[PATCH AUTOSEL 4.19 2/6] cfg80211: initialize rekey_data

[PATCH AUTOSEL 4.19 2/6] cfg80211: initialize rekey_data

[Sasha Levin]

From: Sara Sharon <sara.sharon@intel.com>

[ Upstream commit f495acd8851d7b345e5f0e521b2645b1e1f928a0 ]

In case we have old supplicant, the akm field is uninitialized.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201129172929.930f0ab7ebee.Ic546e384efab3f4a89f318eafddc3eb7d556aecb@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/wireless/nl80211.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fbc8875502c3e..5f0605275fa39 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -11502,7 +11502,7 @@ static int nl80211_set_rekey_data(struct sk_buff *skb, struct genl_info *info)
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct nlattr *tb[NUM_NL80211_REKEY_DATA];
-	struct cfg80211_gtk_rekey_data rekey_data;
+	struct cfg80211_gtk_rekey_data rekey_data = {};
 	int err;
 
 	if (!info->attrs[NL80211_ATTR_REKEY_DATA])
-- 
2.27.0

[PATCH AUTOSEL 4.19 4/6] lwt: Disable BH too in run_lwt_bpf()

[Sasha Levin]

From: Dongdong Wang <wangdongdong.6@bytedance.com>

[ Upstream commit d9054a1ff585ba01029584ab730efc794603d68f ]

The per-cpu bpf_redirect_info is shared among all skb_do_redirect()
and BPF redirect helpers. Callers on RX path are all in BH context,
disabling preemption is not sufficient to prevent BH interruption.

In production, we observed strange packet drops because of the race
condition between LWT xmit and TC ingress, and we verified this issue
is fixed after we disable BH.

Although this bug was technically introduced from the beginning, that
is commit 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure"),
at that time call_rcu() had to be call_rcu_bh() to match the RCU context.
So this patch may not work well before RCU flavor consolidation has been
completed around v5.0.

Update the comments above the code too, as call_rcu() is now BH friendly.

Signed-off-by: Dongdong Wang <wangdongdong.6@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/bpf/20201205075946.497763-1-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/lwt_bpf.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index a648568c5e8fe..4a5f4fbffd836 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -44,12 +44,11 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
 {
 	int ret;
 
-	/* Preempt disable is needed to protect per-cpu redirect_info between
-	 * BPF prog and skb_do_redirect(). The call_rcu in bpf_prog_put() and
-	 * access to maps strictly require a rcu_read_lock() for protection,
-	 * mixing with BH RCU lock doesn't work.
+	/* Preempt disable and BH disable are needed to protect per-cpu
+	 * redirect_info between BPF prog and skb_do_redirect().
 	 */
 	preempt_disable();
+	local_bh_disable();
 	bpf_compute_data_pointers(skb);
 	ret = bpf_prog_run_save_cb(lwt->prog, skb);
 
@@ -82,6 +81,7 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt,
 		break;
 	}
 
+	local_bh_enable();
 	preempt_enable();
 
 	return ret;
-- 
2.27.0