Derive std::error::Error for more types

Also make use of displaydoc::Display and generated From impls in more places.

Cargo.lock

@@ -278,6 +278,7 @@ dependencies = [
  "strum",
  "subtle",
  "test-case",
+ "thiserror",
  "uuid",
  "x25519-dalek",
 ]
@@ -3516,6 +3517,7 @@ dependencies = [
  "rand_core",
  "sha2",
  "static_assertions",
+ "thiserror",
 ]
 
 [[package]]
@@ -4625,6 +4627,7 @@ dependencies = [
  "serde",
  "sha2",
  "subtle",
+ "thiserror",
 ]
 
 [[package]]
@@ -4653,6 +4656,7 @@ dependencies = [
  "signal-crypto",
  "subtle",
  "test-case",
+ "thiserror",
  "uuid",
  "zkcredential",
 ]

rust/attest/Cargo.toml

@@ -35,6 +35,7 @@ snow = { version = "0.9.5", default-features = false }
 static_assertions = "1.1"
 strum = { version = "0.26", features = ["derive"] }
 subtle = "2.5"
+thiserror = "1.0.57"
 uuid = "1.1.2"
 x25519-dalek = "2.0.0"
 

rust/attest/src/client_connection.rs

@@ -10,8 +10,6 @@
 //! with [ClientConnection::send]. Likewise a single received message consisting internally
 //! of one or more noise transport messages can be decrypted with [ClientConnection::recv]
 
-use std::fmt;
-
 pub const NOISE_PATTERN: &str = "Noise_NK_25519_ChaChaPoly_SHA256";
 
 pub(crate) const NOISE_HANDSHAKE_OVERHEAD: usize = 64;
@@ -29,24 +27,10 @@ pub struct ClientConnection {
 /// Result type for client connection.
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error, displaydoc::Display)]
 pub enum Error {
-    /// Error in noise protocol.
-    NoiseError(snow::Error),
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            Error::NoiseError(n) => write!(f, "Noise error ({})", n),
-        }
-    }
-}
-
-impl From<snow::Error> for Error {
-    fn from(e: snow::Error) -> Self {
-        Error::NoiseError(e)
-    }
+    /// Noise error ({0})
+    NoiseError(#[from] snow::Error),
 }
 
 fn ceil_div(total: usize, chunk_size: usize) -> usize {

rust/attest/src/enclave.rs

@@ -15,19 +15,13 @@ use prost::Message;
 
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
+/// Failure to attest remote enclave.
+#[error("{message}")]
 pub struct AttestationError {
     message: String,
 }
 
-impl std::fmt::Display for AttestationError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.message.fmt(f)
-    }
-}
-
-impl std::error::Error for AttestationError {}
-
 impl From<dcap::Error> for AttestationError {
     fn from(e: dcap::Error) -> Self {
         Self {
@@ -37,38 +31,20 @@ impl From<dcap::Error> for AttestationError {
 }
 
 /// Error types for an enclave noise session.
-#[derive(Display, Debug)]
+#[derive(Display, Debug, thiserror::Error)]
 pub enum Error {
     /// failure to attest remote enclave: {0:?}
-    AttestationError(AttestationError),
+    AttestationError(#[from] AttestationError),
     /// failure to communicate on established Noise channel to the enclave: {0}
-    NoiseError(client_connection::Error),
+    NoiseError(#[from] client_connection::Error),
     /// failure to complete Noise handshake to the enclave: {0}
-    NoiseHandshakeError(snow::Error),
+    NoiseHandshakeError(#[from] snow::Error),
     /// attestation data invalid: {reason}
     AttestationDataError { reason: String },
     /// invalid bridge state
     InvalidBridgeStateError,
 }
 
-impl From<snow::Error> for Error {
-    fn from(e: snow::Error) -> Self {
-        Error::NoiseHandshakeError(e)
-    }
-}
-
-impl From<AttestationError> for Error {
-    fn from(err: AttestationError) -> Error {
-        Error::AttestationError(err)
-    }
-}
-
-impl From<client_connection::Error> for Error {
-    fn from(err: client_connection::Error) -> Self {
-        Error::NoiseError(err)
-    }
-}
-
 impl From<prost::DecodeError> for Error {
     fn from(err: prost::DecodeError) -> Self {
         Error::AttestationDataError {

rust/attest/src/hsm_enclave.rs

@@ -9,18 +9,17 @@
 #![warn(missing_docs)]
 
 use log::*;
-use std::convert::From;
 use std::fmt;
 
 use crate::{client_connection, snow_resolver};
 
 /// Error types for HSM enclave.
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
     /// Failure to connect to a trusted HSM.
-    HSMCommunicationError(client_connection::Error),
+    HSMCommunicationError(#[from] client_connection::Error),
     /// Failure to handshake to trusted HSM.
-    HSMHandshakeError(snow::Error),
+    HSMHandshakeError(#[from] snow::Error),
     /// Failure to connect to trusted code on the given HSM.
     TrustedCodeError,
     /// Invalid public key provided (used in bridging)
@@ -59,18 +58,6 @@ impl fmt::Display for Error {
     }
 }
 
-impl From<client_connection::Error> for Error {
-    fn from(e: client_connection::Error) -> Self {
-        Error::HSMCommunicationError(e)
-    }
-}
-
-impl From<snow::Error> for Error {
-    fn from(e: snow::Error) -> Self {
-        Error::HSMHandshakeError(e)
-    }
-}
-
 /// Wraps a connection handshake to an HSM-resident enclave.
 ///
 /// ```pseudocode

rust/attest/src/nitro.rs

@@ -68,7 +68,7 @@ pub fn new_handshake(
     Ok(handshake)
 }
 
-#[derive(Debug, displaydoc::Display, PartialEq, Eq)]
+#[derive(Debug, displaydoc::Display, thiserror::Error, PartialEq, Eq)]
 pub enum NitroError {
     /// Invalid CBOR
     InvalidCbor,
@@ -90,8 +90,6 @@ pub enum NitroError {
     InvalidUserData,
 }
 
-impl std::error::Error for NitroError {}
-
 impl From<ciborium::de::Error<std::io::Error>> for NitroError {
     fn from(_err: ciborium::de::Error<std::io::Error>) -> NitroError {
         NitroError::InvalidCbor

rust/pin/Cargo.toml

@@ -18,6 +18,7 @@ hkdf = "0.12"
 rand_core = { version = "0.6", features = ["getrandom"] }
 sha2 = "0.10"
 static_assertions = "1.1"
+thiserror = "1.0.57"
 
 [dev-dependencies]
 hex-literal = "0.4.1"

rust/pin/src/error.rs

@@ -4,7 +4,7 @@
 //
 
 /// Error types for pin operations
-#[derive(displaydoc::Display, Debug, Clone, Eq, PartialEq)]
+#[derive(displaydoc::Display, thiserror::Error, Debug, Clone, Eq, PartialEq)]
 pub enum Error {
     /// Argon2 hashing error: {0}
     Argon2Error(argon2::Error),

rust/usernames/src/error.rs

@@ -31,11 +31,11 @@ pub enum UsernameError {
     DiscriminatorTooLarge,
 }
 
-#[derive(displaydoc::Display, Debug)]
+#[derive(displaydoc::Display, Debug, thiserror::Error)]
 /// Username could not be verified
 pub struct ProofVerificationFailure;
 
-#[derive(displaydoc::Display, Debug)]
+#[derive(displaydoc::Display, Debug, thiserror::Error)]
 pub enum UsernameLinkError {
     /// The combined length of all input data is too long
     InputDataTooLong,

rust/zkcredential/Cargo.toml

@@ -22,6 +22,7 @@ partial-default = { version = "0.1.0", features = ["derive"] }
 serde = { version = "1.0.106", features = ["derive"] }
 sha2 = "0.10"
 subtle = "2.3"
+thiserror = "1.0.57"
 
 # If rayon is enabled, certain operations will use rayon's thread pool.
 rayon = { version = "1.8.0", optional = true }

rust/zkcredential/src/lib.rs

@@ -39,7 +39,7 @@
 #![warn(missing_docs)]
 
 /// A zkcredential operation failed to verify.
-#[derive(Debug, displaydoc::Display)]
+#[derive(Debug, thiserror::Error, displaydoc::Display)]
 pub struct VerificationFailure;
 
 /// A reasonable size of entropy to request for operations.

rust/zkgroup/Cargo.toml

@@ -33,6 +33,7 @@ rayon = "1.8.0"
 serde = { version = "1.0.106", features = ["derive"] }
 sha2 = "0.10.0"
 subtle = "2.3"
+thiserror = "1.0.57"
 uuid = "1.1.2"
 
 # For generation

rust/zkgroup/src/common/errors.rs

@@ -5,11 +5,11 @@
 
 use zkcredential::VerificationFailure;
 
-#[derive(Debug, displaydoc::Display)]
+#[derive(Debug, thiserror::Error, displaydoc::Display)]
 /// Verification failure in zkgroup
 pub struct ZkGroupVerificationFailure;
 
-#[derive(Debug, displaydoc::Display)]
+#[derive(Debug, thiserror::Error, displaydoc::Display)]
 /// Deserialization failure in zkgroup
 pub struct ZkGroupDeserializationFailure;