From:   Jiasheng Jiang <jiasheng@iscas.ac.cn>
To:     johannes@sipsolutions.net, davem@davemloft.net, kuba@kernel.org
Cc:     linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jiasheng Jiang <jiasheng@iscas.ac.cn>
Subject: [PATCH] mac80211: mlme: check for null after calling kmemdup
Date:   Fri, 31 Dec 2021 18:03:11 +0800
Message-Id: <20211231100311.1964437-1-jiasheng@iscas.ac.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

As the possible failure of the alloc, the ifmgd->assoc_req_ies might be
NULL pointer and will be used by cfg80211_rx_assoc_resp() with the wrong
length.
Therefore it might be better to set length to 0 if fails as same as
ieee80211_mgd_stop().

Fixes: 4d9ec73d2b78 ("cfg80211: Report Association Request frame IEs in association events")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
 net/mac80211/mlme.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 9bed6464c5bd..258b492c699c 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1058,7 +1058,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	pos = skb_tail_pointer(skb);
 	kfree(ifmgd->assoc_req_ies);
 	ifmgd->assoc_req_ies = kmemdup(ie_start, pos - ie_start, GFP_ATOMIC);
-	ifmgd->assoc_req_ies_len = pos - ie_start;
+	if (!ifmgd->assoc_req_ies)
+		ifmgd->assoc_req_ies_len = 0;
+	else
+		ifmgd->assoc_req_ies_len = pos - ie_start;
 
 	drv_mgd_prepare_tx(local, sdata, 0);
 
-- 
2.25.1