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+From fdf7cb4185b60c68e1a75e61691c4afdc15dea0e Mon Sep 17 00:00:00 2001
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+From: Johannes Berg <johannes.berg@intel.com>
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+Date: Tue, 5 Sep 2017 14:54:54 +0200
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+Subject: [PATCH] mac80211: accept key reinstall without changing anything
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+
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+When a key is reinstalled we can reset the replay counters
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+etc. which can lead to nonce reuse and/or replay detection
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+being impossible, breaking security properties, as described
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+in the "KRACK attacks".
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+
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+In particular, CVE-2017-13080 applies to GTK rekeying that
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+happened in firmware while the host is in D3, with the second
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+part of the attack being done after the host wakes up. In
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+this case, the wpa_supplicant mitigation isn't sufficient
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+since wpa_supplicant doesn't know the GTK material.
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+
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+In case this happens, simply silently accept the new key
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+coming from userspace but don't take any action on it since
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+it's the same key; this keeps the PN replay counters intact.
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+
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+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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+---
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+ net/mac80211/key.c | 21 +++++++++++++++++----
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+ 1 file changed, 17 insertions(+), 4 deletions(-)
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+
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+diff --git a/net/mac80211/key.c b/net/mac80211/key.c
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+index a98fc2b5e0dc..ae995c8480db 100644
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+--- a/net/mac80211/key.c
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++++ b/net/mac80211/key.c
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+@@ -4,7 +4,7 @@
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+ * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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+ * Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
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+ * Copyright 2013-2014 Intel Mobile Communications GmbH
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+- * Copyright 2015 Intel Deutschland GmbH
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++ * Copyright 2015-2017 Intel Deutschland GmbH
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+@@ -620,9 +620,6 @@ int ieee80211_key_link(struct ieee80211_key *key,
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+
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+ pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
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+ idx = key->conf.keyidx;
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+- key->local = sdata->local;
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+- key->sdata = sdata;
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+- key->sta = sta;
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+
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+ mutex_lock(&sdata->local->key_mtx);
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+
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+@@ -633,6 +630,21 @@ int ieee80211_key_link(struct ieee80211_key *key,
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+ else
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+ old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
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+
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++ /*
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++ * Silently accept key re-installation without really installing the
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++ * new version of the key to avoid nonce reuse or replay issues.
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++ */
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++ if (old_key && key->conf.keylen == old_key->conf.keylen &&
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++ !memcmp(key->conf.key, old_key->conf.key, key->conf.keylen)) {
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++ ieee80211_key_free_unused(key);
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++ ret = 0;
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++ goto out;
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++ }
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++
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++ key->local = sdata->local;
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++ key->sdata = sdata;
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++ key->sta = sta;
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++
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+ increment_tailroom_need_count(sdata);
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+
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+ ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
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+@@ -648,6 +660,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
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+ ret = 0;
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+ }
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+
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++ out:
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+ mutex_unlock(&sdata->local->key_mtx);
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+
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+ return ret;
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+--
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+2.13.6
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+
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