1 files changed, 50 insertions, 4 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index a98fc2b5e0dc..938049395f90 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -4,7 +4,7 @@
  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
  * Copyright 2007-2008  Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
- * Copyright 2015       Intel Deutschland GmbH
+ * Copyright 2015-2017  Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <net/mac80211.h>
+#include <crypto/algapi.h>
 #include <asm/unaligned.h>
 #include "ieee80211_i.h"
 #include "driver-ops.h"
@@ -609,6 +610,39 @@ void ieee80211_key_free_unused(struct ieee80211_key *key)
         ieee80211_key_free_common(key);
 }
 
+static bool ieee80211_key_identical(struct ieee80211_sub_if_data *sdata,
+                                    struct ieee80211_key *old,
+                                    struct ieee80211_key *new)
+{
+        u8 tkip_old[WLAN_KEY_LEN_TKIP], tkip_new[WLAN_KEY_LEN_TKIP];
+        u8 *tk_old, *tk_new;
+
+        if (!old || new->conf.keylen != old->conf.keylen)
+                return false;
+
+        tk_old = old->conf.key;
+        tk_new = new->conf.key;
+
+        /*
+         * In station mode, don't compare the TX MIC key, as it's never used
+         * and offloaded rekeying may not care to send it to the host. This
+         * is the case in iwlwifi, for example.
+         */
+        if (sdata->vif.type == NL80211_IFTYPE_STATION &&
+            new->conf.cipher == WLAN_CIPHER_SUITE_TKIP &&
+            new->conf.keylen == WLAN_KEY_LEN_TKIP &&
+            !(new->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
+                memcpy(tkip_old, tk_old, WLAN_KEY_LEN_TKIP);
+                memcpy(tkip_new, tk_new, WLAN_KEY_LEN_TKIP);
+                memset(tkip_old + NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY, 0, 8);
+                memset(tkip_new + NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY, 0, 8);
+                tk_old = tkip_old;
+                tk_new = tkip_new;
+        }
+
+        return !crypto_memneq(tk_old, tk_new, new->conf.keylen);
+}
+
 int ieee80211_key_link(struct ieee80211_key *key,
                        struct ieee80211_sub_if_data *sdata,
                        struct sta_info *sta)
@@ -620,9 +654,6 @@ int ieee80211_key_link(struct ieee80211_key *key,
 
         pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
         idx = key->conf.keyidx;
-        key->local = sdata->local;
-        key->sdata = sdata;
-        key->sta = sta;
 
         mutex_lock(&sdata->local->key_mtx);
 
@@ -633,6 +664,20 @@ int ieee80211_key_link(struct ieee80211_key *key,
         else
                 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
 
+        /*
+         * Silently accept key re-installation without really installing the
+         * new version of the key to avoid nonce reuse or replay issues.
+         */
+        if (ieee80211_key_identical(sdata, old_key, key)) {
+                ieee80211_key_free_unused(key);
+                ret = 0;
+                goto out;
+        }
+
+        key->local = sdata->local;
+        key->sdata = sdata;
+        key->sta = sta;
+
         increment_tailroom_need_count(sdata);
 
         ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
@@ -648,6 +693,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
                 ret = 0;
         }
 
+ out:
         mutex_unlock(&sdata->local->key_mtx);
 
         return ret;