/usr/include/tins/crypto.h is in libtins-dev 3.4-2build1.
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* Copyright (c) 2016, 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.
*
*/
#include "config.h"
#if !defined(TINS_CRYPTO_H) && defined(TINS_HAVE_DOT11)
#define TINS_CRYPTO_H
#include <map>
#include <string>
#include <algorithm>
#include <vector>
#ifdef TINS_HAVE_WPA2_CALLBACKS
#include <functional>
#endif // TINS_HAVE_WPA2_CALLBACKS
#include "utils.h"
#include "snap.h"
#include "rawpdu.h"
#include "macros.h"
#include "handshake_capturer.h"
namespace Tins {
class PDU;
class Dot11;
class Dot11Data;
namespace Crypto {
struct RC4Key;
#ifdef TINS_HAVE_WPA2_DECRYPTION
namespace WPA2 {
/**
* \brief Class that represents the keys used to decrypt a session.
*/
class TINS_API SessionKeys {
public:
/**
* The size of the Pairwise Master Key.
*/
static const size_t PMK_SIZE;
/**
* The size of the Pairwise Transient Key.
*/
static const size_t PTK_SIZE;
/**
* The type used to hold the PTK (this has to be PTK_SIZE bytes long).
*/
typedef std::vector<uint8_t> ptk_type;
/**
* The type used to hold the PMK (this has to be PMK_SIZE bytes long).
*/
typedef std::vector<uint8_t> pmk_type;
/**
* Default constructs a SessionKeys object.
*/
SessionKeys();
/**
* \brief Constructs an instance using the provided PTK and a flag
* indicating whether it should use ccmp.
*
* \param ptk The PTK to use.
* \param is_ccmp Indicates whether to use CCMP to decrypt this traffic.
*/
SessionKeys(const ptk_type& ptk, bool is_ccmp);
/**
* \brief Constructs an instance using a handshake and a PMK.
*
* This will internally construct the PTK from the input parameters.
*
* \param hs The handshake to use.
* \param pmk The PMK to use.
*/
SessionKeys(const RSNHandshake& hs, const pmk_type& pmk);
/**
* \brief Decrypts a unicast packet.
*
* \param dot11 The encrypted packet to decrypt.
* \param raw The raw layer on the packet to decrypt.
* \return A SNAP layer containing the decrypted traffic or a null pointer
* if decryption failed.
*/
SNAP* decrypt_unicast(const Dot11Data& dot11, RawPDU& raw) const;
/**
* \brief Gets the PTK for this session keys.
* \return The Pairwise Transcient Key.
*/
const ptk_type& get_ptk() const;
/**
* \brief Indicates whether CCMP is used to decrypt packets
* /return true iff CCMP is used.
*/
bool uses_ccmp() const;
private:
SNAP* ccmp_decrypt_unicast(const Dot11Data& dot11, RawPDU& raw) const;
SNAP* tkip_decrypt_unicast(const Dot11Data& dot11, RawPDU& raw) const;
RC4Key generate_rc4_key(const Dot11Data& dot11, const RawPDU& raw) const;
ptk_type ptk_;
bool is_ccmp_;
};
/**
* \brief Represents a WPA2 supplicant's data.
*
* Objects of this class can be given the pre-shared key and the SSID
* of some access point, and this will generate the Pairwise Master Key
* from those parameters.
*/
class TINS_API SupplicantData {
public:
/**
* The type used to store the PMK.
*/
typedef SessionKeys::pmk_type pmk_type;
/**
* \brief Constructs a SupplicantData.
* \param psk The pre-shared key.
* \param ssid The access point's SSID.
*/
SupplicantData(const std::string& psk, const std::string& ssid);
/**
* \brief Getter for the PMK.
* \return The generated PMK.
*/
const pmk_type& pmk() const;
/**
* \brief Getter for the SSID
* \return The access point's SSID
*/
const std::string& ssid() const;
private:
pmk_type pmk_;
std::string ssid_;
};
} // WPA2
#endif // TINS_HAVE_WPA2_DECRYPTION
/**
* \brief RC4 Key abstraction.
*/
struct RC4Key {
static const size_t data_size = 256;
/**
* \brief Initializes the key using the provided iterator range.
*
* \param start The start of the range.
* \param end The end of the range.
*/
template<typename ForwardIterator>
RC4Key(ForwardIterator start, ForwardIterator end);
/**
* The actual key data.
*/
uint8_t data[data_size];
};
/**
* \brief Decrypts WEP-encrypted traffic.
*/
class TINS_API WEPDecrypter {
public:
typedef HWAddress<6> address_type;
/**
* \brief Constructs a WEPDecrypter object.
*/
WEPDecrypter();
/**
* \brief Adds a decryption password.
*
* \param addr The access point's BSSID.
* \param password The password which will be used to decrypt
* packets sent from and to the AP identifier by the BSSID addr.
*/
void add_password(const address_type& addr, const std::string& password);
/**
* \brief Removes a decryption password
*
* \param addr The BSSID of the access point.
*/
void remove_password(const address_type& addr);
/**
* \brief Decrypts the provided PDU.
*
* A Dot11Data PDU is looked up inside the provided PDU chain.
* If no such PDU exists or there is no password associated
* with the Dot11 packet's BSSID, then the PDU is left intact.
*
* Otherwise, the packet is decrypted using the given password.
* If the CRC found after decrypting is invalid, false is
* returned.
*
* \return false if no decryption was performed or decryption
* failed, true otherwise.
*/
bool decrypt(PDU& pdu);
private:
typedef std::map<address_type, std::string> passwords_type;
PDU* decrypt(RawPDU& raw, const std::string& password);
passwords_type passwords_;
std::vector<uint8_t> key_buffer_;
};
#ifdef TINS_HAVE_WPA2_DECRYPTION
/**
* \brief Decrypts WPA2-encrypted traffic.
*
* This class takes valid PSK and SSID tuples, captures client handshakes,
* and decrypts their traffic afterwards.
*/
class TINS_API WPA2Decrypter {
public:
/*
* \brief The type used to store Dot11 addresses.
*/
typedef HWAddress<6> address_type;
/**
* \brief Represents a pair of mac addresses.
*
* This is used to identify a host and the access point to which
* it is connected. The first element in the pair will always de
* lower or equal than the second one, so that given any host and
* the access point it's connected to, we can uniquely identify
* it with an address pair.
*/
typedef std::pair<address_type, address_type> addr_pair;
/**
* \brief Maps an address pair to the session keys.
*
* This type associates an address pair (host, access point) with the
* session keys, as generated using the packets seen on a handshake.
*
* \sa addr_pair
*/
typedef std::map<addr_pair, WPA2::SessionKeys> keys_map;
#ifdef TINS_HAVE_WPA2_CALLBACKS
/**
* \brief The type used to store the callback type used when a new access
* point is found.
*
* The first argument to the function will be the access point's SSID and
* the second one its BSSID.
*/
typedef std::function<void(const std::string&,
const address_type&)> ap_found_callback_type;
/**
* The type used to store the callback type used when a new handshake
* is captured.
*
* The first argument to the function will be the access point's SSID and
* the second one its BSSID. The third argument will be the client's hardware
* address.
*/
typedef std::function<void(const std::string&,
const address_type&,
const address_type&)> handshake_captured_callback_type;
#endif // TINS_HAVE_WPA2_CALLBACKS
/**
* \brief Adds an access points's information.
*
* This associates an SSID with a PSK, and allows the decryption of
* any BSSIDs that broadcast the same SSID.
*
* The decrypter will inspect beacon frames, looking for SSID tags
* that contain the given SSID.
*
* Note that using this overload, the decryption of data frames and
* handshake capturing will be disabled until any access point
* broadcasts the provided SSID(this shouldn't take long at all).
* If this is not the desired behaviour, then you should check out
* the ovther add_ap_data overload.
*
* \param psk The PSK associated with the SSID.
* \param ssid The network's SSID.
*/
void add_ap_data(const std::string& psk, const std::string& ssid);
/**
* \brief Adds a access points's information, including its BSSID.
*
* This overload can be used if the BSSID associated with this SSID is
* known beforehand. The addr parameter indicates which specific BSSID
* is associated to the SSID.
*
* Note that if any other access point broadcasts the provided SSID,
* it will be taken into account as well.
*
* \param psk The PSK associated with this SSID.
* \param ssid The network's SSID.
* \param addr The access point's BSSID.
*/
void add_ap_data(const std::string& psk,
const std::string& ssid,
const address_type& addr);
/**
* \brief Explicitly add decryption keys.
*
* This method associates a pair (host, access point) with the given decryption keys.
* All encrypted packets sent between the given addresses will be decrypted using the
* provided keys.
*
* This method shouldn't normally be required. The WPA2Decrypter will be waiting for
* handshakes and will automatically extract the session keys, decrypting all
* encrypted packets with them. You should only use this method if for some reason
* you know the actual keys being used (because you checked and stored the keys_map
* somewhere).
*
* The actual order of the addresses doesn't matter, this method will make sure
* they're sorted.
*
* \param addresses The address pair (host, access point) to associate.
* \param session_keys The keys to use when decrypting messages sent between the
* given addresses.
*/
void add_decryption_keys(const addr_pair& addresses,
const WPA2::SessionKeys& session_keys);
/**
* \brief Decrypts the provided PDU.
*
* A Dot11Data PDU is looked up inside the provided PDU chain.
* If no such PDU exists or no PSK was associated with the SSID
* broadcasted by the Dot11 packet's BSSID, or no EAPOL handshake
* was captured for the client involved in the communication,
* then the PDU is left intact.
*
* Otherwise, the packet is decrypted using the generated PTK.
* If the resulting MIC is invalid, then the packet is left intact.
*
* \return false if no decryption was performed, or the decryption
* failed, true otherwise.
*/
bool decrypt(PDU& pdu);
#ifdef TINS_HAVE_WPA2_CALLBACKS
/**
* \brief Sets the handshake captured callback
*
* This callback will be executed every time a new handshake is captured.
*
* \sa handshake_captured_callback_type
* \param callback The new callback to be set
*/
void handshake_captured_callback(const handshake_captured_callback_type& callback);
/**
* \brief Sets the access point found callback
*
* This callback will be executed every time a new access point is found, that's
* advertising an SSID added when calling add_ap_data.
*
* \sa ap_found_callback_type
* \param callback The new callback to be set
*/
void ap_found_callback(const ap_found_callback_type& callback);
#endif // TINS_HAVE_WPA2_CALLBACKS
/**
* \brief Getter for the keys on this decrypter
*
* The returned map will be populated every time a new, complete, handshake
* is captured.
*
* \return The WPA2Decrypter keys map.
*/
const keys_map& get_keys() const;
private:
typedef std::map<std::string, WPA2::SupplicantData> pmks_map;
typedef std::map<address_type, WPA2::SupplicantData> bssids_map;
void try_add_keys(const Dot11Data& dot11, const RSNHandshake& hs);
addr_pair make_addr_pair(const address_type& addr1, const address_type& addr2) {
return (addr1 < addr2) ?
std::make_pair(addr1, addr2) :
std::make_pair(addr2, addr1);
}
addr_pair extract_addr_pair(const Dot11Data& dot11);
addr_pair extract_addr_pair_dst(const Dot11Data& dot11);
bssids_map::const_iterator find_ap(const Dot11Data& dot11);
void add_access_point(const std::string& ssid, const address_type& addr);
RSNHandshakeCapturer capturer_;
pmks_map pmks_;
bssids_map aps_;
keys_map keys_;
#ifdef TINS_HAVE_WPA2_CALLBACKS
handshake_captured_callback_type handshake_captured_callback_;
ap_found_callback_type ap_found_callback_;
#endif // TINS_HAVE_WPA2_CALLBACKS
};
#endif // TINS_HAVE_WPA2_DECRYPTION
/**
* \brief Pluggable decrypter object which can be used to decrypt
* data on sniffing sessions.
*
* This class holds a decrypter object and a functor, and implements
* a suitable operator() to be used on BaseSniffer::sniff_loop, which
* decrypts packets and forwards them to the given functor.
*/
template<typename Functor, typename Decrypter>
class DecrypterProxy {
public:
/**
* The type of the functor object.
*/
typedef Functor functor_type;
/**
* The type of the decrypter object.
*/
typedef Decrypter decrypter_type;
/**
* \brief Constructs an object from a functor and a decrypter.
* \param func The functor to be used to forward decrypted
* packets.
* \param decrypter The decrypter which will be used to decrypt
* packets
*/
DecrypterProxy(const functor_type& func,
const decrypter_type& decr = decrypter_type());
/**
* \brief Retrieves a reference to the decrypter object.
*/
decrypter_type& decrypter();
/**
* \brief Retrieves a const reference to the decrypter object.
*/
const decrypter_type& decrypter() const;
/**
* \brief The operator() which decrypts packets and forwards
* them to the functor.
*/
bool operator() (PDU& pdu);
private:
Functor functor_;
decrypter_type decrypter_;
};
/**
* \brief Performs RC4 encription/decryption of the given byte range,
* using the provided key.
*
* The decrypted range will be copied to the OutputIterator provided.
*
* \param start The beginning of the range.
* \param start The end of the range.
* \param key The key to be used.
* \param output The iterator in which to write the output.
*/
template<typename ForwardIterator, typename OutputIterator>
void rc4(ForwardIterator start, ForwardIterator end, RC4Key& key, OutputIterator output);
/**
* \brief Wrapper function to create a DecrypterProxy using a
* WEPDecrypter as the Decrypter template parameter.
*
* \param functor The functor to be forwarded to the DecrypterProxy
* constructor.
*/
template<typename Functor>
DecrypterProxy<Functor, WEPDecrypter> make_wep_decrypter_proxy(const Functor& functor);
#ifdef TINS_HAVE_WPA2_DECRYPTION
/**
* \brief Wrapper function to create a DecrypterProxy using a
* WPA2Decrypter as the Decrypter template parameter.
*
* \param functor The functor to be forwarded to the DecrypterProxy
* constructor.
*/
template<typename Functor>
DecrypterProxy<Functor, WPA2Decrypter> make_wpa2_decrypter_proxy(const Functor& functor) {
return DecrypterProxy<Functor, WPA2Decrypter>(functor);
}
#endif // TINS_HAVE_WPA2_DECRYPTION
// Implementation section
// DecrypterProxy
template<typename Functor, typename Decrypter>
DecrypterProxy<Functor, Decrypter>::DecrypterProxy(const functor_type& func,
const decrypter_type& decr)
: functor_(func), decrypter_(decr) {
}
template<typename Functor, typename Decrypter>
typename DecrypterProxy<Functor, Decrypter>::decrypter_type &
DecrypterProxy<Functor, Decrypter>::decrypter() {
return decrypter_;
}
template<typename Functor, typename Decrypter>
const typename DecrypterProxy<Functor, Decrypter>::decrypter_type &
DecrypterProxy<Functor, Decrypter>::decrypter() const {
return decrypter_;
}
template<typename Functor, typename Decrypter>
bool DecrypterProxy<Functor, Decrypter>::operator() (PDU& pdu) {
return decrypter_.decrypt(pdu) ? functor_(pdu) : true;
}
template<typename Functor>
DecrypterProxy<Functor, WEPDecrypter> make_wep_decrypter_proxy(const Functor& functor) {
return DecrypterProxy<Functor, WEPDecrypter>(functor);
}
// RC4 stuff
template<typename ForwardIterator>
RC4Key::RC4Key(ForwardIterator start, ForwardIterator end) {
for (size_t i = 0; i < data_size; ++i) {
data[i] = static_cast<uint8_t>(i);
}
size_t j = 0;
ForwardIterator iter = start;
for (size_t i = 0; i < data_size; ++i) {
j = (j + data[i] + *iter++) % 256;
if(iter == end) {
iter = start;
}
std::swap(data[i], data[j]);
}
}
template<typename ForwardIterator, typename OutputIterator>
void rc4(ForwardIterator start, ForwardIterator end, RC4Key& key, OutputIterator output) {
size_t i = 0, j = 0;
while (start != end) {
i = (i + 1) % RC4Key::data_size;
j = (j + key.data[i]) % RC4Key::data_size;
std::swap(key.data[i], key.data[j]);
*output++ = *start++ ^ key.data[(key.data[i] + key.data[j]) % RC4Key::data_size];
}
}
} // Crypto
} // Tins
#endif // TINS_CRYPTO_H
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