Bug: Invalid V in signature with eth_sign (#728)

* Fix invalid V with metamask/ledger

* DONT FORGET TO REVERT BEFORE MERGING: test deployment

* DONT FORGET TO REVERT BEFORE MERGING 2: test deployment

* Revert "DONT FORGET TO REVERT BEFORE MERGING 2: test deployment"

This reverts commit 8331f2a78f7fc8f53eb893899f16edd8238c68ff.

* Revert "DONT FORGET TO REVERT BEFORE MERGING: test deployment"

This reverts commit 03b81e31820ce4fe078a7131c2f0caa2af4870ac.

src/logic/safe/transactions/offchainSigner/ethSigner.js

@@ -53,7 +53,28 @@ export const getEthSigner = async ({
           return
         }
 
-        resolve(signature.result.replace(EMPTY_DATA, ''))
+        const sig = signature.result.replace(EMPTY_DATA, '')
+        let sigV = parseInt(sig.slice(-2), 16)
+
+        // Metamask with ledger returns v = 01, this is not valid for ethereum
+        // For ethereum valid V is 27 or 28
+        // In case V = 0 or 01 we add it to 27 and then add 4
+        // Adding 4 is required to make signature valid for safe contracts:
+        // https://gnosis-safe.readthedocs.io/en/latest/contracts/signatures.html#eth-sign-signature
+        switch (sigV) {
+          case 0:
+          case 1:
+            sigV += 31
+            break
+          case 27:
+          case 28:
+            sigV += 4
+            break
+          default:
+            throw new Error('Invalid signature')
+        }
+
+        resolve(sig.slice(0, -2) + sigV.toString(16))
       },
     )
   })