check EC public key isn't point at infinity

crypto/ec/Makefile

@@ -38,7 +38,7 @@ top:
 all:	lib
 
 lib:	$(LIBOBJ)
-	$(AR) $(LIB) $(LIBOBJ)
+	$(ARX) $(LIB) $(LIBOBJ)
 	$(RANLIB) $(LIB) || echo Never mind.
 	@touch lib
 

crypto/ec/ec_key.c

@@ -304,6 +304,12 @@ int EC_KEY_check_key(const EC_KEY *eckey)
 		ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 		return 0;
 		}
+
+	if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key))
+		{
+		ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_AT_INFINITY);
+		goto err;
+		}
 	
 	if ((ctx = BN_CTX_new()) == NULL)
 		goto err;