/* * Copyright (c) 2009 Joshua Oreman . * * 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 any later version. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ FILE_LICENCE ( GPL2_OR_LATER ); #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** @file * * Handler for the aspects of WPA handshaking that are independent of * 802.1X/PSK or TKIP/CCMP; this mostly involves the 4-Way Handshake. */ /** List of WPA contexts in active use. */ struct list_head wpa_contexts = LIST_HEAD_INIT ( wpa_contexts ); /** * Return an error code and deauthenticate * * @v ctx WPA common context * @v rc Return status code * @ret rc The passed return status code */ static int wpa_fail ( struct wpa_common_ctx *ctx, int rc ) { net80211_deauthenticate ( ctx->dev, rc ); return rc; } /** * Find a cryptosystem handler structure from a crypto ID * * @v crypt Cryptosystem ID * @ret crypto Cryptosystem handler structure * * If support for @a crypt is not compiled in to gPXE, or if @a crypt * is NET80211_CRYPT_UNKNOWN, returns @c NULL. */ static struct net80211_crypto * wpa_find_cryptosystem ( enum net80211_crypto_alg crypt ) { struct net80211_crypto *crypto; for_each_table_entry ( crypto, NET80211_CRYPTOS ) { if ( crypto->algorithm == crypt ) return crypto; } return NULL; } /** * Find WPA key integrity and encryption handler from key version field * * @v ver Version bits of EAPOL-Key info field * @ret kie Key integrity and encryption handler */ struct wpa_kie * wpa_find_kie ( int version ) { struct wpa_kie *kie; for_each_table_entry ( kie, WPA_KIES ) { if ( kie->version == version ) return kie; } return NULL; } /** * Construct RSN or WPA information element * * @v dev 802.11 device * @ret ie_ret RSN or WPA information element * @ret 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 @c dev->associating. * If it is impossible to construct an information element consistent * with gPXE'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 * @a 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. */ int wpa_make_rsn_ie ( struct net80211_device *dev, union ieee80211_ie **ie_ret ) { 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; } /** * Set up generic WPA support to handle 4-Way Handshake * * @v dev 802.11 device * @v ctx WPA common context * @v pmk Pairwise Master Key to use for session * @v pmk_len Length of PMK, almost always 32 * @ret rc Return status code */ int wpa_start ( struct net80211_device *dev, struct wpa_common_ctx *ctx, const void *pmk, size_t pmk_len ) { 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; } /** * Disable handling of received WPA handshake frames * * @v dev 802.11 device */ void wpa_stop ( struct net80211_device *dev ) { 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 ); } } } /** * Derive pairwise transient key * * @v ctx WPA common context */ static void wpa_derive_ptk ( struct wpa_common_ctx *ctx ) { 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, A2 %s\n", ctx, eth_ntoa ( ptk_data.mac1 ), 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 ) ); } /** * Install pairwise transient key * * @v ctx WPA common context * @v len Key length (16 for CCMP, 32 for TKIP) * @ret rc Return status code */ static inline int wpa_install_ptk ( struct wpa_common_ctx *ctx, int len ) { 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 ); } /** * Install group transient key * * @v ctx WPA common context * @v len Key length (16 for CCMP, 32 for TKIP) * @v rsc Receive sequence counter field in EAPOL-Key packet * @ret rc Return status code */ static inline int wpa_install_gtk ( struct wpa_common_ctx *ctx, int len, const void *rsc ) { 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 ); } /** * Search for group transient key, and install it if found * * @v ctx WPA common context * @v ie Pointer to first IE in key data field * @v ie_end Pointer to first byte not in key data field * @v rsc Receive sequence counter field in EAPOL-Key packet * @ret rc Return status code */ static int wpa_maybe_install_gtk ( struct wpa_common_ctx *ctx, union ieee80211_ie *ie, void *ie_end, const void *rsc ) { 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 ); } /** * Allocate I/O buffer for construction of outgoing EAPOL-Key frame * * @v kdlen Maximum number of bytes in the Key Data field * @ret iob Newly allocated I/O buffer * * The returned buffer will have space reserved for the link-layer and * EAPOL headers, and will have @c iob->tail pointing to the start of * the Key Data field. Thus, it is necessary to use iob_put() in * filling the Key Data. */ static struct io_buffer * wpa_alloc_frame ( int kdlen ) { struct io_buffer *ret = alloc_iob ( sizeof ( struct eapol_key_pkt ) + kdlen + EAPOL_HDR_LEN + MAX_LL_HEADER_LEN ); if ( ! ret ) return NULL; iob_reserve ( ret, MAX_LL_HEADER_LEN + EAPOL_HDR_LEN ); memset ( iob_put ( ret, sizeof ( struct eapol_key_pkt ) ), 0, sizeof ( struct eapol_key_pkt ) ); return ret; } /** * Send EAPOL-Key packet * * @v iob I/O buffer, with sufficient headroom for headers * @v dev 802.11 device * @v kie Key integrity and encryption handler * @v is_rsn If TRUE, handshake uses new RSN format * @ret rc Return status code * * If a KIE is specified, the MIC will be filled in before transmission. */ static int wpa_send_eapol ( struct io_buffer *iob, struct wpa_common_ctx *ctx, struct wpa_kie *kie ) { struct eapol_key_pkt *pkt = iob->data; struct eapol_frame *eapol = iob_push ( iob, EAPOL_HDR_LEN ); 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_THIS_VERSION; eapol->type = EAPOL_TYPE_KEY; eapol->length = htons ( iob->tail - iob->data - sizeof ( *eapol ) ); memset ( pkt->mic, 0, sizeof ( pkt->mic ) ); if ( kie ) kie->mic ( &ctx->ptk.kck, eapol, EAPOL_HDR_LEN + sizeof ( *pkt ) + ntohs ( pkt->datalen ), pkt->mic ); return net_tx ( iob, ctx->dev->netdev, &eapol_protocol, ctx->dev->bssid ); } /** * Send second frame in 4-Way Handshake * * @v ctx WPA common context * @v pkt First frame, to which this is a reply * @v is_rsn If TRUE, handshake uses new RSN format * @v kie Key integrity and encryption handler * @ret rc Return status code */ static int wpa_send_2_of_4 ( struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie ) { 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 ); } /** * Handle receipt of first frame in 4-Way Handshake * * @v ctx WPA common context * @v pkt EAPOL-Key packet * @v is_rsn If TRUE, frame uses new RSN format * @v kie Key integrity and encryption handler * @ret rc Return status code */ static int wpa_handle_1_of_4 ( struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie ) { if ( ctx->state == WPA_WAITING ) return -EINVAL; ctx->state = WPA_WORKING; memcpy ( ctx->Anonce, pkt->nonce, sizeof ( ctx->Anonce ) ); if ( ! ctx->have_Snonce ) { get_random_bytes ( 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 ); } /** * Send fourth frame in 4-Way Handshake, or second in Group Key Handshake * * @v ctx WPA common context * @v pkt EAPOL-Key packet for frame to which we're replying * @v is_rsn If TRUE, frame uses new RSN format * @v kie Key integrity and encryption handler * @ret rc Return status code */ static int wpa_send_final ( struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie ) { 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 ); } /** * Handle receipt of third frame in 4-Way Handshake * * @v ctx WPA common context * @v pkt EAPOL-Key packet * @v is_rsn If TRUE, frame uses new RSN format * @v kie Key integrity and encryption handler * @ret rc Return status code */ static int wpa_handle_3_of_4 ( struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie ) { 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; } /** * Handle receipt of first frame in Group Key Handshake * * @v ctx WPA common context * @v pkt EAPOL-Key packet * @v is_rsn If TRUE, frame uses new RSN format * @v kie Key integrity and encryption handler * @ret rc Return status code */ static int wpa_handle_1_of_2 ( struct wpa_common_ctx *ctx, struct eapol_key_pkt *pkt, int is_rsn, struct wpa_kie *kie ) { 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 gPXE 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 ); } /** * Handle receipt of EAPOL-Key frame for WPA * * @v iob I/O buffer * @v netdev Network device * @v ll_source Source link-layer address */ static int eapol_key_rx ( struct io_buffer *iob, struct net_device *netdev, const void *ll_source ) { struct net80211_device *dev = net80211_get ( netdev ); struct eapol_key_pkt *pkt = iob->data; int is_rsn, found_ctx; struct wpa_common_ctx *ctx; int rc = 0; struct wpa_kie *kie; u8 their_mic[16], our_mic[16]; 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, ( void * ) pkt - EAPOL_HDR_LEN, EAPOL_HDR_LEN + 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; } struct eapol_handler eapol_key_handler __eapol_handler = { .type = EAPOL_TYPE_KEY, .rx = eapol_key_rx, }; /* WPA always needs EAPOL in order to be useful */ REQUIRE_OBJECT ( eapol );