From ad5b5a4895f39180f329f2532e2484430c1ac480 Mon Sep 17 00:00:00 2001
From: Gustav Simonsson <gustav.simonsson@gmail.com>
Date: Tue, 9 Jun 2015 15:41:15 +0200
Subject: Pad precompiled EC recover input and add validations
---
core/vm/contracts.go | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
(limited to 'core')
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 742017dd2..b5cb9ccd2 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -67,21 +67,27 @@ func ripemd160Func(in []byte) []byte {
const ecRecoverInputLength = 128
func ecrecoverFunc(in []byte) []byte {
- // "in" is (hash, v, r, s), each 32 bytes
- // but for ecrecover we want (r, s, v)
if len(in) < ecRecoverInputLength {
- return nil
+ in = common.RightPadBytes(in, 128)
}
+ // "in" is (hash, v, r, s), each 32 bytes
+ // but for ecrecover we want (r, s, v)
+ r := common.BytesToBig(in[64:96])
+ s := common.BytesToBig(in[96:128])
// Treat V as a 256bit integer
- v := new(big.Int).Sub(common.Bytes2Big(in[32:64]), big.NewInt(27))
- // Ethereum requires V to be either 0 or 1 => (27 || 28)
- if !(v.Cmp(Zero) == 0 || v.Cmp(One) == 0) {
+ vbig := common.Bytes2Big(in[32:64])
+ v := byte(vbig.Uint64())
+
+ if !crypto.ValidateSignatureValues(v, r, s) {
+ glog.V(logger.Error).Infof("EC RECOVER FAIL: v, r or s value invalid")
return nil
}
- // v needs to be moved to the end
- rsv := append(in[64:128], byte(v.Uint64()))
+ // v needs to be at the end and normalized for libsecp256k1
+ vbignormal := new(big.Int).Sub(vbig, big.NewInt(27))
+ vnormal := byte(vbignormal.Uint64())
+ rsv := append(in[64:128], vnormal)
pubKey, err := crypto.Ecrecover(in[:32], rsv)
// make sure the public key is a valid one
if err != nil {
--
cgit v1.2.3
From 6e3b58e491c822cc6e4aa822c31c6dee034e3df9 Mon Sep 17 00:00:00 2001
From: Gustav Simonsson <gustav.simonsson@gmail.com>
Date: Tue, 9 Jun 2015 16:03:05 +0200
Subject: Remove unneeded if check on EC recover padding
---
core/vm/contracts.go | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
(limited to 'core')
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index b5cb9ccd2..90e356b1d 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -67,9 +67,7 @@ func ripemd160Func(in []byte) []byte {
const ecRecoverInputLength = 128
func ecrecoverFunc(in []byte) []byte {
- if len(in) < ecRecoverInputLength {
- in = common.RightPadBytes(in, 128)
- }
+ in = common.RightPadBytes(in, 128)
// "in" is (hash, v, r, s), each 32 bytes
// but for ecrecover we want (r, s, v)
--
cgit v1.2.3