feat: make new errors also accessible to python

Author: geonnave

ead/lakers-ead-authz/src/device.rs

@@ -132,6 +132,23 @@ fn encode_ead_1_value(
     output
 }
 
+pub(crate) fn verify_voucher<Crypto: CryptoTrait>(
+    crypto: &mut Crypto,
+    received_voucher: &BytesEncodedVoucher,
+    h_message_1: &BytesHashLen,
+    cred_v: &[u8],
+    prk: &BytesHashLen,
+) -> Result<BytesMac, ZeroTouchError> {
+    let prepared_voucher = &prepare_voucher(crypto, 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(&prepared_voucher[1..1 + MAC_LENGTH]);
+        return Ok(voucher_mac);
+    } else {
+        return Err(ZeroTouchError::VoucherVerificationFailed);
+    }
+}
+
 #[cfg(test)]
 mod test_device {
     use super::*;

ead/lakers-ead-authz/src/shared.rs

@@ -1,7 +1,5 @@
 use lakers_shared::{Crypto as CryptoTrait, *};
 
-use crate::ZeroTouchError;
-
 pub(crate) fn compute_prk<Crypto: CryptoTrait>(
     crypto: &mut Crypto,
     a: &BytesP256ElemLen,
@@ -24,23 +22,6 @@ pub(crate) fn compute_prk_from_secret<Crypto: CryptoTrait>(
     crypto.hkdf_extract(&salt, &g_ab)
 }
 
-pub(crate) fn verify_voucher<Crypto: CryptoTrait>(
-    crypto: &mut Crypto,
-    received_voucher: &BytesEncodedVoucher,
-    h_message_1: &BytesHashLen,
-    cred_v: &[u8],
-    prk: &BytesHashLen,
-) -> Result<BytesMac, ZeroTouchError> {
-    let prepared_voucher = &prepare_voucher(crypto, 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(&prepared_voucher[1..1 + MAC_LENGTH]);
-        return Ok(voucher_mac);
-    } else {
-        return Err(ZeroTouchError::VoucherVerificationFailed);
-    }
-}
-
 pub(crate) fn prepare_voucher<Crypto: CryptoTrait>(
     crypto: &mut Crypto,
     h_message_1: &BytesHashLen,

lakers-python/src/initiator.rs

@@ -61,7 +61,7 @@ impl PyEdhocInitiator {
         &mut self,
         message_2: Vec<u8>,
     ) -> PyResult<(u8, Vec<u8>, Option<EADItem>)> {
-        let message_2 = EdhocMessageBuffer::new_from_slice(message_2.as_slice()).unwrap(); // FIXME: avoid unwrap
+        let message_2 = EdhocMessageBuffer::new_from_slice(message_2.as_slice())?; // FIXME: avoid unwrap
 
         match i_parse_message_2(&self.wait_m2, &mut default_crypto(), &message_2) {
             Ok((state, c_r, id_cred_r, ead_2)) => {

lakers-python/test/test_lakers.py

@@ -62,8 +62,14 @@ def test_handshake():
     r_prk_out_new = responder.edhoc_key_update(CONTEXT)
     assert i_prk_out_new == r_prk_out_new
 
-def test_error():
+def test_edhoc_error():
     responder = lakers.EdhocResponder(R, CRED_R)
     with pytest.raises(ValueError) as err:
-        _ead_1 = responder.process_message_1([1, 2, 3])
+        _ = responder.process_message_1([1, 2, 3])
     assert str(err.value) == "EDHOCError::ParsingError"
+
+def test_buffer_error():
+    initiator = lakers.EdhocInitiator()
+    with pytest.raises(ValueError) as err:
+        _ = initiator.parse_message_2([1] * 1000)
+    assert str(err.value) == "MessageBufferError::SliceTooLong"

shared/src/python_bindings.rs

@@ -18,6 +18,18 @@ impl From<EDHOCError> for PyErr {
     }
 }
 
+impl fmt::Display for MessageBufferError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "MessageBufferError::{:?}", self)
+    }
+}
+
+impl From<MessageBufferError> for PyErr {
+    fn from(error: MessageBufferError) -> Self {
+        PyValueError::new_err(error.to_string())
+    }
+}
+
 #[pymethods]
 impl EADItem {
     #[new]