1 files changed, 28 insertions, 4 deletions
diff --git a/src/ecwrapper.cpp b/src/ecwrapper.cpp
index 5ce7e61294..5e3aec25ba 100644
--- a/src/ecwrapper.cpp
+++ b/src/ecwrapper.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2009-2014 The Bitcoin developers
+// Copyright (c) 2009-2014 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -117,10 +117,34 @@ bool CECKey::SetPubKey(const unsigned char* pubkey, size_t size) {
 }
 
 bool CECKey::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];
+    assert(norm_sig);
+    if (d2i_ECDSA_SIG(&norm_sig, &sigptr, vchSig.size()) == NULL)
+    {
+        /* As of OpenSSL 1.0.0p d2i_ECDSA_SIG frees and nulls the pointer on
+         * error. But OpenSSL's own use of this function redundantly frees the
+         * result. As ECDSA_SIG_free(NULL) is a no-op, and in the absence of a
+         * clear contract for the function behaving the same way is more
+         * conservative.
+         */
+        ECDSA_SIG_free(norm_sig);
+        return false;
+    }
+    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 CECKey::Recover(const uint256 &hash, const unsigned char *p64, int rec)