fix(store-encryption): Remove an unwrap that snuck in (#4506)

Author: poljar

crates/matrix-sdk-store-encryption/CHANGELOG.md

@@ -6,6 +6,13 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased] - ReleaseDate
 
+### Bug Fixes
+
+- Remove the usage of an unwrap in the `StoreCipher::import_with_key` method.
+  This could have lead to panics if the second argument was an invalid
+  `StoreCipher` export.
+  ([#4506](https://github.com/matrix-org/matrix-rust-sdk/pull/4506))
+
 ## [0.9.0] - 2024-12-18
 
 No notable changes in this release.

crates/matrix-sdk-store-encryption/src/lib.rs

@@ -334,7 +334,7 @@ impl StoreCipher {
     /// # anyhow::Ok(()) };
     /// ```
     pub fn import_with_key(key: &[u8; 32], encrypted: &[u8]) -> Result<Self, Error> {
-        let encrypted: EncryptedStoreCipher = rmp_serde::from_slice(encrypted).unwrap();
+        let encrypted: EncryptedStoreCipher = rmp_serde::from_slice(encrypted)?;
 
         if let KdfInfo::Pbkdf2ToChaCha20Poly1305 { .. } = encrypted.kdf_info {
             return Err(Error::KdfMismatch);
@@ -903,6 +903,12 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_importing_invalid_store_cipher_does_not_panic() {
+        // This used to panic, we're testing that we're getting a real error.
+        assert!(StoreCipher::import_with_key(&[0; 32], &[0; 64]).is_err())
+    }
+
     #[test]
     fn encrypting_values() -> Result<(), Error> {
         let event = json!({