From 6ed423d1af7410e0f771d3f12a84a5c9690804a3 Mon Sep 17 00:00:00 2001
From: Amir Bandeali <abandeali1@gmail.com>
Date: Tue, 29 Jan 2019 10:15:12 -0800
Subject: [PATCH] Make all cancels permissionless

---
 .../tec/contracts/src/MixinSignatureValidator.sol  |  7 +++++++
 .../tec/contracts/src/MixinTECApprovalVerifier.sol | 14 ++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/contracts/tec/contracts/src/MixinSignatureValidator.sol b/contracts/tec/contracts/src/MixinSignatureValidator.sol
index e530a4321d..2e8e4e896a 100644
--- a/contracts/tec/contracts/src/MixinSignatureValidator.sol
+++ b/contracts/tec/contracts/src/MixinSignatureValidator.sol
@@ -94,5 +94,12 @@ contract MixinSignatureValidator {
             );
             return signerAddress;
         }
+
+        // Anything else is illegal (We do not return false because
+        // the signature may actually be valid, just not in a format
+        // that we currently support. In this case returning false
+        // may lead the caller to incorrectly believe that the
+        // signature was invalid.)
+        revert("SIGNATURE_UNSUPPORTED");
     }
 }
\ No newline at end of file
diff --git a/contracts/tec/contracts/src/MixinTECApprovalVerifier.sol b/contracts/tec/contracts/src/MixinTECApprovalVerifier.sol
index 4f5a41e592..59a6e9e00f 100644
--- a/contracts/tec/contracts/src/MixinTECApprovalVerifier.sol
+++ b/contracts/tec/contracts/src/MixinTECApprovalVerifier.sol
@@ -63,8 +63,7 @@ contract MixinTECApprovalVerifier is
         if (
             exchangeFunctionSelector == FILL_ORDER_SELECTOR ||
             exchangeFunctionSelector == FILL_ORDER_NO_THROW_SELECTOR ||
-            exchangeFunctionSelector == FILL_OR_KILL_ORDER_SELECTOR ||
-            exchangeFunctionSelector == CANCEL_ORDER_SELECTOR
+            exchangeFunctionSelector == FILL_OR_KILL_ORDER_SELECTOR
         ) {
             // Decode single order
             (LibOrder.Order memory order) = abi.decode(
@@ -87,8 +86,7 @@ contract MixinTECApprovalVerifier is
             exchangeFunctionSelector == MARKET_BUY_ORDERS_SELECTOR ||
             exchangeFunctionSelector == MARKET_BUY_ORDERS_NO_THROW_SELECTOR ||
             exchangeFunctionSelector == MARKET_SELL_ORDERS_SELECTOR ||
-            exchangeFunctionSelector == MARKET_SELL_ORDERS_NO_THROW_SELECTOR ||
-            exchangeFunctionSelector == BATCH_CANCEL_ORDERS_SELECTOR
+            exchangeFunctionSelector == MARKET_SELL_ORDERS_NO_THROW_SELECTOR
         ) {
             // Decode all orders
             (LibOrder.Order[] memory orders) = abi.decode(
@@ -124,8 +122,12 @@ contract MixinTECApprovalVerifier is
                 approvalExpirationTimeSeconds,
                 approvalSignatures
             );
-        } else if (exchangeFunctionSelector == CANCEL_ORDERS_UP_TO_SELECTOR) {
-            // `cancelOrdersUpTo` is always permitted
+        } else if (
+            exchangeFunctionSelector == CANCEL_ORDERS_UP_TO_SELECTOR ||
+            exchangeFunctionSelector == CANCEL_ORDER_SELECTOR ||
+            exchangeFunctionSelector == BATCH_CANCEL_ORDERS_SELECTOR
+        ) {
+            // All cancel functions are always permitted
             return;
         } else {
             revert("INVALID_OR_BLOCKED_EXCHANGE_SELECTOR");