Commit e66b7920 authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
Browse files

wifi: mac80211: fix initialization of rx->link and rx->link_sta 



There are some codepaths that do not initialize rx->link_sta properly. This
causes a crash in places which assume that rx->link_sta is valid if rx->sta
is valid.
One known instance is triggered by __ieee80211_rx_h_amsdu being called from
fast-rx. It results in a crash like this one:

 BUG: kernel NULL pointer dereference, address: 00000000000000a8
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page PGD 0 P4D 0
 Oops: 0002 [#1] PREEMPT SMP PTI
 CPU: 1 PID: 506 Comm: mt76-usb-rx phy Tainted: G            E      6.1.0-debian64x+1.7 #3
 Hardware name: ZOTAC ZBOX-ID92/ZBOX-IQ01/ZBOX-ID92/ZBOX-IQ01, BIOS B220P007 05/21/2014
 RIP: 0010:ieee80211_deliver_skb+0x62/0x1f0 [mac80211]
 Code: 00 48 89 04 24 e8 9e a7 c3 df 89 c0 48 03 1c c5 a0 ea 39 a1 4c 01 6b 08 48 ff 03 48
       83 7d 28 00 74 11 48 8b 45 30 48 63 55 44 <48> 83 84 d0 a8 00 00 00 01 41 8b 86 c0
       11 00 00 8d 50 fd 83 fa 01
 RSP: 0018:ffff999040803b10 EFLAGS: 00010286
 RAX: 0000000000000000 RBX: ffffb9903f496480 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: ffff999040803ce0 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8d21828ac900
 R13: 000000000000004a R14: ffff8d2198ed89c0 R15: ffff8d2198ed8000
 FS:  0000000000000000(0000) GS:ffff8d24afe80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000000000a8 CR3: 0000000429810002 CR4: 00000000001706e0
 Call Trace:
  <TASK>
  __ieee80211_rx_h_amsdu+0x1b5/0x240 [mac80211]
  ? ieee80211_prepare_and_rx_handle+0xcdd/0x1320 [mac80211]
  ? __local_bh_enable_ip+0x3b/0xa0
  ieee80211_prepare_and_rx_handle+0xcdd/0x1320 [mac80211]
  ? prepare_transfer+0x109/0x1a0 [xhci_hcd]
  ieee80211_rx_list+0xa80/0xda0 [mac80211]
  mt76_rx_complete+0x207/0x2e0 [mt76]
  mt76_rx_poll_complete+0x357/0x5a0 [mt76]
  mt76u_rx_worker+0x4f5/0x600 [mt76_usb]
  ? mt76_get_min_avg_rssi+0x140/0x140 [mt76]
  __mt76_worker_fn+0x50/0x80 [mt76]
  kthread+0xed/0x120
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x22/0x30

Since the initialization of rx->link and rx->link_sta is rather convoluted
and duplicated in many places, clean it up by using a helper function to
set it.

Fixes: ccdde7c7 ("wifi: mac80211: properly implement MLO key handling")
Fixes: b320d6c4 ("wifi: mac80211: use correct rx link_sta instead of default")
Signed-off-by: default avatarFelix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20221230200747.19040-1-nbd@nbd.name


[remove unnecessary rx->sta->sta.mlo check]
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 7d6ceeb1

net/mac80211/rx.c

+99 −123
Original line number Diff line number Diff line
@@ -4049,6 +4049,58 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_rx_data *rx) 
#undef CALL_RXH

}



static bool

ieee80211_rx_is_valid_sta_link_id(struct ieee80211_sta *sta, u8 link_id)

{

	if (!sta->mlo)

		return false;



	return !!(sta->valid_links & BIT(link_id));

}



static bool ieee80211_rx_data_set_link(struct ieee80211_rx_data *rx,

				       u8 link_id)

{

	rx->link_id = link_id;

	rx->link = rcu_dereference(rx->sdata->link[link_id]);



	if (!rx->sta)

		return rx->link;



	if (!ieee80211_rx_is_valid_sta_link_id(&rx->sta->sta, link_id))

		return false;



	rx->link_sta = rcu_dereference(rx->sta->link[link_id]);



	return rx->link && rx->link_sta;

}



static bool ieee80211_rx_data_set_sta(struct ieee80211_rx_data *rx,

				      struct ieee80211_sta *pubsta,

				      int link_id)

{

	struct sta_info *sta;



	sta = container_of(pubsta, struct sta_info, sta);



	rx->link_id = link_id;

	rx->sta = sta;



	if (sta) {

		rx->local = sta->sdata->local;

		if (!rx->sdata)

			rx->sdata = sta->sdata;

		rx->link_sta = &sta->deflink;

	}



	if (link_id < 0)

		rx->link = &rx->sdata->deflink;

	else if (!ieee80211_rx_data_set_link(rx, link_id))

		return false;



	return true;

}



/*

 * This function makes calls into the RX path, therefore

 * it has to be invoked under RCU read lock.
@@ -4057,16 +4109,19 @@ void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid) 
{

	struct sk_buff_head frames;

	struct ieee80211_rx_data rx = {

		.sta = sta,

		.sdata = sta->sdata,

		.local = sta->local,

		/* This is OK -- must be QoS data frame */

		.security_idx = tid,

		.seqno_idx = tid,

		.link_id = -1,

	};

	struct tid_ampdu_rx *tid_agg_rx;

	u8 link_id;

	int link_id = -1;



	/* FIXME: statistics won't be right with this */

	if (sta->sta.valid_links)

		link_id = ffs(sta->sta.valid_links) - 1;



	if (!ieee80211_rx_data_set_sta(&rx, &sta->sta, link_id))

		return;



	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);

	if (!tid_agg_rx)
@@ -4086,10 +4141,6 @@ void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid) 
		};

		drv_event_callback(rx.local, rx.sdata, &event);

	}

	/* FIXME: statistics won't be right with this */

	link_id = sta->sta.valid_links ? ffs(sta->sta.valid_links) - 1 : 0;

	rx.link = rcu_dereference(sta->sdata->link[link_id]);

	rx.link_sta = rcu_dereference(sta->link[link_id]);



	ieee80211_rx_handlers(&rx, &frames);

}
@@ -4105,7 +4156,6 @@ void ieee80211_mark_rx_ba_filtered_frames(struct ieee80211_sta *pubsta, u8 tid, 
		/* This is OK -- must be QoS data frame */

		.security_idx = tid,

		.seqno_idx = tid,

		.link_id = -1,

	};

	int i, diff;
@@ -4116,10 +4166,8 @@ void ieee80211_mark_rx_ba_filtered_frames(struct ieee80211_sta *pubsta, u8 tid, 


	sta = container_of(pubsta, struct sta_info, sta);



	rx.sta = sta;

	rx.sdata = sta->sdata;

	rx.link = &rx.sdata->deflink;

	rx.local = sta->local;

	if (!ieee80211_rx_data_set_sta(&rx, pubsta, -1))

		return;



	rcu_read_lock();

	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
@@ -4506,15 +4554,6 @@ void ieee80211_check_fast_rx_iface(struct ieee80211_sub_if_data *sdata) 
	mutex_unlock(&local->sta_mtx);

}



static bool

ieee80211_rx_is_valid_sta_link_id(struct ieee80211_sta *sta, u8 link_id)

{

	if (!sta->mlo)

		return false;



	return !!(sta->valid_links & BIT(link_id));

}



static void ieee80211_rx_8023(struct ieee80211_rx_data *rx,

			      struct ieee80211_fast_rx *fast_rx,

			      int orig_len)
@@ -4625,7 +4664,6 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx, 
	struct sk_buff *skb = rx->skb;

	struct ieee80211_hdr *hdr = (void *)skb->data;

	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);

	struct sta_info *sta = rx->sta;

	int orig_len = skb->len;

	int hdrlen = ieee80211_hdrlen(hdr->frame_control);

	int snap_offs = hdrlen;
@@ -4637,7 +4675,6 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx, 
		u8 da[ETH_ALEN];

		u8 sa[ETH_ALEN];

	} addrs __aligned(2);

	struct link_sta_info *link_sta;

	struct ieee80211_sta_rx_stats *stats;



	/* for parallel-rx, we need to have DUP_VALIDATED, otherwise we write
@@ -4740,18 +4777,10 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx, 
 drop:

	dev_kfree_skb(skb);



	if (rx->link_id >= 0) {

		link_sta = rcu_dereference(sta->link[rx->link_id]);

		if (!link_sta)

			return true;

	} else {

		link_sta = &sta->deflink;

	}



	if (fast_rx->uses_rss)

		stats = this_cpu_ptr(link_sta->pcpu_rx_stats);

		stats = this_cpu_ptr(rx->link_sta->pcpu_rx_stats);

	else

		stats = &link_sta->rx_stats;

		stats = &rx->link_sta->rx_stats;



	stats->dropped++;

	return true;
@@ -4769,8 +4798,8 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx, 
	struct ieee80211_local *local = rx->local;

	struct ieee80211_sub_if_data *sdata = rx->sdata;

	struct ieee80211_hdr *hdr = (void *)skb->data;

	struct link_sta_info *link_sta = NULL;

	struct ieee80211_link_data *link;

	struct link_sta_info *link_sta = rx->link_sta;

	struct ieee80211_link_data *link = rx->link;



	rx->skb = skb;
@@ -4792,35 +4821,6 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx, 
	if (!ieee80211_accept_frame(rx))

		return false;



	if (rx->link_id >= 0) {

		link = rcu_dereference(rx->sdata->link[rx->link_id]);



		/* we might race link removal */

		if (!link)

			return true;

		rx->link = link;



		if (rx->sta) {

			rx->link_sta =

				rcu_dereference(rx->sta->link[rx->link_id]);

			if (!rx->link_sta)

				return true;

		}

	} else {

		if (rx->sta)

			rx->link_sta = &rx->sta->deflink;



		rx->link = &sdata->deflink;

	}



	if (unlikely(!is_multicast_ether_addr(hdr->addr1) &&

		     rx->link_id >= 0 && rx->sta && rx->sta->sta.mlo)) {

		link_sta = rcu_dereference(rx->sta->link[rx->link_id]);



		if (WARN_ON_ONCE(!link_sta))

			return true;

	}



	if (!consume) {

		struct skb_shared_hwtstamps *shwt;
@@ -4840,7 +4840,7 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx, 
		shwt->hwtstamp = skb_hwtstamps(skb)->hwtstamp;

	}



	if (unlikely(link_sta)) {

	if (unlikely(rx->sta && rx->sta->sta.mlo)) {

		/* translate to MLD addresses */

		if (ether_addr_equal(link->conf->addr, hdr->addr1))

			ether_addr_copy(hdr->addr1, rx->sdata->vif.addr);
@@ -4870,6 +4870,7 @@ static void __ieee80211_rx_handle_8023(struct ieee80211_hw *hw, 
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);

	struct ieee80211_fast_rx *fast_rx;

	struct ieee80211_rx_data rx;

	int link_id = -1;



	memset(&rx, 0, sizeof(rx));

	rx.skb = skb;
@@ -4886,12 +4887,8 @@ static void __ieee80211_rx_handle_8023(struct ieee80211_hw *hw, 
	if (!pubsta)

		goto drop;



	rx.sta = container_of(pubsta, struct sta_info, sta);

	rx.sdata = rx.sta->sdata;



	if (status->link_valid &&

	    !ieee80211_rx_is_valid_sta_link_id(pubsta, status->link_id))

		goto drop;

	if (status->link_valid)

		link_id = status->link_id;



	/*

	 * TODO: Should the frame be dropped if the right link_id is not
@@ -4900,19 +4897,8 @@ static void __ieee80211_rx_handle_8023(struct ieee80211_hw *hw, 
	 * link_id is used only for stats purpose and updating the stats on

	 * the deflink is fine?

	 */

	if (status->link_valid)

		rx.link_id = status->link_id;



	if (rx.link_id >= 0) {

		struct ieee80211_link_data *link;



		link =  rcu_dereference(rx.sdata->link[rx.link_id]);

		if (!link)

	if (!ieee80211_rx_data_set_sta(&rx, pubsta, link_id))

		goto drop;

		rx.link = link;

	} else {

		rx.link = &rx.sdata->deflink;

	}



	fast_rx = rcu_dereference(rx.sta->fast_rx);

	if (!fast_rx)
@@ -4930,6 +4916,8 @@ static bool ieee80211_rx_for_interface(struct ieee80211_rx_data *rx, 
{

	struct link_sta_info *link_sta;

	struct ieee80211_hdr *hdr = (void *)skb->data;

	struct sta_info *sta;

	int link_id = -1;



	/*

	 * Look up link station first, in case there's a
@@ -4939,24 +4927,19 @@ static bool ieee80211_rx_for_interface(struct ieee80211_rx_data *rx, 
	 */

	link_sta = link_sta_info_get_bss(rx->sdata, hdr->addr2);

	if (link_sta) {

		rx->sta = link_sta->sta;

		rx->link_id = link_sta->link_id;

		sta = link_sta->sta;

		link_id = link_sta->link_id;

	} else {

		struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);



		rx->sta = sta_info_get_bss(rx->sdata, hdr->addr2);

		if (rx->sta) {

			if (status->link_valid &&

			    !ieee80211_rx_is_valid_sta_link_id(&rx->sta->sta,

							       status->link_id))

				return false;



			rx->link_id = status->link_valid ? status->link_id : -1;

		} else {

			rx->link_id = -1;

		}

		sta = sta_info_get_bss(rx->sdata, hdr->addr2);

		if (status->link_valid)

			link_id = status->link_id;

	}



	if (!ieee80211_rx_data_set_sta(rx, &sta->sta, link_id))

		return false;



	return ieee80211_prepare_and_rx_handle(rx, skb, consume);

}
@@ -5015,19 +4998,15 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, 


	if (ieee80211_is_data(fc)) {

		struct sta_info *sta, *prev_sta;

		u8 link_id = status->link_id;

		int link_id = -1;



		if (pubsta) {

			rx.sta = container_of(pubsta, struct sta_info, sta);

			rx.sdata = rx.sta->sdata;

		if (status->link_valid)

			link_id = status->link_id;



			if (status->link_valid &&

			    !ieee80211_rx_is_valid_sta_link_id(pubsta, link_id))

		if (pubsta) {

			if (!ieee80211_rx_data_set_sta(&rx, pubsta, link_id))

				goto out;



			if (status->link_valid)

				rx.link_id = status->link_id;



			/*

			 * In MLO connection, fetch the link_id using addr2

			 * when the driver does not pass link_id in status.
@@ -5045,7 +5024,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, 
				if (!link_sta)

					goto out;



				rx.link_id = link_sta->link_id;

				ieee80211_rx_data_set_link(&rx, link_sta->link_id);

			}



			if (ieee80211_prepare_and_rx_handle(&rx, skb, true))
@@ -5061,30 +5040,27 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, 
				continue;

			}



			if ((status->link_valid &&

			     !ieee80211_rx_is_valid_sta_link_id(&prev_sta->sta,

								link_id)) ||

			    (!status->link_valid && prev_sta->sta.mlo))

			rx.sdata = prev_sta->sdata;

			if (!ieee80211_rx_data_set_sta(&rx, &prev_sta->sta,

						       link_id))

				goto out;



			if (!status->link_valid && prev_sta->sta.mlo)

				continue;



			rx.link_id = status->link_valid ? link_id : -1;

			rx.sta = prev_sta;

			rx.sdata = prev_sta->sdata;

			ieee80211_prepare_and_rx_handle(&rx, skb, false);



			prev_sta = sta;

		}



		if (prev_sta) {

			if ((status->link_valid &&

			     !ieee80211_rx_is_valid_sta_link_id(&prev_sta->sta,

								link_id)) ||

			    (!status->link_valid && prev_sta->sta.mlo))

			rx.sdata = prev_sta->sdata;

			if (!ieee80211_rx_data_set_sta(&rx, &prev_sta->sta,

						       link_id))

				goto out;



			rx.link_id = status->link_valid ? link_id : -1;

			rx.sta = prev_sta;

			rx.sdata = prev_sta->sdata;

			if (!status->link_valid && prev_sta->sta.mlo)

				goto out;



			if (ieee80211_prepare_and_rx_handle(&rx, skb, true))

				return;