From 26bc048feacfa4b313258142afd7562b7014712f Mon Sep 17 00:00:00 2001
From: kdeme <kim.demey@gmail.com>
Date: Fri, 19 Jul 2019 10:56:47 +0200
Subject: [PATCH] Fix possible IndexError in ecrecover

---
 nimbus/vm/precompiles.nim | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/nimbus/vm/precompiles.nim b/nimbus/vm/precompiles.nim
index 439ac11f5..535eee183 100644
--- a/nimbus/vm/precompiles.nim
+++ b/nimbus/vm/precompiles.nim
@@ -21,7 +21,7 @@ proc getSignature*(computation: BaseComputation): (array[32, byte], Signature) =
   template data: untyped = computation.msg.data
   var bytes: array[65, byte]
   let maxPos = min(data.high, 127)
-  if maxPos >= 31:
+  if maxPos >= 63:
     # extract message hash
     result[0][0..31] = data[0..31]
     if maxPos >= 127:
@@ -31,7 +31,7 @@ proc getSignature*(computation: BaseComputation): (array[32, byte], Signature) =
     elif maxPos >= 64:
       bytes[0..(maxPos-64)] = data[64..maxPos]
   else:
-    result[0][0..maxPos] = data[0..maxPos]
+    raise newException(ValidationError, "Invalid V in getSignature")
 
   var VOK = true
   let v = data[63]