From: Mathy Vanhoef Mathy.Vanhoef@kuleuven.be

commit 94034c40ab4a3fcf581fbc7f8fdf4e29943c4a24 upstream.

Simultaneously prevent mixed key attacks (CVE-2020-24587) and fragment cache attacks (CVE-2020-24586). This is accomplished by assigning a unique color to every key (per interface) and using this to track which key was used to decrypt a fragment. When reassembling frames, it is now checked whether all fragments were decrypted using the same key.

To assure that fragment cache attacks are also prevented, the ID that is assigned to keys is unique even over (re)associations and (re)connects. This means fragments separated by a (re)association or (re)connect will not be reassembled. Because mac80211 now also prevents the reassembly of mixed encrypted and plaintext fragments, all cache attacks are prevented.

Cc: stable@vger.kernel.org Signed-off-by: Mathy Vanhoef Mathy.Vanhoef@kuleuven.be Link: https://lore.kernel.org/r/20210511200110.3f8290e59823.I622a67769ed39257327a3... Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/ieee80211_i.h | 1 + net/mac80211/key.c | 7 +++++++ net/mac80211/key.h | 2 ++ net/mac80211/rx.c | 6 ++++++ 4 files changed, 16 insertions(+)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 651705565dfb..74186c2d9e6e 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -99,6 +99,7 @@ struct ieee80211_fragment_entry { u8 rx_queue; bool check_sequential_pn; /* needed for CCMP/GCMP */ u8 last_pn[6]; /* PN of the last fragment if CCMP was used */ + unsigned int key_color; };

diff --git a/net/mac80211/key.c b/net/mac80211/key.c index fa10c6142244..d122031e389a 100644 --- a/net/mac80211/key.c +++ b/net/mac80211/key.c @@ -648,6 +648,7 @@ int ieee80211_key_link(struct ieee80211_key *key, struct sta_info *sta) { struct ieee80211_local *local = sdata->local; + static atomic_t key_color = ATOMIC_INIT(0); struct ieee80211_key *old_key; int idx = key->conf.keyidx; bool pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE; @@ -659,6 +660,12 @@ int ieee80211_key_link(struct ieee80211_key *key, bool delay_tailroom = sdata->vif.type == NL80211_IFTYPE_STATION; int ret;

+ /* + * Assign a unique ID to every key so we can easily prevent mixed + * key and fragment cache attacks. + */ + key->color = atomic_inc_return(&key_color); + mutex_lock(&sdata->local->key_mtx);

if (sta && pairwise) diff --git a/net/mac80211/key.h b/net/mac80211/key.h index ebdb80b85dc3..d8e187bcb751 100644 --- a/net/mac80211/key.h +++ b/net/mac80211/key.h @@ -127,6 +127,8 @@ struct ieee80211_key { } debugfs; #endif

+ unsigned int color; + /* * key config, must be last because it contains key * material as variable length member diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 9b313c2f7d49..8c126854aa06 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2029,6 +2029,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) * next fragment has a sequential PN value. */ entry->check_sequential_pn = true; + entry->key_color = rx->key->color; memcpy(entry->last_pn, rx->key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN); @@ -2066,6 +2067,11 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)

if (!requires_sequential_pn(rx, fc)) return RX_DROP_UNUSABLE; + + /* Prevent mixed key and fragment cache attacks */ + if (entry->key_color != rx->key->color) + return RX_DROP_UNUSABLE; + memcpy(pn, entry->last_pn, IEEE80211_CCMP_PN_LEN); for (i = IEEE80211_CCMP_PN_LEN - 1; i >= 0; i--) { pn[i]++;

From: Mathy Vanhoef Mathy.Vanhoef@kuleuven.be

commit 2b8a1fee3488c602aca8bea004a087e60806a5cf upstream.

Mitigate A-MSDU injection attacks (CVE-2020-24588) by detecting if the destination address of a subframe equals an RFC1042 (i.e., LLC/SNAP) header, and if so dropping the complete A-MSDU frame. This mitigates known attacks, although new (unknown) aggregation-based attacks may remain possible.

This defense works because in A-MSDU aggregation injection attacks, a normal encrypted Wi-Fi frame is turned into an A-MSDU frame. This means the first 6 bytes of the first A-MSDU subframe correspond to an RFC1042 header. In other words, the destination MAC address of the first A-MSDU subframe contains the start of an RFC1042 header during an aggregation attack. We can detect this and thereby prevent this specific attack. For details, see Section 7.2 of "Fragment and Forge: Breaking Wi-Fi Through Frame Aggregation and Fragmentation".

Note that for kernel 4.9 and above this patch depends on "mac80211: properly handle A-MSDUs that start with a rfc1042 header". Otherwise this patch has no impact and attacks will remain possible.

Cc: stable@vger.kernel.org Signed-off-by: Mathy Vanhoef Mathy.Vanhoef@kuleuven.be Link: https://lore.kernel.org/r/20210511200110.25d93176ddaf.I9e265b597f2cd23eb4457... Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/wireless/util.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/net/wireless/util.c b/net/wireless/util.c index 2aef1c487be6..b3895a8a48ab 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -768,6 +768,9 @@ void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list, remaining = skb->len - offset; if (subframe_len > remaining) goto purge; + /* mitigate A-MSDU aggregation injection attacks */ + if (ether_addr_equal(eth.h_dest, rfc1042_header)) + goto purge;

offset += sizeof(struct ethhdr); last = remaining <= subframe_len + padding;

From: Johannes Berg johannes.berg@intel.com

commit 3a11ce08c45b50d69c891d71760b7c5b92074709 upstream.

Prior patches protected against fragmentation cache attacks by coloring keys, but this shows that it can lead to issues when multiple stations use the same sequence number. Add a fragment cache to struct sta_info (in addition to the one in the interface) to separate fragments for different stations properly.

This then automatically clear most of the fragment cache when a station disconnects (or reassociates) from an AP, or when client interfaces disconnect from the network, etc.

On the way, also fix the comment there since this brings us in line with the recommendation in 802.11-2016 ("An AP should support ..."). Additionally, remove a useless condition (since there's no problem purging an already empty list).

Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210511200110.fc35046b0d52.I1ef101e3784d13e8f6600... Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/ieee80211_i.h | 26 ++++-------------------- net/mac80211/iface.c | 9 ++------- net/mac80211/rx.c | 41 ++++++++++++++++++++++++++++---------- net/mac80211/sta_info.c | 4 ++++ net/mac80211/sta_info.h | 30 ++++++++++++++++++++++++++++ 5 files changed, 70 insertions(+), 40 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 74186c2d9e6e..f38748efb98a 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -52,12 +52,6 @@ struct ieee80211_local; #define IEEE80211_ENCRYPT_HEADROOM 8 #define IEEE80211_ENCRYPT_TAILROOM 18

-/* IEEE 802.11 (Ch. 9.5 Defragmentation) requires support for concurrent - * reception of at least three fragmented frames. This limit can be increased - * by changing this define, at the cost of slower frame reassembly and - * increased memory use (about 2 kB of RAM per entry). */ -#define IEEE80211_FRAGMENT_MAX 4 - /* power level hasn't been configured (or set to automatic) */ #define IEEE80211_UNSET_POWER_LEVEL INT_MIN

@@ -90,19 +84,6 @@ extern const u8 ieee80211_ac_to_qos_mask[IEEE80211_NUM_ACS];

#define IEEE80211_MAX_NAN_INSTANCE_ID 255

-struct ieee80211_fragment_entry { - struct sk_buff_head skb_list; - unsigned long first_frag_time; - u16 seq; - u16 extra_len; - u16 last_frag; - u8 rx_queue; - bool check_sequential_pn; /* needed for CCMP/GCMP */ - u8 last_pn[6]; /* PN of the last fragment if CCMP was used */ - unsigned int key_color; -}; - - struct ieee80211_bss { u32 device_ts_beacon, device_ts_presp;

@@ -882,9 +863,7 @@ struct ieee80211_sub_if_data {

char name[IFNAMSIZ];

- /* Fragment table for host-based reassembly */ - struct ieee80211_fragment_entry fragments[IEEE80211_FRAGMENT_MAX]; - unsigned int fragment_next; + struct ieee80211_fragment_cache frags;

/* TID bitmap for NoAck policy */ u16 noack_map; @@ -2164,4 +2143,7 @@ extern const struct ethtool_ops ieee80211_ethtool_ops; #define debug_noinline #endif

+void ieee80211_init_frag_cache(struct ieee80211_fragment_cache *cache); +void ieee80211_destroy_frag_cache(struct ieee80211_fragment_cache *cache); + #endif /* IEEE80211_I_H */ diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index dc398a181678..adafa29d3021 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -1127,16 +1127,12 @@ static void ieee80211_set_multicast_list(struct net_device *dev) */ static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata) { - int i; - /* free extra data */ ieee80211_free_keys(sdata, false);

ieee80211_debugfs_remove_netdev(sdata);

- for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) - __skb_queue_purge(&sdata->fragments[i].skb_list); - sdata->fragment_next = 0; + ieee80211_destroy_frag_cache(&sdata->frags);

if (ieee80211_vif_is_mesh(&sdata->vif)) ieee80211_mesh_teardown_sdata(sdata); @@ -1846,8 +1842,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name, sdata->wdev.wiphy = local->hw.wiphy; sdata->local = local;

- for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) - skb_queue_head_init(&sdata->fragments[i].skb_list); + ieee80211_init_frag_cache(&sdata->frags);

INIT_LIST_HEAD(&sdata->key_list);

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index d6cdd0c025ca..39bc3d78f71a 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1899,19 +1899,34 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) return result; }

+void ieee80211_init_frag_cache(struct ieee80211_fragment_cache *cache) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cache->entries); i++) + skb_queue_head_init(&cache->entries[i].skb_list); +} + +void ieee80211_destroy_frag_cache(struct ieee80211_fragment_cache *cache) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cache->entries); i++) + __skb_queue_purge(&cache->entries[i].skb_list); +} + static inline struct ieee80211_fragment_entry * -ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata, +ieee80211_reassemble_add(struct ieee80211_fragment_cache *cache, unsigned int frag, unsigned int seq, int rx_queue, struct sk_buff **skb) { struct ieee80211_fragment_entry *entry;

- entry = &sdata->fragments[sdata->fragment_next++]; - if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX) - sdata->fragment_next = 0; + entry = &cache->entries[cache->next++]; + if (cache->next >= IEEE80211_FRAGMENT_MAX) + cache->next = 0;

- if (!skb_queue_empty(&entry->skb_list)) - __skb_queue_purge(&entry->skb_list); + __skb_queue_purge(&entry->skb_list);

__skb_queue_tail(&entry->skb_list, *skb); /* no need for locking */ *skb = NULL; @@ -1926,14 +1941,14 @@ ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata, }

static inline struct ieee80211_fragment_entry * -ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata, +ieee80211_reassemble_find(struct ieee80211_fragment_cache *cache, unsigned int frag, unsigned int seq, int rx_queue, struct ieee80211_hdr *hdr) { struct ieee80211_fragment_entry *entry; int i, idx;

- idx = sdata->fragment_next; + idx = cache->next; for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) { struct ieee80211_hdr *f_hdr;

@@ -1941,7 +1956,7 @@ ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata, if (idx < 0) idx = IEEE80211_FRAGMENT_MAX - 1;

- entry = &sdata->fragments[idx]; + entry = &cache->entries[idx]; if (skb_queue_empty(&entry->skb_list) || entry->seq != seq || entry->rx_queue != rx_queue || entry->last_frag + 1 != frag) @@ -1981,6 +1996,7 @@ static bool requires_sequential_pn(struct ieee80211_rx_data *rx, __le16 fc) static ieee80211_rx_result debug_noinline ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) { + struct ieee80211_fragment_cache *cache = &rx->sdata->frags; struct ieee80211_hdr *hdr; u16 sc; __le16 fc; @@ -2002,6 +2018,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) goto out_no_led; }

+ if (rx->sta) + cache = &rx->sta->frags; + if (likely(!ieee80211_has_morefrags(fc) && frag == 0)) goto out;

@@ -2020,7 +2039,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)

if (frag == 0) { /* This is the first fragment of a new frame. */ - entry = ieee80211_reassemble_add(rx->sdata, frag, seq, + entry = ieee80211_reassemble_add(cache, frag, seq, rx->seqno_idx, &(rx->skb)); if (requires_sequential_pn(rx, fc)) { int queue = rx->security_idx; @@ -2048,7 +2067,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) /* This is a fragment for a frame that should already be pending in * fragment cache. Add this fragment to the end of the pending entry. */ - entry = ieee80211_reassemble_find(rx->sdata, frag, seq, + entry = ieee80211_reassemble_find(cache, frag, seq, rx->seqno_idx, hdr); if (!entry) { I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag); diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 32fede73ecd4..0d5265adf539 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -367,6 +367,8 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,

u64_stats_init(&sta->rx_stats.syncp);

+ ieee80211_init_frag_cache(&sta->frags); + sta->sta_state = IEEE80211_STA_NONE;

/* Mark TID as unreserved */ @@ -1005,6 +1007,8 @@ static void __sta_info_destroy_part2(struct sta_info *sta) rate_control_remove_sta_debugfs(sta); ieee80211_sta_debugfs_remove(sta);

+ ieee80211_destroy_frag_cache(&sta->frags); + cleanup_single_sta(sta); }

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 3acbdfa9f649..0447197c4a2b 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -398,6 +398,33 @@ struct ieee80211_sta_rx_stats { u64 msdu[IEEE80211_NUM_TIDS + 1]; };

+/* + * IEEE 802.11-2016 (10.6 "Defragmentation") recommends support for "concurrent + * reception of at least one MSDU per access category per associated STA" + * on APs, or "at least one MSDU per access category" on other interface types. + * + * This limit can be increased by changing this define, at the cost of slower + * frame reassembly and increased memory use while fragments are pending. + */ +#define IEEE80211_FRAGMENT_MAX 4 + +struct ieee80211_fragment_entry { + struct sk_buff_head skb_list; + unsigned long first_frag_time; + u16 seq; + u16 extra_len; + u16 last_frag; + u8 rx_queue; + bool check_sequential_pn; /* needed for CCMP/GCMP */ + u8 last_pn[6]; /* PN of the last fragment if CCMP was used */ + unsigned int key_color; +}; + +struct ieee80211_fragment_cache { + struct ieee80211_fragment_entry entries[IEEE80211_FRAGMENT_MAX]; + unsigned int next; +}; + /** * The bandwidth threshold below which the per-station CoDel parameters will be * scaled to be more lenient (to prevent starvation of slow stations). This @@ -470,6 +497,7 @@ struct ieee80211_sta_rx_stats { * @pcpu_rx_stats: per-CPU RX statistics, assigned only if the driver needs * this (by advertising the USES_RSS hw flag) * @status_stats: TX status statistics + * @frags: fragment cache */ struct sta_info { /* General information, mostly static */ @@ -569,6 +597,8 @@ struct sta_info {

struct cfg80211_chan_def tdls_chandef;

+ struct ieee80211_fragment_cache frags; + /* keep last! */ struct ieee80211_sta sta; };

From: Johannes Berg johannes.berg@intel.com

commit 7e44a0b597f04e67eee8cdcbe7ee706c6f5de38b upstream.

Similar to the issues fixed in previous patches, TKIP and WEP should be protected even if for TKIP we have the Michael MIC protecting it, and WEP is broken anyway.

However, this also somewhat protects potential other algorithms that drivers might implement.

Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210511200110.430e8c202313.Ia37e4e5b6b3eaab1a5ae0... Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/rx.c | 12 ++++++++++++ net/mac80211/sta_info.h | 3 ++- 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index a00ec2ccb363..61fe65696e6e 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2048,6 +2048,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) * next fragment has a sequential PN value. */ entry->check_sequential_pn = true; + entry->is_protected = true; entry->key_color = rx->key->color; memcpy(entry->last_pn, rx->key->u.ccmp.rx_pn[queue], @@ -2060,6 +2061,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) sizeof(rx->key->u.gcmp.rx_pn[queue])); BUILD_BUG_ON(IEEE80211_CCMP_PN_LEN != IEEE80211_GCMP_PN_LEN); + } else if (rx->key && ieee80211_has_protected(fc)) { + entry->is_protected = true; + entry->key_color = rx->key->color; } return RX_QUEUED; } @@ -2101,6 +2105,14 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN)) return RX_DROP_UNUSABLE; memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN); + } else if (entry->is_protected && + (!rx->key || !ieee80211_has_protected(fc) || + rx->key->color != entry->key_color)) { + /* Drop this as a mixed key or fragment cache attack, even + * if for TKIP Michael MIC should protect us, and WEP is a + * lost cause anyway. + */ + return RX_DROP_UNUSABLE; }

skb_pull(rx->skb, ieee80211_hdrlen(fc)); diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 0447197c4a2b..f1d293f5678f 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -415,7 +415,8 @@ struct ieee80211_fragment_entry { u16 extra_len; u16 last_frag; u8 rx_queue; - bool check_sequential_pn; /* needed for CCMP/GCMP */ + u8 check_sequential_pn:1, /* needed for CCMP/GCMP */ + is_protected:1; u8 last_pn[6]; /* PN of the last fragment if CCMP was used */ unsigned int key_color; };

From: Wen Gong wgong@codeaurora.org

commit 3edc6b0d6c061a70d8ca3c3c72eb1f58ce29bfb1 upstream.

For some chips/drivers, e.g., QCA6174 with ath10k, the decryption is done by the hardware, and the Protected bit in the Frame Control field is cleared in the lower level driver before the frame is passed to mac80211. In such cases, the condition for ieee80211_has_protected() is not met in ieee80211_rx_h_defragment() of mac80211 and the new security validation steps are not executed.

Extend mac80211 to cover the case where the Protected bit has been cleared, but the frame is indicated as having been decrypted by the hardware. This extends protection against mixed key and fragment cache attack for additional drivers/chips. This fixes CVE-2020-24586 and CVE-2020-24587 for such cases.

Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1

Cc: stable@vger.kernel.org Signed-off-by: Wen Gong wgong@codeaurora.org Signed-off-by: Jouni Malinen jouni@codeaurora.org Link: https://lore.kernel.org/r/20210511200110.037aa5ca0390.I7bb888e2965a0db02a670... Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/rx.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 2fe18dc6af86..6b4fd56800f7 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2003,6 +2003,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) unsigned int frag, seq; struct ieee80211_fragment_entry *entry; struct sk_buff *skb; + struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);

hdr = (struct ieee80211_hdr *)rx->skb->data; fc = hdr->frame_control; @@ -2061,7 +2062,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) sizeof(rx->key->u.gcmp.rx_pn[queue])); BUILD_BUG_ON(IEEE80211_CCMP_PN_LEN != IEEE80211_GCMP_PN_LEN); - } else if (rx->key && ieee80211_has_protected(fc)) { + } else if (rx->key && + (ieee80211_has_protected(fc) || + (status->flag & RX_FLAG_DECRYPTED))) { entry->is_protected = true; entry->key_color = rx->key->color; } @@ -2106,13 +2109,19 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) return RX_DROP_UNUSABLE; memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN); } else if (entry->is_protected && - (!rx->key || !ieee80211_has_protected(fc) || + (!rx->key || + (!ieee80211_has_protected(fc) && + !(status->flag & RX_FLAG_DECRYPTED)) || rx->key->color != entry->key_color)) { /* Drop this as a mixed key or fragment cache attack, even * if for TKIP Michael MIC should protect us, and WEP is a * lost cause anyway. */ return RX_DROP_UNUSABLE; + } else if (entry->is_protected && rx->key && + entry->key_color != rx->key->color && + (status->flag & RX_FLAG_DECRYPTED)) { + return RX_DROP_UNUSABLE; }

skb_pull(rx->skb, ieee80211_hdrlen(fc));