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From:   Jeff Johnson <quic_jjohnson@quicinc.com>
Date:   Tue, 29 Aug 2023 06:29:36 -0700
Subject: [PATCH v2 1/2] wifi: cw1200: Avoid processing an invalid TIM IE
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Message-ID: <20230829-ieee80211_tim_ie-v2-1-fdaf19fb1c0e@quicinc.com>
References: <20230829-ieee80211_tim_ie-v2-0-fdaf19fb1c0e@quicinc.com>
In-Reply-To: <20230829-ieee80211_tim_ie-v2-0-fdaf19fb1c0e@quicinc.com>
To:     <kernel@quicinc.com>, Kalle Valo <kvalo@kernel.org>,
        =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>,
        "Christian Lamparter" <chunkeey@googlemail.com>,
        Stanislaw Gruszka <stf_xl@wp.pl>,
        "Helmut Schaa" <helmut.schaa@googlemail.com>,
        Ping-Ke Shih <pkshih@realtek.com>,
        Johannes Berg <johannes@sipsolutions.net>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
CC:     <linux-wireless@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <netdev@vger.kernel.org>, Jeff Johnson <quic_jjohnson@quicinc.com>
Precedence: bulk

While converting struct ieee80211_tim_ie::virtual_map to be a flexible
array it was observed that the TIM IE processing in cw1200_rx_cb()
could potentially process a malformed IE in a manner that could result
in a buffer over-read. Add logic to verify that the TIM IE length is
large enough to hold a valid TIM payload before processing it.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
---
 drivers/net/wireless/st/cw1200/txrx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/st/cw1200/txrx.c b/drivers/net/wireless/st/cw1200/txrx.c
index 6894b919ff94..e16e9ae90d20 100644
--- a/drivers/net/wireless/st/cw1200/txrx.c
+++ b/drivers/net/wireless/st/cw1200/txrx.c
@@ -1166,7 +1166,7 @@ void cw1200_rx_cb(struct cw1200_common *priv,
 		size_t ies_len = skb->len - (ies - (u8 *)(skb->data));
 
 		tim_ie = cfg80211_find_ie(WLAN_EID_TIM, ies, ies_len);
-		if (tim_ie) {
+		if (tim_ie && tim_ie[1] >= sizeof(struct ieee80211_tim_ie)) {
 			struct ieee80211_tim_ie *tim =
 				(struct ieee80211_tim_ie *)&tim_ie[2];
 

-- 
2.25.1