[WIP] #248 Handle malformed QR code

Sources/WalletConnectSign/Engine/Controller/PairEngine.swift

@@ -19,13 +19,31 @@ actor PairEngine {
             throw WalletConnectError.pairingAlreadyExist
         }
         var pairing = WCPairing(uri: uri)
-        try await networkingInteractor.subscribe(topic: pairing.topic)
-        let symKey = try! SymmetricKey(hex: uri.symKey) // FIXME: Malformed QR code from external source can crash the SDK
-        try! kms.setSymmetricKey(symKey, for: pairing.topic)
+
+        try await subscribe(to: uri.topic)
+        try await setSymmetricKey(uri.symKey, topic: pairing.topic)
+
         pairing.activate()
         pairingStore.setPairing(pairing)
     }
-
+
+    private func setSymmetricKey(_ uriSymKey: String, topic: String) async throws {
+        do {
+            let symKey = try SymmetricKey(hex: uriSymKey)
+            try kms.setSymmetricKey(symKey, for: topic)
+        } catch {
+            throw WalletConnectError.malformedPairingURI
+        }
+    }
+
+    private func subscribe(to topic: String) async throws {
+        do {
+            try await networkingInteractor.subscribe(topic: topic)
+        } catch {
+            throw WalletConnectError.noPairingMatchingTopic(topic)
+        }
+    }
+
     func hasPairing(for topic: String) -> Bool {
         return pairingStore.hasPairing(forTopic: topic)
     }

Sources/WalletConnectSign/WalletConnectError.swift

@@ -1,5 +1,5 @@
-enum WalletConnectError: Error {
-
+enum WalletConnectError: Error, Equatable {
+    
     case pairingProposalFailed
     case malformedPairingURI
     case noPairingMatchingTopic(String)

Tests/WalletConnectSignTests/PairEngineTests.swift

@@ -28,6 +28,8 @@ final class PairEngineTests: XCTestCase {
         networkingInteractor = nil
         storageMock = nil
         cryptoMock = nil
+        topicGenerator = nil
+        proposalPayloadsStore = nil
         engine = nil
     }
 
@@ -44,7 +46,9 @@ final class PairEngineTests: XCTestCase {
             if i == 1 {
                 await XCTAssertNoThrowAsync(try await engine.pair(uri))
             } else {
-                await XCTAssertThrowsErrorAsync(try await engine.pair(uri))
+                await XCTAssertThrowsErrorAsync(try await engine.pair(uri)) {
+                    XCTAssertEqual($0 as! WalletConnectError, WalletConnectError.pairingAlreadyExist)
+                }
             }
         }
     }
@@ -57,4 +61,13 @@ final class PairEngineTests: XCTestCase {
         XCTAssert(cryptoMock.hasSymmetricKey(for: topic), "Responder must store the symmetric key matching the pairing topic")
         XCTAssert(storageMock.hasPairing(forTopic: topic), "The engine must store a pairing")
     }
+
+    func testPairMalformedQRCode() async {
+        let uri = WalletConnectURI(topic: topicGenerator.getTopic(),
+                                   symKey: "0653ca620c7b4990392e1c53c4a51c14a2840cd20f0f1524cf435b17b6fe988c",
+                                   relay: RelayProtocolOptions(protocol: "waku", data: nil))
+        await XCTAssertThrowsErrorAsync(try await engine.pair(uri)) {
+            XCTAssertEqual($0 as! WalletConnectError, WalletConnectError.malformedPairingURI)
+        }
+    }
 }