Skip to content

Commit

Permalink
wifi: mac80211: fix initialization of rx->link and rx->link_sta
Browse files Browse the repository at this point in the history 
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: ccdde7c ("wifi: mac80211: properly implement MLO key handling")
Fixes: b320d6c ("wifi: mac80211: use correct rx link_sta instead of default")
Signed-off-by: Felix 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: Johannes Berg <johannes.berg@intel.com>
  • Loading branch information
@nbd168 @jmberg-intel
nbd168 authored and jmberg-intel committed Jan 10, 2023
1 parent 7d6ceeb commit e66b792
Showing 1 changed file with 99 additions and 123 deletions.
222 changes: 99 additions & 123 deletions net/mac80211/rx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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)
Expand All @@ -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);
}
Expand All @@ -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;

Expand All @@ -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]);
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand All @@ -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;

Expand All @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand All @@ -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)
goto drop;
rx.link = link;
} else {
rx.link = &rx.sdata->deflink;
}
if (!ieee80211_rx_data_set_sta(&rx, pubsta, link_id))
goto drop;

fast_rx = rcu_dereference(rx.sta->fast_rx);
if (!fast_rx)
Expand All @@ -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
Expand All @@ -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);
}

Expand Down Expand Up @@ -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.
Expand All @@ -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))
Expand All @@ -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;
Expand Down

0 comments on commit e66b792

Please sign in to comment.