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.
Change-Id: I6c63c06b6b2fb289549289051e7024859bd8a5c0
Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
Signed-off-by: Glen Kuhne <kuh@google.com>
Merged-In: I54f22e16b4fca5c541fd7f7e6cf6c9503e875f4e
Bug: 65245581
Test: WiFi integration tests
diff --git a/src/common/wpa_common.h b/src/common/wpa_common.h
index 0ef5a9d..52ac2c3 100644
--- a/src/common/wpa_common.h
+++ b/src/common/wpa_common.h
@@ -208,6 +208,17 @@
} u;
} STRUCT_PACKED;
+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 d6fb6a1..92e2cab 100644
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -639,6 +639,15 @@
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)",
@@ -673,6 +682,9 @@
}
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;
}
@@ -744,6 +756,48 @@
}
+#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)
{
@@ -754,30 +808,14 @@
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);
+ if (wpa_supplicant_install_igtk(sm, igtk) < 0)
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;
- }
}
return 0;
@@ -2106,7 +2144,7 @@
*/
void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
{
- int clear_ptk = 1;
+ int clear_keys = 1;
if (sm == NULL)
return;
@@ -2132,11 +2170,11 @@
/* 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.
@@ -2146,6 +2184,10 @@
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
@@ -2648,6 +2690,10 @@
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 */
}
#endif /* CONFIG_TESTING_OPTIONS */
@@ -2716,29 +2762,11 @@
os_memset(&gd, 0, sizeof(gd));
#ifdef CONFIG_IEEE80211W
} else if (subelem_id == WNM_SLEEP_SUBELEM_IGTK) {
- struct wpa_igtk_kde igd;
- u16 keyidx;
+ const struct wpa_igtk_kde *igtk;
- 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));
+ 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 e20e9da..0f2083d 100644
--- a/src/rsn_supp/wpa_i.h
+++ b/src/rsn_supp/wpa_i.h
@@ -29,6 +29,10 @@
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 */