hostapd/src/rsn_supp/wpa_ie.c

/*
 * wpa_supplicant - WPA/RSN IE and KDE processing
 * Copyright (c) 2003-2008, 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.
 */

#include "includes.h"

#include "common.h"
#include "wpa.h"
#include "pmksa_cache.h"
#include "common/ieee802_11_defs.h"
#include "wpa_i.h"
#include "wpa_ie.h"


static int wpa_selector_to_bitfield(const u8 *s)
{
	if (RSN_SELECTOR_GET(s) == WPA_CIPHER_SUITE_NONE)
		return WPA_CIPHER_NONE;
	if (RSN_SELECTOR_GET(s) == WPA_CIPHER_SUITE_WEP40)
		return WPA_CIPHER_WEP40;
	if (RSN_SELECTOR_GET(s) == WPA_CIPHER_SUITE_TKIP)
		return WPA_CIPHER_TKIP;
	if (RSN_SELECTOR_GET(s) == WPA_CIPHER_SUITE_CCMP)
		return WPA_CIPHER_CCMP;
	if (RSN_SELECTOR_GET(s) == WPA_CIPHER_SUITE_WEP104)
		return WPA_CIPHER_WEP104;
	return 0;
}


static int wpa_key_mgmt_to_bitfield(const u8 *s)
{
	if (RSN_SELECTOR_GET(s) == WPA_AUTH_KEY_MGMT_UNSPEC_802_1X)
		return WPA_KEY_MGMT_IEEE8021X;
	if (RSN_SELECTOR_GET(s) == WPA_AUTH_KEY_MGMT_PSK_OVER_802_1X)
		return WPA_KEY_MGMT_PSK;
	if (RSN_SELECTOR_GET(s) == WPA_AUTH_KEY_MGMT_NONE)
		return WPA_KEY_MGMT_WPA_NONE;
	return 0;
}


static int wpa_parse_wpa_ie_wpa(const u8 *wpa_ie, size_t wpa_ie_len,
				struct wpa_ie_data *data)
{
	const struct wpa_ie_hdr *hdr;
	const u8 *pos;
	int left;
	int i, count;

	os_memset(data, 0, sizeof(*data));
	data->proto = WPA_PROTO_WPA;
	data->pairwise_cipher = WPA_CIPHER_TKIP;
	data->group_cipher = WPA_CIPHER_TKIP;
	data->key_mgmt = WPA_KEY_MGMT_IEEE8021X;
	data->capabilities = 0;
	data->pmkid = NULL;
	data->num_pmkid = 0;
	data->mgmt_group_cipher = 0;

	if (wpa_ie_len == 0) {
		/* No WPA IE - fail silently */
		return -1;
	}

	if (wpa_ie_len < sizeof(struct wpa_ie_hdr)) {
		wpa_printf(MSG_DEBUG, "%s: ie len too short %lu",
			   __func__, (unsigned long) wpa_ie_len);
		return -1;
	}

	hdr = (const struct wpa_ie_hdr *) wpa_ie;

	if (hdr->elem_id != WLAN_EID_VENDOR_SPECIFIC ||
	    hdr->len != wpa_ie_len - 2 ||
	    RSN_SELECTOR_GET(hdr->oui) != WPA_OUI_TYPE ||
	    WPA_GET_LE16(hdr->version) != WPA_VERSION) {
		wpa_printf(MSG_DEBUG, "%s: malformed ie or unknown version",
			   __func__);
		return -1;
	}

	pos = (const u8 *) (hdr + 1);
	left = wpa_ie_len - sizeof(*hdr);

	if (left >= WPA_SELECTOR_LEN) {
		data->group_cipher = wpa_selector_to_bitfield(pos);
		pos += WPA_SELECTOR_LEN;
		left -= WPA_SELECTOR_LEN;
	} else if (left > 0) {
		wpa_printf(MSG_DEBUG, "%s: ie length mismatch, %u too much",
			   __func__, left);
		return -1;
	}

	if (left >= 2) {
		data->pairwise_cipher = 0;
		count = WPA_GET_LE16(pos);
		pos += 2;
		left -= 2;
		if (count == 0 || left < count * WPA_SELECTOR_LEN) {
			wpa_printf(MSG_DEBUG, "%s: ie count botch (pairwise), "
				   "count %u left %u", __func__, count, left);
			return -1;
		}
		for (i = 0; i < count; i++) {
			data->pairwise_cipher |= wpa_selector_to_bitfield(pos);
			pos += WPA_SELECTOR_LEN;
			left -= WPA_SELECTOR_LEN;
		}
	} else if (left == 1) {
		wpa_printf(MSG_DEBUG, "%s: ie too short (for key mgmt)",
			   __func__);
		return -1;
	}

	if (left >= 2) {
		data->key_mgmt = 0;
		count = WPA_GET_LE16(pos);
		pos += 2;
		left -= 2;
		if (count == 0 || left < count * WPA_SELECTOR_LEN) {
			wpa_printf(MSG_DEBUG, "%s: ie count botch (key mgmt), "
				   "count %u left %u", __func__, count, left);
			return -1;
		}
		for (i = 0; i < count; i++) {
			data->key_mgmt |= wpa_key_mgmt_to_bitfield(pos);
			pos += WPA_SELECTOR_LEN;
			left -= WPA_SELECTOR_LEN;
		}
	} else if (left == 1) {
		wpa_printf(MSG_DEBUG, "%s: ie too short (for capabilities)",
			   __func__);
		return -1;
	}

	if (left >= 2) {
		data->capabilities = WPA_GET_LE16(pos);
		pos += 2;
		left -= 2;
	}

	if (left > 0) {
		wpa_printf(MSG_DEBUG, "%s: ie has %u trailing bytes - ignored",
			   __func__, left);
	}

	return 0;
}


/**
 * wpa_parse_wpa_ie - Parse WPA/RSN IE
 * @wpa_ie: Pointer to WPA or RSN IE
 * @wpa_ie_len: Length of the WPA/RSN IE
 * @data: Pointer to data area for parsing results
 * Returns: 0 on success, -1 on failure
 *
 * Parse the contents of WPA or RSN IE and write the parsed data into data.
 */
int wpa_parse_wpa_ie(const u8 *wpa_ie, size_t wpa_ie_len,
		     struct wpa_ie_data *data)
{
	if (wpa_ie_len >= 1 && wpa_ie[0] == WLAN_EID_RSN)
		return wpa_parse_wpa_ie_rsn(wpa_ie, wpa_ie_len, data);
	else
		return wpa_parse_wpa_ie_wpa(wpa_ie, wpa_ie_len, data);
}


static int wpa_gen_wpa_ie_wpa(u8 *wpa_ie, size_t wpa_ie_len,
			      int pairwise_cipher, int group_cipher,
			      int key_mgmt)
{
	u8 *pos;
	struct wpa_ie_hdr *hdr;

	if (wpa_ie_len < sizeof(*hdr) + WPA_SELECTOR_LEN +
	    2 + WPA_SELECTOR_LEN + 2 + WPA_SELECTOR_LEN)
		return -1;

	hdr = (struct wpa_ie_hdr *) wpa_ie;
	hdr->elem_id = WLAN_EID_VENDOR_SPECIFIC;
	RSN_SELECTOR_PUT(hdr->oui, WPA_OUI_TYPE);
	WPA_PUT_LE16(hdr->version, WPA_VERSION);
	pos = (u8 *) (hdr + 1);

	if (group_cipher == WPA_CIPHER_CCMP) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_CCMP);
	} else if (group_cipher == WPA_CIPHER_TKIP) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_TKIP);
	} else if (group_cipher == WPA_CIPHER_WEP104) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_WEP104);
	} else if (group_cipher == WPA_CIPHER_WEP40) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_WEP40);
	} else {
		wpa_printf(MSG_WARNING, "Invalid group cipher (%d).",
			   group_cipher);
		return -1;
	}
	pos += WPA_SELECTOR_LEN;

	*pos++ = 1;
	*pos++ = 0;
	if (pairwise_cipher == WPA_CIPHER_CCMP) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_CCMP);
	} else if (pairwise_cipher == WPA_CIPHER_TKIP) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_TKIP);
	} else if (pairwise_cipher == WPA_CIPHER_NONE) {
		RSN_SELECTOR_PUT(pos, WPA_CIPHER_SUITE_NONE);
	} else {
		wpa_printf(MSG_WARNING, "Invalid pairwise cipher (%d).",
			   pairwise_cipher);
		return -1;
	}
	pos += WPA_SELECTOR_LEN;

	*pos++ = 1;
	*pos++ = 0;
	if (key_mgmt == WPA_KEY_MGMT_IEEE8021X) {
		RSN_SELECTOR_PUT(pos, WPA_AUTH_KEY_MGMT_UNSPEC_802_1X);
	} else if (key_mgmt == WPA_KEY_MGMT_PSK) {
		RSN_SELECTOR_PUT(pos, WPA_AUTH_KEY_MGMT_PSK_OVER_802_1X);
	} else if (key_mgmt == WPA_KEY_MGMT_WPA_NONE) {
		RSN_SELECTOR_PUT(pos, WPA_AUTH_KEY_MGMT_NONE);
	} else {
		wpa_printf(MSG_WARNING, "Invalid key management type (%d).",
			   key_mgmt);
		return -1;
	}
	pos += WPA_SELECTOR_LEN;

	/* WPA Capabilities; use defaults, so no need to include it */

	hdr->len = (pos - wpa_ie) - 2;

	WPA_ASSERT((size_t) (pos - wpa_ie) <= wpa_ie_len);

	return pos - wpa_ie;
}


static int wpa_gen_wpa_ie_rsn(u8 *rsn_ie, size_t rsn_ie_len,
			      int pairwise_cipher, int group_cipher,
			      int key_mgmt, int mgmt_group_cipher,
			      struct wpa_sm *sm)
{
#ifndef CONFIG_NO_WPA2
	u8 *pos;
	struct rsn_ie_hdr *hdr;
	u16 capab;

	if (rsn_ie_len < sizeof(*hdr) + RSN_SELECTOR_LEN +
	    2 + RSN_SELECTOR_LEN + 2 + RSN_SELECTOR_LEN + 2 +
	    (sm->cur_pmksa ? 2 + PMKID_LEN : 0)) {
		wpa_printf(MSG_DEBUG, "RSN: Too short IE buffer (%lu bytes)",
			   (unsigned long) rsn_ie_len);
		return -1;
	}

	hdr = (struct rsn_ie_hdr *) rsn_ie;
	hdr->elem_id = WLAN_EID_RSN;
	WPA_PUT_LE16(hdr->version, RSN_VERSION);
	pos = (u8 *) (hdr + 1);

	if (group_cipher == WPA_CIPHER_CCMP) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_CCMP);
	} else if (group_cipher == WPA_CIPHER_TKIP) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_TKIP);
	} else if (group_cipher == WPA_CIPHER_WEP104) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_WEP104);
	} else if (group_cipher == WPA_CIPHER_WEP40) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_WEP40);
	} else {
		wpa_printf(MSG_WARNING, "Invalid group cipher (%d).",
			   group_cipher);
		return -1;
	}
	pos += RSN_SELECTOR_LEN;

	*pos++ = 1;
	*pos++ = 0;
	if (pairwise_cipher == WPA_CIPHER_CCMP) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_CCMP);
	} else if (pairwise_cipher == WPA_CIPHER_TKIP) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_TKIP);
	} else if (pairwise_cipher == WPA_CIPHER_NONE) {
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_NONE);
	} else {
		wpa_printf(MSG_WARNING, "Invalid pairwise cipher (%d).",
			   pairwise_cipher);
		return -1;
	}
	pos += RSN_SELECTOR_LEN;

	*pos++ = 1;
	*pos++ = 0;
	if (key_mgmt == WPA_KEY_MGMT_IEEE8021X) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_UNSPEC_802_1X);
	} else if (key_mgmt == WPA_KEY_MGMT_PSK) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_PSK_OVER_802_1X);
#ifdef CONFIG_IEEE80211R
	} else if (key_mgmt == WPA_KEY_MGMT_FT_IEEE8021X) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_FT_802_1X);
	} else if (key_mgmt == WPA_KEY_MGMT_FT_PSK) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_FT_PSK);
#endif /* CONFIG_IEEE80211R */
#ifdef CONFIG_IEEE80211W
	} else if (key_mgmt == WPA_KEY_MGMT_IEEE8021X_SHA256) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_802_1X_SHA256);
	} else if (key_mgmt == WPA_KEY_MGMT_PSK_SHA256) {
		RSN_SELECTOR_PUT(pos, RSN_AUTH_KEY_MGMT_PSK_SHA256);
#endif /* CONFIG_IEEE80211W */
	} else {
		wpa_printf(MSG_WARNING, "Invalid key management type (%d).",
			   key_mgmt);
		return -1;
	}
	pos += RSN_SELECTOR_LEN;

	/* RSN Capabilities */
	capab = 0;
#ifdef CONFIG_IEEE80211W
	if (sm->mfp)
		capab |= WPA_CAPABILITY_MFPC;
	if (sm->mfp == 2)
		capab |= WPA_CAPABILITY_MFPR;
#endif /* CONFIG_IEEE80211W */
	WPA_PUT_LE16(pos, capab);
	pos += 2;

	if (sm->cur_pmksa) {
		/* PMKID Count (2 octets, little endian) */
		*pos++ = 1;
		*pos++ = 0;
		/* PMKID */
		os_memcpy(pos, sm->cur_pmksa->pmkid, PMKID_LEN);
		pos += PMKID_LEN;
	}

#ifdef CONFIG_IEEE80211W
	if (mgmt_group_cipher == WPA_CIPHER_AES_128_CMAC) {
		if (!sm->cur_pmksa) {
			/* PMKID Count */
			WPA_PUT_LE16(pos, 0);
			pos += 2;
		}

		/* Management Group Cipher Suite */
		RSN_SELECTOR_PUT(pos, RSN_CIPHER_SUITE_AES_128_CMAC);
		pos += RSN_SELECTOR_LEN;
	}
#endif /* CONFIG_IEEE80211W */

	hdr->len = (pos - rsn_ie) - 2;

	WPA_ASSERT((size_t) (pos - rsn_ie) <= rsn_ie_len);

	return pos - rsn_ie;
#else /* CONFIG_NO_WPA2 */
	return -1;
#endif /* CONFIG_NO_WPA2 */
}


/**
 * wpa_gen_wpa_ie - Generate WPA/RSN IE based on current security policy
 * @sm: Pointer to WPA state machine data from wpa_sm_init()
 * @wpa_ie: Pointer to memory area for the generated WPA/RSN IE
 * @wpa_ie_len: Maximum length of the generated WPA/RSN IE
 * Returns: Length of the generated WPA/RSN IE or -1 on failure
 */
int wpa_gen_wpa_ie(struct wpa_sm *sm, u8 *wpa_ie, size_t wpa_ie_len)
{
	if (sm->proto == WPA_PROTO_RSN)
		return wpa_gen_wpa_ie_rsn(wpa_ie, wpa_ie_len,
					  sm->pairwise_cipher,
					  sm->group_cipher,
					  sm->key_mgmt, sm->mgmt_group_cipher,
					  sm);
	else
		return wpa_gen_wpa_ie_wpa(wpa_ie, wpa_ie_len,
					  sm->pairwise_cipher,
					  sm->group_cipher,
					  sm->key_mgmt);
}


/**
 * wpa_parse_generic - Parse EAPOL-Key Key Data Generic IEs
 * @pos: Pointer to the IE header
 * @end: Pointer to the end of the Key Data buffer
 * @ie: Pointer to parsed IE data
 * Returns: 0 on success, 1 if end mark is found, -1 on failure
 */
static int wpa_parse_generic(const u8 *pos, const u8 *end,
			     struct wpa_eapol_ie_parse *ie)
{
	if (pos[1] == 0)
		return 1;

	if (pos[1] >= 6 &&
	    RSN_SELECTOR_GET(pos + 2) == WPA_OUI_TYPE &&
	    pos[2 + WPA_SELECTOR_LEN] == 1 &&
	    pos[2 + WPA_SELECTOR_LEN + 1] == 0) {
		ie->wpa_ie = pos;
		ie->wpa_ie_len = pos[1] + 2;
		return 0;
	}

	if (pos + 1 + RSN_SELECTOR_LEN < end &&
	    pos[1] >= RSN_SELECTOR_LEN + PMKID_LEN &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_PMKID) {
		ie->pmkid = pos + 2 + RSN_SELECTOR_LEN;
		return 0;
	}

	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_GROUPKEY) {
		ie->gtk = pos + 2 + RSN_SELECTOR_LEN;
		ie->gtk_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}

	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_MAC_ADDR) {
		ie->mac_addr = pos + 2 + RSN_SELECTOR_LEN;
		ie->mac_addr_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}

#ifdef CONFIG_PEERKEY
	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_SMK) {
		ie->smk = pos + 2 + RSN_SELECTOR_LEN;
		ie->smk_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}

	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_NONCE) {
		ie->nonce = pos + 2 + RSN_SELECTOR_LEN;
		ie->nonce_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}

	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_LIFETIME) {
		ie->lifetime = pos + 2 + RSN_SELECTOR_LEN;
		ie->lifetime_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}

	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_ERROR) {
		ie->error = pos + 2 + RSN_SELECTOR_LEN;
		ie->error_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}
#endif /* CONFIG_PEERKEY */

#ifdef CONFIG_IEEE80211W
	if (pos[1] > RSN_SELECTOR_LEN + 2 &&
	    RSN_SELECTOR_GET(pos + 2) == RSN_KEY_DATA_IGTK) {
		ie->igtk = pos + 2 + RSN_SELECTOR_LEN;
		ie->igtk_len = pos[1] - RSN_SELECTOR_LEN;
		return 0;
	}
#endif /* CONFIG_IEEE80211W */

	return 0;
}


/**
 * wpa_supplicant_parse_ies - Parse EAPOL-Key Key Data IEs
 * @buf: Pointer to the Key Data buffer
 * @len: Key Data Length
 * @ie: Pointer to parsed IE data
 * Returns: 0 on success, -1 on failure
 */
int wpa_supplicant_parse_ies(const u8 *buf, size_t len,
			     struct wpa_eapol_ie_parse *ie)
{
	const u8 *pos, *end;
	int ret = 0;

	os_memset(ie, 0, sizeof(*ie));
	for (pos = buf, end = pos + len; pos + 1 < end; pos += 2 + pos[1]) {
		if (pos[0] == 0xdd &&
		    ((pos == buf + len - 1) || pos[1] == 0)) {
			/* Ignore padding */
			break;
		}
		if (pos + 2 + pos[1] > end) {
			wpa_printf(MSG_DEBUG, "WPA: EAPOL-Key Key Data "
				   "underflow (ie=%d len=%d pos=%d)",
				   pos[0], pos[1], (int) (pos - buf));
			wpa_hexdump_key(MSG_DEBUG, "WPA: Key Data",
					buf, len);
			ret = -1;
			break;
		}
		if (*pos == WLAN_EID_RSN) {
			ie->rsn_ie = pos;
			ie->rsn_ie_len = pos[1] + 2;
#ifdef CONFIG_IEEE80211R
		} else if (*pos == WLAN_EID_MOBILITY_DOMAIN) {
			ie->mdie = pos;
			ie->mdie_len = pos[1] + 2;
#endif /* CONFIG_IEEE80211R */
		} else if (*pos == WLAN_EID_VENDOR_SPECIFIC) {
			ret = wpa_parse_generic(pos, end, ie);
			if (ret < 0)
				break;
			if (ret > 0) {
				ret = 0;
				break;
			}
		} else {
			wpa_hexdump(MSG_DEBUG, "WPA: Unrecognized EAPOL-Key "
				    "Key Data IE", pos, 2 + pos[1]);
		}
	}

	return ret;
}