From 95479ca7f635a3343710bcb021c637783ec8d7e1 Mon Sep 17 00:00:00 2001 From: Cory Fields Date: Fri, 9 Jan 2015 20:53:19 -1000 Subject: [PATCH] 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: 488ed32f2ada1d1dd108fc245d025c4d5f252783 fail immediately on an empty signature Rebased-from: 8dccba6a45db0466370726ed462b9da2eae43bce --- src/key.cpp | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/src/key.cpp b/src/key.cpp index 03d978bd3..eed035f7d 100644 --- a/src/key.cpp +++ b/src/key.cpp @@ -202,10 +202,23 @@ public: } bool Verify(const uint256 &hash, const std::vector& 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) {