wpa.c File Reference

Handler for the aspects of WPA handshaking that are independent of 802.1X/PSK or TKIP/CCMP; this mostly involves the 4-Way Handshake. More...

#include <ipxe/net80211.h>
#include <ipxe/sec80211.h>
#include <ipxe/wpa.h>
#include <ipxe/eapol.h>
#include <ipxe/crypto.h>
#include <ipxe/arc4.h>
#include <ipxe/crc32.h>
#include <ipxe/sha1.h>
#include <ipxe/hmac.h>
#include <ipxe/list.h>
#include <ipxe/ethernet.h>
#include <ipxe/rbg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <byteswap.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
static int	wpa_fail (struct wpa_common_ctx *ctx, int rc)
	Return an error code and deauthenticate. More...
static struct net80211_crypto *	wpa_find_cryptosystem (enum net80211_crypto_alg crypt)
	Find a cryptosystem handler structure from a crypto ID. More...
struct wpa_kie *	wpa_find_kie (int version)
	Find WPA key integrity and encryption handler from key version field. More...
int	wpa_make_rsn_ie (struct net80211_device *dev, union ieee80211_ie **ie_ret)
	Construct RSN or WPA information element. More...
int	wpa_start (struct net80211_device *dev, struct wpa_common_ctx *ctx, const void *pmk, size_t pmk_len)
	Set up generic WPA support to handle 4-Way Handshake. More...
void	wpa_stop (struct net80211_device *dev)
	Disable handling of received WPA handshake frames. More...
static void	wpa_derive_ptk (struct wpa_common_ctx *ctx)
	Derive pairwise transient key. More...
static int	wpa_install_ptk (struct wpa_common_ctx *ctx, int len)
	Install pairwise transient key. More...
static int	wpa_install_gtk (struct wpa_common_ctx *ctx, int len, const void *rsc)
	Install group transient key. More...
static int	wpa_maybe_install_gtk (struct wpa_common_ctx *ctx, union ieee80211_ie *ie, void *ie_end, const void *rsc)
	Search for group transient key, and install it if found. More...
static struct io_buffer *	wpa_alloc_frame (int kdlen)
	Allocate I/O buffer for construction of outgoing EAPOL-Key frame. More...
static int	wpa_send_eapol (struct io_buffer *iob, struct wpa_common_ctx *ctx, struct wpa_kie *kie)
	Send EAPOL-Key packet. More...
static int	wpa_send_2_of_4 (struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie)
	Send second frame in 4-Way Handshake. More...
static int	wpa_handle_1_of_4 (struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie)
	Handle receipt of first frame in 4-Way Handshake. More...
static int	wpa_send_final (struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie)
	Send fourth frame in 4-Way Handshake, or second in Group Key Handshake. More...
static int	wpa_handle_3_of_4 (struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie)
	Handle receipt of third frame in 4-Way Handshake. More...
static int	wpa_handle_1_of_2 (struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie)
	Handle receipt of first frame in Group Key Handshake. More...
static int	eapol_key_rx (struct eapol_supplicant *supplicant, struct io_buffer *iob, const void *ll_source)
	Handle receipt of EAPOL-Key frame for WPA. More...
	REQUIRING_SYMBOL (eapol_key_handler)
	REQUIRE_OBJECT (eapol)

Variables
struct list_head	wpa_contexts = LIST_HEAD_INIT ( wpa_contexts )
	List of WPA contexts in active use. More...
struct eapol_handler eapol_key_handler	__eapol_handler

Detailed Description

Handler for the aspects of WPA handshaking that are independent of 802.1X/PSK or TKIP/CCMP; this mostly involves the 4-Way Handshake.

Definition in file wpa.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER

)

wpa_fail()

static int wpa_fail ( struct wpa_common_ctx *  ctx, int  rc  )

static

Return an error code and deauthenticate.

Parameters

ctx	WPA common context
rc	Return status code

Return values

rc	The passed return status code

Definition at line 56 of file wpa.c.

{
        net80211_deauthenticate ( ctx->dev, rc );
        return rc;
}

References ctx, net80211_deauthenticate(), and rc.

Referenced by eapol_key_rx(), wpa_handle_1_of_2(), and wpa_handle_3_of_4().

wpa_find_cryptosystem()

static struct net80211_crypto* wpa_find_cryptosystem ( enum net80211_crypto_alg  crypt )

static

Find a cryptosystem handler structure from a crypto ID.

Parameters

crypt

Cryptosystem ID

Return values

crypto

Cryptosystem handler structure

If support for crypt is not compiled in to iPXE, or if crypt is NET80211_CRYPT_UNKNOWN, returns NULL.

Definition at line 73 of file wpa.c.

{
        struct net80211_crypto *crypto;

        for_each_table_entry ( crypto, NET80211_CRYPTOS ) {
                if ( crypto->algorithm == crypt )
                        return crypto;
        }

        return NULL;
}

References net80211_crypto::algorithm, for_each_table_entry, NET80211_CRYPTOS, and NULL.

Referenced by wpa_make_rsn_ie().

wpa_find_kie()

struct wpa_kie* wpa_find_kie

(

int

version

)

Find WPA key integrity and encryption handler from key version field.

Parameters

ver	Version bits of EAPOL-Key info field

Return values

kie	Key integrity and encryption handler

Definition at line 92 of file wpa.c.

{
        struct wpa_kie *kie;

        for_each_table_entry ( kie, WPA_KIES ) {
                if ( kie->version == version )
                        return kie;
        }

        return NULL;
}

References for_each_table_entry, NULL, wpa_kie::version, version, and WPA_KIES.

Referenced by eapol_key_rx().

wpa_make_rsn_ie()

int wpa_make_rsn_ie	(	struct net80211_device *	dev,
		union ieee80211_ie **	ie_ret
	)

Construct RSN or WPA information element.

Parameters

dev	802.11 device

Return values

ie_ret	RSN or WPA information element
rc	Return status code

This function allocates, fills, and returns a RSN or WPA information element suitable for including in an association request frame to the network identified by dev->associating. If it is impossible to construct an information element consistent with iPXE's capabilities that is compatible with that network, or if none should be sent because that network's beacon included no security information, returns an error indication and leaves ie_ret unchanged.

The returned IE will be of the same type (RSN or WPA) as was included in the beacon for the network it is destined for.

Definition at line 124 of file wpa.c.

{
        u8 *rsn, *rsn_end;
        int is_rsn;
        u32 group_cipher;
        enum net80211_crypto_alg gcrypt;
        int ie_len;
        u8 *iep;
        struct ieee80211_ie_rsn *ie;
        struct ieee80211_frame *hdr;
        struct ieee80211_beacon *beacon;

        if ( ! dev->associating ) {
                DBG ( "WPA: Can't make RSN IE for a non-associating device\n" );
                return -EINVAL;
        }

        hdr = dev->associating->beacon->data;
        beacon = ( struct ieee80211_beacon * ) hdr->data;
        rsn = sec80211_find_rsn ( beacon->info_element,
                                  dev->associating->beacon->tail, &is_rsn,
                                  &rsn_end );
        if ( ! rsn ) {
                DBG ( "WPA: Can't make RSN IE when we didn't get one\n" );
                return -EINVAL;
        }

        rsn += 2;               /* skip version */
        group_cipher = *( u32 * ) rsn;
        gcrypt = sec80211_rsn_get_net80211_crypt ( group_cipher );

        if ( ! wpa_find_cryptosystem ( gcrypt ) ||
             ! wpa_find_cryptosystem ( dev->associating->crypto ) ) {
                DBG ( "WPA: No support for (GC:%d, PC:%d)\n",
                      gcrypt, dev->associating->crypto );
                return -ENOTSUP;
        }

        /* Everything looks good - make our IE. */

        /* WPA IEs need 4 more bytes for the OUI+type */
        ie_len = ieee80211_rsn_size ( 1, 1, 0, is_rsn ) + ( 4 * ! is_rsn );
        iep = malloc ( ie_len );
        if ( ! iep )
                return -ENOMEM;

        *ie_ret = ( union ieee80211_ie * ) iep;

        /* Store ID and length bytes. */
        *iep++ = ( is_rsn ? IEEE80211_IE_RSN : IEEE80211_IE_VENDOR );
        *iep++ = ie_len - 2;

        /* Store OUI+type for WPA IEs. */
        if ( ! is_rsn ) {
                *( u32 * ) iep = IEEE80211_WPA_OUI_VEN;
                iep += 4;
        }

        /* If this is a WPA IE, the id and len bytes in the
           ieee80211_ie_rsn structure will not be valid, but by doing
           the cast we can fill all the other fields much more
           readily. */

        ie = ( struct ieee80211_ie_rsn * ) ( iep - 2 );
        ie->version = IEEE80211_RSN_VERSION;
        ie->group_cipher = group_cipher;
        ie->pairwise_count = 1;
        ie->pairwise_cipher[0] =
                sec80211_rsn_get_crypto_desc ( dev->associating->crypto,
                                               is_rsn );
        ie->akm_count = 1;
        ie->akm_list[0] =
                sec80211_rsn_get_akm_desc ( dev->associating->handshaking,
                                            is_rsn );
        if ( is_rsn ) {
                ie->rsn_capab = 0;
                ie->pmkid_count = 0;
        }

        return 0;
}

References ieee80211_ie_rsn::akm_count, ieee80211_ie_rsn::akm_list, net80211_device::associating, net80211_wlan::beacon, net80211_wlan::crypto, io_buffer::data, DBG, EINVAL, ENOMEM, ENOTSUP, group_cipher, ieee80211_ie_rsn::group_cipher, net80211_wlan::handshaking, hdr, ieee80211_beacon, IEEE80211_IE_RSN, IEEE80211_IE_VENDOR, ieee80211_rsn_size(), IEEE80211_RSN_VERSION, IEEE80211_WPA_OUI_VEN, malloc(), ieee80211_ie_rsn::pairwise_cipher, ieee80211_ie_rsn::pairwise_count, ieee80211_ie_rsn::pmkid_count, ieee80211_ie_rsn::rsn_capab, sec80211_find_rsn(), sec80211_rsn_get_akm_desc(), sec80211_rsn_get_crypto_desc(), sec80211_rsn_get_net80211_crypt(), io_buffer::tail, ieee80211_ie_rsn::version, and wpa_find_cryptosystem().

Referenced by wpa_psk_init().

wpa_start()

int wpa_start	(	struct net80211_device *	dev,
		struct wpa_common_ctx *	ctx,
		const void *	pmk,
		size_t	pmk_len
	)

Set up generic WPA support to handle 4-Way Handshake.

Parameters

dev	802.11 device
ctx	WPA common context
pmk	Pairwise Master Key to use for session
pmk_len	Length of PMK, almost always 32

Return values

rc	Return status code

Definition at line 216 of file wpa.c.

{
        struct io_buffer *iob;
        struct ieee80211_frame *hdr;
        struct ieee80211_beacon *beacon;
        u8 *ap_rsn_ie = NULL, *ap_rsn_ie_end;

        if ( ! dev->rsn_ie || ! dev->associating )
                return -EINVAL;

        ctx->dev = dev;
        memcpy ( ctx->pmk, pmk, ctx->pmk_len = pmk_len );
        ctx->state = WPA_READY;
        ctx->replay = ~0ULL;

        iob = dev->associating->beacon;
        hdr = iob->data;
        beacon = ( struct ieee80211_beacon * ) hdr->data;
        ap_rsn_ie = sec80211_find_rsn ( beacon->info_element, iob->tail,
                                        &ctx->ap_rsn_is_rsn, &ap_rsn_ie_end );
        if ( ap_rsn_ie ) {
                ctx->ap_rsn_ie = malloc ( ap_rsn_ie_end - ap_rsn_ie );
                if ( ! ctx->ap_rsn_ie )
                        return -ENOMEM;
                memcpy ( ctx->ap_rsn_ie, ap_rsn_ie, ap_rsn_ie_end - ap_rsn_ie );
                ctx->ap_rsn_ie_len = ap_rsn_ie_end - ap_rsn_ie;
        } else {
                return -ENOENT;
        }

        ctx->crypt = dev->associating->crypto;
        ctx->gcrypt = NET80211_CRYPT_UNKNOWN;

        list_add_tail ( &ctx->list, &wpa_contexts );
        return 0;
}

References net80211_device::associating, net80211_wlan::beacon, net80211_wlan::crypto, ctx, io_buffer::data, EINVAL, ENOENT, ENOMEM, hdr, ieee80211_beacon, list_add_tail, malloc(), memcpy(), NET80211_CRYPT_UNKNOWN, NULL, net80211_device::rsn_ie, sec80211_find_rsn(), io_buffer::tail, wpa_contexts, and WPA_READY.

Referenced by wpa_psk_start().

wpa_stop()

void wpa_stop

(

struct net80211_device *

dev

)

Disable handling of received WPA handshake frames.

Parameters

dev	802.11 device

Definition at line 260 of file wpa.c.

{
        struct wpa_common_ctx *ctx, *tmp;

        list_for_each_entry_safe ( ctx, tmp, &wpa_contexts, list ) {
                if ( ctx->dev == dev ) {
                        free ( ctx->ap_rsn_ie );
                        ctx->ap_rsn_ie = NULL;
                        list_del ( &ctx->list );
                }
        }
}

References ctx, wpa_common_ctx::dev, free, wpa_common_ctx::list, list_del, list_for_each_entry_safe, NULL, tmp, and wpa_contexts.

Referenced by wpa_psk_stop().

wpa_derive_ptk()

static void wpa_derive_ptk ( struct wpa_common_ctx *  ctx )

static

Derive pairwise transient key.

Parameters

ctx	WPA common context

Definition at line 279 of file wpa.c.

{
        struct {
                u8 mac1[ETH_ALEN];
                u8 mac2[ETH_ALEN];
                u8 nonce1[WPA_NONCE_LEN];
                u8 nonce2[WPA_NONCE_LEN];
        } __attribute__ (( packed )) ptk_data;

        /* The addresses and nonces are stored in numerical order (!) */

        if ( memcmp ( ctx->dev->netdev->ll_addr, ctx->dev->bssid,
                      ETH_ALEN ) < 0 ) {
                memcpy ( ptk_data.mac1, ctx->dev->netdev->ll_addr, ETH_ALEN );
                memcpy ( ptk_data.mac2, ctx->dev->bssid, ETH_ALEN );
        } else {
                memcpy ( ptk_data.mac1, ctx->dev->bssid, ETH_ALEN );
                memcpy ( ptk_data.mac2, ctx->dev->netdev->ll_addr, ETH_ALEN );
        }

        if ( memcmp ( ctx->Anonce, ctx->Snonce, WPA_NONCE_LEN ) < 0 ) {
                memcpy ( ptk_data.nonce1, ctx->Anonce, WPA_NONCE_LEN );
                memcpy ( ptk_data.nonce2, ctx->Snonce, WPA_NONCE_LEN );
        } else {
                memcpy ( ptk_data.nonce1, ctx->Snonce, WPA_NONCE_LEN );
                memcpy ( ptk_data.nonce2, ctx->Anonce, WPA_NONCE_LEN );
        }

        DBGC2 ( ctx, "WPA %p A1 %s", ctx, eth_ntoa ( ptk_data.mac1 ) );
        DBGC2 ( ctx, ", A2 %s\n", eth_ntoa ( ptk_data.mac2 ) );

        DBGC2 ( ctx, "WPA %p Nonce1, Nonce2:\n", ctx );
        DBGC2_HD ( ctx, ptk_data.nonce1, WPA_NONCE_LEN );
        DBGC2_HD ( ctx, ptk_data.nonce2, WPA_NONCE_LEN );

        prf_sha1 ( ctx->pmk, ctx->pmk_len,
                   "Pairwise key expansion",
                   &ptk_data, sizeof ( ptk_data ),
                   &ctx->ptk, sizeof ( ctx->ptk ) );

        DBGC2 ( ctx, "WPA %p PTK:\n", ctx );
        DBGC2_HD ( ctx, &ctx->ptk, sizeof ( ctx->ptk ) );
}

References __attribute__, ctx, DBGC2, DBGC2_HD, ETH_ALEN, eth_ntoa(), memcmp(), memcpy(), prf_sha1(), and WPA_NONCE_LEN.

Referenced by wpa_handle_1_of_4().

wpa_install_ptk()

static int wpa_install_ptk ( struct wpa_common_ctx *  ctx, int  len  )

inlinestatic

Install pairwise transient key.

Parameters

ctx	WPA common context
len	Key length (16 for CCMP, 32 for TKIP)

Return values

rc	Return status code

Definition at line 331 of file wpa.c.

{
        DBGC ( ctx, "WPA %p: installing %d-byte pairwise transient key\n",
               ctx, len );
        DBGC2_HD ( ctx, &ctx->ptk.tk, len );

        return sec80211_install ( &ctx->dev->crypto, ctx->crypt,
                                  &ctx->ptk.tk, len, NULL );
}

References ctx, DBGC, DBGC2_HD, len, NULL, and sec80211_install().

Referenced by wpa_handle_3_of_4().

wpa_install_gtk()

static int wpa_install_gtk ( struct wpa_common_ctx *  ctx, int  len, const void *  rsc  )

inlinestatic

Install group transient key.

Parameters

ctx	WPA common context
len	Key length (16 for CCMP, 32 for TKIP)
rsc	Receive sequence counter field in EAPOL-Key packet

Return values

rc	Return status code

Definition at line 349 of file wpa.c.

{
        DBGC ( ctx, "WPA %p: installing %d-byte group transient key\n",
               ctx, len );
        DBGC2_HD ( ctx, &ctx->gtk.tk, len );

        return sec80211_install ( &ctx->dev->gcrypto, ctx->gcrypt,
                                  &ctx->gtk.tk, len, rsc );
}

References ctx, DBGC, DBGC2_HD, len, rsc, and sec80211_install().

Referenced by wpa_handle_1_of_2(), and wpa_maybe_install_gtk().

wpa_maybe_install_gtk()

static int wpa_maybe_install_gtk ( struct wpa_common_ctx *  ctx, union ieee80211_ie *  ie, void *  ie_end, const void *  rsc  )

static

Search for group transient key, and install it if found.

Parameters

ctx	WPA common context
ie	Pointer to first IE in key data field
ie_end	Pointer to first byte not in key data field
rsc	Receive sequence counter field in EAPOL-Key packet

Return values

rc	Return status code

Definition at line 369 of file wpa.c.

{
        struct wpa_kde *kde;

        if ( ! ieee80211_ie_bound ( ie, ie_end ) )
                return -ENOENT;

        while ( ie ) {
                if ( ie->id == IEEE80211_IE_VENDOR &&
                     ie->vendor.oui == WPA_KDE_GTK )
                        break;

                ie = ieee80211_next_ie ( ie, ie_end );
        }

        if ( ! ie )
                return -ENOENT;

        if ( ie->len - 6u > sizeof ( ctx->gtk.tk ) ) {
                DBGC ( ctx, "WPA %p: GTK KDE is too long (%d bytes, max %zd)\n",
                       ctx, ie->len - 4, sizeof ( ctx->gtk.tk ) );
                return -EINVAL;
        }

        /* XXX We ignore key ID for now. */
        kde = ( struct wpa_kde * ) ie;
        memcpy ( &ctx->gtk.tk, &kde->gtk_encap.gtk, kde->len - 6 );

        return wpa_install_gtk ( ctx, kde->len - 6, rsc );
}

References ctx, DBGC, EINVAL, ENOENT, wpa_kde_gtk_encap::gtk, wpa_kde::gtk_encap, ieee80211_ie::id, ieee80211_ie_bound(), IEEE80211_IE_VENDOR, ieee80211_next_ie(), wpa_kde::len, ieee80211_ie::len, memcpy(), ieee80211_ie_vendor::oui, rsc, u, ieee80211_ie::vendor, wpa_install_gtk(), and WPA_KDE_GTK.

Referenced by wpa_handle_1_of_2(), and wpa_handle_3_of_4().

wpa_alloc_frame()

static struct io_buffer* wpa_alloc_frame ( int  kdlen )

static

Allocate I/O buffer for construction of outgoing EAPOL-Key frame.

Parameters

kdlen

Maximum number of bytes in the Key Data field

Return values

iob	Newly allocated I/O buffer

The returned buffer will have space reserved for the link-layer and EAPOL headers, and will have iob->tail pointing to the start of the Key Data field. Thus, it is necessary to use iob_put() in filling the Key Data.

Definition at line 414 of file wpa.c.

{
        struct io_buffer *ret = alloc_iob ( sizeof ( struct eapol_key_pkt ) +
                                            kdlen +
                                            sizeof ( struct eapol_header ) +
                                            MAX_LL_HEADER_LEN );
        if ( ! ret )
                return NULL;

        iob_reserve ( ret, MAX_LL_HEADER_LEN + sizeof ( struct eapol_header ) );
        memset ( iob_put ( ret, sizeof ( struct eapol_key_pkt ) ), 0,
                 sizeof ( struct eapol_key_pkt ) );

        return ret;
}

References alloc_iob(), iob_put, iob_reserve, MAX_LL_HEADER_LEN, memset(), and NULL.

Referenced by wpa_send_2_of_4(), and wpa_send_final().

wpa_send_eapol()

static int wpa_send_eapol ( struct io_buffer *  iob, struct wpa_common_ctx *  ctx, struct wpa_kie *  kie  )

static

Send EAPOL-Key packet.

Parameters

iob	I/O buffer, with sufficient headroom for headers
dev	802.11 device
kie	Key integrity and encryption handler
is_rsn	If TRUE, handshake uses new RSN format

Return values

rc	Return status code

If a KIE is specified, the MIC will be filled in before transmission.

Definition at line 442 of file wpa.c.

{
        struct eapol_key_pkt *pkt = iob->data;
        struct eapol_header *eapol = iob_push ( iob, sizeof ( *eapol ) );

        pkt->info = htons ( pkt->info );
        pkt->keysize = htons ( pkt->keysize );
        pkt->datalen = htons ( pkt->datalen );
        pkt->replay = cpu_to_be64 ( pkt->replay );
        eapol->version = EAPOL_VERSION_2001;
        eapol->type = EAPOL_TYPE_KEY;
        eapol->len = htons ( iob->tail - iob->data - sizeof ( *eapol ) );

        memset ( pkt->mic, 0, sizeof ( pkt->mic ) );
        if ( kie )
                kie->mic ( &ctx->ptk.kck, eapol, sizeof ( *eapol ) +
                           sizeof ( *pkt ) + ntohs ( pkt->datalen ),
                           pkt->mic );

        return net_tx ( iob, ctx->dev->netdev, &eapol_protocol,
                        ctx->dev->bssid, ctx->dev->netdev->ll_addr );
}

References cpu_to_be64, ctx, io_buffer::data, eapol_key_pkt::datalen, EAPOL_TYPE_KEY, EAPOL_VERSION_2001, htons, eapol_key_pkt::info, iob_push, eapol_key_pkt::keysize, eapol_header::len, memset(), eapol_key_pkt::mic, wpa_kie::mic, net_tx(), ntohs, eapol_key_pkt::replay, io_buffer::tail, eapol_header::type, and eapol_header::version.

Referenced by wpa_send_2_of_4(), and wpa_send_final().

wpa_send_2_of_4()

static int wpa_send_2_of_4 ( struct wpa_common_ctx *  ctx, struct eapol_key_pkt *  pkt, int  is_rsn, struct wpa_kie *  kie  )

static

Send second frame in 4-Way Handshake.

Parameters

ctx	WPA common context
pkt	First frame, to which this is a reply
is_rsn	If TRUE, handshake uses new RSN format
kie	Key integrity and encryption handler

Return values

rc	Return status code

Definition at line 476 of file wpa.c.

{
        struct io_buffer *iob = wpa_alloc_frame ( ctx->dev->rsn_ie->len + 2 );
        struct eapol_key_pkt *npkt;

        if ( ! iob )
                return -ENOMEM;

        npkt = iob->data;
        memcpy ( npkt, pkt, sizeof ( *pkt ) );
        npkt->info &= ~EAPOL_KEY_INFO_KEY_ACK;
        npkt->info |= EAPOL_KEY_INFO_KEY_MIC;
        if ( is_rsn )
                npkt->keysize = 0;
        memcpy ( npkt->nonce, ctx->Snonce, sizeof ( npkt->nonce ) );
        npkt->datalen = ctx->dev->rsn_ie->len + 2;
        memcpy ( iob_put ( iob, npkt->datalen ), ctx->dev->rsn_ie,
                 npkt->datalen );

        DBGC ( ctx, "WPA %p: sending 2/4\n", ctx );

        return wpa_send_eapol ( iob, ctx, kie );
}

References ctx, io_buffer::data, eapol_key_pkt::datalen, DBGC, EAPOL_KEY_INFO_KEY_ACK, EAPOL_KEY_INFO_KEY_MIC, ENOMEM, eapol_key_pkt::info, iob_put, eapol_key_pkt::keysize, memcpy(), eapol_key_pkt::nonce, wpa_alloc_frame(), and wpa_send_eapol().

Referenced by wpa_handle_1_of_4().

wpa_handle_1_of_4()

static int wpa_handle_1_of_4 ( struct wpa_common_ctx *  ctx, struct eapol_key_pkt *  pkt, int  is_rsn, struct wpa_kie *  kie  )

static

Handle receipt of first frame in 4-Way Handshake.

Parameters

ctx	WPA common context
pkt	EAPOL-Key packet
is_rsn	If TRUE, frame uses new RSN format
kie	Key integrity and encryption handler

Return values

rc	Return status code

Definition at line 512 of file wpa.c.

{
        if ( ctx->state == WPA_WAITING )
                return -EINVAL;

        ctx->state = WPA_WORKING;
        memcpy ( ctx->Anonce, pkt->nonce, sizeof ( ctx->Anonce ) );
        if ( ! ctx->have_Snonce ) {
                rbg_generate ( NULL, 0, 0, ctx->Snonce,
                               sizeof ( ctx->Snonce ) );
                ctx->have_Snonce = 1;
        }

        DBGC ( ctx, "WPA %p: received 1/4, looks OK\n", ctx );

        wpa_derive_ptk ( ctx );

        return wpa_send_2_of_4 ( ctx, pkt, is_rsn, kie );
}

References ctx, DBGC, EINVAL, memcpy(), eapol_key_pkt::nonce, NULL, rbg_generate(), wpa_derive_ptk(), wpa_send_2_of_4(), WPA_WAITING, and WPA_WORKING.

Referenced by eapol_key_rx().

wpa_send_final()

static int wpa_send_final ( struct wpa_common_ctx *  ctx, struct eapol_key_pkt *  pkt, int  is_rsn, struct wpa_kie *  kie  )

static

Send fourth frame in 4-Way Handshake, or second in Group Key Handshake.

Parameters

ctx	WPA common context
pkt	EAPOL-Key packet for frame to which we're replying
is_rsn	If TRUE, frame uses new RSN format
kie	Key integrity and encryption handler

Return values

rc	Return status code

Definition at line 544 of file wpa.c.

{
        struct io_buffer *iob = wpa_alloc_frame ( 0 );
        struct eapol_key_pkt *npkt;

        if ( ! iob )
                return -ENOMEM;

        npkt = iob->data;
        memcpy ( npkt, pkt, sizeof ( *pkt ) );
        npkt->info &= ~( EAPOL_KEY_INFO_KEY_ACK | EAPOL_KEY_INFO_INSTALL |
                         EAPOL_KEY_INFO_KEY_ENC );
        if ( is_rsn )
                npkt->keysize = 0;
        memset ( npkt->nonce, 0, sizeof ( npkt->nonce ) );
        memset ( npkt->iv, 0, sizeof ( npkt->iv ) );
        npkt->datalen = 0;

        if ( npkt->info & EAPOL_KEY_INFO_TYPE )
                DBGC ( ctx, "WPA %p: sending 4/4\n", ctx );
        else
                DBGC ( ctx, "WPA %p: sending 2/2\n", ctx );

        return wpa_send_eapol ( iob, ctx, kie );

}

References ctx, io_buffer::data, eapol_key_pkt::datalen, DBGC, EAPOL_KEY_INFO_INSTALL, EAPOL_KEY_INFO_KEY_ACK, EAPOL_KEY_INFO_KEY_ENC, EAPOL_KEY_INFO_TYPE, ENOMEM, eapol_key_pkt::info, eapol_key_pkt::iv, eapol_key_pkt::keysize, memcpy(), memset(), eapol_key_pkt::nonce, wpa_alloc_frame(), and wpa_send_eapol().

Referenced by wpa_handle_1_of_2(), and wpa_handle_3_of_4().

wpa_handle_3_of_4()

static int wpa_handle_3_of_4 ( struct wpa_common_ctx *  ctx, struct eapol_key_pkt *  pkt, int  is_rsn, struct wpa_kie *  kie  )

static

Handle receipt of third frame in 4-Way Handshake.

Parameters

ctx	WPA common context
pkt	EAPOL-Key packet
is_rsn	If TRUE, frame uses new RSN format
kie	Key integrity and encryption handler

Return values

rc	Return status code

Definition at line 583 of file wpa.c.

{
        int rc;
        u8 *this_rsn, *this_rsn_end;
        u8 *new_rsn, *new_rsn_end;
        int this_is_rsn, new_is_rsn;

        if ( ctx->state == WPA_WAITING )
                return -EINVAL;

        ctx->state = WPA_WORKING;

        /* Check nonce */
        if ( memcmp ( ctx->Anonce, pkt->nonce, WPA_NONCE_LEN ) != 0 ) {
                DBGC ( ctx, "WPA %p ALERT: nonce mismatch in 3/4\n", ctx );
                return wpa_fail ( ctx, -EACCES );
        }

        /* Check RSN IE */
        this_rsn = sec80211_find_rsn ( ( union ieee80211_ie * ) pkt->data,
                                       pkt->data + pkt->datalen,
                                       &this_is_rsn, &this_rsn_end );
        if ( this_rsn )
                new_rsn = sec80211_find_rsn ( ( union ieee80211_ie * )
                                                      this_rsn_end,
                                              pkt->data + pkt->datalen,
                                              &new_is_rsn, &new_rsn_end );
        else
                new_rsn = NULL;

        if ( ! ctx->ap_rsn_ie || ! this_rsn ||
             ctx->ap_rsn_ie_len != ( this_rsn_end - this_rsn ) ||
             ctx->ap_rsn_is_rsn != this_is_rsn ||
             memcmp ( ctx->ap_rsn_ie, this_rsn, ctx->ap_rsn_ie_len ) != 0 ) {
                DBGC ( ctx, "WPA %p ALERT: RSN mismatch in 3/4\n", ctx );
                DBGC2 ( ctx, "WPA %p RSNs (in 3/4, in beacon):\n", ctx );
                DBGC2_HD ( ctx, this_rsn, this_rsn_end - this_rsn );
                DBGC2_HD ( ctx, ctx->ap_rsn_ie, ctx->ap_rsn_ie_len );
                return wpa_fail ( ctx, -EACCES );
        }

        /* Don't switch if they just supplied both styles of IE
           simultaneously; we need two RSN IEs or two WPA IEs to
           switch ciphers. They'll be immediately consecutive because
           of ordering guarantees. */
        if ( new_rsn && this_is_rsn == new_is_rsn ) {
                struct net80211_wlan *assoc = ctx->dev->associating;
                DBGC ( ctx, "WPA %p: accommodating bait-and-switch tactics\n",
                       ctx );
                DBGC2 ( ctx, "WPA %p RSNs (in 3/4+beacon, new in 3/4):\n",
                        ctx );
                DBGC2_HD ( ctx, this_rsn, this_rsn_end - this_rsn );
                DBGC2_HD ( ctx, new_rsn, new_rsn_end - new_rsn );

                if ( ( rc = sec80211_detect_ie ( new_is_rsn, new_rsn,
                                                 new_rsn_end,
                                                 &assoc->handshaking,
                                                 &assoc->crypto ) ) != 0 )
                        DBGC ( ctx, "WPA %p: bait-and-switch invalid, staying "
                               "with original request\n", ctx );
        } else {
                new_rsn = this_rsn;
                new_is_rsn = this_is_rsn;
                new_rsn_end = this_rsn_end;
        }

        /* Grab group cryptosystem ID */
        ctx->gcrypt = sec80211_rsn_get_net80211_crypt ( *( u32 * )
                                                        ( new_rsn + 2 ) );

        /* Check for a GTK, if info field is encrypted */
        if ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) {
                rc = wpa_maybe_install_gtk ( ctx,
                                             ( union ieee80211_ie * ) pkt->data,
                                             pkt->data + pkt->datalen,
                                             pkt->rsc );
                if ( rc < 0 ) {
                        DBGC ( ctx, "WPA %p did not install GTK in 3/4: %s\n",
                               ctx, strerror ( rc ) );
                        if ( rc != -ENOENT )
                                return wpa_fail ( ctx, rc );
                }
        }

        DBGC ( ctx, "WPA %p: received 3/4, looks OK\n", ctx );

        /* Send final message */
        rc = wpa_send_final ( ctx, pkt, is_rsn, kie );
        if ( rc < 0 )
                return wpa_fail ( ctx, rc );

        /* Install PTK */
        rc = wpa_install_ptk ( ctx, pkt->keysize );
        if ( rc < 0 ) {
                DBGC ( ctx, "WPA %p failed to install PTK: %s\n", ctx,
                       strerror ( rc ) );
                return wpa_fail ( ctx, rc );
        }

        /* Mark us as needing a new Snonce if we rekey */
        ctx->have_Snonce = 0;

        /* Done! */
        ctx->state = WPA_SUCCESS;
        return 0;
}

References net80211_wlan::crypto, ctx, eapol_key_pkt::data, eapol_key_pkt::datalen, DBGC, DBGC2, DBGC2_HD, EACCES, EAPOL_KEY_INFO_KEY_ENC, EINVAL, ENOENT, net80211_wlan::handshaking, eapol_key_pkt::info, eapol_key_pkt::keysize, memcmp(), eapol_key_pkt::nonce, NULL, rc, eapol_key_pkt::rsc, sec80211_detect_ie(), sec80211_find_rsn(), sec80211_rsn_get_net80211_crypt(), strerror(), wpa_fail(), wpa_install_ptk(), wpa_maybe_install_gtk(), WPA_NONCE_LEN, wpa_send_final(), WPA_SUCCESS, WPA_WAITING, and WPA_WORKING.

Referenced by eapol_key_rx().

wpa_handle_1_of_2()

static int wpa_handle_1_of_2 ( struct wpa_common_ctx *  ctx, struct eapol_key_pkt *  pkt, int  is_rsn, struct wpa_kie *  kie  )

static

Handle receipt of first frame in Group Key Handshake.

Parameters

ctx	WPA common context
pkt	EAPOL-Key packet
is_rsn	If TRUE, frame uses new RSN format
kie	Key integrity and encryption handler

Return values

rc	Return status code

Definition at line 702 of file wpa.c.

{
        int rc;

        /*
         * WPA and RSN do this completely differently.
         *
         * The idea of encoding the GTK (or PMKID, or various other
         * things) into a KDE that looks like an information element
         * is an RSN innovation; old WPA code never encapsulates
         * things like that. If it looks like an info element, it
         * really is (for the WPA IE check in frames 2/4 and 3/4). The
         * "key data encrypted" bit in the info field is also specific
         * to RSN.
         *
         * So from an old WPA host, 3/4 does not contain an
         * encapsulated GTK. The first frame of the GK handshake
         * contains it, encrypted, but without a KDE wrapper, and with
         * the key ID field (which iPXE doesn't use) shoved away in
         * the reserved bits in the info field, and the TxRx bit
         * stealing the Install bit's spot.
         */

        if ( is_rsn && ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) ) {
                rc = wpa_maybe_install_gtk ( ctx,
                                             ( union ieee80211_ie * ) pkt->data,
                                             pkt->data + pkt->datalen,
                                             pkt->rsc );
                if ( rc < 0 ) {
                        DBGC ( ctx, "WPA %p: failed to install GTK in 1/2: "
                               "%s\n", ctx, strerror ( rc ) );
                        return wpa_fail ( ctx, rc );
                }
        } else {
                rc = kie->decrypt ( &ctx->ptk.kek, pkt->iv, pkt->data,
                                    &pkt->datalen );
                if ( rc < 0 ) {
                        DBGC ( ctx, "WPA %p: failed to decrypt GTK: %s\n",
                               ctx, strerror ( rc ) );
                        return rc; /* non-fatal */
                }
                if ( pkt->datalen > sizeof ( ctx->gtk.tk ) ) {
                        DBGC ( ctx, "WPA %p: too much GTK data (%d > %zd)\n",
                               ctx, pkt->datalen, sizeof ( ctx->gtk.tk ) );
                        return wpa_fail ( ctx, -EINVAL );
                }

                memcpy ( &ctx->gtk.tk, pkt->data, pkt->datalen );
                wpa_install_gtk ( ctx, pkt->datalen, pkt->rsc );
        }

        DBGC ( ctx, "WPA %p: received 1/2, looks OK\n", ctx );

        return wpa_send_final ( ctx, pkt, is_rsn, kie );
}

References ctx, eapol_key_pkt::data, eapol_key_pkt::datalen, DBGC, wpa_kie::decrypt, EAPOL_KEY_INFO_KEY_ENC, EINVAL, eapol_key_pkt::info, eapol_key_pkt::iv, memcpy(), rc, eapol_key_pkt::rsc, strerror(), wpa_fail(), wpa_install_gtk(), wpa_maybe_install_gtk(), and wpa_send_final().

Referenced by eapol_key_rx().

eapol_key_rx()

static int eapol_key_rx ( struct eapol_supplicant *  supplicant, struct io_buffer *  iob, const void *  ll_source  )

static

Handle receipt of EAPOL-Key frame for WPA.

Parameters

supplicant	EAPoL supplicant
iob	I/O buffer
ll_source	Source link-layer address

Definition at line 768 of file wpa.c.

{
        struct net_device *netdev = supplicant->eap.netdev;
        struct net80211_device *dev = net80211_get ( netdev );
        struct eapol_header *eapol;
        struct eapol_key_pkt *pkt;
        int is_rsn, found_ctx;
        struct wpa_common_ctx *ctx;
        int rc = 0;
        struct wpa_kie *kie;
        u8 their_mic[16], our_mic[16];

        eapol = iob->data;
        pkt = ( ( ( void * ) eapol ) + sizeof ( *eapol ) );

        if ( pkt->type != EAPOL_KEY_TYPE_WPA &&
             pkt->type != EAPOL_KEY_TYPE_RSN ) {
                DBG ( "EAPOL-Key: packet not of 802.11 type\n" );
                rc = -EINVAL;
                goto drop;
        }

        is_rsn = ( pkt->type == EAPOL_KEY_TYPE_RSN );

        if ( ! dev ) {
                DBG ( "EAPOL-Key: packet not from 802.11\n" );
                rc = -EINVAL;
                goto drop;
        }

        if ( memcmp ( dev->bssid, ll_source, ETH_ALEN ) != 0 ) {
                DBG ( "EAPOL-Key: packet not from associated AP\n" );
                rc = -EINVAL;
                goto drop;
        }

        if ( ! ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_KEY_ACK ) ) {
                DBG ( "EAPOL-Key: packet sent in wrong direction\n" );
                rc = -EINVAL;
                goto drop;
        }

        found_ctx = 0;
        list_for_each_entry ( ctx, &wpa_contexts, list ) {
                if ( ctx->dev == dev ) {
                        found_ctx = 1;
                        break;
                }
        }

        if ( ! found_ctx ) {
                DBG ( "EAPOL-Key: no WPA context to handle packet for %p\n",
                      dev );
                rc = -ENOENT;
                goto drop;
        }

        if ( ( void * ) ( pkt + 1 ) + ntohs ( pkt->datalen ) > iob->tail ) {
                DBGC ( ctx, "WPA %p: packet truncated (has %zd extra bytes, "
                       "states %d)\n", ctx, iob->tail - ( void * ) ( pkt + 1 ),
                       ntohs ( pkt->datalen ) );
                rc = -EINVAL;
                goto drop;
        }

        /* Get a handle on key integrity/encryption handler */
        kie = wpa_find_kie ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_VERSION );
        if ( ! kie ) {
                DBGC ( ctx, "WPA %p: no support for packet version %d\n", ctx,
                       ntohs ( pkt->info ) & EAPOL_KEY_INFO_VERSION );
                rc = wpa_fail ( ctx, -ENOTSUP );
                goto drop;
        }

        /* Check MIC */
        if ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_KEY_MIC ) {
                memcpy ( their_mic, pkt->mic, sizeof ( pkt->mic ) );
                memset ( pkt->mic, 0, sizeof ( pkt->mic ) );
                kie->mic ( &ctx->ptk.kck, eapol,
                           sizeof ( *eapol ) + sizeof ( *pkt ) +
                           ntohs ( pkt->datalen ), our_mic );
                DBGC2 ( ctx, "WPA %p MIC comparison (theirs, ours):\n", ctx );
                DBGC2_HD ( ctx, their_mic, 16 );
                DBGC2_HD ( ctx, our_mic, 16 );
                if ( memcmp ( their_mic, our_mic, sizeof ( pkt->mic ) ) != 0 ) {
                        DBGC ( ctx, "WPA %p: EAPOL MIC failure\n", ctx );
                        goto drop;
                }
        }

        /* Fix byte order to local */
        pkt->info = ntohs ( pkt->info );
        pkt->keysize = ntohs ( pkt->keysize );
        pkt->datalen = ntohs ( pkt->datalen );
        pkt->replay = be64_to_cpu ( pkt->replay );

        /* Check replay counter */
        if ( ctx->replay != ~0ULL && ctx->replay >= pkt->replay ) {
                DBGC ( ctx, "WPA %p ALERT: Replay detected! "
                       "(%08x:%08x >= %08x:%08x)\n", ctx,
                       ( u32 ) ( ctx->replay >> 32 ), ( u32 ) ctx->replay,
                       ( u32 ) ( pkt->replay >> 32 ), ( u32 ) pkt->replay );
                rc = 0;         /* ignore without error */
                goto drop;
        }
        ctx->replay = pkt->replay;

        /* Decrypt key data */
        if ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) {
                rc = kie->decrypt ( &ctx->ptk.kek, pkt->iv, pkt->data,
                                    &pkt->datalen );
                if ( rc < 0 ) {
                        DBGC ( ctx, "WPA %p: failed to decrypt packet: %s\n",
                               ctx, strerror ( rc ) );
                        goto drop;
                }
        }

        /* Hand it off to appropriate handler */
        switch ( pkt->info & ( EAPOL_KEY_INFO_TYPE |
                               EAPOL_KEY_INFO_KEY_MIC ) ) {
        case EAPOL_KEY_TYPE_PTK:
                rc = wpa_handle_1_of_4 ( ctx, pkt, is_rsn, kie );
                break;

        case EAPOL_KEY_TYPE_PTK | EAPOL_KEY_INFO_KEY_MIC:
                rc = wpa_handle_3_of_4 ( ctx, pkt, is_rsn, kie );
                break;

        case EAPOL_KEY_TYPE_GTK | EAPOL_KEY_INFO_KEY_MIC:
                rc = wpa_handle_1_of_2 ( ctx, pkt, is_rsn, kie );
                break;

        default:
                DBGC ( ctx, "WPA %p: Invalid combination of key flags %04x\n",
                       ctx, pkt->info );
                rc = -EINVAL;
                break;
        }

 drop:
        free_iob ( iob );
        return rc;
}

References be64_to_cpu, net80211_device::bssid, ctx, io_buffer::data, eapol_key_pkt::data, eapol_key_pkt::datalen, DBG, DBGC, DBGC2, DBGC2_HD, wpa_kie::decrypt, eapol_supplicant::eap, EAPOL_KEY_INFO_KEY_ACK, EAPOL_KEY_INFO_KEY_ENC, EAPOL_KEY_INFO_KEY_MIC, EAPOL_KEY_INFO_TYPE, EAPOL_KEY_INFO_VERSION, EAPOL_KEY_TYPE_GTK, EAPOL_KEY_TYPE_PTK, EAPOL_KEY_TYPE_RSN, EAPOL_KEY_TYPE_WPA, EINVAL, ENOENT, ENOTSUP, ETH_ALEN, free_iob(), eapol_key_pkt::info, eapol_key_pkt::iv, eapol_key_pkt::keysize, list_for_each_entry, memcmp(), memcpy(), memset(), eapol_key_pkt::mic, wpa_kie::mic, net80211_get(), netdev, eap_supplicant::netdev, ntohs, rc, eapol_key_pkt::replay, strerror(), io_buffer::tail, eapol_key_pkt::type, wpa_contexts, wpa_fail(), wpa_find_kie(), wpa_handle_1_of_2(), wpa_handle_1_of_4(), and wpa_handle_3_of_4().

REQUIRING_SYMBOL()

REQUIRING_SYMBOL

(

eapol_key_handler

)

REQUIRE_OBJECT()

REQUIRE_OBJECT

(

eapol

)

Variable Documentation

wpa_contexts

struct list_head wpa_contexts = LIST_HEAD_INIT ( wpa_contexts )

List of WPA contexts in active use.

Definition at line 46 of file wpa.c.

Referenced by eapol_key_rx(), wpa_start(), and wpa_stop().

__eapol_handler

struct eapol_handler eapol_key_handler __eapol_handler

Initial value:

= {
        .type = EAPOL_TYPE_KEY,
        .rx = eapol_key_rx,
}

Definition at line 914 of file wpa.c.