/*************************************************************************** * HopByHopHeader.cc -- The HopByHopHeader Class represents an IPv6 * * Hop-by-Hop extension header. * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2019 Insecure.Com LLC ("The Nmap * * Project"). Nmap is also a registered trademark of the Nmap Project. * * This program is free software; you may redistribute and/or modify it * * under the terms of the GNU General Public License as published by the * * Free Software Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE * * CLARIFICATIONS AND EXCEPTIONS DESCRIBED HEREIN. This guarantees your * * right to use, modify, and redistribute this software under certain * * conditions. If you wish to embed Nmap technology into proprietary * * software, we sell alternative licenses (contact sales@nmap.com). * * Dozens of software vendors already license Nmap technology such as * * host discovery, port scanning, OS detection, version detection, and * * the Nmap Scripting Engine. * * * * Note that the GPL places important restrictions on "derivative works", * * yet it does not provide a detailed definition of that term. To avoid * * misunderstandings, we interpret that term as broadly as copyright law * * allows. For example, we consider an application to constitute a * * derivative work for the purpose of this license if it does any of the * * following with any software or content covered by this license * * ("Covered Software"): * * * * o Integrates source code from Covered Software. * * * * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db * * or nmap-service-probes. * * * * o Is designed specifically to execute Covered Software and parse the * * results (as opposed to typical shell or execution-menu apps, which will * * execute anything you tell them to). * * * * o Includes Covered Software in a proprietary executable installer. The * * installers produced by InstallShield are an example of this. Including * * Nmap with other software in compressed or archival form does not * * trigger this provision, provided appropriate open source decompression * * or de-archiving software is widely available for no charge. For the * * purposes of this license, an installer is considered to include Covered * * Software even if it actually retrieves a copy of Covered Software from * * another source during runtime (such as by downloading it from the * * Internet). * * * * o Links (statically or dynamically) to a library which does any of the * * above. * * * * o Executes a helper program, module, or script to do any of the above. * * * * This list is not exclusive, but is meant to clarify our interpretation * * of derived works with some common examples. Other people may interpret * * the plain GPL differently, so we consider this a special exception to * * the GPL that we apply to Covered Software. Works which meet any of * * these conditions must conform to all of the terms of this license, * * particularly including the GPL Section 3 requirements of providing * * source code and allowing free redistribution of the work as a whole. * * * * As another special exception to the GPL terms, the Nmap Project grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. * * * * The Nmap Project has permission to redistribute Npcap, a packet * * capturing driver and library for the Microsoft Windows platform. * * Npcap is a separate work with it's own license rather than this Nmap * * license. Since the Npcap license does not permit redistribution * * without special permission, our Nmap Windows binary packages which * * contain Npcap may not be redistributed without special permission. * * * * Any redistribution of Covered Software, including any derived works, * * must obey and carry forward all of the terms of this license, including * * obeying all GPL rules and restrictions. For example, source code of * * the whole work must be provided and free redistribution must be * * allowed. All GPL references to "this License", are to be treated as * * including the terms and conditions of this license text as well. * * * * Because this license imposes special exceptions to the GPL, Covered * * Work may not be combined (even as part of a larger work) with plain GPL * * software. The terms, conditions, and exceptions of this license must * * be included as well. This license is incompatible with some other open * * source licenses as well. In some cases we can relicense portions of * * Nmap or grant special permissions to use it in other open source * * software. Please contact fyodor@nmap.org with any such requests. * * Similarly, we don't incorporate incompatible open source software into * * Covered Software without special permission from the copyright holders. * * * * If you have any questions about the licensing restrictions on using * * Nmap in other works, we are happy to help. As mentioned above, we also * * offer an alternative license to integrate Nmap into proprietary * * applications and appliances. These contracts have been sold to dozens * * of software vendors, and generally include a perpetual license as well * * as providing support and updates. They also fund the continued * * development of Nmap. Please email sales@nmap.com for further * * information. * * * * If you have received a written license agreement or contract for * * Covered Software stating terms other than these, you may choose to use * * and redistribute Covered Software under those terms instead of these. * * * * Source is provided to this software because we believe users have a * * right to know exactly what a program is going to do before they run it. * * This also allows you to audit the software for security holes. * * * * Source code also allows you to port Nmap to new platforms, fix bugs, * * and add new features. You are highly encouraged to send your changes * * to the dev@nmap.org mailing list for possible incorporation into the * * main distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, or checking them into the Nmap * * source code repository, it is understood (unless you specify * * otherwise) that you are offering the Nmap Project the unlimited, * * non-exclusive right to reuse, modify, and relicense the code. Nmap * * will always be available Open Source, but this is important because * * the inability to relicense code has caused devastating problems for * * other Free Software projects (such as KDE and NASM). We also * * occasionally relicense the code to third parties as discussed above. * * If you wish to specify special license conditions of your * * contributions, just say so when you send them. * * * * 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 Nmap * * license file for more details (it's in a COPYING file included with * * Nmap, and also available from https://svn.nmap.org/nmap/COPYING) * * * ***************************************************************************/ /* This code was originally part of the Nping tool. */ #include "HopByHopHeader.h" #include /******************************************************************************/ /* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */ /******************************************************************************/ HopByHopHeader::HopByHopHeader() { this->reset(); } /* End of HopByHopHeader constructor */ HopByHopHeader::~HopByHopHeader() { } /* End of HopByHopHeader destructor */ /** Sets every attribute to its default value */ void HopByHopHeader::reset(){ memset(&this->h, 0, sizeof(nping_ipv6_ext_hopbyhop_hdr_t)); curr_option=(u8*)this->h.options; this->length=2; this->addOption(EXTOPT_PADN, 4, (const u8*)"\x00\x00\x00\x00"); } /* End of reset() */ /******************************************************************************/ /* PacketElement:: OVERWRITTEN METHODS */ /******************************************************************************/ /** @warning This method is essential for the superclass getBinaryBuffer() * method to work. Do NOT change a thing unless you know what you're doing */ u8 *HopByHopHeader::getBufferPointer(){ return (u8*)(&this->h); } /* End of getBufferPointer() */ /** Stores supplied packet in the internal buffer so the information * can be accessed using the standard get & set methods. * @warning The HopByHopHeader class is able to hold a maximum of * sizeof(nping_icmpv6_hdr_t) bytes. If the supplied buffer is longer than * that, only the first 1508 bytes will be stored in the internal buffer. * @warning Supplied len MUST be at least 8 bytes (min ICMPv6 header length). * @return OP_SUCCESS on success and OP_FAILURE in case of error */ int HopByHopHeader::storeRecvData(const u8 *buf, size_t len){ if(buf==NULL || lenlength=0; return OP_FAILURE; }else{ /* Store the first 4 bytes, so we can access the HdrExtLen field. */ memcpy(&(this->h), buf, 4); /* Check that the HdrExtLen field makes sense: * 1) Check that it carries as many octets as it claims * 2) Check that we don't exceed our internal storage space. */ if( ((unsigned int)(this->h.len+1))*8 > len || (this->h.len+1)*8 > HOPBYHOP_MAX_HEADER_LEN){ this->length=0; return OP_FAILURE; }else{ int mylen=(this->h.len+1)*8; this->reset(); this->length=mylen; memcpy(&(this->h), buf, this->length); return OP_SUCCESS; } } return OP_FAILURE; } /* End of storeRecvData() */ /* Returns a protocol identifier. This is used by packet parsing funtions * that return linked lists of PacketElement objects, to determine the protocol * the object represents. */ int HopByHopHeader::protocol_id() const { return HEADER_TYPE_IPv6_HOPOPT; } /* End of protocol_id() */ /** Determines if the data stored in the object after an storeRecvData() call * is valid and safe to use. This mainly checks the length of the data but may * also test the value of certain protocol fields to ensure their correctness. * @return the length, in bytes, of the header, if its found to be valid or * OP_FAILURE (-1) otherwise. */ int HopByHopHeader::validate(){ nping_ipv6_ext_hopbyhop_opt_t *curr_opt=NULL; u8 *curr_pnt=(u8 *)this->h.options; int bytes_left=this->length-2; /* Check the object's length makes sense*/ if(this->length%8!=0 || this->length < HOPBYHOP_MIN_HEADER_LEN || this->length > HOPBYHOP_MAX_HEADER_LEN){ return OP_FAILURE; } /* Check the header's length field. It should match the object's length */ if( (this->h.len+1)*8 != this->length){ return OP_FAILURE; } /* Now validate the TLV-encoded options. */ while(bytes_left>0){ /* Use the opts structure as a template to access current option */ curr_opt=(nping_ipv6_ext_hopbyhop_opt_t *)curr_pnt; /* Let's see what we have. */ switch(curr_opt->type){ /* Pad1 +-+-+-+-+-+-+-+-+ | 0 | +-+-+-+-+-+-+-+-+ */ case EXTOPT_PAD1: curr_pnt++; /* Skip one octet */ bytes_left++; break; /* PadN +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - | 1 | Padding Len | Padding +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - */ case EXTOPT_PADN: /* Check we have as many octets as the option advertises */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; /* Jumbo Payload Option (RFC 2675). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Opt Data Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Jumbo Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_JUMBO: /* Jumbo has a fixed length of 4 octets (plus 2). */ if(curr_opt->len!=4) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+4) return OP_FAILURE; curr_pnt+=6; bytes_left-=6; break; /* Tunnel Encapsulation limit (RFC 2473). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | 1 | Tun Encap Lim | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_TUNENCAPLIM: /* This one also has a fixed length. */ if(curr_opt->len!=1) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+1) return OP_FAILURE; curr_pnt+=3; bytes_left-=3; break; /* Router Alert (RFC 2711). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | 2 | Value (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_ROUTERALERT: /* Fixed length (two octets)*/ if(curr_opt->len!=2) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+2) return OP_FAILURE; curr_pnt+=4; bytes_left-=4; break; /* Quick-Start (RFC 4782). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option | Length=6 | Func. | Rate | Not Used | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | QS Nonce | R | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_QUICKSTART: /* Fixed length (two octets)*/ if(curr_opt->len!=6) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+6) return OP_FAILURE; curr_pnt+=8; bytes_left-=8; break; /* CALIPSO (RFC 5570). +----------------------------+ | Option Type | Option Length| +-------------+---------------+-------------+--------------+ | CALIPSO Domain of Interpretation | +-------------+---------------+-------------+--------------+ | Cmpt Length | Sens Level | Checksum (CRC-16) | +-------------+---------------+-------------+--------------+ | Compartment Bitmap (Optional; variable length) | +-------------+---------------+-------------+--------------+ */ case EXTOPT_CALIPSO: /* The length of the CALIPSO option is variable because the * Compartment Bitmap is not mandatory. However, the length * must be at least 8. */ if(curr_opt->len<8) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; /* Home Address (RFC 6275). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Home Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/ case EXTOPT_HOMEADDR: /* Fixed length of 16 */ if(curr_opt->len!=16) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+16) return OP_FAILURE; curr_pnt+=18; bytes_left-=18; break; /* Option Type Unknown */ default: /* If we don't know the option, we can still try to validate it, * checking if the OptionLength contains something reasonable. */ /* Fixed length of 16 */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; } } return this->length; } /* End of validate() */ /** Prints the contents of the header and calls print() on the next protocol * header in the chain (if there is any). * @return OP_SUCCESS on success and OP_FAILURE in case of error. */ int HopByHopHeader::print(FILE *output, int detail) const { fprintf(output, "HopByHop[%d,%d]", this->h.nh, this->h.len); // TODO: @todo : Implement this if(this->next!=NULL){ print_separator(output, detail); next->print(output, detail); } return OP_SUCCESS; } /* End of print() */ /******************************************************************************/ /* PROTOCOL-SPECIFIC METHODS */ /******************************************************************************/ /** Set Next Header field */ int HopByHopHeader::setNextHeader(u8 val){ this->h.nh = val; return OP_SUCCESS; } /* End of setNextHeader() */ /** Returns next header id */ u8 HopByHopHeader::getNextHeader(){ return this->h.nh; } /* End of getNextHeader() */ /* Add TLV encoded option */ int HopByHopHeader::addOption(u8 type, u8 len, const u8 *data){ /* Make sure we don't screw up due to buffer length issues */ if(data==NULL) return OP_FAILURE; if ( (this->length+len+2) > HOPBYHOP_MAX_HEADER_LEN ) /* No space for more */ return OP_FAILURE; /* Store the option */ curr_option[0]=type; curr_option[1]=len; memcpy(curr_option+2, data, len); /* Update internal option offset and object's length */ curr_option+=(len+2); this->length+=(len+2); this->addPadding(); return OP_SUCCESS; } /* End of addOption() */ /* If the current length of the extension header is not a multiple of 8 octets, * this method adds the necessary padding (either PadN or Pad1 options)*/ int HopByHopHeader::addPadding(){ u8 zeroes[8]={0,0,0,0,0,0,0,0}; int required_octets=8-(this->length%8); /* Make sure we have enough space for the padding. */ if ( (this->length+required_octets) > HOPBYHOP_MAX_HEADER_LEN ) return OP_FAILURE; /* Insert Pad1 or PadN to fill the necessary octets */ if(required_octets>0 && required_octets<8){ if(required_octets==1){ curr_option[0]=EXTOPT_PAD1; curr_option++; this->length++; }else{ this->addOption(EXTOPT_PADN, required_octets-2, zeroes ); } } assert(this->length%8==0); this->h.len=(this->length/8)-1; return OP_SUCCESS; } /* End of addPadding() */