RIOT-OS/RIOT
RIOT-OS/RIOT
1
0
Fork 0
mirror of https://github.com/RIOT-OS/RIOT.git synced 2024-12-29 04:50:03 +01:00
Code Releases Activity

Merge pull request #8112 from cladmi/pr/crypto/input_len

Browse Source 
crypto/ccm: fix input_len checking with length_encoding
This commit is contained in:
Gaëtan Harter 2018-05-09 18:56:34 +02:00 committed by GitHub
commit d0f22b787c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 73 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
sys/crypto/modes/ccm.c
View File

@ -129,6 +129,17 @@ int ccm_compute_adata_mac(cipher_t* cipher, uint8_t* auth_data,
}
/* Check if 'value' can be stored in 'num_bytes' */
static inline int _fits_in_nbytes(size_t value, uint8_t num_bytes)
{
/* Not allowed to shift more or equal than left operand width
* So we shift by maximum num bits of size_t -1 and compare to 1
*/
unsigned shift = (8 * min(sizeof(size_t), num_bytes)) - 1;
return (value >> shift) <= 1;
}
int cipher_encrypt_ccm(cipher_t* cipher, uint8_t* auth_data, uint32_t auth_data_len,
uint8_t mac_length, uint8_t length_encoding,
uint8_t* nonce, size_t nonce_len,
@ -136,7 +147,6 @@ int cipher_encrypt_ccm(cipher_t* cipher, uint8_t* auth_data, uint32_t auth_data_
uint8_t* output)
{
int len = -1;
uint32_t length_max;
uint8_t nonce_counter[16] = {0}, mac_iv[16] = {0}, mac[16] = {0},
stream_block[16] = {0}, zero_block[16] = {0}, block_size;
@ -144,9 +154,8 @@ int cipher_encrypt_ccm(cipher_t* cipher, uint8_t* auth_data, uint32_t auth_data_
return CCM_ERR_INVALID_MAC_LENGTH;
}
length_max = 2 << (8 * length_encoding);
if (length_encoding < 2 || length_encoding > 8 ||
input_len - auth_data_len > length_max) {
!_fits_in_nbytes(input_len, length_encoding)) {
return CCM_ERR_INVALID_LENGTH_ENCODING;
}
@ -197,7 +206,6 @@ int cipher_decrypt_ccm(cipher_t* cipher, uint8_t* auth_data,
uint8_t* input, size_t input_len, uint8_t* plain)
{
int len = -1;
uint32_t length_max;
uint8_t nonce_counter[16] = {0}, mac_iv[16] = {0}, mac[16] = {0},
mac_recv[16] = {0}, stream_block[16] = {0}, zero_block[16] = {0},
plain_len, block_size;
@ -206,9 +214,8 @@ int cipher_decrypt_ccm(cipher_t* cipher, uint8_t* auth_data,
return CCM_ERR_INVALID_MAC_LENGTH;
}
length_max = 2 << (8 * length_encoding);
if (length_encoding < 2 || length_encoding > 8 ||
input_len - auth_data_len > length_max) {
!_fits_in_nbytes(input_len, length_encoding)) {
return CCM_ERR_INVALID_LENGTH_ENCODING;
}

60
tests/unittests/tests-crypto/tests-crypto-modes-ccm.c
View File

@ -190,11 +190,71 @@ static void test_crypto_modes_ccm_decrypt(void)
}
typedef int (*func_ccm_t)(cipher_t*, uint8_t*, uint32_t, uint8_t, uint8_t,
uint8_t*, size_t, uint8_t*, size_t, uint8_t*);
static int _test_ccm_len(func_ccm_t func, uint8_t len_encoding,
uint8_t *input, size_t input_len, size_t adata_len)
{
int ret;
cipher_t cipher;
uint8_t mac_length = 8;
uint8_t nonce[15] = {0};
uint8_t key[16] = {0};
uint8_t nonce_len = nonce_and_len_encoding_size - len_encoding;
cipher_init(&cipher, CIPHER_AES_128, key, 16);
ret = func(&cipher, NULL, adata_len, mac_length, len_encoding,
nonce, nonce_len, input, input_len, data);
return ret;
}
/* Test length checking in ccm functions. */
static void test_crypto_modes_ccm_check_len(void)
{
int ret;
/* Just 1 to big to fit */
ret = _test_ccm_len(cipher_encrypt_ccm, 2, NULL, 1 << 16, 0);
TEST_ASSERT_EQUAL_INT(CCM_ERR_INVALID_LENGTH_ENCODING, ret);
ret = _test_ccm_len(cipher_decrypt_ccm, 2, NULL, 1 << 16, 0);
TEST_ASSERT_EQUAL_INT(CCM_ERR_INVALID_LENGTH_ENCODING, ret);
/* adata_len should not change the result (was wrong in previous implem) */
ret = _test_ccm_len(cipher_encrypt_ccm, 2, NULL, 1 << 16, 65535);
TEST_ASSERT_EQUAL_INT(CCM_ERR_INVALID_LENGTH_ENCODING, ret);
ret = _test_ccm_len(cipher_decrypt_ccm, 2, NULL, 1 << 16, 65535);
TEST_ASSERT_EQUAL_INT(CCM_ERR_INVALID_LENGTH_ENCODING, ret);
/* Valid length that were wrongly checked */
/* Check should work with len_encoding >= 4, test with 8 */
uint8_t input[8];
ret = _test_ccm_len(cipher_encrypt_ccm, 8, input, 8, 0);
TEST_ASSERT_MESSAGE(ret > 0, "Encryption : failed with valid input_len");
/* einput is encrypted value for
* - 8 * 0 input
* - All 0 nonce and key
* - adata_len == 0
* - mac_len == 8 and len_encoding = 8
*/
uint8_t einput[16] = {
0xa2, 0x46, 0x75, 0xfc, 0x5f, 0x1b, 0x01, 0x37,
0x8a, 0x85, 0xd7, 0xf8, 0x42, 0x82, 0x6a, 0x63,
};
ret = _test_ccm_len(cipher_decrypt_ccm, 8, einput, 16, 0);
TEST_ASSERT_MESSAGE(ret > 0, "Decryption : failed with valid input_len");
}
Test* tests_crypto_modes_ccm_tests(void)
{
EMB_UNIT_TESTFIXTURES(fixtures) {
new_TestFixture(test_crypto_modes_ccm_encrypt),
new_TestFixture(test_crypto_modes_ccm_decrypt),
new_TestFixture(test_crypto_modes_ccm_check_len),
};
EMB_UNIT_TESTCALLER(crypto_modes_ccm_tests, NULL, NULL, fixtures);