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consensus: guard against openssl's new strict DER checks

New versions of OpenSSL will reject non-canonical DER signatures. However,
it'll happily decode them. Decode then re-encode before verification in order
to ensure that it is properly consumed.

Rebased-from: 488ed32f2a

fail immediately on an empty signature

Rebased-from: 8dccba6a45
0.8
Cory Fields 10 years ago committed by Warren Togami
parent
commit
95479ca7f6
  1. 19
      src/key.cpp

19
src/key.cpp

@ -202,10 +202,23 @@ public:
} }
bool Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig) { bool Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig) {
// -1 = error, 0 = bad sig, 1 = good if (vchSig.empty())
if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1)
return false; return false;
return true;
// New versions of OpenSSL will reject non-canonical DER signatures. de/re-serialize first.
unsigned char *norm_der = NULL;
ECDSA_SIG *norm_sig = ECDSA_SIG_new();
const unsigned char* sigptr = &vchSig[0];
d2i_ECDSA_SIG(&norm_sig, &sigptr, vchSig.size());
int derlen = i2d_ECDSA_SIG(norm_sig, &norm_der);
ECDSA_SIG_free(norm_sig);
if (derlen <= 0)
return false;
// -1 = error, 0 = bad sig, 1 = good
bool ret = ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), norm_der, derlen, pkey) == 1;
OPENSSL_free(norm_der);
return ret;
} }
bool SignCompact(const uint256 &hash, unsigned char *p64, int &rec) { bool SignCompact(const uint256 &hash, unsigned char *p64, int &rec) {

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