GH-3406 another attempt to fix crash

Potential reason: crash in arithmetic operations
safe-global · May 31, 2024 · 4c70747 · 4c70747
1 parent ced3b19
commit 4c70747
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/Multisig/UI/Settings/OwnerKeyManagement/KeystoneOwnerKey/KeystoneSignFlow.swift b/Multisig/UI/Settings/OwnerKeyManagement/KeystoneOwnerKey/KeystoneSignFlow.swift
@@ -113,19 +113,19 @@ extension SECP256K1.UnmarshaledSignature {
             let vBytes = [UInt8](data.suffix(from: 64).prefix(8))
             let vInt =  UInt64(vBytes)
             // recover V by deducting (chainId * 2 + 35) according to EIP-155
-            let vRecovered = vInt - (chainIdInt * 2 + 35)
-            v = try! UInt8(vRecovered % 256)
+            let vRecovered = vInt % 256 - (chainIdInt * 2 + 35) % 256
+            v = try! UInt8(vRecovered)
         } else {
             vBytes = [UInt8]([data[64]])
             let vInt = UInt8(vBytes)
             if isLegacyTx {
                 // Legacy ethereum (pre-eip-155) adds 27 to v
                 v = vInt - 27
             } else {
-                // v still can be chainId * 2 + 35 for non-legacy transactions (chaiId >=0)
+                // v still can be `{0, 1} + chainId * 2 + 35` for non-legacy transactions (chainId >=0)
                 if vInt >= 35 {
-                    let vRecovered = UInt64(vBytes) - (chainIdInt * 2 + 35)
-                    v = try! UInt8(vRecovered % 256)
+                    let vRecovered = UInt64(vBytes) - (chainIdInt * 2 + 35) % 256
+                    v = try! UInt8(vRecovered)
                 } else {
                     v = vInt
                 }
@@ -138,3 +138,4 @@ extension SECP256K1.UnmarshaledSignature {
         return (v, r, s)
     }
 }
+