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refactor: use smaller arrays for voucher
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@geonnave
geonnave committed Oct 25, 2023
1 parent e994bf2 commit 125df8d
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Showing 2 changed files with 46 additions and 41 deletions.
4 changes: 3 additions & 1 deletion consts/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -70,7 +70,6 @@ mod structs {
pub type BytesCcmIvLen = [u8; AES_CCM_IV_LEN];
pub type BufferPlaintext2 = EdhocMessageBuffer;
pub type BufferPlaintext3 = EdhocMessageBuffer;
pub type BytesMac = [u8; MAC_LENGTH];
pub type BytesMac2 = [u8; MAC_LENGTH_2];
pub type BytesMac3 = [u8; MAC_LENGTH_3];
pub type BufferMessage1 = EdhocMessageBuffer;
Expand All @@ -86,6 +85,9 @@ mod structs {
pub type BytesMaxLabelBuffeer = [u8; MAX_KDF_LABEL_LEN];
pub type BytesEncStructureLen = [u8; ENC_STRUCTURE_LEN];

pub type BytesMac = [u8; MAC_LENGTH];
pub type BytesEncodedVoucher = [u8; ENCODED_VOUCHER_LEN];

#[repr(C)]
#[derive(Default, PartialEq, Copy, Clone, Debug)]
pub enum EDHOCState {
Expand Down
83 changes: 43 additions & 40 deletions ead/edhoc-ead-zeroconf/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -102,7 +102,8 @@ pub fn i_process_ead_2(
if ead_2.label != EAD_ZEROCONF_LABEL || ead_2.value.is_none() {
return Err(());
}
let ead_2_value = ead_2.value.unwrap();
let mut ead_2_value: BytesEncodedVoucher = Default::default();
ead_2_value[..].copy_from_slice(&ead_2.value.unwrap().content[..ENCODED_VOUCHER_LEN]);

let state = ead_initiator_get_global_state();

Expand All @@ -127,15 +128,15 @@ pub fn i_prepare_ead_3() -> Option<EADItem> {
}

fn verify_voucher(
received_voucher: &EdhocMessageBuffer,
received_voucher: &BytesEncodedVoucher,
h_message_1: &BytesHashLen,
cred_v: &EdhocMessageBuffer,
prk: &BytesHashLen,
) -> Result<BytesMac, ()> {
let computed_voucher = prepare_voucher(h_message_1, cred_v, prk);
if received_voucher.content == computed_voucher.content {
let prepared_voucher = &prepare_voucher(h_message_1, cred_v, prk);
if received_voucher == prepared_voucher {
let mut voucher_mac: BytesMac = Default::default();
voucher_mac[..MAC_LENGTH].copy_from_slice(&computed_voucher.content[1..1 + MAC_LENGTH]);
voucher_mac[..MAC_LENGTH].copy_from_slice(&prepared_voucher[1..1 + MAC_LENGTH]);
return Ok(voucher_mac);
} else {
return Err(());
Expand Down Expand Up @@ -347,14 +348,16 @@ pub fn r_prepare_ead_2(voucher_response: &Option<EdhocMessageBuffer>) -> Option<
let (_message_1, voucher, _opaque_state) =
parse_voucher_response(voucher_response).unwrap();

let mut voucher_value = EdhocMessageBuffer::new();
voucher_value.len = ENCODED_VOUCHER_LEN;
voucher_value.content[..ENCODED_VOUCHER_LEN].copy_from_slice(&voucher[..]);
output = Some(EADItem {
label: EAD_ZEROCONF_LABEL,
is_critical: true,
value: Some(voucher),
value: Some(voucher_value),
});
}

// NOTE: see the note in lib.rs::test_ead
// set as completed even if the voucher response is not present
ead_responder_set_global_state(EADResponderState {
protocol_state: EADResponderProtocolState::Completed,
Expand All @@ -376,13 +379,13 @@ fn parse_voucher_response(
) -> Result<
(
EdhocMessageBuffer,
EdhocMessageBuffer,
BytesEncodedVoucher,
Option<EdhocMessageBuffer>,
),
(),
> {
let mut message_1 = EdhocMessageBuffer::new();
let mut voucher = EdhocMessageBuffer::new();
let mut voucher: BytesEncodedVoucher = Default::default();

let array_byte = voucher_response.content[0];
let array_size = array_byte - (array_byte & CBOR_MAJOR_ARRAY);
Expand All @@ -406,23 +409,24 @@ fn parse_voucher_response(
if !is_cbor_bstr_1byte_prefix(voucher_byte) || voucher_len != ENCODED_VOUCHER_LEN {
return Err(());
}
voucher.len = voucher_len;
voucher.content[..voucher.len].copy_from_slice(
&voucher_response.content[4 + message_1.len..4 + message_1.len + voucher.len],
voucher[..].copy_from_slice(
&voucher_response.content[4 + message_1.len..4 + message_1.len + ENCODED_VOUCHER_LEN],
);

if array_size == 3 {
let opaque_state_len = voucher_response.content[5 + message_1.len + voucher.len] as usize;
if !is_cbor_bstr_2bytes_prefix(voucher_response.content[4 + message_1.len + voucher.len])
|| opaque_state_len > (voucher_response.len - voucher.len - message_1.len)
let opaque_state_len =
voucher_response.content[5 + message_1.len + ENCODED_VOUCHER_LEN] as usize;
if !is_cbor_bstr_2bytes_prefix(
voucher_response.content[4 + message_1.len + ENCODED_VOUCHER_LEN],
) || opaque_state_len > (voucher_response.len - ENCODED_VOUCHER_LEN - message_1.len)
{
return Err(());
}
let mut opaque_state = EdhocMessageBuffer::new();
opaque_state.len = opaque_state_len;
opaque_state.content[..opaque_state.len].copy_from_slice(
&voucher_response.content[6 + message_1.len + voucher.len
..6 + message_1.len + voucher.len + opaque_state.len],
&voucher_response.content[6 + message_1.len + ENCODED_VOUCHER_LEN
..6 + message_1.len + ENCODED_VOUCHER_LEN + opaque_state.len],
);
return Ok((message_1, voucher, Some(opaque_state)));
} else {
Expand Down Expand Up @@ -512,7 +516,7 @@ fn prepare_voucher(
h_message_1: &BytesHashLen,
cred_v: &EdhocMessageBuffer,
prk: &BytesP256ElemLen,
) -> EdhocMessageBuffer {
) -> BytesEncodedVoucher {
let voucher_input = encode_voucher_input(&h_message_1, &cred_v);
let voucher_mac = compute_voucher_mac(&prk, &voucher_input);
encode_voucher(&voucher_mac)
Expand Down Expand Up @@ -589,18 +593,17 @@ fn compute_voucher_mac(prk: &BytesHashLen, voucher_input: &EdhocMessageBuffer) -
voucher_mac
}

fn encode_voucher(voucher_mac: &BytesMac) -> EdhocMessageBuffer {
let mut voucher = EdhocMessageBuffer::new();
voucher.content[0] = CBOR_MAJOR_BYTE_STRING + MAC_LENGTH as u8;
voucher.content[1..1 + MAC_LENGTH].copy_from_slice(&voucher_mac[..MAC_LENGTH]);
voucher.len = 1 + MAC_LENGTH;
fn encode_voucher(voucher_mac: &BytesMac) -> BytesEncodedVoucher {
let mut voucher: BytesEncodedVoucher = Default::default();
voucher[0] = CBOR_MAJOR_BYTE_STRING + MAC_LENGTH as u8;
voucher[1..1 + MAC_LENGTH].copy_from_slice(&voucher_mac[..MAC_LENGTH]);

voucher
}

fn encode_voucher_response(
message_1: &EdhocMessageBuffer,
voucher: &EdhocMessageBuffer,
voucher: &BytesEncodedVoucher,
opaque_state: &Option<EdhocMessageBuffer>,
) -> EdhocMessageBuffer {
let mut output = EdhocMessageBuffer::new();
Expand All @@ -609,23 +612,23 @@ fn encode_voucher_response(
output.content[2] = message_1.len as u8;
output.content[3..3 + message_1.len].copy_from_slice(&message_1.content[..message_1.len]);

output.content[3 + message_1.len] = CBOR_MAJOR_BYTE_STRING + voucher.len as u8;
output.content[4 + message_1.len..4 + message_1.len + voucher.len]
.copy_from_slice(&voucher.content[..voucher.len]);
output.content[3 + message_1.len] = CBOR_MAJOR_BYTE_STRING + ENCODED_VOUCHER_LEN as u8;
output.content[4 + message_1.len..4 + message_1.len + ENCODED_VOUCHER_LEN]
.copy_from_slice(&voucher[..]);

if let Some(opaque_state) = opaque_state {
output.content[0] = CBOR_MAJOR_ARRAY | 3;

output.content[4 + message_1.len + voucher.len] = CBOR_BYTE_STRING;
output.content[5 + message_1.len + voucher.len] = opaque_state.len as u8;
output.content
[6 + message_1.len + voucher.len..6 + message_1.len + voucher.len + opaque_state.len]
output.content[4 + message_1.len + ENCODED_VOUCHER_LEN] = CBOR_BYTE_STRING;
output.content[5 + message_1.len + ENCODED_VOUCHER_LEN] = opaque_state.len as u8;
output.content[6 + message_1.len + ENCODED_VOUCHER_LEN
..6 + message_1.len + ENCODED_VOUCHER_LEN + opaque_state.len]
.copy_from_slice(&opaque_state.content[..opaque_state.len]);

output.len = 6 + message_1.len + voucher.len + opaque_state.len;
output.len = 6 + message_1.len + ENCODED_VOUCHER_LEN + opaque_state.len;
} else {
output.content[0] = CBOR_MAJOR_ARRAY | 2;
output.len = 4 + message_1.len + voucher.len;
output.len = 4 + message_1.len + ENCODED_VOUCHER_LEN;
}

output
Expand Down Expand Up @@ -843,13 +846,13 @@ mod test_responder {
fn test_parse_voucher_response() {
let voucher_response_tv: EdhocMessageBuffer = VOUCHER_RESPONSE_TV.try_into().unwrap();
let message_1_tv: EdhocMessageBuffer = MESSAGE_1_WITH_EAD_TV.try_into().unwrap();
let voucher_tv: EdhocMessageBuffer = VOUCHER_TV.try_into().unwrap();
let voucher_tv: BytesEncodedVoucher = VOUCHER_TV.try_into().unwrap();

let res = parse_voucher_response(&voucher_response_tv);
assert!(res.is_ok());
let (message_1, voucher, opaque_state) = res.unwrap();
assert_eq!(message_1.content, message_1_tv.content);
assert_eq!(voucher.content, voucher_tv.content);
assert_eq!(voucher, voucher_tv);
assert!(opaque_state.is_none());
}

Expand Down Expand Up @@ -885,14 +888,14 @@ mod test_responder {
fn slo_test_parse_voucher_response() {
let voucher_response_tv: EdhocMessageBuffer = SLO_VOUCHER_RESPONSE_TV.try_into().unwrap();
let message_1_tv: EdhocMessageBuffer = MESSAGE_1_WITH_EAD_TV.try_into().unwrap();
let voucher_tv: EdhocMessageBuffer = VOUCHER_TV.try_into().unwrap();
let voucher_tv: BytesEncodedVoucher = VOUCHER_TV.try_into().unwrap();
let opaque_state_tv: EdhocMessageBuffer = OPAQUE_STATE_TV.try_into().unwrap();

let res = parse_voucher_response(&voucher_response_tv);
assert!(res.is_ok());
let (message_1, voucher, opaque_state) = res.unwrap();
assert_eq!(message_1.content, message_1_tv.content);
assert_eq!(voucher.content, voucher_tv.content);
assert_eq!(voucher, voucher_tv);
assert_eq!(opaque_state.unwrap().content, opaque_state_tv.content);
}
}
Expand Down Expand Up @@ -928,16 +931,16 @@ mod test_enrollment_server {
let h_message_1: BytesHashLen = H_MESSAGE_1_TV.try_into().unwrap();
let cred_v: EdhocMessageBuffer = CRED_V_TV.try_into().unwrap();
let prk: BytesHashLen = PRK_TV.try_into().unwrap();
let voucher_tv: EdhocMessageBuffer = VOUCHER_TV.try_into().unwrap();
let voucher_tv: BytesEncodedVoucher = VOUCHER_TV.try_into().unwrap();

let voucher = prepare_voucher(&h_message_1, &cred_v, &prk);
assert_eq!(voucher.content, voucher_tv.content);
assert_eq!(voucher, voucher_tv);
}

#[test]
fn test_encode_voucher_response() {
let message_1_tv: EdhocMessageBuffer = MESSAGE_1_WITH_EAD_TV.try_into().unwrap();
let voucher_tv: EdhocMessageBuffer = VOUCHER_TV.try_into().unwrap();
let voucher_tv: BytesEncodedVoucher = VOUCHER_TV.try_into().unwrap();
let opaque_state_tv: EdhocMessageBuffer = OPAQUE_STATE_TV.try_into().unwrap();
let voucher_response_tv: EdhocMessageBuffer = SLO_VOUCHER_RESPONSE_TV.try_into().unwrap();

Expand Down

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