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authorGustav Simonsson <gustav.simonsson@gmail.com>2015-06-09 21:41:15 +0800
committerGustav Simonsson <gustav.simonsson@gmail.com>2015-06-09 21:41:15 +0800
commitad5b5a4895f39180f329f2532e2484430c1ac480 (patch)
tree5afc5de988581a9659c10564e5d63561aa386359 /core
parentd8e55a5cc3230af8071df6bf25f6202c0a2e2647 (diff)
downloaddexon-ad5b5a4895f39180f329f2532e2484430c1ac480.tar.gz
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dexon-ad5b5a4895f39180f329f2532e2484430c1ac480.zip
Pad precompiled EC recover input and add validations
Diffstat (limited to 'core')
-rw-r--r--core/vm/contracts.go22
1 files changed, 14 insertions, 8 deletions
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 {