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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Andrei Otcheretianski <andrei.otcheretianski@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 092/293] iwlwifi: mvm: Drop large non sta frames
Date:   Mon, 29 Jul 2019 21:19:43 +0200
Message-Id: <20190729190831.657269062@linuxfoundation.org>
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[ 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 <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 62a6e293cf12..f0f2be432d20 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -621,6 +621,9 @@ 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