summaryrefslogtreecommitdiff
path: root/src/charon/plugins/eap_aka/eap_aka.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/charon/plugins/eap_aka/eap_aka.c')
-rw-r--r--src/charon/plugins/eap_aka/eap_aka.c1539
1 files changed, 1539 insertions, 0 deletions
diff --git a/src/charon/plugins/eap_aka/eap_aka.c b/src/charon/plugins/eap_aka/eap_aka.c
new file mode 100644
index 000000000..9e35de9e1
--- /dev/null
+++ b/src/charon/plugins/eap_aka/eap_aka.c
@@ -0,0 +1,1539 @@
+/*
+ * Copyright (C) 2006 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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 GNU General Public License
+ * for more details.
+ *
+ * $Id: eap_aka.c 4008 2008-05-23 15:49:43Z martin $
+ */
+
+
+/* The EAP-AKA method uses it's own simple parser for processing EAP-AKA
+ * payloads, as the IKEv2 parser is not suitable for that job. There are
+ * two simple methods for parsing payloads, read_header() and read_attribute().
+ * Every EAP-AKA payload consists of a header and a list of attributes. Those
+ * functions mentioned read the data and return the type of the found
+ * attribute/EAP-AKA-type. For generating a EAP-AKA message, we have a
+ * build_aka_payload(), which builds the whole message from a variable
+ * argument list containing its attributes.
+ * The processing of messages is split up in various functions:
+ * - peer_process() - General processing multiplexer for the peer
+ * - peer_process_challenge() - Specific AKA-Challenge processor
+ * - peer_process_notification() - Processing of AKA-Notification
+ * - server_process() - General processing multiplexer for the server
+ * - peer_process_challenge() - Processing of a received Challenge response
+ * - peer_process_synchronize() - Process a sequence number synchronization
+ * - server_initiate() - Initiation method for the server, calls
+ * - server_initiate_challenge() - Initiation of AKA-Challenge
+ */
+
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <time.h>
+#include <gmp.h>
+
+#include "eap_aka.h"
+
+#include <daemon.h>
+#include <library.h>
+#include <crypto/hashers/hasher.h>
+
+/* Use test vectors specified in S.S0055
+#define TEST_VECTORS */
+
+#define RAND_LENGTH 16
+#define RES_LENGTH 16
+#define SQN_LENGTH 6
+#define K_LENGTH 16
+#define MAC_LENGTH 8
+#define CK_LENGTH 16
+#define IK_LENGTH 16
+#define AK_LENGTH 6
+#define AMF_LENGTH 2
+#define FMK_LENGTH 4
+#define AUTN_LENGTH (SQN_LENGTH + AMF_LENGTH + MAC_LENGTH)
+#define AUTS_LENGTH (SQN_LENGTH + MAC_LENGTH)
+#define PAYLOAD_LENGTH 64
+#define MK_LENGTH 20
+#define MSK_LENGTH 64
+#define EMSK_LENGTH 64
+#define KAUTH_LENGTH 16
+#define KENCR_LENGTH 16
+#define AT_MAC_LENGTH 16
+
+#define F1 0x42
+#define F1STAR 0x43
+#define F2 0x44
+#define F3 0x45
+#define F4 0x46
+#define F5 0x47
+#define F5STAR 0x48
+
+typedef enum aka_subtype_t aka_subtype_t;
+typedef enum aka_attribute_t aka_attribute_t;
+
+/**
+ * Subtypes of AKA messages
+ */
+enum aka_subtype_t {
+ AKA_CHALLENGE = 1,
+ AKA_AUTHENTICATION_REJECT = 2,
+ AKA_SYNCHRONIZATION_FAILURE = 4,
+ AKA_IDENTITY = 5,
+ AKA_NOTIFICATION = 12,
+ AKA_REAUTHENTICATION = 13,
+ AKA_CLIENT_ERROR = 14,
+};
+
+/**
+ * Attribute types in AKA messages
+ */
+enum aka_attribute_t {
+ /** defines the end of attribute list */
+ AT_END = -1,
+ AT_RAND = 1,
+ AT_AUTN = 2,
+ AT_RES = 3,
+ AT_AUTS = 4,
+ AT_PADDING = 6,
+ AT_NONCE_MT = 7,
+ AT_PERMANENT_ID_REQ = 10,
+ AT_MAC = 11,
+ AT_NOTIFICATION = 12,
+ AT_ANY_ID_REQ = 13,
+ AT_IDENTITY = 14,
+ AT_VERSION_LIST = 15,
+ AT_SELECTED_VERSION = 16,
+ AT_FULLAUTH_ID_REQ = 17,
+ AT_COUNTER = 19,
+ AT_COUNTER_TOO_SMALL = 20,
+ AT_NONCE_S = 21,
+ AT_CLIENT_ERROR_CODE = 22,
+ AT_IV = 129,
+ AT_ENCR_DATA = 130,
+ AT_NEXT_PSEUDONYM = 132,
+ AT_NEXT_REAUTH_ID = 133,
+ AT_CHECKCODE = 134,
+ AT_RESULT_IND = 135,
+};
+
+ENUM_BEGIN(aka_subtype_names, AKA_CHALLENGE, AKA_IDENTITY,
+ "AKA_CHALLENGE",
+ "AKA_AUTHENTICATION_REJECT",
+ "AKA_3",
+ "AKA_SYNCHRONIZATION_FAILURE",
+ "AKA_IDENTITY");
+ENUM_NEXT(aka_subtype_names, AKA_NOTIFICATION, AKA_CLIENT_ERROR, AKA_IDENTITY,
+ "AKA_NOTIFICATION",
+ "AKA_REAUTHENTICATION",
+ "AKA_CLIENT_ERROR");
+ENUM_END(aka_subtype_names, AKA_CLIENT_ERROR);
+
+
+ENUM_BEGIN(aka_attribute_names, AT_END, AT_CLIENT_ERROR_CODE,
+ "AT_END",
+ "AT_0",
+ "AT_RAND",
+ "AT_AUTN",
+ "AT_RES",
+ "AT_AUTS",
+ "AT_5",
+ "AT_PADDING",
+ "AT_NONCE_MT",
+ "AT_8",
+ "AT_9",
+ "AT_PERMANENT_ID_REQ",
+ "AT_MAC",
+ "AT_NOTIFICATION",
+ "AT_ANY_ID_REQ",
+ "AT_IDENTITY",
+ "AT_VERSION_LIST",
+ "AT_SELECTED_VERSION",
+ "AT_FULLAUTH_ID_REQ",
+ "AT_18",
+ "AT_COUNTER",
+ "AT_COUNTER_TOO_SMALL",
+ "AT_NONCE_S",
+ "AT_CLIENT_ERROR_CODE");
+ENUM_NEXT(aka_attribute_names, AT_IV, AT_RESULT_IND, AT_CLIENT_ERROR_CODE,
+ "AT_IV",
+ "AT_ENCR_DATA",
+ "AT_131",
+ "AT_NEXT_PSEUDONYM",
+ "AT_NEXT_REAUTH_ID",
+ "AT_CHECKCODE",
+ "AT_RESULT_IND");
+ENUM_END(aka_attribute_names, AT_RESULT_IND);
+
+
+typedef struct private_eap_aka_t private_eap_aka_t;
+
+/**
+ * Private data of an eap_aka_t object.
+ */
+struct private_eap_aka_t {
+
+ /**
+ * Public authenticator_t interface.
+ */
+ eap_aka_t public;
+
+ /**
+ * ID of the server
+ */
+ identification_t *server;
+
+ /**
+ * ID of the peer
+ */
+ identification_t *peer;
+
+ /**
+ * SHA11 hasher
+ */
+ hasher_t *sha1;
+
+ /**
+ * MAC function used in EAP-AKA
+ */
+ signer_t *signer;
+
+ /**
+ * pseudo random function used in EAP-aka
+ */
+ prf_t *prf;
+
+ /**
+ * Special keyed SHA1 hasher used in EAP-AKA, implemented as PRF
+ */
+ prf_t *keyed_prf;
+
+ /**
+ * Key for EAP MAC
+ */
+ chunk_t k_auth;
+
+ /**
+ * Key for EAP encryption
+ */
+ chunk_t k_encr;
+
+ /**
+ * MSK
+ */
+ chunk_t msk;
+
+ /**
+ * Extendend MSK
+ */
+ chunk_t emsk;
+
+ /**
+ * Expected result from client XRES
+ */
+ chunk_t xres;
+
+ /**
+ * Shared secret K from ipsec.conf (padded)
+ */
+ chunk_t k;
+
+ /**
+ * random value RAND generated by server
+ */
+ chunk_t rand;
+};
+
+/** Family key, as proposed in S.S0055 */
+static u_int8_t fmk_buf[] = {0x41, 0x48, 0x41, 0x47};
+static chunk_t fmk = chunk_from_buf(fmk_buf);
+
+/** Authentication management field */
+static u_int8_t amf_buf[] = {0x00, 0x01};
+static chunk_t amf = chunk_from_buf(amf_buf);
+
+/** AT_CLIENT_ERROR_CODE AKA attribute */
+static u_int8_t client_error_code_buf[] = {0, 0};
+static chunk_t client_error_code = chunk_from_buf(client_error_code_buf);
+
+/** previously used sqn by peer, next one must be greater */
+static u_int8_t peer_sqn_buf[6];
+static chunk_t peer_sqn = chunk_from_buf(peer_sqn_buf);
+
+/** set SQN to the current time */
+static void update_sqn(u_int8_t *sqn, time_t offset)
+{
+ timeval_t time;
+ gettimeofday(&time, NULL);
+ /* set sqb_sqn to an integer containing seconds followed by most
+ * significant useconds */
+ time.tv_sec = htonl(time.tv_sec + offset);
+ /* usec's are never larger than 0x000f423f, so we shift the 12 first bits */
+ time.tv_usec <<= 12;
+ time.tv_usec = htonl(time.tv_usec);
+ memcpy(sqn, &time.tv_sec, 4);
+ memcpy(sqn + 4, &time.tv_usec, 2);
+}
+
+/** initialize peers SQN to the current system time at startup */
+static void __attribute__ ((constructor))init_sqn(void)
+{
+ update_sqn(peer_sqn_buf, 0);
+}
+
+/**
+ * Binary represnation of the polynom T^160 + T^5 + T^3 + T^2 + 1
+ */
+static u_int8_t g[] = {
+ 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x2d
+};
+
+/**
+ * Predefined random bits from the RAND Corporation book
+ */
+static u_int8_t a[] = {
+ 0x9d, 0xe9, 0xc9, 0xc8, 0xef, 0xd5, 0x78, 0x11,
+ 0x48, 0x23, 0x14, 0x01, 0x90, 0x1f, 0x2d, 0x49,
+ 0x3f, 0x4c, 0x63, 0x65
+};
+
+/**
+ * Predefined random bits from the RAND Corporation book
+ */
+static u_int8_t b[] = {
+ 0x75, 0xef, 0xd1, 0x5c, 0x4b, 0x8f, 0x8f, 0x51,
+ 0x4e, 0xf3, 0xbc, 0xc3, 0x79, 0x4a, 0x76, 0x5e,
+ 0x7e, 0xec, 0x45, 0xe0
+};
+
+/**
+ * Multiplicate two mpz_t with bits interpreted as polynoms.
+ */
+static void mpz_mul_poly(mpz_t r, mpz_t a, mpz_t b)
+{
+ mpz_t bm, rm;
+ int current = 0, shifted = 0, shift;
+
+ mpz_init_set(bm, b);
+ mpz_init_set_ui(rm, 0);
+ /* scan through a, for each found bit: */
+ while ((current = mpz_scan1(a, current)) != ULONG_MAX)
+ {
+ /* XOR shifted b into r */
+ shift = current - shifted;
+ mpz_mul_2exp(bm, bm, shift);
+ shifted += shift;
+ mpz_xor(rm, rm, bm);
+ current++;
+ }
+
+ mpz_swap(r, rm);
+ mpz_clear(rm);
+ mpz_clear(bm);
+}
+
+/**
+ * Calculate the sum of a + b interpreted as polynoms.
+ */
+static void mpz_add_poly(mpz_t res, mpz_t a, mpz_t b)
+{
+ /* addition of polynominals is just the XOR */
+ mpz_xor(res, a, b);
+}
+
+/**
+ * Calculate the remainder of a/b interpreted as polynoms.
+ */
+static void mpz_mod_poly(mpz_t r, mpz_t a, mpz_t b)
+{
+ /* Example:
+ * a = 10001010
+ * b = 00000101
+ */
+ int a_bit, b_bit, diff;
+ mpz_t bm, am;
+
+ mpz_init_set(am, a);
+ mpz_init(bm);
+
+ a_bit = mpz_sizeinbase(a, 2);
+ b_bit = mpz_sizeinbase(b, 2);
+
+ /* don't do anything if b > a */
+ if (a_bit >= b_bit)
+ {
+ /* shift b left to align up most signaficant "1" to a:
+ * a = 10001010
+ * b = 10100000
+ */
+ mpz_mul_2exp(bm, b, a_bit - b_bit);
+ do
+ {
+ /* XOR b into a, this kills the most significant "1":
+ * a = 00101010
+ */
+ mpz_xor(am, am, bm);
+ /* find the next most significant "1" in a, and align up b:
+ * a = 00101010
+ * b = 00101000
+ */
+ diff = a_bit - mpz_sizeinbase(am, 2);
+ mpz_div_2exp(bm, bm, diff);
+ a_bit -= diff;
+ }
+ while (b_bit <= mpz_sizeinbase(bm, 2));
+ /* While b is not shifted to its original value */
+ }
+ /* after another iteration:
+ * a = 00000010
+ * which is the polynomial modulo
+ */
+
+ mpz_swap(r, am);
+ mpz_clear(am);
+ mpz_clear(bm);
+}
+
+/**
+ * Step 4 of the various fx() functions:
+ * Polynomial whiten calculations
+ */
+static void step4(private_eap_aka_t *this, u_int8_t x[])
+{
+ mpz_t xm, am, bm, gm;
+
+ mpz_init(xm);
+ mpz_init(am);
+ mpz_init(bm);
+ mpz_init(gm);
+
+ mpz_import(xm, HASH_SIZE_SHA1, 1, 1, 1, 0, x);
+ mpz_import(am, sizeof(a), 1, 1, 1, 0, a);
+ mpz_import(bm, sizeof(b), 1, 1, 1, 0, b);
+ mpz_import(gm, sizeof(g), 1, 1, 1, 0, g);
+
+ mpz_mul_poly(xm, am, xm);
+ mpz_add_poly(xm, bm, xm);
+ mpz_mod_poly(xm, xm, gm);
+
+ mpz_export(x, NULL, 1, HASH_SIZE_SHA1, 1, 0, xm);
+
+ mpz_clear(xm);
+ mpz_clear(am);
+ mpz_clear(bm);
+ mpz_clear(gm);
+}
+
+/**
+ * Step 3 of the various fx() functions:
+ * XOR the key into the SHA1 IV
+ */
+static void step3(private_eap_aka_t *this,
+ chunk_t k, chunk_t payload, u_int8_t h[])
+{
+ u_int8_t buf[64];
+
+ if (payload.len < sizeof(buf))
+ {
+ /* pad c with zeros */
+ memset(buf, 0, sizeof(buf));
+ memcpy(buf, payload.ptr, payload.len);
+ payload.ptr = buf;
+ payload.len = sizeof(buf);
+ }
+ else
+ {
+ /* not more than 512 bits can be G()-ed */
+ payload.len = sizeof(buf);
+ }
+
+ /* use the keyed hasher to build the hash */
+ this->keyed_prf->set_key(this->keyed_prf, k);
+ this->keyed_prf->get_bytes(this->keyed_prf, payload, h);
+}
+
+/**
+ * Calculation function for f2(), f3(), f4()
+ */
+static void fx(private_eap_aka_t *this,
+ u_int8_t f, chunk_t k, chunk_t rand, u_int8_t out[])
+{
+ chunk_t payload = chunk_alloca(PAYLOAD_LENGTH);
+ u_int8_t h[HASH_SIZE_SHA1];
+ u_int8_t i;
+
+ for (i = 0; i < 2; i++)
+ {
+ memset(payload.ptr, 0x5c, payload.len);
+ payload.ptr[11] ^= f;
+ memxor(payload.ptr + 12, fmk.ptr, fmk.len);
+ memxor(payload.ptr + 24, rand.ptr, rand.len);
+
+ payload.ptr[3] ^= i;
+ payload.ptr[19] ^= i;
+ payload.ptr[35] ^= i;
+ payload.ptr[51] ^= i;
+
+ step3(this, k, payload, h);
+ step4(this, h);
+ memcpy(out + i * 8, h, 8);
+ }
+}
+
+/**
+ * Calculation function of f1() and f1star()
+ */
+static void f1x(private_eap_aka_t *this,
+ u_int8_t f, chunk_t k, chunk_t rand, chunk_t sqn,
+ chunk_t amf, u_int8_t mac[])
+{
+ /* generate MAC = f1(FMK, SQN, RAND, AMF)
+ * K is loaded into hashers IV; FMK, RAND, SQN, AMF are XORed in a 512-bit
+ * payload which gets hashed
+ */
+ chunk_t payload = chunk_alloca(PAYLOAD_LENGTH);
+ u_int8_t h[HASH_SIZE_SHA1];
+
+ memset(payload.ptr, 0x5c, PAYLOAD_LENGTH);
+ payload.ptr[11] ^= f;
+ memxor(payload.ptr + 12, fmk.ptr, fmk.len);
+ memxor(payload.ptr + 16, rand.ptr, rand.len);
+ memxor(payload.ptr + 34, sqn.ptr, sqn.len);
+ memxor(payload.ptr + 42, amf.ptr, amf.len);
+
+ step3(this, k, payload, h);
+ step4(this, h);
+ memcpy(mac, h, MAC_LENGTH);
+}
+
+/**
+ * Calculation function of f5() and f5star()
+ */
+static void f5x(private_eap_aka_t *this,
+ u_int8_t f, chunk_t k, chunk_t rand, u_int8_t ak[])
+{
+ chunk_t payload = chunk_alloca(PAYLOAD_LENGTH);
+ u_int8_t h[HASH_SIZE_SHA1];
+
+ memset(payload.ptr, 0x5c, payload.len);
+ payload.ptr[11] ^= f;
+ memxor(payload.ptr + 12, fmk.ptr, fmk.len);
+ memxor(payload.ptr + 16, rand.ptr, rand.len);
+
+ step3(this, k, payload, h);
+ step4(this, h);
+ memcpy(ak, h, AK_LENGTH);
+}
+
+/**
+ * Calculate the MAC from a RAND, SQN, AMF value using K
+ */
+static void f1(private_eap_aka_t *this, chunk_t k, chunk_t rand, chunk_t sqn,
+ chunk_t amf, u_int8_t mac[])
+{
+ f1x(this, F1, k, rand, sqn, amf, mac);
+ DBG3(DBG_IKE, "MAC %b", mac, MAC_LENGTH);
+}
+
+/**
+ * Calculate the MACS from a RAND, SQN, AMF value using K
+ */
+static void f1star(private_eap_aka_t *this, chunk_t k, chunk_t rand,
+ chunk_t sqn, chunk_t amf, u_int8_t macs[])
+{
+ f1x(this, F1STAR, k, rand, sqn, amf, macs);
+ DBG3(DBG_IKE, "MACS %b", macs, MAC_LENGTH);
+}
+
+/**
+ * Calculate RES from RAND using K
+ */
+static void f2(private_eap_aka_t *this, chunk_t k, chunk_t rand, u_int8_t res[])
+{
+ fx(this, F2, k, rand, res);
+ DBG3(DBG_IKE, "RES %b", res, RES_LENGTH);
+}
+
+/**
+ * Calculate CK from RAND using K
+ */
+static void f3(private_eap_aka_t *this, chunk_t k, chunk_t rand, u_int8_t ck[])
+{
+ fx(this, F3, k, rand, ck);
+ DBG3(DBG_IKE, "CK %b", ck, CK_LENGTH);
+}
+
+/**
+ * Calculate IK from RAND using K
+ */
+static void f4(private_eap_aka_t *this, chunk_t k, chunk_t rand, u_int8_t ik[])
+{
+ fx(this, F4, k, rand, ik);
+ DBG3(DBG_IKE, "IK %b", ik, IK_LENGTH);
+}
+
+/**
+ * Calculate AK from a RAND using K
+ */
+static void f5(private_eap_aka_t *this, chunk_t k, chunk_t rand, u_int8_t ak[])
+{
+ f5x(this, F5, k, rand, ak);
+ DBG3(DBG_IKE, "AK %b", ak, AK_LENGTH);
+}
+
+/**
+ * Calculate AKS from a RAND using K
+ */
+static void f5star(private_eap_aka_t *this, chunk_t k, chunk_t rand, u_int8_t aks[])
+{
+ f5x(this, F5STAR, k, rand, aks);
+ DBG3(DBG_IKE, "AKS %b", aks, AK_LENGTH);
+}
+
+/**
+ * derive the keys needed for EAP_AKA
+ */
+static bool derive_keys(private_eap_aka_t *this, identification_t *id)
+{
+ chunk_t ck, ik, mk, identity, tmp;
+
+ ck = chunk_alloca(CK_LENGTH);
+ ik = chunk_alloca(IK_LENGTH);
+ mk = chunk_alloca(MK_LENGTH);
+ identity = id->get_encoding(id);
+
+ /* MK = SHA1( Identity | IK | CK ) */
+ f3(this, this->k, this->rand, ck.ptr);
+ f4(this, this->k, this->rand, ik.ptr);
+ DBG3(DBG_IKE, "Identity %B", &identity);
+ tmp = chunk_cata("ccc", identity, ik, ck);
+ DBG3(DBG_IKE, "Identity|IK|CK %B", &tmp);
+ this->sha1->get_hash(this->sha1, tmp, mk.ptr);
+
+ /* K_encr | K_auth | MSK | EMSK = prf(0) | prf(0)
+ * FIPS PRF has 320 bit block size, we need 160 byte for keys
+ * => run prf four times */
+ this->prf->set_key(this->prf, mk);
+ tmp = chunk_alloca(this->prf->get_block_size(this->prf) * 4);
+ this->prf->get_bytes(this->prf, chunk_empty, tmp.ptr);
+ this->prf->get_bytes(this->prf, chunk_empty, tmp.ptr + tmp.len / 4 * 1);
+ this->prf->get_bytes(this->prf, chunk_empty, tmp.ptr + tmp.len / 4 * 2);
+ this->prf->get_bytes(this->prf, chunk_empty, tmp.ptr + tmp.len / 4 * 3);
+ chunk_free(&this->k_encr);
+ chunk_free(&this->k_auth);
+ chunk_free(&this->msk);
+ chunk_free(&this->emsk);
+ chunk_split(tmp, "aaaa", 16, &this->k_encr, 16, &this->k_auth,
+ 64, &this->msk, 64, &this->emsk);
+ DBG3(DBG_IKE, "MK %B", &mk);
+ DBG3(DBG_IKE, "PRF res %B", &tmp);
+ DBG3(DBG_IKE, "K_encr %B", &this->k_encr);
+ DBG3(DBG_IKE, "K_auth %B", &this->k_auth);
+ DBG3(DBG_IKE, "MSK %B", &this->msk);
+ DBG3(DBG_IKE, "EMSK %B", &this->emsk);
+ return TRUE;
+}
+
+/*
+ * Get a shared key from ipsec.secrets.
+ * We use the standard keys as used in preshared key authentication. As
+ * these keys have an undefined length, we:
+ * - strip them if they are longer
+ * - fill them up with '\0' if they are shorter
+ */
+static status_t load_key(identification_t *me, identification_t *other, chunk_t *k)
+{
+ shared_key_t *shared;
+ chunk_t key;
+
+ shared = charon->credentials->get_shared(charon->credentials, SHARED_EAP,
+ me, other);
+ if (shared == NULL)
+ {
+ return NOT_FOUND;
+ }
+ key = shared->get_key(shared);
+ chunk_free(k);
+ *k = chunk_alloc(K_LENGTH);
+ memset(k->ptr, '\0', k->len);
+ memcpy(k->ptr, key.ptr, min(key.len, k->len));
+ shared->destroy(shared);
+ return SUCCESS;
+}
+
+/**
+ * skip EAP_AKA header in message and returns its AKA subtype
+ */
+static aka_subtype_t read_header(chunk_t *message)
+{
+ aka_subtype_t type;
+
+ if (message->len < 8)
+ {
+ *message = chunk_empty;
+ return 0;
+ }
+ type = *(message->ptr + 5);
+ *message = chunk_skip(*message, 8);
+ return type;
+}
+
+/**
+ * read the next attribute from the chunk data
+ */
+static aka_attribute_t read_attribute(chunk_t *data, chunk_t *attr_data)
+{
+ aka_attribute_t attribute;
+ size_t length;
+
+ DBG3(DBG_IKE, "reading attribute from %B", data);
+
+ if (data->len < 2)
+ {
+ return AT_END;
+ }
+ /* read attribute and length */
+ attribute = *data->ptr++;
+ length = *data->ptr++ * 4 - 2;
+ data->len -= 2;
+ DBG3(DBG_IKE, "found attribute %N with length %d",
+ aka_attribute_names, attribute, length);
+ if (length > data->len)
+ {
+ return AT_END;
+ }
+ /* apply attribute value to attr_data */
+ attr_data->len = length;
+ attr_data->ptr = data->ptr;
+ /* update data to point to next attribute */
+ *data = chunk_skip(*data, length);
+ return attribute;
+}
+
+/**
+ * Build an AKA payload from different attributes.
+ * The variable argument takes an aka_attribute_t
+ * followed by its data in a chunk.
+ */
+static eap_payload_t *build_aka_payload(private_eap_aka_t *this, eap_code_t code,
+ u_int8_t identifier, aka_subtype_t type, ...)
+{
+ chunk_t message = chunk_alloca(512); /* is enought for all current messages */
+ chunk_t pos = message;
+ eap_payload_t *payload;
+ va_list args;
+ aka_attribute_t attr;
+ u_int8_t *mac_pos = NULL;
+
+ /* write EAP header, skip length bytes */
+ *pos.ptr++ = code;
+ *pos.ptr++ = identifier;
+ pos.ptr += 2;
+ pos.len -= 4;
+ /* write AKA header with type and subtype, null reserved bytes */
+ *pos.ptr++ = EAP_AKA;
+ *pos.ptr++ = type;
+ *pos.ptr++ = 0;
+ *pos.ptr++ = 0;
+ pos.len -= 4;
+
+ va_start(args, type);
+ while ((attr = va_arg(args, aka_attribute_t)) != AT_END)
+ {
+ chunk_t data = va_arg(args, chunk_t);
+
+ DBG3(DBG_IKE, "building %N %B", aka_attribute_names, attr, &data);
+
+ /* write attribute header */
+ *pos.ptr++ = attr;
+ pos.len--;
+
+ switch (attr)
+ {
+ case AT_RES:
+ {
+ /* attribute length in 4byte words */
+ *pos.ptr = data.len/4 + 1;
+ pos = chunk_skip(pos, 1);
+ /* RES length in bits */
+ *(u_int16_t*)pos.ptr = htons(data.len * 8);
+ pos = chunk_skip(pos, sizeof(u_int16_t));
+ memcpy(pos.ptr, data.ptr, data.len);
+ pos = chunk_skip(pos, data.len);
+ break;
+ }
+ case AT_AUTN:
+ case AT_RAND:
+ {
+ *pos.ptr++ = data.len/4 + 1; pos.len--;
+ *pos.ptr++ = 0; pos.len--;
+ *pos.ptr++ = 0; pos.len--;
+ memcpy(pos.ptr, data.ptr, data.len);
+ pos = chunk_skip(pos, data.len);
+ break;
+ }
+ case AT_MAC:
+ {
+ *pos.ptr++ = 5; pos.len--;
+ *pos.ptr++ = 0; pos.len--;
+ *pos.ptr++ = 0; pos.len--;
+ mac_pos = pos.ptr;
+ /* MAC is calculated over message including zeroed AT_MAC attribute */
+ memset(mac_pos, 0, AT_MAC_LENGTH);
+ pos.ptr += AT_MAC_LENGTH;
+ pos.len -= AT_MAC_LENGTH;
+ break;
+ }
+ default:
+ {
+ /* length is data length in 4-bytes + 1 for header */
+ *pos.ptr = data.len/4 + 1;
+ pos = chunk_skip(pos, 1);
+ memcpy(pos.ptr, data.ptr, data.len);
+ pos = chunk_skip(pos, data.len);
+ }
+ }
+ }
+ va_end(args);
+
+ /* calculate message length, write into header */
+ message.len = pos.ptr - message.ptr;
+ *(u_int16_t*)(message.ptr + 2) = htons(message.len);
+
+ /* create MAC if AT_MAC attribte was included */
+ if (mac_pos)
+ {
+ this->signer->set_key(this->signer, this->k_auth);
+ DBG3(DBG_IKE, "AT_MAC signature of %B", &message);
+ DBG3(DBG_IKE, "using key %B", &this->k_auth);
+ this->signer->get_signature(this->signer, message, mac_pos);
+ DBG3(DBG_IKE, "is %b", mac_pos, AT_MAC_LENGTH);
+ }
+
+ /* payload constructor takes data with some bytes skipped */
+ payload = eap_payload_create_data(message);
+
+ DBG3(DBG_IKE, "created EAP message %B", &message);
+ return payload;
+}
+
+/**
+ * Initiate a AKA-Challenge using SQN
+ */
+static status_t server_initiate_challenge(private_eap_aka_t *this, chunk_t sqn,
+ eap_payload_t **out)
+{
+ rng_t *rng;
+ chunk_t mac, ak, autn;
+
+ mac = chunk_alloca(MAC_LENGTH);
+ ak = chunk_alloca(AK_LENGTH);
+ chunk_free(&this->rand);
+ chunk_free(&this->xres);
+
+ /* generate RAND:
+ * we use a registered RNG, not f0() proposed in S.S0055
+ */
+ rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+ if (!rng)
+ {
+ DBG1(DBG_IKE, "generating RAND for EAP-AKA authentication failed");
+ return FAILED;
+ }
+ rng->allocate_bytes(rng, RAND_LENGTH, &this->rand);
+ rng->destroy(rng);
+
+# ifdef TEST_VECTORS
+ /* Test vector for RAND */
+ u_int8_t test_rand[] = {
+ 0x4b,0x05,0x2b,0x20,0xe2,0xa0,0x6c,0x8f,
+ 0xf7,0x00,0xda,0x51,0x2b,0x4e,0x11,0x1e,
+ };
+ memcpy(this->rand.ptr, test_rand, this->rand.len);
+# endif /* TEST_VECTORS */
+
+ /* Get the shared key K: */
+ if (load_key(this->server, this->peer, &this->k) != SUCCESS)
+ {
+ DBG1(DBG_IKE, "no shared key found for IDs '%D' - '%D' to authenticate "
+ "with EAP-AKA", this->server, this->peer);
+ return FAILED;
+ }
+
+# ifdef TEST_VECTORS
+ /* Test vector for K */
+ u_int8_t test_k[] = {
+ 0xad,0x1b,0x5a,0x15,0x9b,0xe8,0x6b,0x2c,
+ 0xa6,0x6c,0x7a,0xe4,0x0b,0xba,0x9b,0x9d,
+ };
+ memcpy(this->k.ptr, test_k, this->k.len);
+# endif /* TEST_VECTORS */
+
+ /* generate MAC */
+ f1(this, this->k, this->rand, sqn, amf, mac.ptr);
+
+ /* generate AK */
+ f5(this, this->k, this->rand, ak.ptr);
+
+ /* precalculate XRES as expected from client */
+ this->xres = chunk_alloc(RES_LENGTH);
+ f2(this, this->k, this->rand, this->xres.ptr);
+
+ /* calculate AUTN = (SQN xor AK) || AMF || MAC */
+ autn = chunk_cata("ccc", sqn, amf, mac);
+ memxor(autn.ptr, ak.ptr, ak.len);
+ DBG3(DBG_IKE, "AUTN %B", &autn);
+
+
+ /* derive K_encr, K_auth, MSK, EMSK */
+ derive_keys(this, this->peer);
+
+ /* build payload */
+ *out = build_aka_payload(this, EAP_REQUEST, 0, AKA_CHALLENGE,
+ AT_RAND, this->rand, AT_AUTN, autn, AT_MAC,
+ chunk_empty, AT_END);
+ return NEED_MORE;
+}
+
+/**
+ * Implementation of eap_method_t.initiate for an EAP_AKA server
+ */
+static status_t server_initiate(private_eap_aka_t *this, eap_payload_t **out)
+{
+ chunk_t sqn = chunk_alloca(SQN_LENGTH);
+
+ /* we use an offset of 3 minutes to tolerate clock inaccuracy
+ * without the need to synchronize sequence numbers */
+ update_sqn(sqn.ptr, 180);
+
+# ifdef TEST_VECTORS
+ /* Test vector for SQN */
+ u_int8_t test_sqn[] = {0x00,0x00,0x00,0x00,0x00,0x01};
+ memcpy(sqn.ptr, test_sqn, sqn.len);
+# endif /* TEST_VECTORS */
+
+ return server_initiate_challenge(this, sqn, out);
+}
+
+static status_t server_process_synchronize(private_eap_aka_t *this,
+ eap_payload_t *in, eap_payload_t **out)
+{
+ chunk_t attr, auts = chunk_empty, pos, message, macs, xmacs, sqn, aks, amf;
+ u_int i;
+
+ message = in->get_data(in);
+ pos = message;
+ read_header(&pos);
+
+ /* iterate over attributes */
+ while (TRUE)
+ {
+ aka_attribute_t attribute = read_attribute(&pos, &attr);
+ switch (attribute)
+ {
+ case AT_END:
+ break;
+ case AT_AUTS:
+ auts = attr;
+ continue;
+ default:
+ if (attribute >= 0 && attribute <= 127)
+ {
+ DBG1(DBG_IKE, "found non skippable attribute %N",
+ aka_attribute_names, attribute);
+ return FAILED;
+ }
+ DBG1(DBG_IKE, "ignoring skippable attribute %N",
+ aka_attribute_names, attribute);
+ continue;
+ }
+ break;
+ }
+
+ if (auts.len != AUTS_LENGTH)
+ {
+ DBG1(DBG_IKE, "synchronization request didn't contain useable AUTS");
+ return FAILED;
+ }
+
+ chunk_split(auts, "mm", SQN_LENGTH, &sqn, MAC_LENGTH, &macs);
+ aks = chunk_alloca(AK_LENGTH);
+ f5star(this, this->k, this->rand, aks.ptr);
+ /* decrypt serial number by XORing AKS */
+ memxor(sqn.ptr, aks.ptr, aks.len);
+
+ /* verify MACS */
+ xmacs = chunk_alloca(MAC_LENGTH);
+ amf = chunk_alloca(AMF_LENGTH);
+ /* an AMF of zero is used for MACS calculation */
+ memset(amf.ptr, 0, amf.len);
+ f1star(this, this->k, this->rand, sqn, amf, xmacs.ptr);
+ if (!chunk_equals(macs, xmacs))
+ {
+ DBG1(DBG_IKE, "received MACS does not match XMACS");
+ DBG3(DBG_IKE, "MACS %B XMACS %B", &macs, &xmacs);
+ return FAILED;
+ }
+
+ /* retry the challenge with the received SQN + 1*/
+ for (i = SQN_LENGTH - 1; i >= 0; i--)
+ {
+ if (++sqn.ptr[i] != 0)
+ {
+ break;
+ }
+ }
+ return server_initiate_challenge(this, sqn, out);
+}
+
+/**
+ * process an AKA_Challenge response
+ */
+static status_t server_process_challenge(private_eap_aka_t *this, eap_payload_t *in)
+{
+ chunk_t attr, res = chunk_empty, at_mac = chunk_empty, pos, message;
+
+ message = in->get_data(in);
+ pos = message;
+ read_header(&pos);
+
+ /* iterate over attributes */
+ while (TRUE)
+ {
+ aka_attribute_t attribute = read_attribute(&pos, &attr);
+ switch (attribute)
+ {
+ case AT_END:
+ break;
+ case AT_RES:
+ res = attr;
+ if (attr.len == 2 + RES_LENGTH &&
+ *(u_int16_t*)attr.ptr == htons(RES_LENGTH * 8))
+ {
+ res = chunk_skip(attr, 2);
+ }
+ continue;
+
+ case AT_MAC:
+ attr = chunk_skip(attr, 2);
+ at_mac = chunk_clonea(attr);
+ /* zero MAC in message for MAC verification */
+ memset(attr.ptr, 0, attr.len);
+ continue;
+ default:
+ if (attribute >= 0 && attribute <= 127)
+ {
+ DBG1(DBG_IKE, "found non skippable attribute %N",
+ aka_attribute_names, attribute);
+ return FAILED;
+ }
+ DBG1(DBG_IKE, "ignoring skippable attribute %N",
+ aka_attribute_names, attribute);
+ continue;
+ }
+ break;
+ }
+
+ /* verify EAP message MAC AT_MAC */
+ {
+ this->signer->set_key(this->signer, this->k_auth);
+ DBG3(DBG_IKE, "verifying AT_MAC signature of %B", &message);
+ DBG3(DBG_IKE, "using key %B", &this->k_auth);
+ if (!this->signer->verify_signature(this->signer, message, at_mac))
+ {
+ DBG1(DBG_IKE, "MAC in AT_MAC attribute verification failed");
+ return FAILED;
+ }
+ }
+
+ /* compare received RES against stored precalculated XRES */
+ if (!chunk_equals(res, this->xres))
+ {
+ DBG1(DBG_IKE, "received RES does not match XRES");
+ DBG3(DBG_IKE, "RES %Bb XRES %B", &res, &this->xres);
+ return FAILED;
+ }
+ return SUCCESS;
+}
+
+/**
+ * Implementation of eap_method_t.process for EAP_AKA servers
+ */
+static status_t server_process(private_eap_aka_t *this,
+ eap_payload_t *in, eap_payload_t **out)
+{
+ chunk_t message;
+ aka_subtype_t type;
+
+ message = in->get_data(in);
+ type = read_header(&message);
+
+ DBG3(DBG_IKE, "received EAP message %B", &message);
+
+ switch (type)
+ {
+ case AKA_CHALLENGE:
+ {
+ return server_process_challenge(this, in);
+ }
+ case AKA_AUTHENTICATION_REJECT:
+ case AKA_CLIENT_ERROR:
+ {
+ DBG1(DBG_IKE, "received %N, authentication failed",
+ aka_subtype_names, type);
+ return FAILED;
+ }
+ case AKA_SYNCHRONIZATION_FAILURE:
+ {
+ DBG1(DBG_IKE, "received %N, retrying with received SQN",
+ aka_subtype_names, type);
+ return server_process_synchronize(this, in, out);
+ }
+ default:
+ DBG1(DBG_IKE, "received unknown AKA subtype %N, authentication failed",
+ aka_subtype_names, type);
+ return FAILED;
+ }
+}
+
+/**
+ * Process an incoming AKA-Challenge client side
+ */
+static status_t peer_process_challenge(private_eap_aka_t *this,
+ eap_payload_t *in, eap_payload_t **out)
+{
+ chunk_t attr = chunk_empty;
+ chunk_t autn = chunk_empty, at_mac = chunk_empty;
+ chunk_t ak, sqn, sqn_ak, mac, xmac, res, amf, message, pos;
+ u_int8_t identifier;
+
+ ak = chunk_alloca(AK_LENGTH);
+ xmac = chunk_alloca(MAC_LENGTH);
+ res = chunk_alloca(RES_LENGTH);
+ chunk_free(&this->rand);
+
+ message = in->get_data(in);
+ pos = message;
+ read_header(&pos);
+ identifier = in->get_identifier(in);
+
+ DBG3(DBG_IKE, "reading attributes from %B", &pos);
+
+ /* iterate over attributes */
+ while (TRUE)
+ {
+ aka_attribute_t attribute = read_attribute(&pos, &attr);
+ switch (attribute)
+ {
+ case AT_END:
+ break;
+ case AT_RAND:
+ this->rand = chunk_clone(chunk_skip(attr, 2));
+ continue;
+ case AT_AUTN:
+ autn = chunk_skip(attr, 2);
+ continue;
+ case AT_MAC:
+ attr = chunk_skip(attr, 2);
+ at_mac = chunk_clonea(attr);
+ /* set MAC in message to zero for own MAC verification */
+ memset(attr.ptr, 0, attr.len);
+ continue;
+ default:
+ if (attribute >= 0 && attribute <= 127)
+ {
+ /* non skippable attribute, abort */
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier, AKA_CLIENT_ERROR,
+ AT_CLIENT_ERROR_CODE, client_error_code, AT_END);
+ DBG1(DBG_IKE, "found non skippable attribute %N, sending %N %d",
+ aka_attribute_names, attribute,
+ aka_attribute_names, AT_CLIENT_ERROR_CODE, 0);
+ return NEED_MORE;
+ }
+ DBG1(DBG_IKE, "ignoring skippable attribute %N",
+ aka_attribute_names, attribute);
+ continue;
+ }
+ break;
+ }
+
+ if (this->rand.len != RAND_LENGTH || autn.len != AUTN_LENGTH)
+ {
+ /* required attributes wrong/not found, abort */
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier, AKA_CLIENT_ERROR,
+ AT_CLIENT_ERROR_CODE, client_error_code, AT_END);
+ DBG1(DBG_IKE, "could not find valid RAND/AUTN attribute, sending %N %d",
+ aka_attribute_names, AT_CLIENT_ERROR_CODE, 0);
+ return NEED_MORE;
+ }
+
+ DBG3(DBG_IKE, "using autn %B", &autn);
+ /* split up AUTN = SQN xor AK | AMF | MAC */
+ chunk_split(autn, "mmm", SQN_LENGTH, &sqn_ak, AMF_LENGTH, &amf, MAC_LENGTH, &mac);
+
+ /* Get the shared key K: */
+ chunk_free(&this->k);
+ if (load_key(this->peer, this->server, &this->k) != SUCCESS)
+ {
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier,
+ AKA_AUTHENTICATION_REJECT, AT_END);
+ DBG3(DBG_IKE, "no shared key found for IDs '%D' - '%D' to authenticate "
+ "with EAP-AKA, sending %N", this->peer, this->server,
+ aka_subtype_names, AKA_AUTHENTICATION_REJECT);
+ return NEED_MORE;
+ }
+ DBG3(DBG_IKE, "using K %B", &this->k);
+# ifdef TEST_VECTORS
+ /* Test vector for K */
+ u_int8_t test_k[] = {
+ 0xad,0x1b,0x5a,0x15,0x9b,0xe8,0x6b,0x2c,
+ 0xa6,0x6c,0x7a,0xe4,0x0b,0xba,0x9b,0x9d,
+ };
+ memcpy(this->k.ptr, test_k, this->k.len);
+# endif /* TEST_VECTORS */
+
+ /* calculate anonymity key AK */
+ f5(this, this->k, this->rand, ak.ptr);
+ DBG3(DBG_IKE, "using rand %B", &this->rand);
+ DBG3(DBG_IKE, "using ak %B", &ak);
+ /* XOR AK into SQN to decrypt it */
+
+ sqn = chunk_clonea(sqn_ak);
+
+ DBG3(DBG_IKE, "using ak xor sqn %B", &sqn_ak);
+ memxor(sqn.ptr, ak.ptr, sqn.len);
+ DBG3(DBG_IKE, "using sqn %B", &sqn);
+
+ /* calculate expected MAC and compare against received one */
+ f1(this, this->k, this->rand, sqn, amf, xmac.ptr);
+ if (!chunk_equals(mac, xmac))
+ {
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier,
+ AKA_AUTHENTICATION_REJECT, AT_END);
+ DBG1(DBG_IKE, "received MAC does not match XMAC, sending %N",
+ aka_subtype_names, AKA_AUTHENTICATION_REJECT);
+ DBG3(DBG_IKE, "MAC %B\nXMAC %B", &mac, &xmac);
+ return NEED_MORE;
+ }
+
+#if SEQ_CHECK
+ if (memcmp(peer_sqn.ptr, sqn.ptr, sqn.len) >= 0)
+ {
+ /* sequence number invalid. send AUTS */
+ chunk_t auts, macs, aks, amf;
+
+ macs = chunk_alloca(MAC_LENGTH);
+ aks = chunk_alloca(AK_LENGTH);
+ amf = chunk_alloca(AMF_LENGTH);
+
+ /* AMF is set to zero in AKA_SYNCHRONIZATION_FAILURE */
+ memset(amf.ptr, 0, amf.len);
+ /* AKS = f5*(RAND) */
+ f5star(this, this->k, this->rand, aks.ptr);
+ /* MACS = f1*(RAND) */
+ f1star(this, this->k, this->rand, peer_sqn, amf, macs.ptr);
+ /* AUTS = SQN xor AKS | MACS */
+ memxor(aks.ptr, peer_sqn.ptr, aks.len);
+ auts = chunk_cata("cc", aks, macs);
+
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier,
+ AKA_SYNCHRONIZATION_FAILURE,
+ AT_AUTS, auts, AT_END);
+ DBG1(DBG_IKE, "received SQN invalid, sending %N",
+ aka_subtype_names, AKA_SYNCHRONIZATION_FAILURE);
+ DBG3(DBG_IKE, "received SQN %B\ncurrent SQN %B", &sqn, &peer_sqn);
+ return NEED_MORE;
+ }
+#endif /* SEQ_CHECK */
+
+ /* derive K_encr, K_auth, MSK, EMSK */
+ derive_keys(this, this->peer);
+
+ /* verify EAP message MAC AT_MAC */
+ DBG3(DBG_IKE, "verifying AT_MAC signature of %B", &message);
+ DBG3(DBG_IKE, "using key %B", &this->k_auth);
+ this->signer->set_key(this->signer, this->k_auth);
+ if (!this->signer->verify_signature(this->signer, message, at_mac))
+ {
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier, AKA_CLIENT_ERROR,
+ AT_CLIENT_ERROR_CODE, client_error_code, AT_END);
+ DBG1(DBG_IKE, "MAC in AT_MAC attribute verification "
+ "failed, sending %N %d", aka_attribute_names,
+ AT_CLIENT_ERROR_CODE, 0);
+ return NEED_MORE;
+ }
+
+ /* update stored SQN to the received one */
+ memcpy(peer_sqn.ptr, sqn.ptr, sqn.len);
+
+ /* calculate RES */
+ f2(this, this->k, this->rand, res.ptr);
+
+ /* build response */
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier, AKA_CHALLENGE,
+ AT_RES, res, AT_MAC, chunk_empty, AT_END);
+ return NEED_MORE;
+}
+
+/**
+ * Process an incoming AKA-Notification as client
+ */
+static status_t peer_process_notification(private_eap_aka_t *this,
+ eap_payload_t *in, eap_payload_t **out)
+{
+ chunk_t message, pos, attr;
+ u_int8_t identifier;
+
+ message = in->get_data(in);
+ pos = message;
+ read_header(&pos);
+ identifier = in->get_identifier(in);
+
+ DBG3(DBG_IKE, "reading attributes from %B", &pos);
+
+ /* iterate over attributes */
+ while (TRUE)
+ {
+ aka_attribute_t attribute = read_attribute(&pos, &attr);
+ switch (attribute)
+ {
+ case AT_END:
+ break;
+ case AT_NOTIFICATION:
+ {
+ u_int16_t code;
+
+ if (attr.len != 2)
+ {
+ DBG1(DBG_IKE, "received invalid AKA notification, ignored");
+ continue;
+ }
+ code = ntohs(*(u_int16_t*)attr.ptr);
+ switch (code)
+ {
+ case 0:
+ DBG1(DBG_IKE, "received AKA notification 'general "
+ "failure after authentication' (%d)", code);
+ return FAILED;
+ case 16384:
+ DBG1(DBG_IKE, "received AKA notification 'general "
+ "failure' (%d)", code);
+ return FAILED;
+ case 32768:
+ DBG1(DBG_IKE, "received AKA notification 'successfully "
+ "authenticated' (%d)", code);
+ continue;
+ case 1026:
+ DBG1(DBG_IKE, "received AKA notification 'access "
+ "temporarily denied' (%d)", code);
+ return FAILED;
+ case 1031:
+ DBG1(DBG_IKE, "received AKA notification 'not "
+ "subscribed to service' (%d)", code);
+ return FAILED;
+ default:
+ DBG1(DBG_IKE, "received AKA notification code %d, "
+ "ignored", code);
+ continue;
+ }
+ }
+ default:
+ if (attribute >= 0 && attribute <= 127)
+ {
+ DBG1(DBG_IKE, "ignoring non-skippable attribute %N in %N",
+ aka_attribute_names, attribute, aka_subtype_names,
+ AKA_NOTIFICATION);
+ }
+ else
+ {
+ DBG1(DBG_IKE, "ignoring skippable attribute %N",
+ aka_attribute_names, attribute);
+ }
+ continue;
+ }
+ break;
+ }
+ return NEED_MORE;
+}
+
+/**
+ * Implementation of eap_method_t.process for an EAP_AKA peer
+ */
+static status_t peer_process(private_eap_aka_t *this,
+ eap_payload_t *in, eap_payload_t **out)
+{
+ aka_subtype_t type;
+ chunk_t message;
+ u_int8_t identifier;
+
+ message = in->get_data(in);
+ type = read_header(&message);
+ identifier = in->get_identifier(in);
+
+ DBG3(DBG_IKE, "received EAP message %B", &message);
+
+ switch (type)
+ {
+ case AKA_CHALLENGE:
+ {
+ return peer_process_challenge(this, in, out);
+ }
+ case AKA_NOTIFICATION:
+ {
+ return peer_process_notification(this, in, out);
+ }
+ default:
+ {
+ *out = build_aka_payload(this, EAP_RESPONSE, identifier, AKA_CLIENT_ERROR,
+ AT_CLIENT_ERROR_CODE, client_error_code, AT_END);
+ DBG1(DBG_IKE, "received unsupported %N request, sending %N %d",
+ aka_subtype_names, type,
+ aka_attribute_names, AT_CLIENT_ERROR_CODE, 0);
+ return NEED_MORE;
+ }
+ }
+}
+
+/**
+ * Implementation of eap_method_t.initiate for an EAP AKA peer
+ */
+static status_t peer_initiate(private_eap_aka_t *this, eap_payload_t **out)
+{
+ /* peer never initiates */
+ return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.get_type.
+ */
+static eap_type_t get_type(private_eap_aka_t *this, u_int32_t *vendor)
+{
+ *vendor = 0;
+ return EAP_AKA;
+}
+
+/**
+ * Implementation of eap_method_t.get_msk.
+ */
+static status_t get_msk(private_eap_aka_t *this, chunk_t *msk)
+{
+ if (this->msk.ptr)
+ {
+ *msk = this->msk;
+ return SUCCESS;
+ }
+ return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.is_mutual.
+ */
+static bool is_mutual(private_eap_aka_t *this)
+{
+ return TRUE;
+}
+
+/**
+ * Implementation of eap_method_t.destroy.
+ */
+static void destroy(private_eap_aka_t *this)
+{
+ DESTROY_IF(this->sha1);
+ DESTROY_IF(this->signer);
+ DESTROY_IF(this->prf);
+ DESTROY_IF(this->keyed_prf);
+ chunk_free(&this->k_encr);
+ chunk_free(&this->k_auth);
+ chunk_free(&this->msk);
+ chunk_free(&this->emsk);
+ chunk_free(&this->xres);
+ chunk_free(&this->k);
+ chunk_free(&this->rand);
+ free(this);
+}
+
+/**
+ * generic constructor used by client & server
+ */
+static private_eap_aka_t *eap_aka_create_generic(identification_t *server,
+ identification_t *peer)
+{
+ private_eap_aka_t *this = malloc_thing(private_eap_aka_t);
+
+ this->public.eap_method_interface.initiate = NULL;
+ this->public.eap_method_interface.process = NULL;
+ this->public.eap_method_interface.get_type = (eap_type_t(*)(eap_method_t*,u_int32_t*))get_type;
+ this->public.eap_method_interface.is_mutual = (bool(*)(eap_method_t*))is_mutual;
+ this->public.eap_method_interface.get_msk = (status_t(*)(eap_method_t*,chunk_t*))get_msk;
+ this->public.eap_method_interface.destroy = (void(*)(eap_method_t*))destroy;
+
+ /* private data */
+ this->server = server;
+ this->peer = peer;
+ this->k_encr = chunk_empty;
+ this->k_auth = chunk_empty;
+ this->msk = chunk_empty;
+ this->emsk = chunk_empty;
+ this->xres = chunk_empty;
+ this->k = chunk_empty;
+ this->rand = chunk_empty;
+
+ this->sha1 = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
+ this->signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_SHA1_128);
+ this->prf = lib->crypto->create_prf(lib->crypto, PRF_FIPS_SHA1_160);
+ this->keyed_prf = lib->crypto->create_prf(lib->crypto, PRF_KEYED_SHA1);
+
+ if (!this->sha1 || !this->signer || !this->prf || !this->keyed_prf)
+ {
+ DBG1(DBG_IKE, "unable to initiate EAP-AKA, FIPS-PRF/SHA1 not supported");
+ DESTROY_IF(this->sha1);
+ DESTROY_IF(this->signer);
+ DESTROY_IF(this->prf);
+ DESTROY_IF(this->keyed_prf);
+ destroy(this);
+ return NULL;
+ }
+ return this;
+}
+
+/*
+ * Described in header.
+ */
+eap_aka_t *eap_aka_create_server(identification_t *server, identification_t *peer)
+{
+ private_eap_aka_t *this = eap_aka_create_generic(server, peer);
+
+ if (this)
+ {
+ this->public.eap_method_interface.initiate = (status_t(*)(eap_method_t*,eap_payload_t**))server_initiate;
+ this->public.eap_method_interface.process = (status_t(*)(eap_method_t*,eap_payload_t*,eap_payload_t**))server_process;
+ }
+ return (eap_aka_t*)this;
+}
+
+/*
+ * Described in header.
+ */
+eap_aka_t *eap_aka_create_peer(identification_t *server, identification_t *peer)
+{
+ private_eap_aka_t *this = eap_aka_create_generic(server, peer);
+
+ if (this)
+ {
+ this->public.eap_method_interface.initiate = (status_t(*)(eap_method_t*,eap_payload_t**))peer_initiate;
+ this->public.eap_method_interface.process = (status_t(*)(eap_method_t*,eap_payload_t*,eap_payload_t**))peer_process;
+ }
+ return (eap_aka_t*)this;
+}
+