Added a hook to alter the payload length field of arbitrary payloads
authorMartin Willi <martin@revosec.ch>
Mon, 15 Nov 2010 10:54:35 +0000 (11:54 +0100)
committerMartin Willi <martin@revosec.ch>
Wed, 5 Jan 2011 15:45:47 +0000 (16:45 +0100)
src/conftest/Makefile.am
src/conftest/hooks/set_length.c [new file with mode: 0644]

index 3d669ae..d496578 100644 (file)
@@ -6,7 +6,7 @@ conftest_SOURCES = conftest.c conftest.h config.c config.h actions.c actions.h \
        hooks/hook.h hooks/ike_auth_fill.c hooks/unsort_message.c \
        hooks/add_notify.c hooks/unencrypted_notify.c hooks/ignore_message.c \
        hooks/add_payload.c hooks/set_critical.c hooks/force_cookie.c \
-       hooks/set_ike_version.c hooks/pretend_auth.c
+       hooks/set_ike_version.c hooks/pretend_auth.c hooks/set_length.c
 
 INCLUDES = \
        -I$(top_srcdir)/src/libstrongswan \
diff --git a/src/conftest/hooks/set_length.c b/src/conftest/hooks/set_length.c
new file mode 100644 (file)
index 0000000..0379dcb
--- /dev/null
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "hook.h"
+
+typedef struct private_set_length_t private_set_length_t;
+
+/**
+ * Private data of an set_length_t object.
+ */
+struct private_set_length_t {
+
+       /**
+        * Implements the hook_t interface.
+        */
+       hook_t hook;
+
+       /**
+        * Alter requests or responses?
+        */
+       bool req;
+
+       /**
+        * ID of message to alter.
+        */
+       int id;
+
+       /**
+        * Payload type
+        */
+       char *type;
+
+       /**
+        * Difference to correct length
+        */
+       int diff;
+};
+
+METHOD(listener_t, message, bool,
+       private_set_length_t *this, ike_sa_t *ike_sa, message_t *message,
+       bool incoming)
+{
+       if (!incoming &&
+               message->get_request(message) == this->req &&
+               message->get_message_id(message) == this->id)
+       {
+               payload_t *payload;
+               enumerator_t *enumerator;
+               payload_type_t type;
+
+               type = atoi(this->type);
+               if (!type)
+               {
+                       type = enum_from_name(payload_type_short_names, this->type);
+                       if (type == -1)
+                       {
+                               DBG1(DBG_CFG, "unknown payload: '%s', skipped", this->type);
+                               return TRUE;
+                       }
+               }
+               enumerator = message->create_payload_enumerator(message);
+               while (enumerator->enumerate(enumerator, &payload))
+               {
+                       if (type == payload->get_type(payload))
+                       {
+                               encoding_rule_t *rules;
+                               size_t count;
+                               u_int16_t *len;
+                               int i;
+
+                               payload->get_encoding_rules(payload, &rules, &count);
+                               for (i = 0; i < count; i++)
+                               {
+                                       if (rules[i].type == PAYLOAD_LENGTH)
+                                       {
+                                               len = (u_int16_t*)(((void*)payload) + rules[i].offset);
+                                               DBG1(DBG_CFG, "adjusting length of %N payload "
+                                                        "from %d to %d", payload_type_short_names, type,
+                                                        *len, *len + this->diff);
+                                               *len = *len + this->diff;
+                                       }
+                               }
+                       }
+               }
+               enumerator->destroy(enumerator);
+       }
+       return TRUE;
+}
+
+METHOD(hook_t, destroy, void,
+       private_set_length_t *this)
+{
+       free(this);
+}
+
+/**
+ * Create the IKE_AUTH fill hook
+ */
+hook_t *set_length_hook_create(char *name)
+{
+       private_set_length_t *this;
+
+       INIT(this,
+               .hook = {
+                       .listener = {
+                               .message = _message,
+                       },
+                       .destroy = _destroy,
+               },
+               .req = conftest->test->get_bool(conftest->test,
+                                                                               "hooks.%s.request", TRUE, name),
+               .id = conftest->test->get_int(conftest->test,
+                                                                               "hooks.%s.id", 0, name),
+               .type = conftest->test->get_str(conftest->test,
+                                                                               "hooks.%s.type", "", name),
+               .diff = conftest->test->get_int(conftest->test,
+                                                                               "hooks.%s.diff", 0, name),
+       );
+
+       return &this->hook;
+}