eapol: encrypt key data for AKM-defined ciphers

Support encrypting key data when the cipher is AKM-defined. This is
needed to support SAE in AP mode.
This commit is contained in:
John Brandt 2024-05-05 17:30:35 -07:00 committed by Denis Kenzior
parent 3132e9f595
commit 78bdb26296
1 changed files with 38 additions and 15 deletions

View File

@ -387,6 +387,23 @@ error:
return NULL;
}
static int padded_aes_wrap(const uint8_t *kek, uint8_t *key_data,
size_t *key_data_len,
struct eapol_key *out_frame, size_t mic_len)
{
if (*key_data_len < 16 || *key_data_len % 8)
key_data[(*key_data_len)++] = 0xdd;
while (*key_data_len < 16 || *key_data_len % 8)
key_data[(*key_data_len)++] = 0x00;
if (!aes_wrap(kek, key_data, *key_data_len,
EAPOL_KEY_DATA(out_frame, mic_len)))
return -ENOPROTOOPT;
*key_data_len += 8;
return 0;
}
/*
* Pad and encrypt the plaintext Key Data contents in @key_data using
* the encryption scheme required by @out_frame->key_descriptor_version,
@ -395,12 +412,12 @@ error:
* Note that for efficiency @key_data is being modified, including in
* case of failure, so it must be sufficiently larger than @key_data_len.
*/
static int eapol_encrypt_key_data(const uint8_t *kek, uint8_t *key_data,
size_t key_data_len,
static int eapol_encrypt_key_data(enum ie_rsn_akm_suite akm, const uint8_t *kek,
uint8_t *key_data, size_t key_data_len,
struct eapol_key *out_frame, size_t mic_len)
{
uint8_t key[32];
bool ret;
int ret;
switch (out_frame->key_descriptor_version) {
case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4:
@ -426,18 +443,23 @@ static int eapol_encrypt_key_data(const uint8_t *kek, uint8_t *key_data,
break;
case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES:
case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES:
if (key_data_len < 16 || key_data_len % 8)
key_data[key_data_len++] = 0xdd;
while (key_data_len < 16 || key_data_len % 8)
key_data[key_data_len++] = 0x00;
if (!aes_wrap(kek, key_data, key_data_len,
EAPOL_KEY_DATA(out_frame, mic_len)))
return -ENOPROTOOPT;
key_data_len += 8;
ret = padded_aes_wrap(kek, key_data, &key_data_len,
out_frame, mic_len);
if (ret < 0)
return ret;
break;
case EAPOL_KEY_DESCRIPTOR_VERSION_AKM_DEFINED:
switch (akm) {
case IE_RSN_AKM_SUITE_SAE_SHA256:
ret = padded_aes_wrap(kek, key_data, &key_data_len,
out_frame, mic_len);
if (ret < 0)
return ret;
break;
default:
return -ENOTSUP;
}
}
l_put_be16(key_data_len, EAPOL_KEY_DATA(out_frame, mic_len) - 2);
@ -1467,8 +1489,9 @@ static void eapol_send_ptk_3_of_4(struct eapol_sm *sm)
}
kek = handshake_state_get_kek(sm->handshake);
key_data_len = eapol_encrypt_key_data(kek, key_data_buf,
key_data_len, ek, sm->mic_len);
key_data_len = eapol_encrypt_key_data(sm->handshake->akm_suite, kek,
key_data_buf, key_data_len, ek,
sm->mic_len);
explicit_bzero(key_data_buf, sizeof(key_data_buf));
if (key_data_len < 0)