aboutsummaryrefslogtreecommitdiffstats
path: root/main/wpa_supplicant/rebased-v2.6-0002-Prevent-reinstallation-of-an-already-in-use-group-ke.patch
blob: 1802d664add6f3e83b4bb64c5f7114c2e4b36298 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
From 927f891007c402fefd1ff384645b3f07597c3ede Mon Sep 17 00:00:00 2001
From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
Date: Wed, 12 Jul 2017 16:03:24 +0200
Subject: [PATCH 2/8] Prevent reinstallation of an already in-use group key

Track the current GTK and IGTK that is in use and when receiving a
(possibly retransmitted) Group Message 1 or WNM-Sleep Mode Response, do
not install the given key if it is already in use. This prevents an
attacker from trying to trick the client into resetting or lowering the
sequence counter associated to the group key.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
---
 src/common/wpa_common.h |  11 +++++
 src/rsn_supp/wpa.c      | 116 ++++++++++++++++++++++++++++++------------------
 src/rsn_supp/wpa_i.h    |   4 ++
 3 files changed, 87 insertions(+), 44 deletions(-)

diff --git a/src/common/wpa_common.h b/src/common/wpa_common.h
index af1d0f0..d200285 100644
--- a/src/common/wpa_common.h
+++ b/src/common/wpa_common.h
@@ -217,6 +217,17 @@ struct wpa_ptk {
 	size_t tk_len;
 };
 
+struct wpa_gtk {
+	u8 gtk[WPA_GTK_MAX_LEN];
+	size_t gtk_len;
+};
+
+#ifdef CONFIG_IEEE80211W
+struct wpa_igtk {
+	u8 igtk[WPA_IGTK_MAX_LEN];
+	size_t igtk_len;
+};
+#endif /* CONFIG_IEEE80211W */
 
 /* WPA IE version 1
  * 00-50-f2:1 (OUI:OUI type)
diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
index 3c47879..95bd7be 100644
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -714,6 +714,15 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm,
 	const u8 *_gtk = gd->gtk;
 	u8 gtk_buf[32];
 
+	/* Detect possible key reinstallation */
+	if (sm->gtk.gtk_len == (size_t) gd->gtk_len &&
+	    os_memcmp(sm->gtk.gtk, gd->gtk, sm->gtk.gtk_len) == 0) {
+		wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
+			"WPA: Not reinstalling already in-use GTK to the driver (keyidx=%d tx=%d len=%d)",
+			gd->keyidx, gd->tx, gd->gtk_len);
+		return 0;
+	}
+
 	wpa_hexdump_key(MSG_DEBUG, "WPA: Group Key", gd->gtk, gd->gtk_len);
 	wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
 		"WPA: Installing GTK to the driver (keyidx=%d tx=%d len=%d)",
@@ -748,6 +757,9 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm,
 	}
 	os_memset(gtk_buf, 0, sizeof(gtk_buf));
 
+	sm->gtk.gtk_len = gd->gtk_len;
+	os_memcpy(sm->gtk.gtk, gd->gtk, sm->gtk.gtk_len);
+
 	return 0;
 }
 
@@ -854,6 +866,48 @@ static int wpa_supplicant_pairwise_gtk(struct wpa_sm *sm,
 }
 
 
+#ifdef CONFIG_IEEE80211W
+static int wpa_supplicant_install_igtk(struct wpa_sm *sm,
+				       const struct wpa_igtk_kde *igtk)
+{
+	size_t len = wpa_cipher_key_len(sm->mgmt_group_cipher);
+	u16 keyidx = WPA_GET_LE16(igtk->keyid);
+
+	/* Detect possible key reinstallation */
+	if (sm->igtk.igtk_len == len &&
+	    os_memcmp(sm->igtk.igtk, igtk->igtk, sm->igtk.igtk_len) == 0) {
+		wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
+			"WPA: Not reinstalling already in-use IGTK to the driver (keyidx=%d)",
+			keyidx);
+		return  0;
+	}
+
+	wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
+		"WPA: IGTK keyid %d pn %02x%02x%02x%02x%02x%02x",
+		keyidx, MAC2STR(igtk->pn));
+	wpa_hexdump_key(MSG_DEBUG, "WPA: IGTK", igtk->igtk, len);
+	if (keyidx > 4095) {
+		wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
+			"WPA: Invalid IGTK KeyID %d", keyidx);
+		return -1;
+	}
+	if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher),
+			   broadcast_ether_addr,
+			   keyidx, 0, igtk->pn, sizeof(igtk->pn),
+			   igtk->igtk, len) < 0) {
+		wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
+			"WPA: Failed to configure IGTK to the driver");
+		return -1;
+	}
+
+	sm->igtk.igtk_len = len;
+	os_memcpy(sm->igtk.igtk, igtk->igtk, sm->igtk.igtk_len);
+
+	return 0;
+}
+#endif /* CONFIG_IEEE80211W */
+
+
 static int ieee80211w_set_keys(struct wpa_sm *sm,
 			       struct wpa_eapol_ie_parse *ie)
 {
@@ -864,30 +918,14 @@ static int ieee80211w_set_keys(struct wpa_sm *sm,
 	if (ie->igtk) {
 		size_t len;
 		const struct wpa_igtk_kde *igtk;
-		u16 keyidx;
+
 		len = wpa_cipher_key_len(sm->mgmt_group_cipher);
 		if (ie->igtk_len != WPA_IGTK_KDE_PREFIX_LEN + len)
 			return -1;
+
 		igtk = (const struct wpa_igtk_kde *) ie->igtk;
-		keyidx = WPA_GET_LE16(igtk->keyid);
-		wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: IGTK keyid %d "
-			"pn %02x%02x%02x%02x%02x%02x",
-			keyidx, MAC2STR(igtk->pn));
-		wpa_hexdump_key(MSG_DEBUG, "WPA: IGTK",
-				igtk->igtk, len);
-		if (keyidx > 4095) {
-			wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
-				"WPA: Invalid IGTK KeyID %d", keyidx);
-			return -1;
-		}
-		if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher),
-				   broadcast_ether_addr,
-				   keyidx, 0, igtk->pn, sizeof(igtk->pn),
-				   igtk->igtk, len) < 0) {
-			wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
-				"WPA: Failed to configure IGTK to the driver");
+		if (wpa_supplicant_install_igtk(sm, igtk) < 0)
 			return -1;
-		}
 	}
 
 	return 0;
@@ -2307,7 +2345,7 @@ void wpa_sm_deinit(struct wpa_sm *sm)
  */
 void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
 {
-	int clear_ptk = 1;
+	int clear_keys = 1;
 
 	if (sm == NULL)
 		return;
@@ -2333,11 +2371,11 @@ void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
 		/* Prepare for the next transition */
 		wpa_ft_prepare_auth_request(sm, NULL);
 
-		clear_ptk = 0;
+		clear_keys = 0;
 	}
 #endif /* CONFIG_IEEE80211R */
 
-	if (clear_ptk) {
+	if (clear_keys) {
 		/*
 		 * IEEE 802.11, 8.4.10: Delete PTK SA on (re)association if
 		 * this is not part of a Fast BSS Transition.
@@ -2347,6 +2385,10 @@ void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
 		os_memset(&sm->ptk, 0, sizeof(sm->ptk));
 		sm->tptk_set = 0;
 		os_memset(&sm->tptk, 0, sizeof(sm->tptk));
+		os_memset(&sm->gtk, 0, sizeof(sm->gtk));
+#ifdef CONFIG_IEEE80211W
+		os_memset(&sm->igtk, 0, sizeof(sm->igtk));
+#endif /* CONFIG_IEEE80211W */
 	}
 
 #ifdef CONFIG_TDLS
@@ -2877,6 +2919,10 @@ void wpa_sm_drop_sa(struct wpa_sm *sm)
 	os_memset(sm->pmk, 0, sizeof(sm->pmk));
 	os_memset(&sm->ptk, 0, sizeof(sm->ptk));
 	os_memset(&sm->tptk, 0, sizeof(sm->tptk));
+	os_memset(&sm->gtk, 0, sizeof(sm->gtk));
+#ifdef CONFIG_IEEE80211W
+	os_memset(&sm->igtk, 0, sizeof(sm->igtk));
+#endif /* CONFIG_IEEE80211W */
 #ifdef CONFIG_IEEE80211R
 	os_memset(sm->xxkey, 0, sizeof(sm->xxkey));
 	os_memset(sm->pmk_r0, 0, sizeof(sm->pmk_r0));
@@ -2949,29 +2995,11 @@ int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf)
 		os_memset(&gd, 0, sizeof(gd));
 #ifdef CONFIG_IEEE80211W
 	} else if (subelem_id == WNM_SLEEP_SUBELEM_IGTK) {
-		struct wpa_igtk_kde igd;
-		u16 keyidx;
-
-		os_memset(&igd, 0, sizeof(igd));
-		keylen = wpa_cipher_key_len(sm->mgmt_group_cipher);
-		os_memcpy(igd.keyid, buf + 2, 2);
-		os_memcpy(igd.pn, buf + 4, 6);
-
-		keyidx = WPA_GET_LE16(igd.keyid);
-		os_memcpy(igd.igtk, buf + 10, keylen);
-
-		wpa_hexdump_key(MSG_DEBUG, "Install IGTK (WNM SLEEP)",
-				igd.igtk, keylen);
-		if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher),
-				   broadcast_ether_addr,
-				   keyidx, 0, igd.pn, sizeof(igd.pn),
-				   igd.igtk, keylen) < 0) {
-			wpa_printf(MSG_DEBUG, "Failed to install the IGTK in "
-				   "WNM mode");
-			os_memset(&igd, 0, sizeof(igd));
+		const struct wpa_igtk_kde *igtk;
+
+		igtk = (const struct wpa_igtk_kde *) (buf + 2);
+		if (wpa_supplicant_install_igtk(sm, igtk) < 0)
 			return -1;
-		}
-		os_memset(&igd, 0, sizeof(igd));
 #endif /* CONFIG_IEEE80211W */
 	} else {
 		wpa_printf(MSG_DEBUG, "Unknown element id");
diff --git a/src/rsn_supp/wpa_i.h b/src/rsn_supp/wpa_i.h
index f653ba6..afc9e37 100644
--- a/src/rsn_supp/wpa_i.h
+++ b/src/rsn_supp/wpa_i.h
@@ -31,6 +31,10 @@ struct wpa_sm {
 	u8 rx_replay_counter[WPA_REPLAY_COUNTER_LEN];
 	int rx_replay_counter_set;
 	u8 request_counter[WPA_REPLAY_COUNTER_LEN];
+	struct wpa_gtk gtk;
+#ifdef CONFIG_IEEE80211W
+	struct wpa_igtk igtk;
+#endif /* CONFIG_IEEE80211W */
 
 	struct eapol_sm *eapol; /* EAPOL state machine from upper level code */
 
-- 
2.7.4