Subject: [PATCH AUTOSEL 4.19 134/158] iwlwifi: mvm: Drop large non sta frames

From: Sasha Levin <[email-masked]>
Date: Mon, 15 Jul 2019 10:17:45 -0400

From: Andrei Otcheretianski <[email-masked]>

[ Upstream commit ac70499ee97231a418dc1a4d6c9dc102e8f64631 ]

In some buggy scenarios we could possible attempt to transmit frames larger
than maximum MSDU size. Since our devices don't know how to handle this,
it may result in asserts, hangs etc.
This can happen, for example, when we receive a large multicast frame
and try to transmit it back to the air in AP mode.
Since in a legal scenario this should never happen, drop such frames and
warn about it.

Signed-off-by: Andrei Otcheretianski <[email-masked]>
Signed-off-by: Luca Coelho <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/wireless/intel/iwlwifi/mvm/tx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
index 2d21f0a1fa00..ffae299c3492 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -641,6 +641,9 @@ int iwl_mvm_tx_skb_non_sta(struct iwl_mvm *mvm, struct sk_buff *skb)
 
 	memcpy(&info, skb->cb, sizeof(info));
 
+	if (WARN_ON_ONCE(skb->len > IEEE80211_MAX_DATA_LEN + hdrlen))
+		return -1;
+
 	if (WARN_ON_ONCE(info.flags & IEEE80211_TX_CTL_AMPDU))
 		return -1;
 
-- 
2.20.1