linux-kernel - [PATCH] staging: wfx: check ssidlen and prevent an array overflow

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Date:   Fri, 24 Apr 2020 13:42:35 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Jérôme Pouiller <jerome.pouiller@...abs.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH] staging: wfx: check ssidlen and prevent an array overflow

We need to cap "ssidlen" to prevent a memcpy() overflow.

Fixes: 40115bbc40e2 ("staging: wfx: implement the rest of mac80211 API")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 drivers/staging/wfx/sta.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
index c73dbb3a0de8c..3bff0f1e3d9ba 100644
--- a/drivers/staging/wfx/sta.c
+++ b/drivers/staging/wfx/sta.c
@@ -479,7 +479,9 @@ static void wfx_do_join(struct wfx_vif *wvif)
 		ssidie = ieee80211_bss_get_ie(bss, WLAN_EID_SSID);
 	if (ssidie) {
 		ssidlen = ssidie[1];
-		memcpy(ssid, &ssidie[2], ssidie[1]);
+		if (ssidlen > IEEE80211_MAX_SSID_LEN)
+			ssidlen = IEEE80211_MAX_SSID_LEN;
+		memcpy(ssid, &ssidie[2], ssidlen);
 	}
 	rcu_read_unlock();
 
-- 
2.26.1