mirror of
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422 lines
19 KiB
C++
422 lines
19 KiB
C++
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/***************************************************************************
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* HopByHopHeader.cc -- The HopByHopHeader Class represents an IPv6 *
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* Hop-by-Hop extension header. *
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***********************IMPORTANT NMAP LICENSE TERMS************************
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* *
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* The Nmap Security Scanner is (C) 1996-2012 Insecure.Com LLC. Nmap is *
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* also a registered trademark of Insecure.Com LLC. This program is free *
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* software; you may redistribute and/or modify it under the terms of the *
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* GNU General Public License as published by the Free Software *
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* Foundation; Version 2 with the clarifications and exceptions described *
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* below. This guarantees your right to use, modify, and redistribute *
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* this software under certain conditions. If you wish to embed Nmap *
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* technology into proprietary software, we sell alternative licenses *
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* (contact sales@insecure.com). Dozens of software vendors already *
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* license Nmap technology such as host discovery, port scanning, OS *
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* detection, version detection, and the Nmap Scripting Engine. *
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* *
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* Note that the GPL places important restrictions on "derived works", yet *
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* it does not provide a detailed definition of that term. To avoid *
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* misunderstandings, we interpret that term as broadly as copyright law *
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* allows. For example, we consider an application to constitute a *
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* "derivative work" for the purpose of this license if it does any of the *
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* following: *
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* o Integrates source code from Nmap *
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* o Reads or includes Nmap copyrighted data files, such as *
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* nmap-os-db or nmap-service-probes. *
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* o Executes Nmap and parses the results (as opposed to typical shell or *
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* execution-menu apps, which simply display raw Nmap output and so are *
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* not derivative works.) *
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* o Integrates/includes/aggregates Nmap into a proprietary executable *
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* installer, such as those produced by InstallShield. *
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* o Links to a library or executes a program that does any of the above *
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* *
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* The term "Nmap" should be taken to also include any portions or derived *
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* works of Nmap, as well as other software we distribute under this *
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* license such as Zenmap, Ncat, and Nping. This list is not exclusive, *
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* but is meant to clarify our interpretation of derived works with some *
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* common examples. Our interpretation applies only to Nmap--we don't *
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* speak for other people's GPL works. *
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* *
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* If you have any questions about the GPL licensing restrictions on using *
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* Nmap in non-GPL works, we would be happy to help. As mentioned above, *
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* we also offer alternative license to integrate Nmap into proprietary *
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* applications and appliances. These contracts have been sold to dozens *
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* of software vendors, and generally include a perpetual license as well *
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* as providing for priority support and updates. They also fund the *
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* continued development of Nmap. Please email sales@insecure.com for *
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* further information. *
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* *
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* As a special exception to the GPL terms, Insecure.Com LLC grants *
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* permission to link the code of this program with any version of the *
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* OpenSSL library which is distributed under a license identical to that *
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* listed in the included docs/licenses/OpenSSL.txt file, and distribute *
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* linked combinations including the two. You must obey the GNU GPL in all *
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* respects for all of the code used other than OpenSSL. If you modify *
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* this file, you may extend this exception to your version of the file, *
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* but you are not obligated to do so. *
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* *
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* If you received these files with a written license agreement or *
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* contract stating terms other than the terms above, then that *
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* alternative license agreement takes precedence over these comments. *
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* *
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* Source is provided to this software because we believe users have a *
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* right to know exactly what a program is going to do before they run it. *
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* This also allows you to audit the software for security holes (none *
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* have been found so far). *
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* *
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* Source code also allows you to port Nmap to new platforms, fix bugs, *
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* and add new features. You are highly encouraged to send your changes *
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* to nmap-dev@insecure.org for possible incorporation into the main *
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* distribution. By sending these changes to Fyodor or one of the *
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* Insecure.Org development mailing lists, or checking them into the Nmap *
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* source code repository, it is understood (unless you specify otherwise) *
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* that you are offering the Nmap Project (Insecure.Com LLC) the *
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* unlimited, non-exclusive right to reuse, modify, and relicense the *
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* code. Nmap will always be available Open Source, but this is important *
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* because the inability to relicense code has caused devastating problems *
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* for other Free Software projects (such as KDE and NASM). We also *
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* occasionally relicense the code to third parties as discussed above. *
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* If you wish to specify special license conditions of your *
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* contributions, just say so when you send them. *
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* *
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* This program is distributed in the hope that it will be useful, but *
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* WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
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* General Public License v2.0 for more details at *
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* http://www.gnu.org/licenses/gpl-2.0.html , or in the COPYING file *
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* included with Nmap. *
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* *
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***************************************************************************/
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/* This code was originally part of the Nping tool. */
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#include "HopByHopHeader.h"
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#include <assert.h>
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/******************************************************************************/
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/* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */
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/******************************************************************************/
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HopByHopHeader::HopByHopHeader() {
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this->reset();
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} /* End of HopByHopHeader constructor */
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HopByHopHeader::~HopByHopHeader() {
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} /* End of HopByHopHeader destructor */
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/** Sets every attribute to its default value */
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void HopByHopHeader::reset(){
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memset(&this->h, 0, sizeof(nping_ipv6_ext_hopbyhop_hdr_t));
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curr_option=(u8*)this->h.options;
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this->length=2;
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this->addOption(EXTOPT_PADN, 4, (const u8*)"\x00\x00\x00\x00");
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} /* End of reset() */
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/******************************************************************************/
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/* PacketElement:: OVERWRITTEN METHODS */
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/******************************************************************************/
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/** @warning This method is essential for the superclass getBinaryBuffer()
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* method to work. Do NOT change a thing unless you know what you're doing */
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u8 *HopByHopHeader::getBufferPointer(){
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return (u8*)(&this->h);
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} /* End of getBufferPointer() */
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/** Stores supplied packet in the internal buffer so the information
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* can be accessed using the standard get & set methods.
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* @warning The HopByHopHeader class is able to hold a maximum of
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* sizeof(nping_icmpv6_hdr_t) bytes. If the supplied buffer is longer than
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* that, only the first 1508 bytes will be stored in the internal buffer.
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* @warning Supplied len MUST be at least 8 bytes (min ICMPv6 header length).
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* @return OP_SUCCESS on success and OP_FAILURE in case of error */
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int HopByHopHeader::storeRecvData(const u8 *buf, size_t len){
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if(buf==NULL || len<HOPBYHOP_MIN_HEADER_LEN){
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this->length=0;
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return OP_FAILURE;
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}else{
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/* Store the first 4 bytes, so we can access the HdrExtLen field. */
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memcpy(&(this->h), buf, 4);
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/* Check that the HdrExtLen field makes sense:
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* 1) Check that it carries as many octets as it claims
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* 2) Check that we don't exceed our internal storage space. */
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if( ((unsigned int)(this->h.len+1))*8 > len || (this->h.len+1)*8 > HOPBYHOP_MAX_HEADER_LEN){
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this->length=0;
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return OP_FAILURE;
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}else{
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int mylen=(this->h.len+1)*8;
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this->reset();
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this->length=mylen;
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memcpy(&(this->h), buf, this->length);
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return OP_SUCCESS;
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}
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}
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return OP_FAILURE;
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} /* End of storeRecvData() */
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/* Returns a protocol identifier. This is used by packet parsing funtions
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* that return linked lists of PacketElement objects, to determine the protocol
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* the object represents. */
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int HopByHopHeader::protocol_id() const {
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return HEADER_TYPE_IPv6_HOPOPT;
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} /* End of protocol_id() */
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/** Determines if the data stored in the object after an storeRecvData() call
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* is valid and safe to use. This mainly checks the length of the data but may
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* also test the value of certain protocol fields to ensure their correctness.
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* @return the length, in bytes, of the header, if its found to be valid or
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* OP_FAILURE (-1) otherwise. */
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int HopByHopHeader::validate(){
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nping_ipv6_ext_hopbyhop_opt_t *curr_opt=NULL;
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u8 *curr_pnt=(u8 *)this->h.options;
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int bytes_left=this->length-2;
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/* Check the object's length makes sense*/
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if(this->length%8!=0 || this->length < HOPBYHOP_MIN_HEADER_LEN || this->length > HOPBYHOP_MAX_HEADER_LEN){
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return OP_FAILURE;
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}
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/* Check the header's length field. It should match the object's length */
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if( (this->h.len+1)*8 != this->length){
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return OP_FAILURE;
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}
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/* Now validate the TLV-encoded options. */
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while(bytes_left>0){
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/* Use the opts structure as a template to access current option */
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curr_opt=(nping_ipv6_ext_hopbyhop_opt_t *)curr_pnt;
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/* Let's see what we have. */
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switch(curr_opt->type){
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/* Pad1
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+-+-+-+-+-+-+-+-+
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| 0 |
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+-+-+-+-+-+-+-+-+ */
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case EXTOPT_PAD1:
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curr_pnt++; /* Skip one octet */
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bytes_left++;
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break;
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/* PadN
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -
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| 1 | Padding Len | Padding
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - */
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case EXTOPT_PADN:
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/* Check we have as many octets as the option advertises */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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/* Jumbo Payload Option (RFC 2675).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | Opt Data Len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Jumbo Payload Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_JUMBO:
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/* Jumbo has a fixed length of 4 octets (plus 2). */
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if(curr_opt->len!=4)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+4)
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return OP_FAILURE;
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curr_pnt+=6;
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bytes_left-=6;
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break;
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/* Tunnel Encapsulation limit (RFC 2473).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | 1 | Tun Encap Lim |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_TUNENCAPLIM:
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/* This one also has a fixed length. */
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if(curr_opt->len!=1)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+1)
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return OP_FAILURE;
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curr_pnt+=3;
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bytes_left-=3;
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break;
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/* Router Alert (RFC 2711).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | 2 | Value (2 octets) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_ROUTERALERT:
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/* Fixed length (two octets)*/
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if(curr_opt->len!=2)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+2)
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return OP_FAILURE;
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curr_pnt+=4;
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bytes_left-=4;
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break;
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/* Quick-Start (RFC 4782).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option | Length=6 | Func. | Rate | Not Used |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| QS Nonce | R |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_QUICKSTART:
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/* Fixed length (two octets)*/
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if(curr_opt->len!=6)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+6)
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return OP_FAILURE;
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curr_pnt+=8;
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bytes_left-=8;
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break;
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/* CALIPSO (RFC 5570).
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+----------------------------+
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| Option Type | Option Length|
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+-------------+---------------+-------------+--------------+
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| CALIPSO Domain of Interpretation |
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+-------------+---------------+-------------+--------------+
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| Cmpt Length | Sens Level | Checksum (CRC-16) |
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+-------------+---------------+-------------+--------------+
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| Compartment Bitmap (Optional; variable length) |
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+-------------+---------------+-------------+--------------+ */
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case EXTOPT_CALIPSO:
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/* The length of the CALIPSO option is variable because the
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* Compartment Bitmap is not mandatory. However, the length
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* must be at least 8. */
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if(curr_opt->len<8)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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/* Home Address (RFC 6275).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | Option Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+ +
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+ Home Address +
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+ +
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/
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case EXTOPT_HOMEADDR:
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/* Fixed length of 16 */
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if(curr_opt->len!=16)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+16)
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return OP_FAILURE;
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curr_pnt+=18;
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bytes_left-=18;
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break;
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/* Option Type Unknown */
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default:
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/* If we don't know the option, we can still try to validate it,
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* checking if the OptionLength contains something reasonable. */
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/* Fixed length of 16 */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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}
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}
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return this->length;
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} /* End of validate() */
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/** Prints the contents of the header and calls print() on the next protocol
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* header in the chain (if there is any).
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* @return OP_SUCCESS on success and OP_FAILURE in case of error. */
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int HopByHopHeader::print(FILE *output, int detail) const {
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fprintf(output, "HopByHop[%d,%d]", this->h.nh, this->h.len);
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// TODO: @todo : Implement this
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if(this->next!=NULL){
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print_separator(output, detail);
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next->print(output, detail);
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}
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return OP_SUCCESS;
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} /* End of print() */
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/******************************************************************************/
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/* PROTOCOL-SPECIFIC METHODS */
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/******************************************************************************/
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/** Set Next Header field */
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int HopByHopHeader::setNextHeader(u8 val){
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this->h.nh = val;
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return OP_SUCCESS;
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} /* End of setNextHeader() */
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/** Returns next header id */
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u8 HopByHopHeader::getNextHeader(){
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return this->h.nh;
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} /* End of getNextHeader() */
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/* Add TLV encoded option */
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int HopByHopHeader::addOption(u8 type, u8 len, const u8 *data){
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/* Make sure we don't screw up due to buffer length issues */
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if(data==NULL)
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return OP_FAILURE;
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if ( (this->length+len+2) > HOPBYHOP_MAX_HEADER_LEN ) /* No space for more */
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return OP_FAILURE;
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/* Store the option */
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curr_option[0]=type;
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curr_option[1]=len;
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memcpy(curr_option+2, data, len);
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/* Update internal option offset and object's length */
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curr_option+=(len+2);
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this->length+=(len+2);
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this->addPadding();
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return OP_SUCCESS;
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} /* End of addOption() */
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/* If the current length of the extension header is not a multiple of 8 octets,
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* this method adds the neccessary padding (either PadN or Pad1 options)*/
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int HopByHopHeader::addPadding(){
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u8 zeroes[8]={0,0,0,0,0,0,0,0};
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int required_octets=8-(this->length%8);
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/* Make sure we have enough space for the padding. */
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if ( (this->length+required_octets) > HOPBYHOP_MAX_HEADER_LEN )
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return OP_FAILURE;
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/* Insert Pad1 or PadN to fill the necessary octets */
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if(required_octets>0 && required_octets<8){
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if(required_octets==1){
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curr_option[0]=EXTOPT_PAD1;
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curr_option++;
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this->length++;
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}else{
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this->addOption(EXTOPT_PADN, required_octets-2, zeroes );
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}
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}
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assert(this->length%8==0);
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this->h.len=(this->length/8)-1;
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return OP_SUCCESS;
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} /* End of addPadding() */
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