[PATCH AUTOSEL 5.7 012/388] staging: wfx: check ssidlen and prevent an array overflow

[Sasha Levin]

From: Dan Carpenter <dan.carpenter at oracle.com>

[ Upstream commit 87f86cddda65cab8a7e3df8a00e16abeccaa0730 ]

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 at oracle.com>
Reviewed-by: Jérôme Pouiller <jerome.pouiller at silabs.com>
Link: https://lore.kernel.org/r/20200424104235.GA416402@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 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 9d430346a58b..969d7a4a7fbd 100644
--- a/drivers/staging/wfx/sta.c
+++ b/drivers/staging/wfx/sta.c
@@ -520,7 +520,9 @@ 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();
 
-- 
2.25.1