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consensus: guard against openssl's new strict DER checks

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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: 488ed32f2ada1d1dd108fc245d025c4d5f252783

fail immediately on an empty signature

Rebased-from: 8dccba6a45db0466370726ed462b9da2eae43bce
This commit is contained in:
Cory Fields 2015-01-09 20:53:19 -10:00 committed by Warren Togami
parent c1e46ab3a9
commit 95479ca7f6
1 changed files with 16 additions and 3 deletions
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19
src/key.cpp
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@ -202,10 +202,23 @@ public:
}
bool Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig) {
// -1 = error, 0 = bad sig, 1 = good
if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1)
if (vchSig.empty())
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) {