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-rw-r--r--src/eap_server/eap_server_psk.c517
1 files changed, 517 insertions, 0 deletions
diff --git a/src/eap_server/eap_server_psk.c b/src/eap_server/eap_server_psk.c
new file mode 100644
index 0000000..4c30346
--- /dev/null
+++ b/src/eap_server/eap_server_psk.c
@@ -0,0 +1,517 @@
+/*
+ * hostapd / EAP-PSK (RFC 4764) server
+ * Copyright (c) 2005-2007, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ *
+ * Note: EAP-PSK is an EAP authentication method and as such, completely
+ * different from WPA-PSK. This file is not needed for WPA-PSK functionality.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto/aes_wrap.h"
+#include "eap_common/eap_psk_common.h"
+#include "eap_server/eap_i.h"
+
+
+struct eap_psk_data {
+ enum { PSK_1, PSK_3, SUCCESS, FAILURE } state;
+ u8 rand_s[EAP_PSK_RAND_LEN];
+ u8 rand_p[EAP_PSK_RAND_LEN];
+ u8 *id_p, *id_s;
+ size_t id_p_len, id_s_len;
+ u8 ak[EAP_PSK_AK_LEN], kdk[EAP_PSK_KDK_LEN], tek[EAP_PSK_TEK_LEN];
+ u8 msk[EAP_MSK_LEN];
+ u8 emsk[EAP_EMSK_LEN];
+};
+
+
+static void * eap_psk_init(struct eap_sm *sm)
+{
+ struct eap_psk_data *data;
+
+ data = os_zalloc(sizeof(*data));
+ if (data == NULL)
+ return NULL;
+ data->state = PSK_1;
+ data->id_s = (u8 *) "hostapd";
+ data->id_s_len = 7;
+
+ return data;
+}
+
+
+static void eap_psk_reset(struct eap_sm *sm, void *priv)
+{
+ struct eap_psk_data *data = priv;
+ os_free(data->id_p);
+ os_free(data);
+}
+
+
+static struct wpabuf * eap_psk_build_1(struct eap_sm *sm,
+ struct eap_psk_data *data, u8 id)
+{
+ struct wpabuf *req;
+ struct eap_psk_hdr_1 *psk;
+
+ wpa_printf(MSG_DEBUG, "EAP-PSK: PSK-1 (sending)");
+
+ if (os_get_random(data->rand_s, EAP_PSK_RAND_LEN)) {
+ wpa_printf(MSG_ERROR, "EAP-PSK: Failed to get random data");
+ data->state = FAILURE;
+ return NULL;
+ }
+ wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: RAND_S (server rand)",
+ data->rand_s, EAP_PSK_RAND_LEN);
+
+ req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PSK,
+ sizeof(*psk) + data->id_s_len,
+ EAP_CODE_REQUEST, id);
+ if (req == NULL) {
+ wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory "
+ "request");
+ data->state = FAILURE;
+ return NULL;
+ }
+
+ psk = wpabuf_put(req, sizeof(*psk));
+ psk->flags = EAP_PSK_FLAGS_SET_T(0); /* T=0 */
+ os_memcpy(psk->rand_s, data->rand_s, EAP_PSK_RAND_LEN);
+ wpabuf_put_data(req, data->id_s, data->id_s_len);
+
+ return req;
+}
+
+
+static struct wpabuf * eap_psk_build_3(struct eap_sm *sm,
+ struct eap_psk_data *data, u8 id)
+{
+ struct wpabuf *req;
+ struct eap_psk_hdr_3 *psk;
+ u8 *buf, *pchannel, nonce[16];
+ size_t buflen;
+
+ wpa_printf(MSG_DEBUG, "EAP-PSK: PSK-3 (sending)");
+
+ req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PSK,
+ sizeof(*psk) + 4 + 16 + 1, EAP_CODE_REQUEST, id);
+ if (req == NULL) {
+ wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory "
+ "request");
+ data->state = FAILURE;
+ return NULL;
+ }
+
+ psk = wpabuf_put(req, sizeof(*psk));
+ psk->flags = EAP_PSK_FLAGS_SET_T(2); /* T=2 */
+ os_memcpy(psk->rand_s, data->rand_s, EAP_PSK_RAND_LEN);
+
+ /* MAC_S = OMAC1-AES-128(AK, ID_S||RAND_P) */
+ buflen = data->id_s_len + EAP_PSK_RAND_LEN;
+ buf = os_malloc(buflen);
+ if (buf == NULL)
+ goto fail;
+
+ os_memcpy(buf, data->id_s, data->id_s_len);
+ os_memcpy(buf + data->id_s_len, data->rand_p, EAP_PSK_RAND_LEN);
+ if (omac1_aes_128(data->ak, buf, buflen, psk->mac_s))
+ goto fail;
+ os_free(buf);
+
+ if (eap_psk_derive_keys(data->kdk, data->rand_p, data->tek, data->msk,
+ data->emsk))
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: TEK", data->tek, EAP_PSK_TEK_LEN);
+ wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: MSK", data->msk, EAP_MSK_LEN);
+ wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: EMSK", data->emsk, EAP_EMSK_LEN);
+
+ os_memset(nonce, 0, sizeof(nonce));
+ pchannel = wpabuf_put(req, 4 + 16 + 1);
+ os_memcpy(pchannel, nonce + 12, 4);
+ os_memset(pchannel + 4, 0, 16); /* Tag */
+ pchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_SUCCESS << 6;
+ wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL (plaintext)",
+ pchannel, 4 + 16 + 1);
+ if (aes_128_eax_encrypt(data->tek, nonce, sizeof(nonce),
+ wpabuf_head(req), 22,
+ pchannel + 4 + 16, 1, pchannel + 4))
+ goto fail;
+ wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL (encrypted)",
+ pchannel, 4 + 16 + 1);
+
+ return req;
+
+fail:
+ wpabuf_free(req);
+ data->state = FAILURE;
+ return NULL;
+}
+
+
+static struct wpabuf * eap_psk_buildReq(struct eap_sm *sm, void *priv, u8 id)
+{
+ struct eap_psk_data *data = priv;
+
+ switch (data->state) {
+ case PSK_1:
+ return eap_psk_build_1(sm, data, id);
+ case PSK_3:
+ return eap_psk_build_3(sm, data, id);
+ default:
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Unknown state %d in buildReq",
+ data->state);
+ break;
+ }
+ return NULL;
+}
+
+
+static Boolean eap_psk_check(struct eap_sm *sm, void *priv,
+ struct wpabuf *respData)
+{
+ struct eap_psk_data *data = priv;
+ size_t len;
+ u8 t;
+ const u8 *pos;
+
+ pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, respData, &len);
+ if (pos == NULL || len < 1) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Invalid frame");
+ return TRUE;
+ }
+ t = EAP_PSK_FLAGS_GET_T(*pos);
+
+ wpa_printf(MSG_DEBUG, "EAP-PSK: received frame: T=%d", t);
+
+ if (data->state == PSK_1 && t != 1) {
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Expected PSK-2 - "
+ "ignore T=%d", t);
+ return TRUE;
+ }
+
+ if (data->state == PSK_3 && t != 3) {
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Expected PSK-4 - "
+ "ignore T=%d", t);
+ return TRUE;
+ }
+
+ if ((t == 1 && len < sizeof(struct eap_psk_hdr_2)) ||
+ (t == 3 && len < sizeof(struct eap_psk_hdr_4))) {
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Too short frame");
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+
+static void eap_psk_process_2(struct eap_sm *sm,
+ struct eap_psk_data *data,
+ struct wpabuf *respData)
+{
+ const struct eap_psk_hdr_2 *resp;
+ u8 *pos, mac[EAP_PSK_MAC_LEN], *buf;
+ size_t left, buflen;
+ int i;
+ const u8 *cpos;
+
+ if (data->state != PSK_1)
+ return;
+
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Received PSK-2");
+
+ cpos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, respData,
+ &left);
+ if (cpos == NULL || left < sizeof(*resp)) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Invalid frame");
+ return;
+ }
+ resp = (const struct eap_psk_hdr_2 *) cpos;
+ cpos = (const u8 *) (resp + 1);
+ left -= sizeof(*resp);
+
+ os_free(data->id_p);
+ data->id_p = os_malloc(left);
+ if (data->id_p == NULL) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Failed to allocate memory for "
+ "ID_P");
+ return;
+ }
+ os_memcpy(data->id_p, cpos, left);
+ data->id_p_len = left;
+ wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PSK: ID_P",
+ data->id_p, data->id_p_len);
+
+ if (eap_user_get(sm, data->id_p, data->id_p_len, 0) < 0) {
+ wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: unknown ID_P",
+ data->id_p, data->id_p_len);
+ data->state = FAILURE;
+ return;
+ }
+
+ for (i = 0;
+ i < EAP_MAX_METHODS &&
+ (sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
+ sm->user->methods[i].method != EAP_TYPE_NONE);
+ i++) {
+ if (sm->user->methods[i].vendor == EAP_VENDOR_IETF &&
+ sm->user->methods[i].method == EAP_TYPE_PSK)
+ break;
+ }
+
+ if (i >= EAP_MAX_METHODS ||
+ sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
+ sm->user->methods[i].method != EAP_TYPE_PSK) {
+ wpa_hexdump_ascii(MSG_DEBUG,
+ "EAP-PSK: EAP-PSK not enabled for ID_P",
+ data->id_p, data->id_p_len);
+ data->state = FAILURE;
+ return;
+ }
+
+ if (sm->user->password == NULL ||
+ sm->user->password_len != EAP_PSK_PSK_LEN) {
+ wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: invalid password in "
+ "user database for ID_P",
+ data->id_p, data->id_p_len);
+ data->state = FAILURE;
+ return;
+ }
+ if (eap_psk_key_setup(sm->user->password, data->ak, data->kdk)) {
+ data->state = FAILURE;
+ return;
+ }
+ wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: AK", data->ak, EAP_PSK_AK_LEN);
+ wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: KDK", data->kdk, EAP_PSK_KDK_LEN);
+
+ wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: RAND_P (client rand)",
+ resp->rand_p, EAP_PSK_RAND_LEN);
+ os_memcpy(data->rand_p, resp->rand_p, EAP_PSK_RAND_LEN);
+
+ /* MAC_P = OMAC1-AES-128(AK, ID_P||ID_S||RAND_S||RAND_P) */
+ buflen = data->id_p_len + data->id_s_len + 2 * EAP_PSK_RAND_LEN;
+ buf = os_malloc(buflen);
+ if (buf == NULL) {
+ data->state = FAILURE;
+ return;
+ }
+ os_memcpy(buf, data->id_p, data->id_p_len);
+ pos = buf + data->id_p_len;
+ os_memcpy(pos, data->id_s, data->id_s_len);
+ pos += data->id_s_len;
+ os_memcpy(pos, data->rand_s, EAP_PSK_RAND_LEN);
+ pos += EAP_PSK_RAND_LEN;
+ os_memcpy(pos, data->rand_p, EAP_PSK_RAND_LEN);
+ if (omac1_aes_128(data->ak, buf, buflen, mac)) {
+ os_free(buf);
+ data->state = FAILURE;
+ return;
+ }
+ os_free(buf);
+ wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_P", resp->mac_p, EAP_PSK_MAC_LEN);
+ if (os_memcmp(mac, resp->mac_p, EAP_PSK_MAC_LEN) != 0) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Invalid MAC_P");
+ wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: Expected MAC_P",
+ mac, EAP_PSK_MAC_LEN);
+ data->state = FAILURE;
+ return;
+ }
+
+ data->state = PSK_3;
+}
+
+
+static void eap_psk_process_4(struct eap_sm *sm,
+ struct eap_psk_data *data,
+ struct wpabuf *respData)
+{
+ const struct eap_psk_hdr_4 *resp;
+ u8 *decrypted, nonce[16];
+ size_t left;
+ const u8 *pos, *tag;
+
+ if (data->state != PSK_3)
+ return;
+
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Received PSK-4");
+
+ pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, respData, &left);
+ if (pos == NULL || left < sizeof(*resp)) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Invalid frame");
+ return;
+ }
+ resp = (const struct eap_psk_hdr_4 *) pos;
+ pos = (const u8 *) (resp + 1);
+ left -= sizeof(*resp);
+
+ wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: Encrypted PCHANNEL", pos, left);
+
+ if (left < 4 + 16 + 1) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Too short PCHANNEL data in "
+ "PSK-4 (len=%lu, expected 21)",
+ (unsigned long) left);
+ return;
+ }
+
+ if (pos[0] == 0 && pos[1] == 0 && pos[2] == 0 && pos[3] == 0) {
+ wpa_printf(MSG_DEBUG, "EAP-PSK: Nonce did not increase");
+ return;
+ }
+
+ os_memset(nonce, 0, 12);
+ os_memcpy(nonce + 12, pos, 4);
+ pos += 4;
+ left -= 4;
+ tag = pos;
+ pos += 16;
+ left -= 16;
+
+ decrypted = os_malloc(left);
+ if (decrypted == NULL)
+ return;
+ os_memcpy(decrypted, pos, left);
+
+ if (aes_128_eax_decrypt(data->tek, nonce, sizeof(nonce),
+ wpabuf_head(respData), 22, decrypted, left,
+ tag)) {
+ wpa_printf(MSG_WARNING, "EAP-PSK: PCHANNEL decryption failed");
+ os_free(decrypted);
+ data->state = FAILURE;
+ return;
+ }
+ wpa_hexdump(MSG_DEBUG, "EAP-PSK: Decrypted PCHANNEL message",
+ decrypted, left);
+
+ /* Verify R flag */
+ switch (decrypted[0] >> 6) {
+ case EAP_PSK_R_FLAG_CONT:
+ wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - CONT - unsupported");
+ data->state = FAILURE;
+ break;
+ case EAP_PSK_R_FLAG_DONE_SUCCESS:
+ wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_SUCCESS");
+ data->state = SUCCESS;
+ break;
+ case EAP_PSK_R_FLAG_DONE_FAILURE:
+ wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_FAILURE");
+ data->state = FAILURE;
+ break;
+ }
+ os_free(decrypted);
+}
+
+
+static void eap_psk_process(struct eap_sm *sm, void *priv,
+ struct wpabuf *respData)
+{
+ struct eap_psk_data *data = priv;
+ const u8 *pos;
+ size_t len;
+
+ if (sm->user == NULL || sm->user->password == NULL) {
+ wpa_printf(MSG_INFO, "EAP-PSK: Plaintext password not "
+ "configured");
+ data->state = FAILURE;
+ return;
+ }
+
+ pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, respData, &len);
+ if (pos == NULL || len < 1)
+ return;
+
+ switch (EAP_PSK_FLAGS_GET_T(*pos)) {
+ case 1:
+ eap_psk_process_2(sm, data, respData);
+ break;
+ case 3:
+ eap_psk_process_4(sm, data, respData);
+ break;
+ }
+}
+
+
+static Boolean eap_psk_isDone(struct eap_sm *sm, void *priv)
+{
+ struct eap_psk_data *data = priv;
+ return data->state == SUCCESS || data->state == FAILURE;
+}
+
+
+static u8 * eap_psk_getKey(struct eap_sm *sm, void *priv, size_t *len)
+{
+ struct eap_psk_data *data = priv;
+ u8 *key;
+
+ if (data->state != SUCCESS)
+ return NULL;
+
+ key = os_malloc(EAP_MSK_LEN);
+ if (key == NULL)
+ return NULL;
+ os_memcpy(key, data->msk, EAP_MSK_LEN);
+ *len = EAP_MSK_LEN;
+
+ return key;
+}
+
+
+static u8 * eap_psk_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
+{
+ struct eap_psk_data *data = priv;
+ u8 *key;
+
+ if (data->state != SUCCESS)
+ return NULL;
+
+ key = os_malloc(EAP_EMSK_LEN);
+ if (key == NULL)
+ return NULL;
+ os_memcpy(key, data->emsk, EAP_EMSK_LEN);
+ *len = EAP_EMSK_LEN;
+
+ return key;
+}
+
+
+static Boolean eap_psk_isSuccess(struct eap_sm *sm, void *priv)
+{
+ struct eap_psk_data *data = priv;
+ return data->state == SUCCESS;
+}
+
+
+int eap_server_psk_register(void)
+{
+ struct eap_method *eap;
+ int ret;
+
+ eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
+ EAP_VENDOR_IETF, EAP_TYPE_PSK, "PSK");
+ if (eap == NULL)
+ return -1;
+
+ eap->init = eap_psk_init;
+ eap->reset = eap_psk_reset;
+ eap->buildReq = eap_psk_buildReq;
+ eap->check = eap_psk_check;
+ eap->process = eap_psk_process;
+ eap->isDone = eap_psk_isDone;
+ eap->getKey = eap_psk_getKey;
+ eap->isSuccess = eap_psk_isSuccess;
+ eap->get_emsk = eap_psk_get_emsk;
+
+ ret = eap_server_method_register(eap);
+ if (ret)
+ eap_server_method_free(eap);
+ return ret;
+}