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Secure link working
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@podhrmic
podhrmic committed Nov 27, 2017
1 parent ddc9c0b commit 48d81ec
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Showing 3 changed files with 23 additions and 19 deletions.
30 changes: 15 additions & 15 deletions lib/v1.0/C/secure_pprz_transport.c
View file
Expand Up @@ -149,32 +149,32 @@ static void end_message(struct spprz_transport *trans, struct link_device *dev,
// copy message to the tx buffer
memcpy(&trans->tx_buffer[trans->tx_idx], trans->tx_msg.msg, trans->tx_msg.msg_idx);
trans->tx_idx += trans->tx_msg.msg_idx;

// return without sending anything
return;
}

// set nonce
trans->tx_cnt++; // increment first
memcpy(trans->tx_msg.nonce, &trans->tx_cnt, sizeof(uint32_t)); // simply copy 4 byte counter
memcpy(trans->tx_nonce, &trans->tx_cnt, sizeof(uint32_t)); // simply copy 4 byte counter
trans->tx_idx = 2; // explicitly set the value

// append counter to the buffer
memcpy(&trans->tx_buffer[trans->tx_idx], &trans->tx_cnt, sizeof(uint32_t));
trans->tx_idx += sizeof(uint32_t);

// we authenticate the counter
memcpy(trans->tx_msg.aad, &trans->tx_cnt, sizeof(uint32_t));
trans->tx_msg.aad_idx += sizeof(uint32_t);
// // we authenticate the counter
//memcpy(trans->tx_msg.aad, &trans->tx_cnt, sizeof(uint32_t));
//trans->tx_msg.aad_idx += sizeof(uint32_t);

// encrypt
uint32_t res = Chacha20Poly1305_aead_encrypt(&trans->tx_buffer[trans->tx_idx], // ciphertext
trans->tx_msg.mac, // mac
trans->tx_msg.msg, // plaintext
trans->tx_msg.msg_idx, // plaintext len
trans->tx_msg.aad, // aad
trans->tx_msg.aad_idx, // aad len
NULL,//trans->tx_msg.aad, // aad
0,//trans->tx_msg.aad_idx, // aad len
trans->tx_key, // key
trans->tx_msg.nonce); // nonce
trans->tx_nonce); // nonce

// check result
if (res != 0) {
Expand All @@ -183,7 +183,7 @@ static void end_message(struct spprz_transport *trans, struct link_device *dev,
}

// increment tx buffer index with the ciphertext
trans->tx_cnt += trans->tx_msg.msg_idx;
trans->tx_idx += trans->tx_msg.msg_idx;

// append 16 byte tag to the tx buffer
memcpy(&trans->tx_buffer[trans->tx_idx], trans->tx_msg.mac, PPRZ_MAC_LEN);
Expand All @@ -194,7 +194,7 @@ static void end_message(struct spprz_transport *trans, struct link_device *dev,
trans->ck_b_tx = trans->tx_buffer[PPRZ_MSG_LEN_IDX];

// calculate checksum
for (uint8_t i = 1; i < trans->tx_idx; i++) {
for (uint8_t i = 2; i < trans->tx_idx; i++) {
accumulate_checksum(trans, trans->tx_buffer[i]);
}

Expand All @@ -218,7 +218,7 @@ extern void spprz_send_plaintext(struct link_device *dev, struct spprz_transport
trans->ck_b_tx = trans->tx_buffer[PPRZ_MSG_LEN_IDX];

// calculate checksum
for (uint8_t i = 1; i < trans->tx_idx; i++) {
for (uint8_t i = 2; i < trans->tx_idx; i++) {
accumulate_checksum(trans, trans->tx_buffer[i]);
}

Expand Down Expand Up @@ -359,7 +359,7 @@ inline void spprz_handle_encrypted_message(struct spprz_transport *trans, uint8_
}

// update nonce
memcpy(trans->rx_msg.nonce, &new_cnt, PPRZ_COUNTER_LEN);
memcpy(trans->rx_nonce, &new_cnt, PPRZ_COUNTER_LEN);

// authenticate and decrypt
memset(&(trans->rx_msg), 0, sizeof(trans->rx_msg)); // erase aux variables
Expand All @@ -369,10 +369,10 @@ inline void spprz_handle_encrypted_message(struct spprz_transport *trans, uint8_
&trans->trans_rx.payload[PPRZ_CIPHERTEXT_IDX], // ciphertext
clen, // ciphertext len
&trans->trans_rx.payload[PPRZ_CIPHERTEXT_IDX + clen], // mac
&trans->trans_rx.payload[PPRZ_COUNTER_IDX], // aad (counter)
PPRZ_COUNTER_LEN, // aad len
NULL,//&trans->trans_rx.payload[PPRZ_COUNTER_IDX], // aad (counter)
0,//PPRZ_COUNTER_LEN, // aad len
trans->rx_key, // key
trans->rx_msg.nonce); // nonce
trans->rx_nonce); // nonce

if (res != 0) {
*msg_available = false;
Expand Down
5 changes: 3 additions & 2 deletions lib/v1.0/C/secure_pprz_transport.h
View file
Expand Up @@ -67,13 +67,12 @@ extern "C" {

#define PPRZ_MSG_LEN_IDX 1
#define PPRZ_COUNTER_IDX 2
#define PPRZ_CIPHERTEXT_IDX 6
#define PPRZ_CIPHERTEXT_IDX 4

struct spprz_message {
uint8_t msg[PPRZ_MAX_PAYLOAD_LEN]; // ciphertext/plaintext
uint8_t msg_idx; // msg length
uint8_t mac[PPRZ_MAC_LEN]; // message authentication tag
uint8_t nonce[PPRZ_NONCE_LEN]; // nonce (using only 4 bytes)
uint8_t aad[PPRZ_MAX_AAD_LEN]; // additional authentication data
uint8_t aad_idx; // aad length
};
Expand All @@ -100,8 +99,10 @@ struct spprz_transport {
uint8_t tx_idx; // length of outgoing buffer
uint8_t rx_key[PPRZ_KEY_LEN]; // key to decrypt incoming messages
uint32_t rx_cnt; // counter (IV) for incoming messages
uint8_t rx_nonce[PPRZ_NONCE_LEN]; // nonce
uint8_t tx_key[PPRZ_KEY_LEN]; // key to encrypt outgoing messages
uint32_t tx_cnt; // counter (IV) for outgoing messages
uint8_t tx_nonce[PPRZ_NONCE_LEN]; // nonce

bool crypto_ok; // when true it is ok to send encrypted messages (i.e. the key exchange happened)
uint32_t decrypt_err;
Expand Down
7 changes: 5 additions & 2 deletions message_definitions/v1.0/messages.xml
View file
Expand Up @@ -1988,10 +1988,13 @@
<field name="msg_data" type="uint8[]"/>
</message>

<message name="SPRRZ_STATUS" id="255">
<description>Message for monitoring ket exchange status</description>
<message name="SPPRZ_STATUS" id="255">
<description>Message for monitoring key exchange status</description>
<field name="sts_stage" type="uint8" values="INIT|WAIT_MSG1|WAIT_MSG2|WAIT_MSG3|CRYPTO_OK"/>
<field name="sts_error" type="uint8" values="NONE|MSG1_TIMEOUT|MSG1_ENCRYPT|MSG3_TIMEOUT|MSG3_DECRYPT|MSG3_SIGNVERIFY|MSG2_TIMEOUT|MSG2_DECRYPT|MSG2_SIGNVERIFY|MSG3_ENCRYPT|UNEXPECTED_TYPE|UNEXPECTED_STAGE|UNEXPECTED_MSG"/>
<field name="counter_err" type="uint32"/>
<field name="decrypt_err" type="uint32"/>
<field name="encrypt_err" type="uint32"/>
</message>

</msg_class>
Expand Down

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