From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xing Song <xing.song@mediatek.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 018/207] mac80211: do not access the IV when it was stripped
Date:   Mon,  6 Dec 2021 15:54:32 +0100
Message-Id: <20211206145610.838456462@linuxfoundation.org>
In-Reply-To: <20211206145610.172203682@linuxfoundation.org>
References: <20211206145610.172203682@linuxfoundation.org>
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From: Xing Song <xing.song@mediatek.com>

[ Upstream commit 77dfc2bc0bb4b8376ecd7a430f27a4a8fff6a5a0 ]

ieee80211_get_keyid() will return false value if IV has been stripped,
such as return 0 for IP/ARP frames due to LLC header, and return -EINVAL
for disassociation frames due to its length... etc. Don't try to access
it if it's not present.

Signed-off-by: Xing Song <xing.song@mediatek.com>
Link: https://lore.kernel.org/r/20211101024657.143026-1-xing.song@mediatek.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/rx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 419f06ef8c986..315a3e8e95496 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1952,7 +1952,8 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 		int keyid = rx->sta->ptk_idx;
 		sta_ptk = rcu_dereference(rx->sta->ptk[keyid]);
 
-		if (ieee80211_has_protected(fc)) {
+		if (ieee80211_has_protected(fc) &&
+		    !(status->flag & RX_FLAG_IV_STRIPPED)) {
 			cs = rx->sta->cipher_scheme;
 			keyid = ieee80211_get_keyid(rx->skb, cs);
 
-- 
2.33.0