2024-02-21 14:52:47 +03:00

1060 lines
27 KiB
C++

/*
* Copyright (c) 2017, Matias Fontanini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef TINS_DNS_H
#define TINS_DNS_H
#include <stdint.h>
#include <vector>
#include <cstring>
#include <string>
#include <map>
#include <tins/macros.h>
#include <tins/pdu.h>
#include <tins/endianness.h>
// Undefining some macros that conflict with some symbols here.
// Eventually, the conflicting names will be removed, but until then
// this is the best we can do.
// - IN is defined by winsock2.h
// - CERT is defined by openssl
#undef IN
#undef CERT
namespace Tins {
namespace Memory {
class InputMemoryStream;
} // Memory
class IPv4Address;
class IPv6Address;
/**
* \class DNS
* \brief Represents a DNS PDU.
*
* This class represents the DNS PDU, and allows easy access
* to queries and answer records.
*
* The DNS PDU is not parsed automatically while sniffing, so you will
* have to parse it manually from an UDP packet's payload, for example:
*
* \code
* // Assume we get an udp packet from somewhere.
* UDP udp = get_udp_packet();
*
* // Now:
* // 1 - Get the RawPDU layer (contains the payload).
* // 2 - Construct a DNS object over its contents.
* DNS dns = udp.rfind_pdu<RawPDU>().to<DNS>();
*
* // Now use the DNS object!
* for(const auto& query : dns.queries()) {
* // Process a query
* }
* \endcode
*/
class TINS_API DNS : public PDU {
public:
/**
* \brief This PDU's flag.
*/
static const PDU::PDUType pdu_flag = PDU::DNS;
/**
* The DNS type.
*/
enum QRType {
QUERY = 0,
RESPONSE = 1
};
/**
* \brief Query types enum.
*/
enum QueryType {
A = 1,
NS,
MD,
MF,
CNAME,
SOA,
MB,
MG,
MR,
NULL_R,
WKS,
PTR,
HINFO,
MINFO,
MX,
TXT,
RP,
AFSDB,
X25,
ISDN,
RT,
NSAP,
NSAP_PTR,
SIG,
KEY,
PX,
GPOS,
AAAA,
LOC,
NXT,
EID,
NIMLOC,
SRV,
ATMA,
NAPTR,
KX,
CERTIFICATE,
A6,
DNAM,
SINK,
OPT,
APL,
DS,
SSHFP,
IPSECKEY,
RRSIG,
NSEC,
DNSKEY,
DHCID,
NSEC3,
NSEC3PARAM,
CERT = CERTIFICATE
};
enum QueryClass {
INTERNET = 1,
CHAOS = 3,
HESIOD = 4,
/**
* \cond
*/
IN = INTERNET,
CH = CHAOS,
HS = HESIOD,
/**
* \endcond
*/
ANY = 255
};
/**
* \brief Struct that represent DNS queries.
*/
class query {
public:
/**
* \brief Constructs a DNS query.
*
* \param nm The name of the domain being resolved.
* \param tp The query type.
* \param cl The query class.
*/
#if TINS_IS_CXX11
query(std::string nm, QueryType tp, QueryClass cl)
: name_(std::move(nm)), type_(tp), qclass_(cl) {}
#else
query(const std::string& nm, QueryType tp, QueryClass cl)
: name_(nm), type_(tp), qclass_(cl) {}
#endif
/**
* \brief Default constructs this Query.
*/
query() : type_(), qclass_() {}
/**
* \brief Setter for the name field.
*
* \param nm The name to be set.
*/
void dname(const std::string& nm) {
name_ = nm;
}
/**
* \brief Setter for the query type field.
*
* \param tp The query type to be set.
*/
void query_type(QueryType tp) {
type_ = tp;
}
/**
* \brief Setter for the query type field.
*
* This method is deprecated. Use query::query_type
*
* \deprecated
* \sa query::query_type
*/
TINS_DEPRECATED(void type(QueryType tp)) {
type_ = tp;
}
/**
* \brief Setter for the query class field.
*
* \param cl The query class to be set.
*/
void query_class(QueryClass cl) {
qclass_ = cl;
}
/**
* \brief Getter for the name field.
*/
const std::string& dname() const {
return name_;
}
/**
* \brief Getter for the query type field.
*/
QueryType query_type() const {
return type_;
}
/**
* \brief Getter for the query type field.
*
* This method is deprecated. Use query::query_type
*
* \deprecated
* \sa query::query_type
*/
TINS_DEPRECATED(QueryType type() const) {
return type_;
}
/**
* \brief Getter for the query class field.
*/
QueryClass query_class() const {
return qclass_;
}
private:
std::string name_;
QueryType type_;
QueryClass qclass_;
};
class resource;
/**
* \brief Class that represents a Start Of Authority record
*/
class soa_record {
public:
/**
* \brief Default constructor
*/
soa_record();
/**
* \brief Constructs a SOA record from a DNS::resource
* \param resource The resource from which to construct this record
*/
soa_record(const DNS::resource& resource);
/**
* \brief Constructs a SOA record from a buffer
* \param buffer The buffer from which to construct this SOA record
* \param total_sz The size of the buffer
*/
soa_record(const uint8_t* buffer, uint32_t total_sz);
/**
* \brief Constructs a SOA record
*
* \param mname The primary source name
* \param rname The responsible person name
* \param serial The serial number
* \param refresh The refresh value
* \param retry The retry value
* \param expire The expire value
* \param minimum_ttl The minimum TTL value
*/
soa_record(const std::string& mname,
const std::string& rname,
uint32_t serial,
uint32_t refresh,
uint32_t retry,
uint32_t expire,
uint32_t minimum_ttl);
/**
* \brief Getter for the primary source name field
*
* The returned domain name is already decoded.
*
* \return mname The primary source name field
*/
const std::string& mname() const {
return mname_;
}
/**
* \brief Getter for the responsible person name field
*
* The returned domain name is already decoded.
*
* \return mname The responsible person name field
*/
const std::string& rname() const {
return rname_;
}
/**
* \brief Getter for the serial number field
* \return The serial number field
*/
uint32_t serial() const {
return serial_;
}
/**
* \brief Getter for the refresh field
* \return The refresh field
*/
uint32_t refresh() const {
return refresh_;
}
/**
* \brief Getter for the retry field
* \return The retry field
*/
uint32_t retry() const {
return retry_;
}
/**
* \brief Getter for the expire field
* \return The expire field
*/
uint32_t expire() const {
return expire_;
}
/**
* \brief Getter for the minimum TTL field
* \return The minimum TTL field
*/
uint32_t minimum_ttl() const {
return minimum_ttl_;
}
/**
* \brief Getter for the primary source name field
* \param value The new primary source name field value
*/
void mname(const std::string& value);
/**
* \brief Getter for the responsible person name field
* \param value The new responsible person name field value
*/
void rname(const std::string& value);
/**
* \brief Getter for the serial number field
* \param value The new serial number field value
*/
void serial(uint32_t value);
/**
* \brief Getter for the refresh field
* \param value The new refresh field value
*/
void refresh(uint32_t value);
/**
* \brief Getter for the retry field
* \param value The new retry field value
*/
void retry(uint32_t value);
/**
* \brief Getter for the expire field
* \param value The new expire field value
*/
void expire(uint32_t value);
/**
* \brief Getter for the minimum TTL field
* \param value The new minimum TTL field value
*/
void minimum_ttl(uint32_t value);
/**
* \brief Serialize this SOA record
* \return The serialized SOA record
*/
PDU::serialization_type serialize() const;
private:
void init(const uint8_t* buffer, uint32_t total_sz);
std::string mname_;
std::string rname_;
uint32_t serial_;
uint32_t refresh_;
uint32_t retry_;
uint32_t expire_;
uint32_t minimum_ttl_;
};
/**
* \brief Class that represent DNS resource records.
*/
class resource {
public:
/**
* Constructs a Resource object.
*
* \param dname The domain name for which this records
* provides an answer.
* \param data The resource's payload.
* \param type The type of this record.
* \param rclass The class of this record.
* \param ttl The time-to-live of this record.
*/
#if TINS_IS_CXX11
resource(std::string dname,
std::string data,
uint16_t type,
uint16_t rclass,
uint32_t ttl,
uint16_t preference = 0)
: dname_(std::move(dname)), data_(std::move(data)), type_(type),
qclass_(rclass), ttl_(ttl), preference_(preference) {}
#else
resource(const std::string& dname,
const std::string& data,
uint16_t type,
uint16_t rclass,
uint32_t ttl,
uint16_t preference = 0)
: dname_(dname), data_(data), type_(type), qclass_(rclass),
ttl_(ttl), preference_(preference) {}
#endif
resource() : type_(), qclass_(), ttl_(), preference_() {}
/**
* \brief Getter for the domain name field.
*
* This returns the domain name for which this record
* provides an answer.
*/
const std::string& dname() const {
return dname_;
}
/**
* Getter for the data field.
*/
const std::string& data() const {
return data_;
}
/**
* Getter for the query type field.
*/
uint16_t query_type() const {
return type_;
}
/**
* \brief Getter for the query type field.
*
* This method is deprecated. Use resource::query_type
*
* \deprecated
* \sa resource::query_type
*/
TINS_DEPRECATED(uint16_t type() const) {
return type_;
}
/**
* Getter for the query class field.
*/
uint16_t query_class() const {
return qclass_;
}
/**
* Getter for the time-to-live field.
*/
uint32_t ttl() const {
return ttl_;
}
/**
* \brief Getter for the preferece field.
*
* This field is only valid for MX resources.
*/
uint16_t preference() const {
return preference_;
}
/**
* Setter for the domain name field.
*/
void dname(const std::string& data) {
dname_ = data;
}
/**
* \brief Setter for the data field.
*
* The data will be encoded properly by the DNS class before
* being added to this packet. That means that if the type is
* A or AAAA, it will be properly encoded as an IPv4 or
* IPv6 address.
*
* The same happens for records that contain domain names,
* such as NS or CNAME. This data will be encoded using
* DNS domain name encoding.
*/
void data(const std::string& data) {
data_ = data;
}
/**
* \brief Sets the contents of this resource to the provided SOA record
* \param data The SOA record that will be stored in this resource
*/
void data(const soa_record& data) {
serialization_type buffer = data.serialize();
data_.assign(buffer.begin(), buffer.end());
}
/**
* Setter for the query type field.
*/
void query_type(uint16_t data) {
type_ = data;
}
/**
* \brief Setter for the query type field.
*
* This method is deprecated. Use query::query_type
*
* \deprecated
* \sa resource::query_type
*/
TINS_DEPRECATED(void type(uint16_t data)) {
type_ = data;
}
/**
* Setter for the query class field.
*/
void query_class(uint16_t data) {
qclass_ = data;
}
/**
* Setter for the time-to-live field.
*/
void ttl(uint32_t data) {
ttl_ = data;
}
/**
* \brief Setter for the preference field.
*
* This field is only valid for MX resources.
*/
void preference(uint16_t data) {
preference_ = data;
}
private:
std::string dname_, data_;
uint16_t type_, qclass_;
uint32_t ttl_;
uint16_t preference_;
};
TINS_DEPRECATED(typedef query Query);
TINS_DEPRECATED(typedef resource Resource);
typedef std::vector<query> queries_type;
typedef std::vector<resource> resources_type;
typedef IPv4Address address_type;
typedef IPv6Address address_v6_type;
/**
* \brief Extracts metadata for this protocol based on the buffer provided
*
* \param buffer Pointer to a buffer
* \param total_sz Size of the buffer pointed by buffer
*/
static metadata extract_metadata(const uint8_t *buffer, uint32_t total_sz);
/**
* \brief Default constructor.
*
* This constructor initializes every field to 0.
*/
DNS();
/**
* \brief Constructs a DNS object from a buffer.
*
* If there's not enough size for the DNS header, or any of the
* records are malformed, a malformed_packet is be thrown.
*
* \param buffer The buffer from which this PDU will be
* constructed.
* \param total_sz The total size of the buffer.
*/
DNS(const uint8_t* buffer, uint32_t total_sz);
// Getters
/**
* \brief Getter for the id field.
*
* \return uint16_t containing the value of the id field.
*/
uint16_t id() const {
return Endian::be_to_host(header_.id);
}
/**
* \brief Getter for the query response field.
*
* \return QRType containing the value of the query response
* field.
*/
QRType type() const {
return static_cast<QRType>(header_.qr);
}
/**
* \brief Getter for the opcode field.
*
* \return uint8_t containing the value of the opcode field.
*/
uint8_t opcode() const {
return header_.opcode;
}
/**
* \brief Getter for the authoritative answer field.
*
* \return uint8_t containing the value of the authoritative
* answer field.
*/
uint8_t authoritative_answer() const {
return header_.aa;
}
/**
* \brief Getter for the truncated field.
*
* \return uint8_t containing the value of the truncated field.
*/
uint8_t truncated() const {
return header_.tc;
}
/**
* \brief Getter for the recursion desired field.
*
* \return uint8_t containing the value of the recursion
* desired field.
*/
uint8_t recursion_desired() const {
return header_.rd;
}
/**
* \brief Getter for the recursion available field.
*
* \return uint8_t containing the value of the recursion
* available field.
*/
uint8_t recursion_available() const {
return header_.ra;
}
/**
* \brief Getter for the z desired field.
*
* \return uint8_t containing the value of the z field.
*/
uint8_t z() const {
return header_.z;
}
/**
* \brief Getter for the authenticated data field.
*
* \return uint8_t containing the value of the authenticated
* data field.
*/
uint8_t authenticated_data() const {
return header_.ad;
}
/**
* \brief Getter for the checking disabled field.
*
* \return uint8_t containing the value of the checking
* disabled field.
*/
uint8_t checking_disabled() const {
return header_.cd;
}
/**
* \brief Getter for the rcode field.
*
* \return uint8_t containing the value of the rcode field.
*/
uint8_t rcode() const {
return header_.rcode;
}
/**
* \brief Getter for the questions field.
*
* \return uint16_t containing the value of the questions field.
*/
uint16_t questions_count() const {
return Endian::be_to_host(header_.questions);
}
/**
* \brief Getter for the answers field.
*
* \return uint16_t containing the value of the answers field.
*/
uint16_t answers_count() const {
return Endian::be_to_host(header_.answers);
}
/**
* \brief Getter for the authority field.
*
* \return uint16_t containing the value of the authority field.
*/
uint16_t authority_count() const {
return Endian::be_to_host(header_.authority);
}
/**
* \brief Getter for the additional field.
*
* \return uint16_t containing the value of the additional field.
*/
uint16_t additional_count() const {
return Endian::be_to_host(header_.additional);
}
/**
* \brief Getter for the PDU's type.
*
* \return Returns the PDUType corresponding to the PDU.
*/
PDUType pdu_type() const {
return pdu_flag;
}
/**
* \brief The header's size
*/
uint32_t header_size() const;
// Setters
/**
* \brief Setter for the id field.
*
* \param new_id The new id to be set.
*/
void id(uint16_t new_id);
/**
* \brief Setter for the query response field.
*
* \param new_qr The new qr to be set.
*/
void type(QRType new_qr);
/**
* \brief Setter for the opcode field.
*
* \param new_opcode The new opcode to be set.
*/
void opcode(uint8_t new_opcode);
/**
* \brief Setter for the authoritative answer field.
*
* \param new_aa The new authoritative answer field value to
* be set.
*/
void authoritative_answer(uint8_t new_aa);
/**
* \brief Setter for the truncated field.
*
* \param new_tc The new truncated field value to
* be set.
*/
void truncated(uint8_t new_tc);
/**
* \brief Setter for the recursion desired field.
*
* \param new_rd The new recursion desired value to
* be set.
*/
void recursion_desired(uint8_t new_rd);
/**
* \brief Setter for the recursion available field.
*
* \param new_ra The new recursion available value to
* be set.
*/
void recursion_available(uint8_t new_ra);
/**
* \brief Setter for the z(reserved) field.
*
* \param new_z The new z value to be set.
*/
void z(uint8_t new_z);
/**
* \brief Setter for the authenticated data field.
*
* \param new_ad The new authenticated data value to
* be set.
*/
void authenticated_data(uint8_t new_ad);
/**
* \brief Setter for the checking disabled field.
*
* \param new_z The new checking disabled value to be set.
*/
void checking_disabled(uint8_t new_cd);
/**
* \brief Setter for the rcode field.
*
* \param new_rcode The new rcode value to be set.
*/
void rcode(uint8_t new_rcode);
// Methods
/**
* \brief Add a query to perform.
*
* \param query The query to be added.
*/
void add_query(const query& query);
/**
* \brief Add an answer resource record.
*
* \param resource The resource to be added.
*/
void add_answer(const resource& resource);
/**
* \brief Add an authority resource record.
*
* \param resource The resource to be added.
*/
void add_authority(const resource& resource);
/**
* \brief Add an additional resource record.
*
* \param resource The resource to be added.
*/
void add_additional(const resource& resource);
/**
* \brief Getter for this PDU's DNS queries.
*
* \return The query records in this PDU.
*/
queries_type queries() const;
/**
* \brief Getter for this PDU's DNS answers
*
* \return The answer records in this PDU.
*/
resources_type answers() const;
/**
* \brief Getter for this PDU's DNS authority records.
*
* \return The authority records in this PDU.
*/
resources_type authority() const;
/**
* \brief Getter for this PDU's DNS additional records.
*
* \return The additional records in this PDU.
*/
resources_type additional() const;
/**
* \brief Encodes a domain name.
*
* This processes the input domain name and returns the encoded
* version. Each label in the original domain name will be
* prefixed with a byte that indicates the label's length.
* The null-terminator byte <b>will</b> be included in the encoded
* string. No compression is performed.
*
* For example, given the input "www.example.com", the output would
* be "\x03www\x07example\x03com\x00".
*
* \param domain_name The domain name to encode.
* \return The encoded domain name.
*/
static std::string encode_domain_name(const std::string& domain_name);
/**
* \brief Decodes a domain name
*
* This method processes an encoded domain name and returns the decoded
* version. This <b>can't handle</b> offset labels.
*
* For example, given the input "\x03www\x07example\x03com\x00",
* the output would be www.example.com".
*
* \param domain_name The domain name to decode.
* \return The decoded domain name.
*/
static std::string decode_domain_name(const std::string& domain_name);
/**
* \brief Check whether ptr points to a valid response for this PDU.
*
* \sa PDU::matches_response
* \param ptr The pointer to the buffer.
* \param total_sz The size of the buffer.
*/
bool matches_response(const uint8_t* ptr, uint32_t total_sz) const;
/**
* \sa PDU::clone
*/
DNS* clone() const {
return new DNS(*this);
}
private:
friend class soa_record;
TINS_BEGIN_PACK
struct dns_header {
uint16_t id;
#if TINS_IS_LITTLE_ENDIAN
uint16_t
rd:1,
tc:1,
aa:1,
opcode:4,
qr:1,
rcode:4,
cd:1,
ad:1,
z:1,
ra:1;
#elif TINS_IS_BIG_ENDIAN
uint16_t
qr:1,
opcode:4,
aa:1,
tc:1,
rd:1,
ra:1,
z:1,
ad:1,
cd:1,
rcode:4;
#endif
uint16_t questions, answers,
authority, additional;
} TINS_END_PACK;
typedef std::vector<std::pair<uint32_t*, uint32_t> > sections_type;
uint32_t compose_name(const uint8_t* ptr, char* out_ptr) const;
void convert_records(const uint8_t* ptr,
const uint8_t* end,
resources_type& res,
const uint16_t rr_count) const;
void skip_to_section_end(Memory::InputMemoryStream& stream,
const uint32_t num_records) const;
void skip_to_dname_end(Memory::InputMemoryStream& stream) const;
void update_records(uint32_t& section_start,
uint32_t num_records,
uint32_t threshold,
uint32_t offset);
uint8_t* update_dname(uint8_t* ptr, uint32_t threshold, uint32_t offset);
static void inline_convert_v4(uint32_t value, char* output);
static bool contains_dname(uint16_t type);
void write_serialization(uint8_t* buffer, uint32_t total_sz);
void add_record(const resource& resource, const sections_type& sections);
dns_header header_;
byte_array records_data_;
uint32_t answers_idx_, authority_idx_, additional_idx_;
};
} // Tins
#endif // TINS_DNS_H