Fix verify_pss returning raw C code instead of boolean

Author: JeremiahM37

tests/test_ciphers.py

@@ -456,14 +456,14 @@ def test_rsa_pss_sign_verify(rsa_private_pss, rsa_public_pss):
             signature = rsa_private_pss.sign_pss(plaintext)
 
             assert 1024 / 8 == len(signature) == rsa_private_pss.output_size
-            assert 0 == rsa_public_pss.verify_pss(plaintext, signature)
+            assert rsa_public_pss.verify_pss(plaintext, signature) is True
 
             # private object holds both private and public info, so it can also verify
             # using the known public key.
             signature = rsa_private_pss.sign_pss(plaintext)
 
             assert 1024 / 8 == len(signature) == rsa_private_pss.output_size
-            assert 0 == rsa_private_pss.verify_pss(plaintext, signature)
+            assert rsa_private_pss.verify_pss(plaintext, signature) is True
 
     def test_rsa_sign_verify_pem(rsa_private_pem, rsa_public_pem):
         plaintext = t2b("Everyone gets Friday off.")

wolfcrypt/ciphers.py

@@ -811,8 +811,10 @@ def verify_pss(self, plaintext, signature):
                 ret = _lib.wc_RsaPSS_CheckPadding(digest, len(digest),
                                                   verify, ret, self._hash_type)
 
-                return ret
+                if ret < 0:  # pragma: no cover
+                    raise WolfCryptError("PSS padding check error (%d)" % ret)
 
+                return ret == 0
 
 
     class RsaPrivate(RsaPublic):