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: I54f22e16b4fca5c541fd7f7e6cf6c9503e875f4e
Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
Signed-off-by: Glen Kuhne <kuh@google.com>
Merged-In: I5a315accb15ca5d2464acc3c370c66e07d57c7ea
Bug: 65245581
Test: WiFi integration tests
(cherry picked from commit 480c21c67806af61aa94b3e49b6a18daf8d428d6)
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 @@
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 @@
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 @@
}
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 @@
}
+#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 @@
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;
@@ -2307,7 +2345,7 @@
*/
void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
{
- int clear_ptk = 1;
+ int clear_keys = 1;
if (sm == NULL)
return;
@@ -2333,11 +2371,11 @@
/* 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.
@@ -2347,6 +2385,10 @@
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
@@ -2877,6 +2919,10 @@
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 */
#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 @@
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 f653ba6..afc9e37 100644
--- a/src/rsn_supp/wpa_i.h
+++ b/src/rsn_supp/wpa_i.h
@@ -31,6 +31,10 @@
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 */
