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250 lines
7.7 KiB
250 lines
7.7 KiB
From 927f891007c402fefd1ff384645b3f07597c3ede Mon Sep 17 00:00:00 2001 |
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From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be> |
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Date: Wed, 12 Jul 2017 16:03:24 +0200 |
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Subject: [PATCH 2/8] Prevent reinstallation of an already in-use group key |
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Track the current GTK and IGTK that is in use and when receiving a |
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(possibly retransmitted) Group Message 1 or WNM-Sleep Mode Response, do |
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not install the given key if it is already in use. This prevents an |
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attacker from trying to trick the client into resetting or lowering the |
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sequence counter associated to the group key. |
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Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be> |
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--- |
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src/common/wpa_common.h | 11 +++++ |
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src/rsn_supp/wpa.c | 116 ++++++++++++++++++++++++++++++------------------ |
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src/rsn_supp/wpa_i.h | 4 ++ |
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3 files changed, 87 insertions(+), 44 deletions(-) |
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diff --git a/src/common/wpa_common.h b/src/common/wpa_common.h |
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index af1d0f0..d200285 100644 |
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--- a/src/common/wpa_common.h |
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+++ b/src/common/wpa_common.h |
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@@ -217,6 +217,17 @@ struct wpa_ptk { |
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size_t tk_len; |
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}; |
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+struct wpa_gtk { |
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+ u8 gtk[WPA_GTK_MAX_LEN]; |
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+ size_t gtk_len; |
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+}; |
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+ |
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+#ifdef CONFIG_IEEE80211W |
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+struct wpa_igtk { |
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+ u8 igtk[WPA_IGTK_MAX_LEN]; |
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+ size_t igtk_len; |
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+}; |
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+#endif /* CONFIG_IEEE80211W */ |
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/* WPA IE version 1 |
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* 00-50-f2:1 (OUI:OUI type) |
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diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c |
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index 3c47879..95bd7be 100644 |
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--- a/src/rsn_supp/wpa.c |
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+++ b/src/rsn_supp/wpa.c |
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@@ -714,6 +714,15 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm, |
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const u8 *_gtk = gd->gtk; |
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u8 gtk_buf[32]; |
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+ /* Detect possible key reinstallation */ |
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+ if (sm->gtk.gtk_len == (size_t) gd->gtk_len && |
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+ os_memcmp(sm->gtk.gtk, gd->gtk, sm->gtk.gtk_len) == 0) { |
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+ wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, |
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+ "WPA: Not reinstalling already in-use GTK to the driver (keyidx=%d tx=%d len=%d)", |
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+ gd->keyidx, gd->tx, gd->gtk_len); |
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+ return 0; |
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+ } |
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+ |
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wpa_hexdump_key(MSG_DEBUG, "WPA: Group Key", gd->gtk, gd->gtk_len); |
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wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, |
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"WPA: Installing GTK to the driver (keyidx=%d tx=%d len=%d)", |
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@@ -748,6 +757,9 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm, |
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} |
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os_memset(gtk_buf, 0, sizeof(gtk_buf)); |
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+ sm->gtk.gtk_len = gd->gtk_len; |
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+ os_memcpy(sm->gtk.gtk, gd->gtk, sm->gtk.gtk_len); |
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+ |
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return 0; |
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} |
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@@ -854,6 +866,48 @@ static int wpa_supplicant_pairwise_gtk(struct wpa_sm *sm, |
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} |
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+#ifdef CONFIG_IEEE80211W |
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+static int wpa_supplicant_install_igtk(struct wpa_sm *sm, |
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+ const struct wpa_igtk_kde *igtk) |
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+{ |
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+ size_t len = wpa_cipher_key_len(sm->mgmt_group_cipher); |
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+ u16 keyidx = WPA_GET_LE16(igtk->keyid); |
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+ |
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+ /* Detect possible key reinstallation */ |
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+ if (sm->igtk.igtk_len == len && |
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+ os_memcmp(sm->igtk.igtk, igtk->igtk, sm->igtk.igtk_len) == 0) { |
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+ wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, |
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+ "WPA: Not reinstalling already in-use IGTK to the driver (keyidx=%d)", |
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+ keyidx); |
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+ return 0; |
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+ } |
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+ |
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+ wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, |
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+ "WPA: IGTK keyid %d pn %02x%02x%02x%02x%02x%02x", |
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+ keyidx, MAC2STR(igtk->pn)); |
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+ wpa_hexdump_key(MSG_DEBUG, "WPA: IGTK", igtk->igtk, len); |
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+ if (keyidx > 4095) { |
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+ wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, |
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+ "WPA: Invalid IGTK KeyID %d", keyidx); |
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+ return -1; |
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+ } |
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+ if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher), |
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+ broadcast_ether_addr, |
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+ keyidx, 0, igtk->pn, sizeof(igtk->pn), |
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+ igtk->igtk, len) < 0) { |
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+ wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, |
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+ "WPA: Failed to configure IGTK to the driver"); |
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+ return -1; |
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+ } |
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+ |
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+ sm->igtk.igtk_len = len; |
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+ os_memcpy(sm->igtk.igtk, igtk->igtk, sm->igtk.igtk_len); |
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+ |
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+ return 0; |
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+} |
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+#endif /* CONFIG_IEEE80211W */ |
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+ |
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+ |
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static int ieee80211w_set_keys(struct wpa_sm *sm, |
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struct wpa_eapol_ie_parse *ie) |
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{ |
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@@ -864,30 +918,14 @@ static int ieee80211w_set_keys(struct wpa_sm *sm, |
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if (ie->igtk) { |
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size_t len; |
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const struct wpa_igtk_kde *igtk; |
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- u16 keyidx; |
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+ |
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len = wpa_cipher_key_len(sm->mgmt_group_cipher); |
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if (ie->igtk_len != WPA_IGTK_KDE_PREFIX_LEN + len) |
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return -1; |
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+ |
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igtk = (const struct wpa_igtk_kde *) ie->igtk; |
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- keyidx = WPA_GET_LE16(igtk->keyid); |
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- wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: IGTK keyid %d " |
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- "pn %02x%02x%02x%02x%02x%02x", |
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- keyidx, MAC2STR(igtk->pn)); |
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- wpa_hexdump_key(MSG_DEBUG, "WPA: IGTK", |
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- igtk->igtk, len); |
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- if (keyidx > 4095) { |
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- wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, |
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- "WPA: Invalid IGTK KeyID %d", keyidx); |
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- return -1; |
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- } |
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- if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher), |
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- broadcast_ether_addr, |
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- keyidx, 0, igtk->pn, sizeof(igtk->pn), |
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- igtk->igtk, len) < 0) { |
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- wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, |
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- "WPA: Failed to configure IGTK to the driver"); |
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+ if (wpa_supplicant_install_igtk(sm, igtk) < 0) |
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return -1; |
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- } |
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} |
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return 0; |
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@@ -2307,7 +2345,7 @@ void wpa_sm_deinit(struct wpa_sm *sm) |
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*/ |
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void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid) |
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{ |
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- int clear_ptk = 1; |
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+ int clear_keys = 1; |
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if (sm == NULL) |
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return; |
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@@ -2333,11 +2371,11 @@ void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid) |
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/* Prepare for the next transition */ |
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wpa_ft_prepare_auth_request(sm, NULL); |
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- clear_ptk = 0; |
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+ clear_keys = 0; |
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} |
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#endif /* CONFIG_IEEE80211R */ |
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- if (clear_ptk) { |
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+ if (clear_keys) { |
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/* |
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* IEEE 802.11, 8.4.10: Delete PTK SA on (re)association if |
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* this is not part of a Fast BSS Transition. |
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@@ -2347,6 +2385,10 @@ void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid) |
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os_memset(&sm->ptk, 0, sizeof(sm->ptk)); |
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sm->tptk_set = 0; |
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os_memset(&sm->tptk, 0, sizeof(sm->tptk)); |
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+ os_memset(&sm->gtk, 0, sizeof(sm->gtk)); |
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+#ifdef CONFIG_IEEE80211W |
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+ os_memset(&sm->igtk, 0, sizeof(sm->igtk)); |
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+#endif /* CONFIG_IEEE80211W */ |
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} |
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#ifdef CONFIG_TDLS |
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@@ -2877,6 +2919,10 @@ void wpa_sm_drop_sa(struct wpa_sm *sm) |
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os_memset(sm->pmk, 0, sizeof(sm->pmk)); |
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os_memset(&sm->ptk, 0, sizeof(sm->ptk)); |
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os_memset(&sm->tptk, 0, sizeof(sm->tptk)); |
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+ os_memset(&sm->gtk, 0, sizeof(sm->gtk)); |
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+#ifdef CONFIG_IEEE80211W |
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+ os_memset(&sm->igtk, 0, sizeof(sm->igtk)); |
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+#endif /* CONFIG_IEEE80211W */ |
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#ifdef CONFIG_IEEE80211R |
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os_memset(sm->xxkey, 0, sizeof(sm->xxkey)); |
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os_memset(sm->pmk_r0, 0, sizeof(sm->pmk_r0)); |
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@@ -2949,29 +2995,11 @@ int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf) |
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os_memset(&gd, 0, sizeof(gd)); |
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#ifdef CONFIG_IEEE80211W |
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} else if (subelem_id == WNM_SLEEP_SUBELEM_IGTK) { |
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- struct wpa_igtk_kde igd; |
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- u16 keyidx; |
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- |
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- os_memset(&igd, 0, sizeof(igd)); |
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- keylen = wpa_cipher_key_len(sm->mgmt_group_cipher); |
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- os_memcpy(igd.keyid, buf + 2, 2); |
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- os_memcpy(igd.pn, buf + 4, 6); |
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- |
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- keyidx = WPA_GET_LE16(igd.keyid); |
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- os_memcpy(igd.igtk, buf + 10, keylen); |
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- |
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- wpa_hexdump_key(MSG_DEBUG, "Install IGTK (WNM SLEEP)", |
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- igd.igtk, keylen); |
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- if (wpa_sm_set_key(sm, wpa_cipher_to_alg(sm->mgmt_group_cipher), |
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- broadcast_ether_addr, |
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- keyidx, 0, igd.pn, sizeof(igd.pn), |
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- igd.igtk, keylen) < 0) { |
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- wpa_printf(MSG_DEBUG, "Failed to install the IGTK in " |
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- "WNM mode"); |
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- os_memset(&igd, 0, sizeof(igd)); |
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+ const struct wpa_igtk_kde *igtk; |
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+ |
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+ igtk = (const struct wpa_igtk_kde *) (buf + 2); |
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+ if (wpa_supplicant_install_igtk(sm, igtk) < 0) |
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return -1; |
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- } |
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- os_memset(&igd, 0, sizeof(igd)); |
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#endif /* CONFIG_IEEE80211W */ |
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} else { |
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wpa_printf(MSG_DEBUG, "Unknown element id"); |
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diff --git a/src/rsn_supp/wpa_i.h b/src/rsn_supp/wpa_i.h |
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index f653ba6..afc9e37 100644 |
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--- a/src/rsn_supp/wpa_i.h |
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+++ b/src/rsn_supp/wpa_i.h |
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@@ -31,6 +31,10 @@ struct wpa_sm { |
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u8 rx_replay_counter[WPA_REPLAY_COUNTER_LEN]; |
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int rx_replay_counter_set; |
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u8 request_counter[WPA_REPLAY_COUNTER_LEN]; |
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+ struct wpa_gtk gtk; |
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+#ifdef CONFIG_IEEE80211W |
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+ struct wpa_igtk igtk; |
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+#endif /* CONFIG_IEEE80211W */ |
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struct eapol_sm *eapol; /* EAPOL state machine from upper level code */ |
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-- |
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2.7.4 |
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