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 f38748efb98a7b227cfc5d98daf5d3a65150bf64..790c771e8108ef3be4c28dd4fc36b8d3683dd58c 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -223,8 +223,15 @@ 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 39bc3d78f71a8b1720bb38f22253c0e73377e153..a00ec2ccb36321c78bbc30b39fa439b0ea46033c 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2082,7 +2082,6 @@ 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;
@@ -2097,8 +2096,8 @@ 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 e3bb69ba688790b9706ed7205de9f7997d7d3b96..09b4f913e20b13bd272cec7ba2e565901837cbc8 100644 (file)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -162,8 +162,8 @@ 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;
 
@@ -289,8 +289,8 @@ 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;
 
@@ -548,6 +548,8 @@ 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 */
@@ -777,6 +779,8 @@ 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 */