hostapd / EAP-SIM database/authenticator gateway More...

#include "includes.h"
#include <sys/un.h>
#include "common.h"
#include "crypto/random.h"
#include "eap_common/eap_sim_common.h"
#include "eap_server/eap_sim_db.h"
#include "eloop.h"

Data Structures
struct	eap_sim_pseudonym

struct	eap_sim_db_pending

struct	eap_sim_db_data

Functions
struct eap_sim_db_data *	eap_sim_db_init (const char config, void(get_complete_cb)(void ctx, void session_ctx), void *ctx)
	Initialize EAP-SIM DB / authentication gateway interface. More...

void	eap_sim_db_deinit (void *priv)
	Deinitialize EAP-SIM DB/authentication gw interface. More...

int	eap_sim_db_get_gsm_triplets (struct eap_sim_db_data data, const char username, int max_chal, u8 _rand, u8 kc, u8 sres, void cb_session_ctx)
	Get GSM triplets. More...

char *	eap_sim_db_get_next_pseudonym (struct eap_sim_db_data *data, enum eap_sim_db_method method)
	EAP-SIM DB: Get next pseudonym. More...

char *	eap_sim_db_get_next_reauth_id (struct eap_sim_db_data *data, enum eap_sim_db_method method)
	EAP-SIM DB: Get next reauth_id. More...

int	eap_sim_db_add_pseudonym (struct eap_sim_db_data data, const char permanent, char *pseudonym)
	EAP-SIM DB: Add new pseudonym. More...

int	eap_sim_db_add_reauth (struct eap_sim_db_data data, const char permanent, char reauth_id, u16 counter, const u8 mk)
	EAP-SIM DB: Add new re-authentication entry. More...

const char *	eap_sim_db_get_permanent (struct eap_sim_db_data data, const char pseudonym)
	EAP-SIM DB: Get permanent identity. More...

struct eap_sim_reauth *	eap_sim_db_get_reauth_entry (struct eap_sim_db_data data, const char reauth_id)
	EAP-SIM DB: Get re-authentication entry. More...

void	eap_sim_db_remove_reauth (struct eap_sim_db_data data, struct eap_sim_reauth reauth)
	EAP-SIM DB: Remove re-authentication entry. More...

int	eap_sim_db_get_aka_auth (struct eap_sim_db_data data, const char username, u8 _rand, u8 autn, u8 ik, u8 ck, u8 res, size_t res_len, void *cb_session_ctx)
	Get AKA authentication values. More...

int	eap_sim_db_resynchronize (struct eap_sim_db_data data, const char username, const u8 auts, const u8 _rand)
	Resynchronize AKA AUTN. More...

char *	sim_get_username (const u8 *identity, size_t identity_len)
	Extract username from SIM identity. More...

Detailed Description

hostapd / EAP-SIM database/authenticator gateway

This is an example implementation of the EAP-SIM/AKA database/authentication gateway interface that is using an external program as an SS7 gateway to GSM/UMTS authentication center (HLR/AuC). hlr_auc_gw is an example implementation of such a gateway program. This eap_sim_db.c takes care of EAP-SIM/AKA pseudonyms and re-auth identities. It can be used with different gateway implementations for HLR/AuC access. Alternatively, it can also be completely replaced if the in-memory database of pseudonyms/re-auth identities is not suitable for some cases.

Function Documentation

int eap_sim_db_add_pseudonym	(	struct eap_sim_db_data *	data,
		const char *	permanent,
		char *	pseudonym
	)

EAP-SIM DB: Add new pseudonym.

Parameters

data	Private data pointer from eap_sim_db_init()
permanent	Permanent username
pseudonym	Pseudonym for this user. This needs to be an allocated buffer, e.g., return value from eap_sim_db_get_next_pseudonym(). Caller must not free it.

Returns: 0 on success, -1 on failure

This function adds a new pseudonym for EAP-SIM user. EAP-SIM DB is responsible of freeing pseudonym buffer once it is not needed anymore.

int eap_sim_db_add_reauth	(	struct eap_sim_db_data *	data,
		const char *	permanent,
		char *	reauth_id,
		u16	counter,
		const u8 *	mk
	)

EAP-SIM DB: Add new re-authentication entry.

Parameters

priv	Private data pointer from eap_sim_db_init()
permanent	Permanent username
identity_len	Length of identity
reauth_id	reauth_id for this user. This needs to be an allocated buffer, e.g., return value from eap_sim_db_get_next_reauth_id(). Caller must not free it.
counter	AT_COUNTER value for fast re-authentication
mk	16-byte MK from the previous full authentication or NULL

Returns: 0 on success, -1 on failure

This function adds a new re-authentication entry for an EAP-SIM user. EAP-SIM DB is responsible of freeing reauth_id buffer once it is not needed anymore.

void eap_sim_db_deinit ( void * priv )

Deinitialize EAP-SIM DB/authentication gw interface.

Parameters

priv	Private data pointer from eap_sim_db_init()

int eap_sim_db_get_aka_auth	(	struct eap_sim_db_data *	data,
		const char *	username,
		u8 *	_rand,
		u8 *	autn,
		u8 *	ik,
		u8 *	ck,
		u8 *	res,
		size_t *	res_len,
		void *	cb_session_ctx
	)

Get AKA authentication values.

Parameters

data	Private data pointer from eap_sim_db_init()
username	Permanent username (prefix \| IMSI)
_rand	Buffer for RAND value
autn	Buffer for AUTN value
ik	Buffer for IK value
ck	Buffer for CK value
res	Buffer for RES value
res_len	Buffer for RES length
cb_session_ctx	Session callback context for get_complete_cb()

Returns: 0 on success, -1 (EAP_SIM_DB_FAILURE) on error (e.g., user not found), or -2 (EAP_SIM_DB_PENDING) if results are not yet available. In this case, the callback function registered with eap_sim_db_init() will be called once the results become available.

When using an external server for AKA authentication, this function can always start a request and return EAP_SIM_DB_PENDING immediately if authentication triplets are not available. Once the authentication data are received, callback function registered with eap_sim_db_init() is called to notify EAP state machine to reprocess the message. This eap_sim_db_get_aka_auth() function will then be called again and the newly received triplets will then be given to the caller.

int eap_sim_db_get_gsm_triplets	(	struct eap_sim_db_data *	data,
		const char *	username,
		int	max_chal,
		u8 *	_rand,
		u8 *	kc,
		u8 *	sres,
		void *	cb_session_ctx
	)

Get GSM triplets.

Parameters

data	Private data pointer from eap_sim_db_init()
username	Permanent username (prefix \| IMSI)
max_chal	Maximum number of triplets
_rand	Buffer for RAND values
kc	Buffer for Kc values
sres	Buffer for SRES values
cb_session_ctx	Session callback context for get_complete_cb()

Returns: Number of triplets received (has to be less than or equal to max_chal), -1 (EAP_SIM_DB_FAILURE) on error (e.g., user not found), or -2 (EAP_SIM_DB_PENDING) if results are not yet available. In this case, the callback function registered with eap_sim_db_init() will be called once the results become available.

When using an external server for GSM triplets, this function can always start a request and return EAP_SIM_DB_PENDING immediately if authentication triplets are not available. Once the triplets are received, callback function registered with eap_sim_db_init() is called to notify EAP state machine to reprocess the message. This eap_sim_db_get_gsm_triplets() function will then be called again and the newly received triplets will then be given to the caller.

char* eap_sim_db_get_next_pseudonym	(	struct eap_sim_db_data *	data,
		enum eap_sim_db_method	method
	)

EAP-SIM DB: Get next pseudonym.

Parameters

data	Private data pointer from eap_sim_db_init()
method	EAP method (SIM/AKA/AKA')

Returns: Next pseudonym (allocated string) or NULL on failure

This function is used to generate a pseudonym for EAP-SIM. The returned pseudonym is not added to database at this point; it will need to be added with eap_sim_db_add_pseudonym() once the authentication has been completed successfully. Caller is responsible for freeing the returned buffer.

char* eap_sim_db_get_next_reauth_id	(	struct eap_sim_db_data *	data,
		enum eap_sim_db_method	method
	)

EAP-SIM DB: Get next reauth_id.

Parameters

data	Private data pointer from eap_sim_db_init()
method	EAP method (SIM/AKA/AKA')

Returns: Next reauth_id (allocated string) or NULL on failure

This function is used to generate a fast re-authentication identity for EAP-SIM. The returned reauth_id is not added to database at this point; it will need to be added with eap_sim_db_add_reauth() once the authentication has been completed successfully. Caller is responsible for freeing the returned buffer.

const char* eap_sim_db_get_permanent	(	struct eap_sim_db_data *	data,
		const char *	pseudonym
	)

EAP-SIM DB: Get permanent identity.

Parameters

data	Private data pointer from eap_sim_db_init()
pseudonym	Pseudonym username

Returns: Pointer to permanent username or NULL if not found

struct eap_sim_reauth* eap_sim_db_get_reauth_entry	(	struct eap_sim_db_data *	data,
		const char *	reauth_id
	)

EAP-SIM DB: Get re-authentication entry.

Parameters

data	Private data pointer from eap_sim_db_init()
reauth_id	Fast re-authentication username

Returns: Pointer to the re-auth entry, or NULL if not found

struct eap_sim_db_data* eap_sim_db_init	(	const char *	config,
		void()(void ctx, void *session_ctx)	get_complete_cb,
		void *	ctx
	)

Initialize EAP-SIM DB / authentication gateway interface.

Parameters

config	Configuration data (e.g., file name)
get_complete_cb	Callback function for reporting availability of triplets
ctx	Context pointer for get_complete_cb

Returns: Pointer to a private data structure or NULL on failure

void eap_sim_db_remove_reauth	(	struct eap_sim_db_data *	data,
		struct eap_sim_reauth *	reauth
	)

EAP-SIM DB: Remove re-authentication entry.

Parameters

data	Private data pointer from eap_sim_db_init()
reauth	Pointer to re-authentication entry from eap_sim_db_get_reauth_entry()

int eap_sim_db_resynchronize	(	struct eap_sim_db_data *	data,
		const char *	username,
		const u8 *	auts,
		const u8 *	_rand
	)

Resynchronize AKA AUTN.

Parameters

data	Private data pointer from eap_sim_db_init()
username	Permanent username
auts	AUTS value from the peer
_rand	RAND value used in the rejected message

Returns: 0 on success, -1 on failure

This function is called when the peer reports synchronization failure in the AUTN value by sending AUTS. The AUTS and RAND values should be sent to HLR/AuC to allow it to resynchronize with the peer. After this, eap_sim_db_get_aka_auth() will be called again to to fetch updated RAND/AUTN values for the next challenge.

char* sim_get_username	(	const u8 *	identity,
		size_t	identity_len
	)

Extract username from SIM identity.

Parameters

identity	Identity
identity_len	Identity length

Returns: Allocated buffer with the username part of the identity

Caller is responsible for freeing the returned buffer with os_free().

Data Structures

Functions

Detailed Description

Function Documentation