Fix for bug #1308: tacacs decoding fails. Introduce TCP desegmentation for

[obnox/wireshark/wip.git] / epan / dissectors / packet-tacacs.c

diff --git a/epan/dissectors/packet-tacacs.c b/epan/dissectors/packet-tacacs.c
index 538bcd4316c74e7caf4d6092c352d8aaf60c0de8..61bf65fdad20e1247e5a7e441616a11cc485a943 100644 (file)
--- a/epan/dissectors/packet-tacacs.c
+++ b/epan/dissectors/packet-tacacs.c
@@ -87,6 +87,8 @@ static int hf_tacacs_result3 = -1;
 
 static gint ett_tacacs = -1;
 
+static gboolean tacplus_preference_desegment = TRUE;
+
 static const char *tacplus_opt_key;
 static GSList *tacplus_keys = NULL;
 
@@ -926,6 +928,15 @@ dissect_tacplus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
        gboolean        request=( pinfo->destport == TCP_PORT_TACACS );
        const char      *key=NULL;
 
+       len = tvb_get_ntohl(tvb, 8);
+       
+       if(len > (guint)tvb_length_remaining(tvb, 12) &&
+          pinfo->can_desegment && tacplus_preference_desegment) {
+               pinfo->desegment_offset = 0;
+               pinfo->desegment_len = len;
+               return;
+       }
+       
        if( request ) {
                key=find_key( &pinfo->dst, &pinfo->src );
        } else {
@@ -985,7 +996,7 @@ dissect_tacplus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
                    tvb, 3, 1, flags);
                proto_tree_add_item(tacplus_tree, hf_tacplus_session_id, tvb, 4, 4,
                    FALSE);
-               len = tvb_get_ntohl(tvb,8);
+
                if ((gint) len < 1) {
                        proto_tree_add_text(tacplus_tree, tvb, 8, 4,
                                "Invalid length: %u", len);
@@ -1088,6 +1099,9 @@ proto_register_tacplus(void)
        proto_register_field_array(proto_tacplus, hf, array_length(hf));
        proto_register_subtree_array(ett, array_length(ett));
        tacplus_module = prefs_register_protocol (proto_tacplus, tacplus_pref_cb );
+
+        prefs_register_bool_preference(tacplus_module, "desegment", "Reassemble TACACS+ messages spanning multiple TCP segments.", "Whether the TACACS+ dissector should reasssemble messages spanning multiple TCP segments.  To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.", &tacplus_preference_desegment);
+
        prefs_register_string_preference ( tacplus_module, "key",
        "TACACS+ Encryption Key", "TACACS+ Encryption Key", &tacplus_opt_key );
 }