2024-01-29 14:54:01

by Johannes Berg

[permalink] [raw]
Subject: [PATCH] wifi: mac80211: fix RCU use in TDLS fast-xmit

From: Johannes Berg <[email protected]>

This looks up the link under RCU protection, but isn't
guaranteed to actually have protection. Fix that.

Fixes: 8cc07265b691 ("wifi: mac80211: handle TDLS data frames with MLO")
Signed-off-by: Johannes Berg <[email protected]>
---
net/mac80211/tx.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 68a48abc7287..e448ab338448 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3100,10 +3100,11 @@ void ieee80211_check_fast_xmit(struct sta_info *sta)
/* DA SA BSSID */
build.da_offs = offsetof(struct ieee80211_hdr, addr1);
build.sa_offs = offsetof(struct ieee80211_hdr, addr2);
+ rcu_read_lock();
link = rcu_dereference(sdata->link[tdls_link_id]);
- if (WARN_ON_ONCE(!link))
- break;
- memcpy(hdr->addr3, link->u.mgd.bssid, ETH_ALEN);
+ if (!WARN_ON_ONCE(!link))
+ memcpy(hdr->addr3, link->u.mgd.bssid, ETH_ALEN);
+ rcu_read_unlock();
build.hdr_len = 24;
break;
}
--
2.43.0