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| author | Felix Lange <fjl@users.noreply.github.com> | 2017-12-20 20:30:00 +0800 |
|---|---|---|
| committer | Péter Szilágyi <peterke@gmail.com> | 2017-12-20 20:30:00 +0800 |
| commit | ce823c9f84a3ab46003d1167ee54ab59b01092d6 (patch) | |
| tree | 6fcd7b6290ac5c0038f0adf2fd41fe312e570e43 /crypto | |
| parent | 5e1581c2c3a88754f5f492b8551a96c2f5d4664a (diff) | |
| download | dexon-ce823c9f84a3ab46003d1167ee54ab59b01092d6.tar.gz dexon-ce823c9f84a3ab46003d1167ee54ab59b01092d6.tar.zst dexon-ce823c9f84a3ab46003d1167ee54ab59b01092d6.zip | |
crypto: ensure that VerifySignature rejects malleable signatures (#15708)
* crypto: ensure that VerifySignature rejects malleable signatures
It already rejected them when using libsecp256k1, make sure the nocgo
version does the same thing.
* crypto: simplify check
* crypto: fix build
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/signature_nocgo.go | 4 | ||||
| -rw-r--r-- | crypto/signature_test.go | 10 |
2 files changed, 14 insertions, 0 deletions
diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go index 78b99c02b..f636b2377 100644 --- a/crypto/signature_nocgo.go +++ b/crypto/signature_nocgo.go @@ -87,6 +87,10 @@ func VerifySignature(pubkey, hash, signature []byte) bool { if err != nil { return false } + // Reject malleable signatures. libsecp256k1 does this check but btcec doesn't. + if sig.S.Cmp(secp256k1_halfN) > 0 { + return false + } return sig.Verify(hash, key) } diff --git a/crypto/signature_test.go b/crypto/signature_test.go index 5e2efc7e0..aecff76bf 100644 --- a/crypto/signature_test.go +++ b/crypto/signature_test.go @@ -75,6 +75,16 @@ func TestVerifySignature(t *testing.T) { } } +// This test checks that VerifySignature rejects malleable signatures with s > N/2. +func TestVerifySignatureMalleable(t *testing.T) { + sig := hexutil.MustDecode("0x638a54215d80a6713c8d523a6adc4e6e73652d859103a36b700851cb0e61b66b8ebfc1a610c57d732ec6e0a8f06a9a7a28df5051ece514702ff9cdff0b11f454") + key := hexutil.MustDecode("0x03ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd3138") + msg := hexutil.MustDecode("0xd301ce462d3e639518f482c7f03821fec1e602018630ce621e1e7851c12343a6") + if VerifySignature(key, msg, sig) { + t.Error("VerifySignature returned true for malleable signature") + } +} + func TestDecompressPubkey(t *testing.T) { key, err := DecompressPubkey(testpubkeyc) if err != nil { |