mac80211: check defrag PN against current frame

commit bf30ca922a0c0176007e074b0acc77ed345e9990 upstream.

As pointed out by Mathy Vanhoef, we implement the RX PN check
on fragmented frames incorrectly - we check against the last
received PN prior to the new frame, rather than to the one in
this frame itself.

Prior patches addressed the security issue here, but in order
to be able to reason better about the code, fix it to really
compare against the current frame's PN, not the last stored
one.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.bfbc340ff071.Id0b690e581da7d03d76df90bb0e3fd55930bc8a0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 1bfcdb671ca6690bb44ca658a68565d6c668c382..a7933279a80b777fc03073249e6fc8c149609dad 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -222,8 +222,15 @@ struct ieee80211_rx_data {
         */
        int security_idx;
 
-       u32 tkip_iv32;
-       u16 tkip_iv16;
+       union {
+               struct {
+                       u32 iv32;
+                       u16 iv16;
+               } tkip;
+               struct {
+                       u8 pn[IEEE80211_CCMP_PN_LEN];
+               } ccm_gcm;
+       };
 };
 
 struct ieee80211_csa_settings {

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 2ecbdff867e2c5b800baebc56a71b6ab569f8f19..7e132431de5a604c3334ebb40efdd26a9eac32f5 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2268,7 +2268,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
        if (entry->check_sequential_pn) {
                int i;
                u8 pn[IEEE80211_CCMP_PN_LEN], *rpn;
-               int queue;
 
                if (!requires_sequential_pn(rx, fc))
                        return RX_DROP_UNUSABLE;
@@ -2283,8 +2282,8 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
                        if (pn[i])
                                break;
                }
-               queue = rx->security_idx;
-               rpn = rx->key->u.ccmp.rx_pn[queue];
+
+               rpn = rx->ccm_gcm.pn;
                if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN))
                        return RX_DROP_UNUSABLE;
                memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN);

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 91bf32af55e9aab807ee350d4db06da2c9bdb161..bca47fad5a16280b808bef4c8832d6f0e0626b37 100644 (file)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -3,6 +3,7 @@
  * Copyright 2002-2004, Instant802 Networks, Inc.
  * Copyright 2008, Jouni Malinen <j@w1.fi>
  * Copyright (C) 2016-2017 Intel Deutschland GmbH
+ * Copyright (C) 2020-2021 Intel Corporation
  */
 
 #include <linux/netdevice.h>
@@ -167,8 +168,8 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 
 update_iv:
        /* update IV in key information to be able to detect replays */
-       rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
-       rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
+       rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip.iv32;
+       rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip.iv16;
 
        return RX_CONTINUE;
 
@@ -294,8 +295,8 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
                                          key, skb->data + hdrlen,
                                          skb->len - hdrlen, rx->sta->sta.addr,
                                          hdr->addr1, hwaccel, rx->security_idx,
-                                         &rx->tkip_iv32,
-                                         &rx->tkip_iv16);
+                                         &rx->tkip.iv32,
+                                         &rx->tkip.iv16);
        if (res != TKIP_DECRYPT_OK)
                return RX_DROP_UNUSABLE;
 
@@ -553,6 +554,8 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
                }
 
                memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
+               if (unlikely(ieee80211_is_frag(hdr)))
+                       memcpy(rx->ccm_gcm.pn, pn, IEEE80211_CCMP_PN_LEN);
        }
 
        /* Remove CCMP header and MIC */
@@ -781,6 +784,8 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
                }
 
                memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
+               if (unlikely(ieee80211_is_frag(hdr)))
+                       memcpy(rx->ccm_gcm.pn, pn, IEEE80211_CCMP_PN_LEN);
        }
 
        /* Remove GCMP header and MIC */