From: Jouni Malinen jouni@codeaurora.org
commit 56c5485c9e444c2e85e11694b6c44f1338fc20fd upstream.
It is possible for there to be pending frames in TXQs with a reference to the key cache entry that is being deleted. If such a key cache entry is cleared, those pending frame in TXQ might get transmitted without proper encryption. It is safer to leave the previously used key into the key cache in such cases. Instead, only clear the MAC address to prevent RX processing from using this key cache entry.
This is needed in particularly in AP mode where the TXQs cannot be flushed on station disconnection. This change alone may not be able to address all cases where the key cache entry might get reused for other purposes immediately (the key cache entry should be released for reuse only once the TXQs do not have any remaining references to them), but this makes it less likely to get unprotected frames and the more complete changes may end up being significantly more complex.
Signed-off-by: Jouni Malinen jouni@codeaurora.org Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/20201214172118.18100-2-jouni@codeaurora.org Cc: Pali Rohár pali@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/ath/key.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/key.c b/drivers/net/wireless/ath/key.c index 1816b4e7dc26..59618bb41f6c 100644 --- a/drivers/net/wireless/ath/key.c +++ b/drivers/net/wireless/ath/key.c @@ -583,7 +583,16 @@ EXPORT_SYMBOL(ath_key_config); */ void ath_key_delete(struct ath_common *common, struct ieee80211_key_conf *key) { - ath_hw_keyreset(common, key->hw_key_idx); + /* Leave CCMP and TKIP (main key) configured to avoid disabling + * encryption for potentially pending frames already in a TXQ with the + * keyix pointing to this key entry. Instead, only clear the MAC address + * to prevent RX processing from using this key cache entry. + */ + if (test_bit(key->hw_key_idx, common->ccmp_keymap) || + test_bit(key->hw_key_idx, common->tkip_keymap)) + ath_hw_keysetmac(common, key->hw_key_idx, NULL); + else + ath_hw_keyreset(common, key->hw_key_idx); if (key->hw_key_idx < IEEE80211_WEP_NKID) return;