wlantest: Add support for decrypting WEP frames

wlantest/Makefile

@@ -66,6 +66,7 @@ OBJS += ccmp.o
 OBJS += tkip.o
 OBJS += ctrl.o
 OBJS += inject.o
+OBJS += wep.o
 
 LIBS += -lpcap
 

wlantest/bss.c

@@ -16,6 +16,7 @@
 
 #include "utils/common.h"
 #include "common/defs.h"
+#include "common/ieee802_11_defs.h"
 #include "common/ieee802_11_common.h"
 #include "crypto/sha1.h"
 #include "wlantest.h"
@@ -132,6 +133,9 @@ void bss_update(struct wlantest *wt, struct wlantest_bss *bss,
 	struct wpa_ie_data data;
 	int update = 0;
 
+	if (bss->capab_info != bss->prev_capab_info)
+		update = 1;
+
 	if (elems->ssid == NULL || elems->ssid_len > 32) {
 		wpa_printf(MSG_INFO, "Invalid or missing SSID in a Beacon "
 			   "frame for " MACSTR, MAC2STR(bss->bssid));
@@ -195,6 +199,7 @@ void bss_update(struct wlantest *wt, struct wlantest_bss *bss,
 	if (!update)
 		return;
 
+	bss->prev_capab_info = bss->capab_info;
 	bss->proto = 0;
 	bss->pairwise_cipher = 0;
 	bss->group_cipher = 0;
@@ -236,6 +241,10 @@ void bss_update(struct wlantest *wt, struct wlantest_bss *bss,
 	    !(bss->rsn_capab & WPA_CAPABILITY_MFPC))
 		bss->mgmt_group_cipher = 0;
 
+	if (!bss->wpaie[0] && !bss->rsnie[0] &&
+	    (bss->capab_info & WLAN_CAPABILITY_PRIVACY))
+		bss->group_cipher = WPA_CIPHER_WEP40;
+
 	wpa_printf(MSG_INFO, "BSS " MACSTR
 		   " proto=%s%s%s"
 		   "pairwise=%s%s%s%s"

wlantest/rx_data.c

@@ -144,7 +144,8 @@ static void rx_data_bss_prot_group(struct wlantest *wt,
 	}
 
 	keyid = data[3] >> 6;
-	if (bss->gtk_len[keyid] == 0) {
+	if (bss->gtk_len[keyid] == 0 && bss->group_cipher != WPA_CIPHER_WEP40)
+	{
 		wpa_printf(MSG_MSGDUMP, "No GTK known to decrypt the frame "
 			   "(A2=" MACSTR " KeyID=%d)",
 			   MAC2STR(hdr->addr2), keyid);
@@ -153,6 +154,8 @@ static void rx_data_bss_prot_group(struct wlantest *wt,
 
 	if (bss->group_cipher == WPA_CIPHER_TKIP)
 		tkip_get_pn(pn, data);
+	else if (bss->group_cipher == WPA_CIPHER_WEP40)
+		goto skip_replay_det;
 	else
 		ccmp_get_pn(pn, data);
 	if (os_memcmp(pn, bss->rsc[keyid], 6) <= 0) {
@@ -167,9 +170,12 @@ static void rx_data_bss_prot_group(struct wlantest *wt,
 		wpa_hexdump(MSG_INFO, "RSC", bss->rsc[keyid], 6);
 	}
 
+skip_replay_det:
 	if (bss->group_cipher == WPA_CIPHER_TKIP)
 		decrypted = tkip_decrypt(bss->gtk[keyid], hdr, data, len,
 					 &dlen);
+	else if (bss->group_cipher == WPA_CIPHER_WEP40)
+		decrypted = wep_decrypt(wt, hdr, data, len, &dlen);
 	else
 		decrypted = ccmp_decrypt(bss->gtk[keyid], hdr, data, len,
 					 &dlen);
@@ -237,7 +243,9 @@ static void rx_data_bss_prot(struct wlantest *wt,
 			}
 		}
 	}
-	if ((sta == NULL || !sta->ptk_set) && tk == NULL) {
+	if ((sta == NULL ||
+	     (!sta->ptk_set && sta->pairwise_cipher != WPA_CIPHER_WEP40)) &&
+	    tk == NULL) {
 		wpa_printf(MSG_MSGDUMP, "No PTK known to decrypt the frame");
 		return;
 	}
@@ -300,6 +308,8 @@ static void rx_data_bss_prot(struct wlantest *wt,
 
 	if (tk == NULL && sta->pairwise_cipher == WPA_CIPHER_TKIP)
 		tkip_get_pn(pn, data);
+	else if (sta->pairwise_cipher == WPA_CIPHER_WEP40)
+		goto skip_replay_det;
 	else
 		ccmp_get_pn(pn, data);
 	if (os_memcmp(pn, rsc, 6) <= 0) {
@@ -314,10 +324,13 @@ static void rx_data_bss_prot(struct wlantest *wt,
 		wpa_hexdump(MSG_INFO, "RSC", rsc, 6);
 	}
 
+skip_replay_det:
 	if (tk)
 		decrypted = ccmp_decrypt(tk, hdr, data, len, &dlen);
 	else if (sta->pairwise_cipher == WPA_CIPHER_TKIP)
 		decrypted = tkip_decrypt(sta->ptk.tk1, hdr, data, len, &dlen);
+	else if (sta->pairwise_cipher == WPA_CIPHER_WEP40)
+		decrypted = wep_decrypt(wt, hdr, data, len, &dlen);
 	else
 		decrypted = ccmp_decrypt(sta->ptk.tk1, hdr, data, len, &dlen);
 	if (decrypted) {

wlantest/sta.c

@@ -16,6 +16,7 @@
 
 #include "utils/common.h"
 #include "common/defs.h"
+#include "common/ieee802_11_defs.h"
 #include "common/ieee802_11_common.h"
 #include "wlantest.h"
 
@@ -97,8 +98,16 @@ void sta_update_assoc(struct wlantest_sta *sta, struct ieee802_11_elems *elems)
 			wpa_printf(MSG_INFO, "Failed to parse WPA IE from "
 				   MACSTR, MAC2STR(sta->addr));
 		}
-	} else
+	} else {
 		sta->rsnie[0] = 0;
+		sta->proto = 0;
+		sta->pairwise_cipher = 0;
+		sta->key_mgmt = 0;
+		sta->rsn_capab = 0;
+		if (sta->assocreq_capab_info & WLAN_CAPABILITY_PRIVACY)
+			sta->pairwise_cipher = WPA_CIPHER_WEP40;
+		goto skip_rsn_wpa;
+	}
 
 	sta->proto = data.proto;
 	sta->pairwise_cipher = data.pairwise_cipher;
@@ -130,6 +139,7 @@ void sta_update_assoc(struct wlantest_sta *sta, struct ieee802_11_elems *elems)
 			   "MFPR", MAC2STR(sta->addr), MAC2STR(bss->bssid));
 	}
 
+skip_rsn_wpa:
 	wpa_printf(MSG_INFO, "STA " MACSTR
 		   " proto=%s%s%s"
 		   "pairwise=%s%s%s%s"

wlantest/tkip.c

@@ -19,6 +19,9 @@
 #include "wlantest.h"
 
 
+void wep_crypt(u8 *key, u8 *buf, size_t plen);
+
+
 static inline u16 RotR1(u16 val)
 {
 	return (val >> 1) | (val << 15);
@@ -172,35 +175,6 @@ static void tkip_mixing_phase2(u8 *WEPSeed, const u8 *TK, const u16 *TTAK,
 }
 
 
-static void wep_crypt(u8 *key, u8 *buf, size_t plen)
-{
-	u32 i, j, k;
-	u8 S[256];
-#define S_SWAP(a,b) do { u8 t = S[a]; S[a] = S[b]; S[b] = t; } while(0)
-	u8 *pos;
-
-	/* Setup RC4 state */
-	for (i = 0; i < 256; i++)
-		S[i] = i;
-	j = 0;
-	for (i = 0; i < 256; i++) {
-		j = (j + S[i] + key[i & 0x0f]) & 0xff;
-		S_SWAP(i, j);
-	}
-
-	/* Apply RC4 to data */
-	pos = buf;
-	i = j = 0;
-	for (k = 0; k < plen; k++) {
-		i = (i + 1) & 0xff;
-		j = (j + S[i]) & 0xff;
-		S_SWAP(i, j);
-		*pos ^= S[(S[i] + S[j]) & 0xff];
-		pos++;
-	}
-}
-
-
 static inline u32 rotl(u32 val, int bits)
 {
 	return (val << bits) | (val >> (32 - bits));

wlantest/wep.c

@@ -0,0 +1,109 @@
+/*
+ * Wired Equivalent Privacy (WEP)
+ * Copyright (c) 2010, 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 "utils/includes.h"
+
+#include "utils/common.h"
+#include "common/ieee802_11_defs.h"
+#include "wlantest.h"
+
+
+void wep_crypt(u8 *key, u8 *buf, size_t plen)
+{
+	u32 i, j, k;
+	u8 S[256];
+#define S_SWAP(a,b) do { u8 t = S[a]; S[a] = S[b]; S[b] = t; } while(0)
+	u8 *pos;
+
+	/* Setup RC4 state */
+	for (i = 0; i < 256; i++)
+		S[i] = i;
+	j = 0;
+	for (i = 0; i < 256; i++) {
+		j = (j + S[i] + key[i & 0x0f]) & 0xff;
+		S_SWAP(i, j);
+	}
+
+	/* Apply RC4 to data */
+	pos = buf;
+	i = j = 0;
+	for (k = 0; k < plen; k++) {
+		i = (i + 1) & 0xff;
+		j = (j + S[i]) & 0xff;
+		S_SWAP(i, j);
+		*pos ^= S[(S[i] + S[j]) & 0xff];
+		pos++;
+	}
+}
+
+
+static int try_wep(const u8 *key, size_t key_len, const u8 *data,
+		   size_t data_len, u8 *plain)
+{
+	u32 icv, rx_icv;
+	u8 k[16];
+	int i, j;
+
+	for (i = 0, j = 0; i < sizeof(k); i++) {
+		k[i] = key[j];
+		j++;
+		if (j >= key_len)
+			j = 0;
+	}
+
+	os_memcpy(plain, data, data_len);
+	wep_crypt(k, plain, data_len);
+	icv = crc32(plain, data_len - 4);
+	rx_icv = WPA_GET_LE32(plain + data_len - 4);
+	if (icv != rx_icv)
+		return -1;
+
+	return 0;
+}
+
+
+u8 * wep_decrypt(struct wlantest *wt, const struct ieee80211_hdr *hdr,
+		 const u8 *data, size_t data_len, size_t *decrypted_len)
+{
+	u8 *plain;
+	struct wlantest_wep *w;
+	int found = 0;
+	u8 key[16];
+
+	if (dl_list_empty(&wt->wep))
+		return NULL;
+
+	if (data_len < 4 + 4)
+		return NULL;
+	plain = os_malloc(data_len - 4);
+	if (plain == NULL)
+		return NULL;
+
+	dl_list_for_each(w, &wt->wep, struct wlantest_wep, list) {
+		os_memcpy(key, data, 3);
+		os_memcpy(key + 3, w->key, w->key_len);
+		if (try_wep(key, 3 + w->key_len, data + 4, data_len - 4, plain)
+		    == 0) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		os_free(plain);
+		return NULL;
+	}
+
+	*decrypted_len = data_len - 4 - 4;
+	return plain;
+}

wlantest/wlantest.c

@@ -66,6 +66,7 @@ static void wlantest_init(struct wlantest *wt)
 	dl_list_init(&wt->secret);
 	dl_list_init(&wt->radius);
 	dl_list_init(&wt->pmk);
+	dl_list_init(&wt->wep);
 }
 
 
@@ -82,6 +83,7 @@ static void wlantest_deinit(struct wlantest *wt)
 	struct wlantest_radius_secret *s, *sn;
 	struct wlantest_radius *r, *rn;
 	struct wlantest_pmk *pmk, *np;
+	struct wlantest_wep *wep, *nw;
 
 	if (wt->ctrl_sock >= 0)
 		ctrl_deinit(wt);
@@ -98,6 +100,8 @@ static void wlantest_deinit(struct wlantest *wt)
 		radius_deinit(r);
 	dl_list_for_each_safe(pmk, np, &wt->pmk, struct wlantest_pmk, list)
 		pmk_deinit(pmk);
+	dl_list_for_each_safe(wep, nw, &wt->wep, struct wlantest_wep, list)
+		os_free(wep);
 	write_pcap_deinit(wt);
 }
 
@@ -132,6 +136,28 @@ static void add_secret(struct wlantest *wt, const char *secret)
 }
 
 
+static void add_wep(struct wlantest *wt, const char *key)
+{
+	struct wlantest_wep *w;
+	size_t len = os_strlen(key);
+
+	if (len != 2 * 5 && len != 2 * 13) {
+		wpa_printf(MSG_INFO, "Invalid WEP key '%s'", key);
+		return;
+	}
+	w = os_zalloc(sizeof(*w));
+	if (w == NULL)
+		return;
+	if (hexstr2bin(key, w->key, len / 2) < 0) {
+		os_free(w);
+		wpa_printf(MSG_INFO, "Invalid WEP key '%s'", key);
+		return;
+	}
+	w->key_len = len / 2;
+	dl_list_add(&wt->wep, &w->list);
+}
+
+
 int main(int argc, char *argv[])
 {
 	int c;
@@ -152,7 +178,7 @@ int main(int argc, char *argv[])
 	wlantest_init(&wt);
 
 	for (;;) {
-		c = getopt(argc, argv, "cdhi:I:p:P:qr:R:w:");
+		c = getopt(argc, argv, "cdhi:I:p:P:qr:R:w:W:");
 		if (c < 0)
 			break;
 		switch (c) {
@@ -190,6 +216,9 @@ int main(int argc, char *argv[])
 		case 'w':
 			write_file = optarg;
 			break;
+		case 'W':
+			add_wep(&wt, optarg);
+			break;
 		default:
 			usage();
 			return -1;

wlantest/wlantest.h

@@ -44,6 +44,12 @@ struct wlantest_pmk {
 	u8 pmk[32];
 };
 
+struct wlantest_wep {
+	struct dl_list list;
+	size_t key_len;
+	u8 key[13];
+};
+
 struct wlantest_sta {
 	struct dl_list list;
 	struct wlantest_bss *bss;
@@ -106,6 +112,7 @@ struct wlantest_bss {
 	struct dl_list list;
 	u8 bssid[ETH_ALEN];
 	u16 capab_info;
+	u16 prev_capab_info;
 	u8 ssid[32];
 	size_t ssid_len;
 	int proberesp_seen;
@@ -154,6 +161,7 @@ struct wlantest {
 	struct dl_list secret; /* struct wlantest_radius_secret */
 	struct dl_list radius; /* struct wlantest_radius */
 	struct dl_list pmk; /* struct wlantest_pmk */
+	struct dl_list wep; /* struct wlantest_wep */
 
 	unsigned int rx_mgmt;
 	unsigned int rx_ctrl;
@@ -223,6 +231,9 @@ u8 * tkip_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
 		  u8 *pn, int keyid, size_t *encrypted_len);
 void tkip_get_pn(u8 *pn, const u8 *data);
 
+u8 * wep_decrypt(struct wlantest *wt, const struct ieee80211_hdr *hdr,
+		 const u8 *data, size_t data_len, size_t *decrypted_len);
+
 int ctrl_init(struct wlantest *wt);
 void ctrl_deinit(struct wlantest *wt);