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Bluetooth: audio: Fix byteorder in csip sef crypto function

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Fix byteorder handling in csip sef crypto function.
On big-endian system we also need to convert the k array from
little-endian to big-endian. The Bluetooth protocol is always using
little-endian ordering.

Signed-off-by: Joakim Andersson <joerchan@gmail.com>
This commit is contained in:
Joakim Andersson 2025-01-14 14:21:35 +01:00 • committed by Benjamin Cabé
commit a238e5c29d
3 changed files with 18 additions and 35 deletions
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16
subsys/bluetooth/audio/csip_crypto.c
View file

@ -171,14 +171,8 @@ int bt_csip_sef(const uint8_t k[BT_CSIP_CRYPTO_KEY_SIZE], const uint8_t sirk[BT_
LOG_DBG("SIRK %s", bt_hex(sirk, BT_CSIP_SIRK_SIZE));
if (IS_ENABLED(CONFIG_LITTLE_ENDIAN)) {
/* Swap because aes_cmac is big endian
* and we are little endian
*/
sys_memcpy_swap(k1_tmp, k, sizeof(k1_tmp));
} else {
(void)memcpy(k1_tmp, k, sizeof(k1_tmp));
}
/* Swap because aes_cmac is big endian and k is little endian */
sys_memcpy_swap(k1_tmp, k, sizeof(k1_tmp));
LOG_DBG("BE: k %s", bt_hex(k1_tmp, sizeof(k1_tmp)));
err = s1(m, sizeof(m), s1_out);
@ -195,10 +189,8 @@ int bt_csip_sef(const uint8_t k[BT_CSIP_CRYPTO_KEY_SIZE], const uint8_t sirk[BT_
LOG_DBG("BE: k1 result %s", bt_hex(k1_out, sizeof(k1_out)));
if (IS_ENABLED(CONFIG_LITTLE_ENDIAN)) {
/* Swap result back to little endian */
sys_mem_swap(k1_out, sizeof(k1_out));
}
/* Get result back to little endian. */
sys_mem_swap(k1_out, sizeof(k1_out));
mem_xor_128(out_sirk, k1_out, sirk);
LOG_DBG("out %s", bt_hex(out_sirk, BT_CSIP_SIRK_SIZE));

18
subsys/bluetooth/audio/csip_set_coordinator.c
View file

@ -266,23 +266,19 @@ static int sirk_decrypt(struct bt_conn *conn,
uint8_t *out_sirk)
{
int err;
uint8_t *k;
const uint8_t *k;
if (IS_ENABLED(CONFIG_BT_CSIP_SET_COORDINATOR_TEST_SAMPLE_DATA)) {
/* test_k is from the sample data from A.2 in the CSIS spec */
static uint8_t test_k[] = {0x67, 0x6e, 0x1b, 0x9b,
0xd4, 0x48, 0x69, 0x6f,
0x06, 0x1e, 0xc6, 0x22,
0x3c, 0xe5, 0xce, 0xd9};
static bool swapped;
static const uint8_t test_k[] = {
/* Sample data is in big-endian, we need it in little-endian. */
REVERSE_ARGS(0x67, 0x6e, 0x1b, 0x9b,
0xd4, 0x48, 0x69, 0x6f,
0x06, 0x1e, 0xc6, 0x22,
0x3c, 0xe5, 0xce, 0xd9) };
LOG_DBG("Decrypting with sample data K");
if (!swapped && IS_ENABLED(CONFIG_LITTLE_ENDIAN)) {
/* Swap test_k to little endian */
sys_mem_swap(test_k, 16);
swapped = true;
}
k = test_k;
} else {
k = conn->le.keys->ltk.val;

19
subsys/bluetooth/audio/csip_set_member.c
View file

@ -145,21 +145,16 @@ static int sirk_encrypt(struct bt_conn *conn, const struct bt_csip_sirk *sirk,
struct bt_csip_sirk *enc_sirk)
{
int err;
uint8_t *k;
const uint8_t *k;
if (IS_ENABLED(CONFIG_BT_CSIP_SET_MEMBER_TEST_SAMPLE_DATA)) {
/* test_k is from the sample data from A.2 in the CSIS spec */
static uint8_t test_k[] = {0x67, 0x6e, 0x1b, 0x9b,
0xd4, 0x48, 0x69, 0x6f,
0x06, 0x1e, 0xc6, 0x22,
0x3c, 0xe5, 0xce, 0xd9};
static bool swapped;
if (!swapped && IS_ENABLED(CONFIG_LITTLE_ENDIAN)) {
/* Swap test_k to little endian */
sys_mem_swap(test_k, 16);
swapped = true;
}
static const uint8_t test_k[] = {
/* Sample data is in big-endian, we need it in little-endian. */
+ REVERSE_ARGS(0x67, 0x6e, 0x1b, 0x9b,
0xd4, 0x48, 0x69, 0x6f,
0x06, 0x1e, 0xc6, 0x22,
0x3c, 0xe5, 0xce, 0xd9) };
LOG_DBG("Encrypting test SIRK");
k = test_k;
} else {