--- /dev/null
+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
+
projects / 15.05 / openwrt.git / blobdiff