From 8c4acf54e0e46f3218c8fda0bc59e66026332840 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damir=20Jeli=C4=87?= <poljar@termina.org.uk>
Date: Wed, 2 Sep 2020 12:11:06 +0200
Subject: [PATCH] crypto: Reorder the errors so unpickling now returns the
 timestamp error.

---
 matrix_sdk_crypto/src/error.rs       | 10 ++++++++++
 matrix_sdk_crypto/src/olm/session.rs | 18 ++++++++++--------
 matrix_sdk_crypto/src/store/mod.rs   |  6 ++++--
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/matrix_sdk_crypto/src/error.rs b/matrix_sdk_crypto/src/error.rs
index cc679c0c..ee4e5f1f 100644
--- a/matrix_sdk_crypto/src/error.rs
+++ b/matrix_sdk_crypto/src/error.rs
@@ -115,6 +115,16 @@ pub enum EventError {
     MissmatchedKeys,
 }
 
+#[derive(Error, Debug)]
+pub enum SessionUnpicklingError {
+    /// The underlying Olm session operation returned an error.
+    #[error("can't finish Olm Session operation {0}")]
+    OlmSession(#[from] OlmSessionError),
+    /// The Session timestamp was invalid.
+    #[error("can't load session timestamps")]
+    SessionTimestampError,
+}
+
 #[derive(Error, Debug)]
 pub enum SignatureError {
     #[error("the signature used a unsupported algorithm")]
diff --git a/matrix_sdk_crypto/src/olm/session.rs b/matrix_sdk_crypto/src/olm/session.rs
index f8545d58..554e75cb 100644
--- a/matrix_sdk_crypto/src/olm/session.rs
+++ b/matrix_sdk_crypto/src/olm/session.rs
@@ -29,7 +29,7 @@ use serde_json::{json, Value};
 
 use super::IdentityKeys;
 use crate::{
-    error::{EventError, OlmResult},
+    error::{EventError, OlmResult, SessionUnpicklingError},
     ReadOnlyDevice,
 };
 
@@ -192,8 +192,8 @@ impl Session {
 
     /// Restore a Session from a previously pickled string.
     ///
-    /// Returns the restored Olm Session or a `OlmSessionError` if there was an
-    /// error.
+    /// Returns the restored Olm Session or a `SessionUnpicklingError` if there
+    /// was an error.
     ///
     /// # Arguments
     ///
@@ -213,17 +213,19 @@ impl Session {
         our_identity_keys: Arc<IdentityKeys>,
         pickle: PickledSession,
         pickle_mode: PicklingMode,
-    ) -> Result<Self, OlmSessionError> {
+    ) -> Result<Self, SessionUnpicklingError> {
         let session = OlmSession::unpickle(pickle.pickle.0, pickle_mode)?;
         let session_id = session.session_id();
 
         // FIXME this should use the UNIX epoch.
         let now = Instant::now();
 
-        let creation_time = now.checked_sub(pickle.creation_time).unwrap();
-        // .ok_or(CryptoStoreError::SessionTimestampError)?;
-        let last_use_time = now.checked_sub(pickle.last_use_time).unwrap();
-        // .ok_or(CryptoStoreError::SessionTimestampError)?;
+        let creation_time = now
+            .checked_sub(pickle.creation_time)
+            .ok_or(SessionUnpicklingError::SessionTimestampError)?;
+        let last_use_time = now
+            .checked_sub(pickle.last_use_time)
+            .ok_or(SessionUnpicklingError::SessionTimestampError)?;
 
         Ok(Session {
             user_id,
diff --git a/matrix_sdk_crypto/src/store/mod.rs b/matrix_sdk_crypto/src/store/mod.rs
index 4a9a4044..3e66661c 100644
--- a/matrix_sdk_crypto/src/store/mod.rs
+++ b/matrix_sdk_crypto/src/store/mod.rs
@@ -34,6 +34,8 @@ use super::{
     user_identity::UserIdentities,
 };
 
+use crate::error::SessionUnpicklingError;
+
 pub mod memorystore;
 
 #[cfg(not(target_arch = "wasm32"))]
@@ -76,8 +78,8 @@ pub enum CryptoStoreError {
     OlmGroupSession(#[from] OlmGroupSessionError),
 
     /// A session time-stamp couldn't be loaded.
-    #[error("can't load session timestamps")]
-    SessionTimestampError,
+    #[error(transparent)]
+    SessionUnpickling(#[from] SessionUnpicklingError),
 
     /// The store failed to (de)serialize a data type.
     #[error(transparent)]