(NULL, NULL, max_data_len + 1,
   326						      NULL, NULL, 0, nonce, nonce_len,
   327						      key);
   328				KUNIT_ASSERT_EQ_MSG(
   329					test, -EOVERFLOW, err,
   330					"data_len=%llu wasn't rejected with -EOVERFLOW with nonce_len=%zu (aes_ccm_decrypt)",
   331					max_data_len + 1, nonce_len);
   332			}
   333			err = aes_ccm_init(&ctx, U64_MAX, 0, nonce, nonce_len, key);
   334			KUNIT_ASSERT_EQ_MSG(
   335				test, -EOVERFLOW, err,
   336				"data_len=U64_MAX wasn't rejected with -EOVERFLOW with nonce_len=%zu (aes_ccm_init)",
   337				nonce_len);
   338		}
   339	}
   340	

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