Merge pull request #1039 from sipa/fix_955

Fix #955: Verify status of encrypt/decrypt calls to detect failed padding

src/crypter.cpp

@@ -73,14 +73,16 @@ bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned
 
     EVP_CIPHER_CTX ctx;
 
-    EVP_CIPHER_CTX_init(&ctx);
+    bool fOk = true;
-    EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
-
-    EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
-    EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0])+nCLen, &nFLen);
 
+    EVP_CIPHER_CTX_init(&ctx);
+    if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
+    if (fOk) fOk = EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
+    if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0])+nCLen, &nFLen);
     EVP_CIPHER_CTX_cleanup(&ctx);
 
+    if (!fOk) return false;
+
     vchCiphertext.resize(nCLen + nFLen);
     return true;
 }
@@ -98,14 +100,16 @@ bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingM
 
     EVP_CIPHER_CTX ctx;
 
-    EVP_CIPHER_CTX_init(&ctx);
+    bool fOk = true;
-    EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
-
-    EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
-    EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0])+nPLen, &nFLen);
 
+    EVP_CIPHER_CTX_init(&ctx);
+    if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
+    if (fOk) fOk = EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
+    if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0])+nPLen, &nFLen);
     EVP_CIPHER_CTX_cleanup(&ctx);
 
+    if (!fOk) return false;
+
     vchPlaintext.resize(nPLen + nFLen);
     return true;
 }

src/keystore.cpp

@@ -84,6 +84,8 @@ bool CCryptoKeyStore::Unlock(const CKeyingMaterial& vMasterKeyIn)
             CSecret vchSecret;
             if(!DecryptSecret(vMasterKeyIn, vchCryptedSecret, Hash(vchPubKey.begin(), vchPubKey.end()), vchSecret))
                 return false;
+            if (vchSecret.size() != 32)
+                return false;
             CKey key;
             key.SetPubKey(vchPubKey);
             key.SetSecret(vchSecret);
@@ -146,6 +148,8 @@ bool CCryptoKeyStore::GetKey(const CBitcoinAddress &address, CKey& keyOut) const
             CSecret vchSecret;
             if (!DecryptSecret(vMasterKey, vchCryptedSecret, Hash(vchPubKey.begin(), vchPubKey.end()), vchSecret))
                 return false;
+            if (vchSecret.size() != 32)
+                return false;
             keyOut.SetPubKey(vchPubKey);
             keyOut.SetSecret(vchSecret);
             return true;