diff options
Diffstat (limited to 'crypto/crypto.go')
| -rw-r--r-- | crypto/crypto.go | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/crypto/crypto.go b/crypto/crypto.go index 7d7623753..850be4da6 100644 --- a/crypto/crypto.go +++ b/crypto/crypto.go @@ -163,12 +163,21 @@ func GenerateKey() (*ecdsa.PrivateKey, error) { return ecdsa.GenerateKey(secp256k1.S256(), rand.Reader) } -func ValidateSignatureValues(v byte, r, s *big.Int) bool { +func ValidateSignatureValues(v byte, r, s *big.Int, homestead bool) bool { if r.Cmp(common.Big1) < 0 || s.Cmp(common.Big1) < 0 { return false } vint := uint32(v) - if r.Cmp(secp256k1.N) < 0 && s.Cmp(secp256k1.N) < 0 && (vint == 27 || vint == 28) { + // reject upper range of s values (ECDSA malleability) + // see discussion in secp256k1/libsecp256k1/include/secp256k1.h + if homestead && s.Cmp(secp256k1.HalfN) > 0 { + return false + } + // Frontier: allow s to be in full N range + if s.Cmp(secp256k1.N) >= 0 { + return false + } + if r.Cmp(secp256k1.N) < 0 && (vint == 27 || vint == 28) { return true } else { return false |