Remove serde trait implementations for requests and replies

CHANGELOG.md

@@ -46,6 +46,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `nonce` argument to `wrap_key` and `unwrap_key` syscalls.
 - Use nonce as IV for Aes256Cbc mechanism.
 - Updated `cbor-smol` to 0.5.0.
+- Removed `serde::{Deserialize, Serialize}` implementations for the API request
+  and reply structs, `types::{consent::{Error, Level}, reboot::To, StorageAttributes,
+  KeySerialization, SignatureSerialization}`.
 
 ### Fixed
 

core/Cargo.toml

@@ -14,7 +14,6 @@ littlefs2-core.workspace = true
 postcard.workspace = true
 rand_core.workspace = true
 serde.workspace = true
-
 serde-indexed = "0.1"
 
 [features]

core/src/api/macros.rs

@@ -70,7 +70,7 @@ macro_rules! impl_request {
     )*)
         => {$(
     $(#[$attr])?
-    #[derive(Clone, Eq, PartialEq, Debug, serde_indexed::DeserializeIndexed, serde_indexed::SerializeIndexed)]
+    #[derive(Clone, Eq, PartialEq, Debug)]
     pub struct $request {
         $(
             pub $name: $type,
@@ -109,7 +109,7 @@ macro_rules! impl_reply {
         => {$(
 
     $(#[$attr])?
-    #[derive(Clone, Eq, PartialEq, Debug, serde_indexed::DeserializeIndexed, serde_indexed::SerializeIndexed)]
+    #[derive(Clone, Eq, PartialEq, Debug)]
     pub struct $reply {
         $(
             pub $name: $type,

core/src/types.rs

@@ -7,15 +7,14 @@ pub use heapless::String;
 pub use heapless_bytes::Bytes;
 pub use littlefs2_core::{DirEntry, Metadata, PathBuf};
 
+use crate::api::{reply, request};
 use crate::config::{
     MAX_KEY_MATERIAL_LENGTH, MAX_MEDIUM_DATA_LENGTH, MAX_MESSAGE_LENGTH, MAX_SHORT_DATA_LENGTH,
     MAX_SIGNATURE_LENGTH, MAX_USER_ATTRIBUTE_LENGTH,
 };
 
 pub mod consent {
-    use serde::{Deserialize, Serialize};
-
-    #[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+    #[derive(Copy, Clone, Eq, PartialEq, Debug)]
     pub enum Level {
         /// There is no user present
         None,
@@ -27,7 +26,7 @@ pub mod consent {
         Strong,
     }
 
-    #[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+    #[derive(Copy, Clone, Eq, PartialEq, Debug)]
     pub enum Error {
         FailedToInterrupt,
         Interrupted,
@@ -39,9 +38,7 @@ pub mod consent {
 }
 
 pub mod reboot {
-    use serde::{Deserialize, Serialize};
-
-    #[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+    #[derive(Copy, Clone, Eq, PartialEq, Debug)]
     pub enum To {
         Application,
         ApplicationUpdate,
@@ -240,7 +237,7 @@ pub enum Location {
     External,
 }
 
-#[derive(Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+#[derive(Clone, Eq, PartialEq, Debug)]
 #[non_exhaustive]
 pub struct StorageAttributes {
     // each object must have a unique ID
@@ -350,7 +347,7 @@ pub enum Mechanism {
     Rsa4096Pkcs1v15,
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub enum KeySerialization {
     // Asn1Der,
     Cose,
@@ -366,10 +363,59 @@ pub enum KeySerialization {
     Pkcs8Der,
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize, Deserialize)]
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub enum SignatureSerialization {
     Asn1Der,
     // Cose,
     Raw,
     // Sec1,
 }
+
+/// Serializable version of [`reply::Encrypt`][].
+///
+/// Sometimes it is necessary the result of an encryption together with the metadata required for
+/// decryption, for example when wrapping keys.  This struct stores the data that is returned by
+/// the [`request::Encrypt`][] syscall, see [`reply::Encrypt`][], in a serializable format.
+#[derive(
+    Clone, Debug, Eq, PartialEq, serde_indexed::DeserializeIndexed, serde_indexed::SerializeIndexed,
+)]
+#[non_exhaustive]
+pub struct EncryptedData {
+    pub ciphertext: Message,
+    pub nonce: ShortData,
+    pub tag: ShortData,
+}
+
+impl EncryptedData {
+    /// Creates a decryption request to decrypt the stored data.
+    pub fn decrypt(
+        self,
+        mechanism: Mechanism,
+        key: KeyId,
+        associated_data: Message,
+    ) -> request::Decrypt {
+        request::Decrypt {
+            mechanism,
+            key,
+            message: self.ciphertext,
+            associated_data,
+            nonce: self.nonce,
+            tag: self.tag,
+        }
+    }
+}
+
+impl From<reply::Encrypt> for EncryptedData {
+    fn from(reply: reply::Encrypt) -> Self {
+        let reply::Encrypt {
+            ciphertext,
+            nonce,
+            tag,
+        } = reply;
+        Self {
+            ciphertext,
+            nonce,
+            tag,
+        }
+    }
+}

src/mechanisms/chacha8poly1305.rs

@@ -1,5 +1,6 @@
 use generic_array::GenericArray;
 use rand_core::RngCore;
+use trussed_core::types::EncryptedData;
 
 use crate::api::{reply, request};
 use crate::error::Error;
@@ -190,8 +191,9 @@ impl WrapKey for super::Chacha8Poly1305 {
         };
         let encryption_reply = <super::Chacha8Poly1305>::encrypt(keystore, &encryption_request)?;
 
+        let wrapped_key = EncryptedData::from(encryption_reply);
         let wrapped_key =
-            crate::postcard_serialize_bytes(&encryption_reply).map_err(|_| Error::CborError)?;
+            crate::postcard_serialize_bytes(&wrapped_key).map_err(|_| Error::CborError)?;
 
         Ok(reply::WrapKey { wrapped_key })
     }
@@ -204,20 +206,14 @@ impl UnwrapKey for super::Chacha8Poly1305 {
         keystore: &mut impl Keystore,
         request: &request::UnwrapKey,
     ) -> Result<reply::UnwrapKey, Error> {
-        let reply::Encrypt {
-            ciphertext,
-            nonce,
-            tag,
-        } = crate::postcard_deserialize(&request.wrapped_key).map_err(|_| Error::CborError)?;
-
-        let decryption_request = request::Decrypt {
-            mechanism: Mechanism::Chacha8Poly1305,
-            key: request.wrapping_key,
-            message: ciphertext,
-            associated_data: request.associated_data.clone(),
-            nonce,
-            tag,
-        };
+        let encrypted_data: EncryptedData =
+            crate::postcard_deserialize(&request.wrapped_key).map_err(|_| Error::CborError)?;
+
+        let decryption_request = encrypted_data.decrypt(
+            Mechanism::Chacha8Poly1305,
+            request.wrapping_key,
+            request.associated_data.clone(),
+        );
 
         let serialized_key = if let Some(serialized_key) =
             <super::Chacha8Poly1305>::decrypt(keystore, &decryption_request)?.plaintext