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 3c61b632dde447b23c89ce0764cc5f210fba421a..21b35255ecc2498c51d919e9de223d39336e909f 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -221,8 +221,15 @@ 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 7b9a5ad7ba7ce6c2c62704e4ad1b2a749cbcc823..b1c017faa1ae99c9ba9d6d29d5145360de37ee86 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2057,7 +2057,6 @@ 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;
@@ -2072,8 +2071,8 @@ 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 c0529c4b60f82e23ff0a9513ff6ffd3822be71f1..7819a2507d3956613c19e3282837121290df1571 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 */