Don't use BMConfigParser in highlevelcrypto, instead use digestAlg kwarg,

both in .sign() and .verify(), extend TestHighlevelcrypto.test_signatures().

Author: g1itch

src/class_singleWorker.py

@@ -50,6 +50,8 @@ class singleWorker(StoppableThread):
 
     def __init__(self):
         super(singleWorker, self).__init__(name="singleWorker")
+        self.digestAlg = config.safeGet(
+            'bitmessagesettings', 'digestalg', 'sha256')
         proofofwork.init()
 
     def stopThread(self):
@@ -368,7 +370,8 @@ def sendOutOrStoreMyV3Pubkey(self, adressHash):
         payload += encodeVarint(config.getint(
             myAddress, 'payloadlengthextrabytes'))
 
-        signature = highlevelcrypto.sign(payload, privSigningKeyHex)
+        signature = highlevelcrypto.sign(
+            payload, privSigningKeyHex, self.digestAlg)
         payload += encodeVarint(len(signature))
         payload += signature
 
@@ -455,8 +458,7 @@ def sendOutOrStoreMyV4Pubkey(self, myAddress):
         ).digest()).digest()
         payload += doubleHashOfAddressData[32:]  # the tag
         signature = highlevelcrypto.sign(
-            payload + dataToEncrypt, privSigningKeyHex
-        )
+            payload + dataToEncrypt, privSigningKeyHex, self.digestAlg)
         dataToEncrypt += encodeVarint(len(signature))
         dataToEncrypt += signature
 
@@ -641,7 +643,7 @@ def sendBroadcast(self):
             dataToSign = payload + dataToEncrypt
 
             signature = highlevelcrypto.sign(
-                dataToSign, privSigningKeyHex)
+                dataToSign, privSigningKeyHex, self.digestAlg)
             dataToEncrypt += encodeVarint(len(signature))
             dataToEncrypt += signature
 
@@ -1223,7 +1225,8 @@ def sendMsg(self):
             payload += fullAckPayload
             dataToSign = pack('>Q', embeddedTime) + '\x00\x00\x00\x02' + \
                 encodeVarint(1) + encodeVarint(toStreamNumber) + payload
-            signature = highlevelcrypto.sign(dataToSign, privSigningKeyHex)
+            signature = highlevelcrypto.sign(
+                dataToSign, privSigningKeyHex, self.digestAlg)
             payload += encodeVarint(len(signature))
             payload += signature
 

src/highlevelcrypto.py

@@ -13,7 +13,6 @@
 from pyelliptic import OpenSSL
 from pyelliptic import arithmetic as a
 
-from bmconfigparser import config
 
 __all__ = ['encrypt', 'makeCryptor', 'pointMult', 'privToPub', 'sign', 'verify']
 
@@ -64,43 +63,44 @@ def decryptFast(msg, cryptor):
     return cryptor.decrypt(msg)
 
 
-def sign(msg, hexPrivkey):
+def _choose_digest_alg(name):
     """
-    Signs with hex private key using SHA1 or SHA256 depending on
-    "digestalg" setting
+    Choose openssl digest constant by name raises ValueError if not appropriate
     """
-    digestAlg = config.safeGet(
-        'bitmessagesettings', 'digestalg', 'sha256')
-    if digestAlg == "sha1":
+    if name not in ("sha1", "sha256"):
+        raise ValueError("Unknown digest algorithm %s" % name)
+    return (
         # SHA1, this will eventually be deprecated
-        return makeCryptor(hexPrivkey).sign(
-            msg, digest_alg=OpenSSL.digest_ecdsa_sha1)
-    elif digestAlg == "sha256":
-        # SHA256. Eventually this will become the default
-        return makeCryptor(hexPrivkey).sign(msg, digest_alg=OpenSSL.EVP_sha256)
-    else:
-        raise ValueError("Unknown digest algorithm %s" % digestAlg)
+        OpenSSL.digest_ecdsa_sha1 if name == "sha1" else OpenSSL.EVP_sha256)
+
 
+def sign(msg, hexPrivkey, digestAlg="sha256"):
+    """
+    Signs with hex private key using SHA1 or SHA256 depending on
+    *digestAlg* keyword.
+    """
+    return makeCryptor(hexPrivkey).sign(
+        msg, digest_alg=_choose_digest_alg(digestAlg))
 
-def verify(msg, sig, hexPubkey):
+
+def verify(msg, sig, hexPubkey, digestAlg=None):
     """Verifies with hex public key using SHA1 or SHA256"""
     # As mentioned above, we must upgrade gracefully to use SHA256. So
     # let us check the signature using both SHA1 and SHA256 and if one
     # of them passes then we will be satisfied. Eventually this can
     # be simplified and we'll only check with SHA256.
-    try:
+    if digestAlg is None:
         # old SHA1 algorithm.
-        sigVerifyPassed = makePubCryptor(hexPubkey).verify(
-            sig, msg, digest_alg=OpenSSL.digest_ecdsa_sha1)
-    except:
-        sigVerifyPassed = False
-    if sigVerifyPassed:
-        # The signature check passed using SHA1
-        return True
-    # The signature check using SHA1 failed. Let us try it with SHA256.
+        sigVerifyPassed = verify(msg, sig, hexPubkey, "sha1")
+        if sigVerifyPassed:
+            # The signature check passed using SHA1
+            return True
+        # The signature check using SHA1 failed. Let us try it with SHA256.
+        return verify(msg, sig, hexPubkey, "sha256")
+
     try:
         return makePubCryptor(hexPubkey).verify(
-            sig, msg, digest_alg=OpenSSL.EVP_sha256)
+            sig, msg, digest_alg=_choose_digest_alg(digestAlg))
     except:
         return False
 

src/tests/test_crypto.py

@@ -70,12 +70,21 @@ def test_signatures(self):
         """Verify sample signatures and newly generated ones"""
         pubkey_hex = hexlify(sample_pubsigningkey)
         # pregenerated signatures
+        self.assertTrue(highlevelcrypto.verify(
+            sample_msg, sample_sig, pubkey_hex, "sha256"))
+        self.assertFalse(highlevelcrypto.verify(
+            sample_msg, sample_sig, pubkey_hex, "sha1"))
+        self.assertTrue(highlevelcrypto.verify(
+            sample_msg, sample_sig_sha1, pubkey_hex, "sha1"))
+        self.assertTrue(highlevelcrypto.verify(
+            sample_msg, sample_sig_sha1, pubkey_hex))
+        # new signatures
+        sig256 = highlevelcrypto.sign(sample_msg, sample_privsigningkey)
+        sig1 = highlevelcrypto.sign(sample_msg, sample_privsigningkey, "sha1")
         self.assertTrue(
-            highlevelcrypto.verify(sample_msg, sample_sig, pubkey_hex))
+            highlevelcrypto.verify(sample_msg, sig256, pubkey_hex))
         self.assertTrue(
-            highlevelcrypto.verify(sample_msg, sample_sig_sha1, pubkey_hex))
-        # new signature
-        sig1 = highlevelcrypto.sign(sample_msg, sample_privsigningkey)
+            highlevelcrypto.verify(sample_msg, sig256, pubkey_hex, "sha256"))
         self.assertTrue(
             highlevelcrypto.verify(sample_msg, sig1, pubkey_hex))