/* * * Wireless daemon for Linux * * Copyright (C) 2013-2014 Intel Corporation. All rights reserved. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * */ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include #include #include #include #include #include #include #include "crypto.h" #include "eapol.h" #include "ie.h" #include "util.h" #include "mpdu.h" #include "eap.h" struct l_queue *state_machines; eapol_get_nonce_func_t get_nonce = NULL; eapol_install_tk_func_t install_tk = NULL; eapol_install_gtk_func_t install_gtk = NULL; eapol_deauthenticate_func_t deauthenticate = NULL; eapol_rekey_offload_func_t rekey_offload = NULL; static struct l_io *pae_io; eapol_tx_packet_func_t tx_packet = NULL; void *tx_user_data; /* * BPF filter to match skb->dev->type == 1 (ARPHRD_ETHER) and * match skb->protocol == 0x888e (PAE). */ static struct sock_filter pae_filter[] = { { 0x28, 0, 0, 0xfffff01c }, /* ldh #hatype */ { 0x15, 0, 3, 0x00000001 }, /* jne #1, drop */ { 0x28, 0, 0, 0xfffff000 }, /* ldh #proto */ { 0x15, 0, 1, 0x0000888e }, /* jne #0x888e, drop */ { 0x06, 0, 0, 0xffffffff }, /* ret #-1 */ { 0x06, 0, 0, 0000000000 }, /* drop: ret #0 */ }; static const struct sock_fprog pae_fprog = { .len = 6, .filter = pae_filter }; static struct l_io *pae_open(void) { struct l_io *io; int fd; fd = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, htons(ETH_P_ALL)); if (fd < 0) return NULL; if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &pae_fprog, sizeof(pae_fprog)) < 0) { close(fd); return NULL; } io = l_io_new(fd); l_io_set_close_on_destroy(io, true); return io; } static bool pae_read(struct l_io *io, void *user_data) { int fd = l_io_get_fd(io); struct sockaddr_ll sll; socklen_t sll_len; ssize_t bytes; uint8_t frame[2304]; /* IEEE Std 802.11 ch. 8.2.3 */ memset(&sll, 0, sizeof(sll)); sll_len = sizeof(sll); bytes = recvfrom(fd, frame, sizeof(frame), 0, (struct sockaddr *) &sll, &sll_len); if (bytes <= 0) { l_error("EAPoL read socket: %s", strerror(errno)); return false; } if (sll.sll_halen != ETH_ALEN) return true; __eapol_rx_packet(sll.sll_ifindex, sll.sll_addr, frame, bytes); return true; } static void pae_destroy() { pae_io = NULL; } static void pae_write(uint32_t ifindex, const uint8_t *aa, const uint8_t *spa, const struct eapol_frame *ef) { size_t frame_size; struct sockaddr_ll sll; ssize_t r; int fd; if (!pae_io) { if (tx_packet) /* Used for unit tests */ tx_packet(ifindex, aa, spa, ef, tx_user_data); return; } fd = l_io_get_fd(pae_io); memset(&sll, 0, sizeof(sll)); sll.sll_family = AF_PACKET; sll.sll_ifindex = ifindex; sll.sll_protocol = htons(ETH_P_PAE); sll.sll_halen = ETH_ALEN; memcpy(sll.sll_addr, aa, ETH_ALEN); frame_size = sizeof(struct eapol_header) + L_BE16_TO_CPU(ef->header.packet_len); r = sendto(fd, ef, frame_size, 0, (struct sockaddr *) &sll, sizeof(sll)); if (r < 0) l_error("EAPoL write socket: %s", strerror(errno)); } void eapol_pae_open() { pae_io = pae_open(); if (!pae_io) return; l_io_set_read_handler(pae_io, pae_read, NULL, pae_destroy); } void eapol_pae_close() { l_io_destroy(pae_io); } #define VERIFY_IS_ZERO(field) \ do { \ unsigned int i; \ for (i = 0; i < sizeof(field); i++) \ if ((field)[i] != 0) \ return false; \ } while (false) \ /* * MIC calculation depends on the selected hash function. The has function * is given in the EAPoL Key Descriptor Version field. * * The MIC length is always 16 bytes for currently known Key Descriptor * Versions. * * The input struct eapol_key *frame should have a zero-d MIC field */ bool eapol_calculate_mic(const uint8_t *kck, const struct eapol_key *frame, uint8_t *mic) { size_t frame_len = sizeof(struct eapol_key); frame_len += L_BE16_TO_CPU(frame->key_data_len); switch (frame->key_descriptor_version) { case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4: return hmac_md5(kck, 16, frame, frame_len, mic, 16); case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES: return hmac_sha1(kck, 16, frame, frame_len, mic, 16); case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES: return cmac_aes(kck, 16, frame, frame_len, mic, 16); default: return false; } } bool eapol_verify_mic(const uint8_t *kck, const struct eapol_key *frame) { size_t frame_len = sizeof(struct eapol_key); uint8_t mic[16]; struct iovec iov[3]; struct l_checksum *checksum = NULL; iov[0].iov_base = (void *) frame; iov[0].iov_len = offsetof(struct eapol_key, key_mic_data); memset(mic, 0, sizeof(mic)); iov[1].iov_base = mic; iov[1].iov_len = sizeof(mic); iov[2].iov_base = ((void *) frame) + offsetof(struct eapol_key, key_data_len); iov[2].iov_len = frame_len - offsetof(struct eapol_key, key_data_len) + L_BE16_TO_CPU(frame->key_data_len); switch (frame->key_descriptor_version) { case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4: checksum = l_checksum_new_hmac(L_CHECKSUM_MD5, kck, 16); break; case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES: checksum = l_checksum_new_hmac(L_CHECKSUM_SHA1, kck, 16); break; case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES: checksum = l_checksum_new_cmac_aes(kck, 16); break; default: return false; } if (checksum == NULL) return false; l_checksum_updatev(checksum, iov, 3); l_checksum_get_digest(checksum, mic, 16); l_checksum_free(checksum); if (!memcmp(frame->key_mic_data, mic, 16)) return true; return false; } uint8_t *eapol_decrypt_key_data(const uint8_t *kek, const struct eapol_key *frame, size_t *decrypted_size) { size_t key_data_len = L_BE16_TO_CPU(frame->key_data_len); const uint8_t *key_data = frame->key_data; size_t expected_len; uint8_t *buf; switch (frame->key_descriptor_version) { case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4: expected_len = key_data_len; break; case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES: case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES: expected_len = key_data_len - 8; break; default: return NULL; }; buf = l_new(uint8_t, expected_len); switch (frame->key_descriptor_version) { case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4: { uint8_t key[32]; bool ret; memcpy(key, frame->eapol_key_iv, 16); memcpy(key + 16, kek, 16); ret = arc4_skip(key, 32, 256, key_data, key_data_len, buf); memset(key, 0, sizeof(key)); if (!ret) goto error; break; } case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES: case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES: if (key_data_len < 8 || key_data_len % 8) goto error; if (!aes_unwrap(kek, key_data, key_data_len, buf)) goto error; break; } if (decrypted_size) *decrypted_size = expected_len; return buf; error: l_free(buf); return NULL; } const struct eapol_key *eapol_key_validate(const uint8_t *frame, size_t len) { const struct eapol_key *ek; uint16_t key_data_len; if (len < sizeof(struct eapol_key)) return NULL; ek = (const struct eapol_key *) frame; switch (ek->header.protocol_version) { case EAPOL_PROTOCOL_VERSION_2001: case EAPOL_PROTOCOL_VERSION_2004: break; default: return NULL; } if (ek->header.packet_type != 3) return NULL; switch (ek->descriptor_type) { case EAPOL_DESCRIPTOR_TYPE_RC4: case EAPOL_DESCRIPTOR_TYPE_80211: case EAPOL_DESCRIPTOR_TYPE_WPA: break; default: return NULL; } switch (ek->key_descriptor_version) { case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4: case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES: case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES: break; default: return NULL; } key_data_len = L_BE16_TO_CPU(ek->key_data_len); if (len < sizeof(struct eapol_key) + key_data_len) return NULL; return ek; } #define VERIFY_PTK_COMMON(ek) \ if (!ek->key_type) \ return false; \ if (ek->smk_message) \ return false; \ if (ek->request) \ return false; \ if (ek->error) \ return false \ bool eapol_verify_ptk_1_of_4(const struct eapol_key *ek) { /* Verify according to 802.11, Section 11.6.6.2 */ VERIFY_PTK_COMMON(ek); if (ek->install) return false; if (!ek->key_ack) return false; if (ek->key_mic) return false; if (ek->secure) return false; if (ek->encrypted_key_data) return false; if (ek->wpa_key_id) return false; VERIFY_IS_ZERO(ek->eapol_key_iv); VERIFY_IS_ZERO(ek->key_rsc); VERIFY_IS_ZERO(ek->reserved); VERIFY_IS_ZERO(ek->key_mic_data); return true; } bool eapol_verify_ptk_2_of_4(const struct eapol_key *ek) { uint16_t key_len; /* Verify according to 802.11, Section 11.6.6.3 */ VERIFY_PTK_COMMON(ek); if (ek->install) return false; if (ek->key_ack) return false; if (!ek->key_mic) return false; if (ek->secure) return false; if (ek->encrypted_key_data) return false; if (ek->wpa_key_id) return false; key_len = L_BE16_TO_CPU(ek->key_length); if (key_len != 0) return false; VERIFY_IS_ZERO(ek->eapol_key_iv); VERIFY_IS_ZERO(ek->key_rsc); VERIFY_IS_ZERO(ek->reserved); return true; } bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek, bool is_wpa) { uint16_t key_len; /* Verify according to 802.11, Section 11.6.6.4 */ VERIFY_PTK_COMMON(ek); /* * TODO: Handle cases where install might be 0: * For PTK generation, 0 only if the AP does not support key mapping * keys, or if the STA has the No Pairwise bit (in the RSN Capabilities * field) equal to 1 and only the group key is used. */ if (!ek->install) return false; if (!ek->key_ack) return false; if (!ek->key_mic) return false; if (ek->secure != !is_wpa) return false; /* Must be encrypted when GTK is present but reserved in WPA */ if (!ek->encrypted_key_data && !is_wpa) return false; if (ek->wpa_key_id) return false; key_len = L_BE16_TO_CPU(ek->key_length); if (key_len != 16 && key_len != 32) return false; VERIFY_IS_ZERO(ek->reserved); /* 0 (Version 2) or random (Version 1) */ if (ek->key_descriptor_version == EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES) VERIFY_IS_ZERO(ek->eapol_key_iv); return true; } bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek, bool is_wpa) { uint16_t key_len; /* Verify according to 802.11, Section 11.6.6.5 */ VERIFY_PTK_COMMON(ek); if (ek->install) return false; if (ek->key_ack) return false; if (!ek->key_mic) return false; if (ek->secure != !is_wpa) return false; if (ek->encrypted_key_data) return false; if (ek->wpa_key_id) return false; key_len = L_BE16_TO_CPU(ek->key_length); if (key_len != 0) return false; VERIFY_IS_ZERO(ek->key_nonce); VERIFY_IS_ZERO(ek->eapol_key_iv); VERIFY_IS_ZERO(ek->key_rsc); VERIFY_IS_ZERO(ek->reserved); return true; } #define VERIFY_GTK_COMMON(ek) \ if (ek->key_type) \ return false; \ if (ek->smk_message) \ return false; \ if (ek->request) \ return false; \ if (ek->error) \ return false; \ if (ek->install) \ return false \ bool eapol_verify_gtk_1_of_2(const struct eapol_key *ek, bool is_wpa) { uint16_t key_len; VERIFY_GTK_COMMON(ek); if (!ek->key_ack) return false; if (!ek->key_mic) return false; if (!ek->secure) return false; /* Must be encrypted when GTK is present but reserved in WPA */ if (!ek->encrypted_key_data && !is_wpa) return false; key_len = L_BE16_TO_CPU(ek->key_length); if (key_len == 0) return false; VERIFY_IS_ZERO(ek->reserved); /* 0 (Version 2) or random (Version 1) */ if (ek->key_descriptor_version == EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES) VERIFY_IS_ZERO(ek->eapol_key_iv); /* * WPA_80211_v3_1, Section 2.2.4: * "Key Index (bits 4 and 5): specifies the key id of the temporal * key of the key derived from the message. The value of this shall be * zero (0) if the value of Key Type (bit 4) is Pairwise (1). The Key * Type and Key Index shall not both be 0 in the same message. * * Group keys shall not use key id 0. This means that key ids 1 to 3 * are available to be used to identify Group keys. This document * recommends that implementations reserve key ids 1 and 2 for Group * Keys, and that key id 3 is not used. */ if (is_wpa && !ek->wpa_key_id) return false; return true; } bool eapol_verify_gtk_2_of_2(const struct eapol_key *ek, bool is_wpa) { uint16_t key_len; /* Verify according to 802.11, Section 11.6.7.3 */ VERIFY_GTK_COMMON(ek); if (ek->key_ack) return false; if (!ek->key_mic) return false; if (!ek->secure) return false; if (ek->encrypted_key_data) return false; key_len = L_BE16_TO_CPU(ek->key_length); if (key_len != 0) return false; VERIFY_IS_ZERO(ek->key_nonce); VERIFY_IS_ZERO(ek->eapol_key_iv); VERIFY_IS_ZERO(ek->key_rsc); VERIFY_IS_ZERO(ek->reserved); return true; } static struct eapol_key *eapol_create_common( enum eapol_protocol_version protocol, enum eapol_key_descriptor_version version, bool secure, uint64_t key_replay_counter, const uint8_t snonce[], size_t extra_len, const uint8_t *extra_data, int key_type, bool is_wpa) { size_t to_alloc = sizeof(struct eapol_key); struct eapol_key *out_frame = l_malloc(to_alloc + extra_len); memset(out_frame, 0, to_alloc + extra_len); out_frame->header.protocol_version = protocol; out_frame->header.packet_type = 0x3; out_frame->header.packet_len = L_CPU_TO_BE16(to_alloc + extra_len - 4); out_frame->descriptor_type = is_wpa ? EAPOL_DESCRIPTOR_TYPE_WPA : EAPOL_DESCRIPTOR_TYPE_80211; out_frame->key_descriptor_version = version; out_frame->key_type = key_type; out_frame->install = false; out_frame->key_ack = false; out_frame->key_mic = true; out_frame->secure = secure; out_frame->error = false; out_frame->request = false; out_frame->encrypted_key_data = false; out_frame->smk_message = false; out_frame->key_length = 0; out_frame->key_replay_counter = L_CPU_TO_BE64(key_replay_counter); memcpy(out_frame->key_nonce, snonce, sizeof(out_frame->key_nonce)); out_frame->key_data_len = L_CPU_TO_BE16(extra_len); memcpy(out_frame->key_data, extra_data, extra_len); return out_frame; } struct eapol_key *eapol_create_ptk_2_of_4( enum eapol_protocol_version protocol, enum eapol_key_descriptor_version version, uint64_t key_replay_counter, const uint8_t snonce[], size_t extra_len, const uint8_t *extra_data, bool is_wpa) { return eapol_create_common(protocol, version, false, key_replay_counter, snonce, extra_len, extra_data, 1, is_wpa); } struct eapol_key *eapol_create_ptk_4_of_4( enum eapol_protocol_version protocol, enum eapol_key_descriptor_version version, uint64_t key_replay_counter, bool is_wpa) { uint8_t snonce[32]; memset(snonce, 0, sizeof(snonce)); return eapol_create_common(protocol, version, is_wpa ? false : true, key_replay_counter, snonce, 0, NULL, 1, is_wpa); } struct eapol_key *eapol_create_gtk_2_of_2( enum eapol_protocol_version protocol, enum eapol_key_descriptor_version version, uint64_t key_replay_counter, bool is_wpa, uint8_t wpa_key_id) { uint8_t snonce[32]; struct eapol_key *step2; memset(snonce, 0, sizeof(snonce)); step2 = eapol_create_common(protocol, version, true, key_replay_counter, snonce, 0, NULL, 0, is_wpa); if (!step2) return step2; /* * WPA_80211_v3_1, Section 2.2.4: * "The Key Type and Key Index shall not both be 0 in the same message" * * The above means that even though sending the key index back to the * AP has no practical value, we must still do so. */ if (is_wpa) step2->wpa_key_id = wpa_key_id; return step2; } struct eapol_sm { enum eapol_protocol_version protocol_version; uint32_t ifindex; uint8_t spa[6]; uint8_t aa[6]; uint8_t *ap_ie; uint8_t *own_ie; enum ie_rsn_cipher_suite pairwise_cipher; enum ie_rsn_cipher_suite group_cipher; enum ie_rsn_akm_suite akm_suite; uint8_t pmk[32]; uint64_t replay_counter; uint8_t snonce[32]; uint8_t anonce[32]; uint8_t ptk[64]; eapol_sm_event_func_t event_func; void *user_data; struct l_timeout *timeout; struct l_timeout *eapol_start_timeout; bool have_snonce:1; bool have_replay:1; bool ptk_complete:1; bool wpa_ie:1; bool have_pmk:1; bool use_eapol_start:1; struct eap_state *eap; }; static void eapol_sm_destroy(void *value) { struct eapol_sm *sm = value; l_free(sm->ap_ie); l_free(sm->own_ie); l_timeout_remove(sm->timeout); l_timeout_remove(sm->eapol_start_timeout); if (sm->eap) eap_free(sm->eap); l_free(sm); } struct eapol_sm *eapol_sm_new() { struct eapol_sm *sm; sm = l_new(struct eapol_sm, 1); return sm; } void eapol_sm_free(struct eapol_sm *sm) { eapol_sm_destroy(sm); } void eapol_sm_set_protocol_version(struct eapol_sm *sm, enum eapol_protocol_version protocol_version) { sm->protocol_version = protocol_version; } void eapol_sm_set_supplicant_address(struct eapol_sm *sm, const uint8_t *spa) { memcpy(sm->spa, spa, sizeof(sm->spa)); } void eapol_sm_set_authenticator_address(struct eapol_sm *sm, const uint8_t *aa) { memcpy(sm->aa, aa, sizeof(sm->aa)); } void eapol_sm_set_pmk(struct eapol_sm *sm, const uint8_t *pmk) { memcpy(sm->pmk, pmk, sizeof(sm->pmk)); sm->have_pmk = true; } static void eapol_sm_set_ap_ie(struct eapol_sm *sm, const uint8_t *ie, size_t len, bool is_wpa) { if (ie[1] + 2u != len) return; l_free(sm->ap_ie); sm->ap_ie = l_memdup(ie, len); sm->wpa_ie = is_wpa; } static void eapol_sm_set_own_ie(struct eapol_sm *sm, const uint8_t *ie, size_t len, bool is_wpa) { if (ie[1] + 2u != len) return; l_free(sm->own_ie); sm->own_ie = l_memdup(ie, len); sm->wpa_ie = is_wpa; } void eapol_sm_set_ap_rsn(struct eapol_sm *sm, const uint8_t *rsn_ie, size_t len) { eapol_sm_set_ap_ie(sm, rsn_ie, len, false); } static bool eapol_sm_setup_own_ciphers(struct eapol_sm *sm, const struct ie_rsn_info *info) { if (__builtin_popcount(info->pairwise_ciphers) != 1) return false; if (__builtin_popcount(info->akm_suites) != 1) return false; sm->akm_suite = info->akm_suites; sm->pairwise_cipher = info->pairwise_ciphers; sm->group_cipher = info->group_cipher; return true; } bool eapol_sm_set_own_rsn(struct eapol_sm *sm, const uint8_t *rsn_ie, size_t len) { struct ie_rsn_info info; eapol_sm_set_own_ie(sm, rsn_ie, len, false); if (ie_parse_rsne_from_data(rsn_ie, rsn_ie[1] + 2, &info) < 0) return false; return eapol_sm_setup_own_ciphers(sm, &info); } void eapol_sm_set_ap_wpa(struct eapol_sm *sm, const uint8_t *wpa_ie, size_t len) { eapol_sm_set_ap_ie(sm, wpa_ie, len, true); } bool eapol_sm_set_own_wpa(struct eapol_sm *sm, const uint8_t *wpa_ie, size_t len) { struct ie_rsn_info info; eapol_sm_set_own_ie(sm, wpa_ie, len, true); if (ie_parse_wpa_from_data(wpa_ie, wpa_ie[1] + 2, &info) < 0) return false; return eapol_sm_setup_own_ciphers(sm, &info); } void eapol_sm_set_user_data(struct eapol_sm *sm, void *user_data) { sm->user_data = user_data; } void eapol_sm_set_event_func(struct eapol_sm *sm, eapol_sm_event_func_t func) { sm->event_func = func; } uint32_t eapol_sm_get_pairwise_cipher(struct eapol_sm *sm) { return sm->pairwise_cipher; } uint32_t eapol_sm_get_group_cipher(struct eapol_sm *sm) { return sm->group_cipher; } const uint8_t *eapol_sm_get_own_ie(struct eapol_sm *sm, size_t *out_ie_len) { if (!sm->own_ie) return NULL; *out_ie_len = sm->own_ie[1] + 2; return sm->own_ie; } static bool eapol_sm_ifindex_match(void *data, void *user_data) { struct eapol_sm *sm = data; uint32_t ifindex = L_PTR_TO_UINT(user_data); if (sm->ifindex != ifindex) return false; eapol_sm_free(sm); return true; } static inline void handshake_failed(uint32_t ifindex, struct eapol_sm *sm, uint16_t reason_code) { if (deauthenticate) deauthenticate(ifindex, sm->aa, sm->spa, reason_code, sm->user_data); l_queue_remove(state_machines, sm); eapol_sm_free(sm); } static void eapol_timeout(struct l_timeout *timeout, void *user_data) { struct eapol_sm *sm = user_data; handshake_failed(sm->ifindex, sm, MPDU_REASON_CODE_4WAY_HANDSHAKE_TIMEOUT); } static void send_eapol_start(struct l_timeout *timeout, void *user_data) { struct eapol_sm *sm = user_data; uint8_t buf[sizeof(struct eapol_frame)]; struct eapol_frame *frame = (struct eapol_frame *) buf; l_timeout_remove(sm->eapol_start_timeout); sm->eapol_start_timeout = NULL; frame->header.protocol_version = sm->protocol_version; frame->header.packet_type = 1; l_put_be16(0, &frame->header.packet_len); pae_write(sm->ifindex, sm->aa, sm->spa, frame); } static void eapol_handle_ptk_1_of_4(uint32_t ifindex, struct eapol_sm *sm, const struct eapol_key *ek) { struct crypto_ptk *ptk = (struct crypto_ptk *) sm->ptk; struct eapol_key *step2; uint8_t mic[16]; bool use_sha256; enum crypto_cipher cipher; size_t ptk_size; if (!eapol_verify_ptk_1_of_4(ek)) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } if (!get_nonce(sm->snonce)) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } sm->have_snonce = true; sm->ptk_complete = false; memcpy(sm->anonce, ek->key_nonce, sizeof(ek->key_nonce)); if (sm->akm_suite == IE_RSN_AKM_SUITE_8021X_SHA256 || sm->akm_suite == IE_RSN_AKM_SUITE_PSK_SHA256) use_sha256 = true; else use_sha256 = false; cipher = ie_rsn_cipher_suite_to_cipher(sm->pairwise_cipher); ptk_size = sizeof(struct crypto_ptk) + crypto_cipher_key_len(cipher); crypto_derive_pairwise_ptk(sm->pmk, sm->spa, sm->aa, sm->anonce, sm->snonce, ptk, ptk_size, use_sha256); step2 = eapol_create_ptk_2_of_4(sm->protocol_version, ek->key_descriptor_version, sm->replay_counter, sm->snonce, sm->own_ie[1] + 2, sm->own_ie, sm->wpa_ie); if (!eapol_calculate_mic(ptk->kck, step2, mic)) { l_info("MIC calculation failed. " "Ensure Kernel Crypto is available."); l_free(step2); handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } memcpy(step2->key_mic_data, mic, sizeof(mic)); pae_write(sm->ifindex, sm->aa, sm->spa, (struct eapol_frame *) step2); l_free(step2); l_timeout_remove(sm->timeout); sm->timeout = NULL; } static const uint8_t *eapol_find_gtk_kde(const uint8_t *data, size_t data_len, size_t *out_gtk_len) { static const unsigned char gtk_oui[] = { 0x00, 0x0f, 0xac, 0x01 }; struct ie_tlv_iter iter; const uint8_t *gtk; unsigned int len; ie_tlv_iter_init(&iter, data, data_len); while (ie_tlv_iter_next(&iter)) { if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_VENDOR_SPECIFIC) continue; len = ie_tlv_iter_get_length(&iter); if (len < 4) /* Take care of padding */ return NULL; /* Check OUI */ gtk = ie_tlv_iter_get_data(&iter); if (memcmp(gtk, gtk_oui, 4)) continue; if (out_gtk_len) *out_gtk_len = len - 4; return gtk + 4; } return NULL; } static const uint8_t *eapol_find_rsne(const uint8_t *data, size_t data_len, const uint8_t **optional) { struct ie_tlv_iter iter; const uint8_t *first = NULL; ie_tlv_iter_init(&iter, data, data_len); while (ie_tlv_iter_next(&iter)) { if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_RSN) continue; if (!first) { first = ie_tlv_iter_get_data(&iter) - 2; continue; } if (optional) *optional = ie_tlv_iter_get_data(&iter) - 2; return first; } return first; } static const uint8_t *eapol_find_wpa_ie(const uint8_t *data, size_t data_len) { struct ie_tlv_iter iter; ie_tlv_iter_init(&iter, data, data_len); while (ie_tlv_iter_next(&iter)) { if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_VENDOR_SPECIFIC) continue; if (is_ie_wpa_ie(ie_tlv_iter_get_data(&iter), ie_tlv_iter_get_length(&iter))) return ie_tlv_iter_get_data(&iter) - 2; } return NULL; } /* * This function performs a match of the RSN/WPA IE obtained from the scan * results vs the RSN/WPA IE obtained as part of the 4-way handshake. If they * don't match, the EAPoL packet must be silently discarded. */ static bool eapol_ap_ie_matches(const uint8_t *eapol_ie, const uint8_t *scan_ie, bool is_wpa) { struct ie_rsn_info eapol_info; struct ie_rsn_info scan_info; /* * First check that the sizes match, if they do, run a bitwise * comparison. */ if (eapol_ie[1] == scan_ie[1] && !memcmp(eapol_ie + 2, scan_ie + 2, eapol_ie[1])) return true; /* * Otherwise we have to parse the IEs and compare the individual * fields */ if (!is_wpa) { if (ie_parse_rsne_from_data(eapol_ie, eapol_ie[1] + 2, &eapol_info) < 0) return false; if (ie_parse_rsne_from_data(scan_ie, scan_ie[1] + 2, &scan_info) < 0) return false; } else { if (ie_parse_wpa_from_data(eapol_ie, eapol_ie[1] + 2, &eapol_info) < 0) return false; if (ie_parse_wpa_from_data(scan_ie, scan_ie[1] + 2, &scan_info) < 0) return false; } if (eapol_info.group_cipher != scan_info.group_cipher) return false; if (eapol_info.pairwise_ciphers != scan_info.pairwise_ciphers) return false; if (eapol_info.akm_suites != scan_info.akm_suites) return false; if (eapol_info.preauthentication != scan_info.preauthentication) return false; if (eapol_info.no_pairwise != scan_info.no_pairwise) return false; if (eapol_info.ptksa_replay_counter != scan_info.ptksa_replay_counter) return false; if (eapol_info.gtksa_replay_counter != scan_info.gtksa_replay_counter) return false; if (eapol_info.mfpr != scan_info.mfpr) return false; if (eapol_info.mfpc != scan_info.mfpc) return false; if (eapol_info.peerkey_enabled != scan_info.peerkey_enabled) return false; if (eapol_info.spp_a_msdu_capable != scan_info.spp_a_msdu_capable) return false; if (eapol_info.spp_a_msdu_required != scan_info.spp_a_msdu_required) return false; if (eapol_info.pbac != scan_info.pbac) return false; if (eapol_info.extended_key_id != scan_info.extended_key_id) return false; /* We don't check the PMKIDs since these might actually be different */ if (eapol_info.group_management_cipher != scan_info.group_management_cipher) return false; return true; } static void eapol_handle_ptk_3_of_4(uint32_t ifindex, struct eapol_sm *sm, const struct eapol_key *ek, const uint8_t *decrypted_key_data, size_t decrypted_key_data_size) { struct crypto_ptk *ptk = (struct crypto_ptk *) sm->ptk; struct eapol_key *step4; uint8_t mic[16]; const uint8_t *gtk; size_t gtk_len; const uint8_t *rsne; const uint8_t *optional_rsne = NULL; uint8_t gtk_key_index; enum ie_rsn_cipher_suite pairwise = sm->pairwise_cipher; if (!eapol_verify_ptk_3_of_4(ek, sm->wpa_ie)) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } /* * 11.6.6.4: "On reception of Message 3, the Supplicant silently * discards the message if ... or if the ANonce value in Message 3 * differs from the ANonce value in Message 1" */ if (memcmp(sm->anonce, ek->key_nonce, sizeof(ek->key_nonce))) return; /* * 11.6.6.4: "Verifies the RSNE. If it is part of a Fast BSS Transition * Initial Mobility Domain Association, see 12.4.2. Otherwise, if it is * not identical to that the STA received in the Beacon or Probe * Response frame, the STA shall disassociate. */ if (!sm->wpa_ie) rsne = eapol_find_rsne(decrypted_key_data, decrypted_key_data_size, &optional_rsne); else rsne = eapol_find_wpa_ie(decrypted_key_data, decrypted_key_data_size); if (!rsne) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT); return; } if (!eapol_ap_ie_matches(rsne, sm->ap_ie, sm->wpa_ie)) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT); return; } /* * 11.6.6.4: "If a second RSNE is provided in the message, the * Supplicant uses the pairwise cipher suite specified in the second * RSNE or deauthenticates." */ if (optional_rsne) { struct ie_rsn_info info1; struct ie_rsn_info info2; uint16_t override; if (ie_parse_rsne_from_data(rsne, rsne[1] + 2, &info1) < 0) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT); return; } if (ie_parse_rsne_from_data(optional_rsne, optional_rsne[1] + 2, &info2) < 0) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT); return; } /* * 11.6.2: * It may happen, for example, that a Supplicant selects a * pairwise cipher suite which is advertised by an AP, but * which policy disallows for this particular STA. An * Authenticator may, therefore, insert a second RSNE to * overrule the STA’s selection. An Authenticator’s SME shall * insert the second RSNE, after the first RSNE, only for this * purpose. The pairwise cipher suite in the second RSNE * included shall be one of the ciphers advertised by the * Authenticator. All other fields in the second RSNE shall be * identical to the first RSNE. * * - Check that akm_suites and group_cipher are the same * between rsne1 and rsne2 * - Check that pairwise_ciphers is not the same between rsne1 * and rsne2 * - Check that rsne2 pairwise_ciphers is a subset of rsne */ if (info1.akm_suites != info2.akm_suites || info1.group_cipher != info2.group_cipher) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT); return; } override = info2.pairwise_ciphers; if (override == info1.pairwise_ciphers || !(info1.pairwise_ciphers & override) || __builtin_popcount(override) != 1) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_INVALID_PAIRWISE_CIPHER); return; } pairwise = override; } /* * TODO: Handle IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC case */ if (!sm->wpa_ie) { gtk = eapol_find_gtk_kde(decrypted_key_data, decrypted_key_data_size, >k_len); if (!gtk || gtk_len < 8) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } /* TODO: Handle tx bit */ gtk_key_index = util_bit_field(gtk[0], 0, 2); gtk += 2; gtk_len -= 2; } else gtk = NULL; step4 = eapol_create_ptk_4_of_4(sm->protocol_version, ek->key_descriptor_version, sm->replay_counter, sm->wpa_ie); /* * 802.11-2012, Section 11.6.6.4, step b): * Verifies the Message 3 MIC. If the calculated MIC does not match * the MIC that the Authenticator included in the EAPOL-Key frame, * the Supplicant silently discards Message 3. */ if (!eapol_calculate_mic(ptk->kck, step4, mic)) goto fail; memcpy(step4->key_mic_data, mic, sizeof(mic)); pae_write(sm->ifindex, sm->aa, sm->spa, (struct eapol_frame *) step4); sm->ptk_complete = true; if (install_tk) { uint32_t cipher = ie_rsn_cipher_suite_to_cipher(pairwise); install_tk(sm->ifindex, sm->aa, ptk->tk, cipher, sm->user_data); } if (gtk && install_gtk) { uint32_t cipher = ie_rsn_cipher_suite_to_cipher(sm->group_cipher); install_gtk(sm->ifindex, gtk_key_index, gtk, gtk_len, ek->key_rsc, 6, cipher, sm->user_data); } if (rekey_offload) rekey_offload(sm->ifindex, ptk->kek, ptk->kck, sm->replay_counter, sm->user_data); fail: l_free(step4); } static void eapol_handle_gtk_1_of_2(uint32_t ifindex, struct eapol_sm *sm, const struct eapol_key *ek, const uint8_t *decrypted_key_data, size_t decrypted_key_data_size) { struct crypto_ptk *ptk = (struct crypto_ptk *) sm->ptk; struct eapol_key *step2; uint8_t mic[16]; const uint8_t *gtk; size_t gtk_len; uint8_t gtk_key_index; if (!eapol_verify_gtk_1_of_2(ek, sm->wpa_ie)) { handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED); return; } if (!sm->wpa_ie) { gtk = eapol_find_gtk_kde(decrypted_key_data, decrypted_key_data_size, >k_len); if (!gtk || gtk_len < 8) return; } else { gtk = decrypted_key_data; gtk_len = decrypted_key_data_size; if (!gtk || gtk_len < 6) return; } if (!sm->wpa_ie) { gtk_key_index = util_bit_field(gtk[0], 0, 2); gtk += 2; gtk_len -= 2; } else gtk_key_index = ek->wpa_key_id; step2 = eapol_create_gtk_2_of_2(sm->protocol_version, ek->key_descriptor_version, sm->replay_counter, sm->wpa_ie, ek->wpa_key_id); /* * 802.11-2012, Section 11.6.7.3, step b): * Verifies that the MIC is valid, i.e., it uses the KCK that is * part of the PTK to verify that there is no data integrity error. */ ptk = (struct crypto_ptk *) sm->ptk; if (!eapol_calculate_mic(ptk->kck, step2, mic)) goto done; memcpy(step2->key_mic_data, mic, sizeof(mic)); pae_write(sm->ifindex, sm->aa, sm->spa, (struct eapol_frame *) step2); if (install_gtk) { uint32_t cipher = ie_rsn_cipher_suite_to_cipher(sm->group_cipher); install_gtk(sm->ifindex, gtk_key_index, gtk, gtk_len, ek->key_rsc, 6, cipher, sm->user_data); } done: l_free(step2); } static struct eapol_sm *eapol_find_sm(uint32_t ifindex, const uint8_t *aa) { const struct l_queue_entry *entry; struct eapol_sm *sm; for (entry = l_queue_get_entries(state_machines); entry; entry = entry->next) { sm = entry->data; if (sm->ifindex != ifindex) continue; if (memcmp(sm->aa, aa, ETH_ALEN)) continue; return sm; } return NULL; } static void eapol_key_handle(struct eapol_sm *sm, uint32_t ifindex, const uint8_t *frame, size_t len) { const struct eapol_key *ek; struct crypto_ptk *ptk; uint8_t *decrypted_key_data = NULL; size_t key_data_len = 0; uint64_t replay_counter; ek = eapol_key_validate(frame, len); if (!ek) return; /* Wrong direction */ if (!ek->key_ack) return; /* Further Descriptor Type check */ if (!sm->wpa_ie && ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_80211) return; else if (sm->wpa_ie && ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_WPA) return; replay_counter = L_BE64_TO_CPU(ek->key_replay_counter); /* * 11.6.6.2: "If the Key Replay Counter field value is less than or * equal to the current local value, the Supplicant discards the * message. * * 11.6.6.4: "On reception of Message 3, the Supplicant silently * discards the message if the Key Replay Counter field value has * already been used... */ if (sm->have_replay && sm->replay_counter >= replay_counter) return; sm->replay_counter = replay_counter; sm->have_replay = true; ptk = (struct crypto_ptk *) sm->ptk; if (ek->key_mic) { /* Haven't received step 1 yet, so no ptk */ if (!sm->have_snonce) return; if (!eapol_verify_mic(ptk->kck, ek)) return; } if ((ek->encrypted_key_data && !sm->wpa_ie) || (ek->key_type == 0 && sm->wpa_ie)) { /* Haven't received step 1 yet, so no ptk */ if (!sm->have_snonce) return; decrypted_key_data = eapol_decrypt_key_data(ptk->kek, ek, &key_data_len); if (!decrypted_key_data) return; } else key_data_len = L_BE16_TO_CPU(ek->key_data_len); if (ek->key_type == 0) { /* Only GTK handshake allowed after PTK handshake complete */ if (!sm->ptk_complete) goto done; if (!decrypted_key_data) goto done; eapol_handle_gtk_1_of_2(ifindex, sm, ek, decrypted_key_data, key_data_len); goto done; } /* If no MIC, then assume packet 1, otherwise packet 3 */ if (!ek->key_mic) eapol_handle_ptk_1_of_4(ifindex, sm, ek); else { if (sm->ptk_complete) goto done; if (!key_data_len) goto done; eapol_handle_ptk_3_of_4(ifindex, sm, ek, decrypted_key_data ?: ek->key_data, key_data_len); } done: l_free(decrypted_key_data); } /* This respresentes the eapMsg message in 802.1X Figure 8-1 */ static void eapol_eap_msg_cb(const uint8_t *eap_data, size_t len, void *user_data) { struct eapol_sm *sm = user_data; uint8_t buf[sizeof(struct eapol_frame) + len]; struct eapol_frame *frame = (struct eapol_frame *) buf; frame->header.protocol_version = sm->protocol_version; frame->header.packet_type = 0; l_put_be16(len, &frame->header.packet_len); memcpy(frame->data, eap_data, len); pae_write(sm->ifindex, sm->aa, sm->spa, frame); } /* This respresentes the eapTimout, eapFail and eapSuccess messages */ static void eapol_eap_complete_cb(enum eap_result result, void *user_data) { struct eapol_sm *sm = user_data; l_info("EAP completed with %s", result == EAP_RESULT_SUCCESS ? "eapSuccess" : (result == EAP_RESULT_FAIL ? "eapFail" : "eapTimeout")); eap_free(sm->eap); sm->eap = NULL; if (result != EAP_RESULT_SUCCESS) handshake_failed(sm->ifindex, sm, MPDU_REASON_CODE_IEEE8021X_FAILED); } /* This respresentes the eapResults message */ static void eapol_eap_results_cb(const uint8_t *msk_data, size_t msk_len, const uint8_t *emsk_data, size_t emsk_len, const uint8_t *iv, size_t iv_len, void *user_data) { struct eapol_sm *sm = user_data; l_debug("EAP key material received"); /* * 802.11i 8.5.1.2: * "When not using a PSK, the PMK is derived from the AAA key. * The PMK shall be computed as the first 256 bits (bits 0–255) * of the AAA key: PMK ← L(PTK, 0, 256)." * 802.11 11.6.1.3: * "When not using a PSK, the PMK is derived from the MSK. * The PMK shall be computed as the first 256 bits (bits 0–255) * of the MSK: PMK ← L(MSK, 0, 256)." * RFC5247 explains AAA-Key refers to the MSK and confirms the * first 32 bytes of the MSK are used. MSK is at least 64 octets * long per RFC3748. Note WEP derives the PTK from MSK differently. * * In a Fast Transition initial mobility domain association the PMK * maps to the XXKey except with EAP: * 802.11 11.6.1.7.3: * "If the AKM negotiated is 00-0F-AC:3, then XXKey shall be the * second 256 bits of the MSK (which is derived from the IEEE * 802.1X authentication), i.e., XXKey = L(MSK, 256, 256)." */ if (sm->akm_suite == IE_RSN_AKM_SUITE_FT_OVER_8021X) eapol_sm_set_pmk(sm, msk_data + 32); else eapol_sm_set_pmk(sm, msk_data); } static void eapol_eap_event_cb(unsigned int event, const void *event_data, void *user_data) { struct eapol_sm *sm = user_data; if (!sm->event_func) return; sm->event_func(event, event_data, sm->user_data); } void eapol_sm_set_8021x_config(struct eapol_sm *sm, struct l_settings *settings) { sm->eap = eap_new(eapol_eap_msg_cb, eapol_eap_complete_cb, sm); if (!sm->eap) return; if (!eap_load_settings(sm->eap, settings, "EAP-")) return; eap_set_key_material_func(sm->eap, eapol_eap_results_cb); eap_set_event_func(sm->eap, eapol_eap_event_cb); } void eapol_sm_set_use_eapol_start(struct eapol_sm *sm, bool enabled) { sm->use_eapol_start = enabled; } static void eapol_rx_packet(struct eapol_sm *sm, const uint8_t *frame, size_t len) { const struct eapol_header *eh; /* Validate Header */ if (len < sizeof(struct eapol_header)) return; eh = (const struct eapol_header *) frame; switch (eh->protocol_version) { case EAPOL_PROTOCOL_VERSION_2001: case EAPOL_PROTOCOL_VERSION_2004: break; default: return; } if (len < (size_t) 4 + L_BE16_TO_CPU(eh->packet_len)) return; if (!sm->protocol_version) sm->protocol_version = eh->protocol_version; switch (eh->packet_type) { case 0: /* EAPOL-EAP */ l_timeout_remove(sm->eapol_start_timeout); sm->eapol_start_timeout = 0; if (!sm->eap) { /* If we're not configured for EAP, send a NAK */ sm->eap = eap_new(eapol_eap_msg_cb, eapol_eap_complete_cb, sm); if (!sm->eap) return; eap_set_key_material_func(sm->eap, eapol_eap_results_cb); } eap_rx_packet(sm->eap, frame + 4, L_BE16_TO_CPU(eh->packet_len)); break; case 3: /* EAPOL-Key */ if (sm->eap) /* An EAP negotiation in progress? */ return; if (!sm->have_pmk) return; eapol_key_handle(sm, sm->ifindex, frame, len); break; default: return; } } void __eapol_rx_packet(uint32_t ifindex, const uint8_t *aa, const uint8_t *frame, size_t len) { struct eapol_sm *sm = eapol_find_sm(ifindex, aa); if (!sm) return; eapol_rx_packet(sm, frame, len); } void __eapol_update_replay_counter(uint32_t ifindex, const uint8_t *spa, const uint8_t *aa, uint64_t replay_counter) { struct eapol_sm *sm; sm = eapol_find_sm(ifindex, aa); if (!sm) return; if (sm->replay_counter >= replay_counter) return; sm->replay_counter = replay_counter; } void __eapol_set_tx_packet_func(eapol_tx_packet_func_t func) { tx_packet = func; } void __eapol_set_tx_user_data(void *user_data) { tx_user_data = user_data; } void __eapol_set_get_nonce_func(eapol_get_nonce_func_t func) { get_nonce = func; } void __eapol_set_install_tk_func(eapol_install_tk_func_t func) { install_tk = func; } void __eapol_set_install_gtk_func(eapol_install_gtk_func_t func) { install_gtk = func; } void __eapol_set_deauthenticate_func(eapol_deauthenticate_func_t func) { deauthenticate = func; } void __eapol_set_rekey_offload_func(eapol_rekey_offload_func_t func) { rekey_offload = func; } static bool eapol_get_nonce(uint8_t nonce[]) { return l_getrandom(nonce, 32); } void eapol_start(uint32_t ifindex, struct eapol_sm *sm) { sm->ifindex = ifindex; sm->timeout = l_timeout_create(2, eapol_timeout, sm, NULL); if (sm->use_eapol_start) { /* * We start a short timeout, if EAP packets are not received * from AP, then we send the EAPoL-Start */ sm->eapol_start_timeout = l_timeout_create(1, send_eapol_start, sm, NULL); } l_queue_push_head(state_machines, sm); } void eapol_cancel(uint32_t ifindex) { l_queue_foreach_remove(state_machines, eapol_sm_ifindex_match, L_UINT_TO_PTR(ifindex)); } bool eapol_init() { state_machines = l_queue_new(); get_nonce = eapol_get_nonce; eap_init(); return true; } bool eapol_exit() { if (!l_queue_isempty(state_machines)) l_warn("stale eapol state machines found"); l_queue_destroy(state_machines, eapol_sm_destroy); get_nonce = NULL; eap_exit(); return true; }