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From:   "Denis Efremov (Oracle)" <efremov@linux.com>
To:     gregkh@linuxfoundation.org
Cc:     "Denis Efremov (Oracle)" <efremov@linux.com>,
        Larry.Finger@lwfinger.net, phil@philpotter.co.uk,
        dan.carpenter@oracle.com, straube.linux@gmail.com,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
        kernel-janitors@vger.kernel.org, stable <stable@vger.kernel.org>
Subject: [PATCH v5.10] staging: rtl8723bs: prevent ->Ssid overflow in rtw_wx_set_scan()
Date:   Fri, 20 May 2022 07:57:30 +0400
Message-Id: <20220520035730.5533-1-efremov@linux.com>
In-Reply-To: <YoZk3YLEDYKGG5xe@kroah.com>
References: <YoZk3YLEDYKGG5xe@kroah.com>
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This code has a check to prevent read overflow but it needs another
check to prevent writing beyond the end of the ->Ssid[] array.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Denis Efremov (Oracle) <efremov@linux.com>
---
 drivers/staging/rtl8723bs/os_dep/ioctl_linux.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
index 902ac8169948..083ff72976cf 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
@@ -1351,9 +1351,11 @@ static int rtw_wx_set_scan(struct net_device *dev, struct iw_request_info *a,
 
 					sec_len = *(pos++); len -= 1;
 
-					if (sec_len > 0 && sec_len <= len) {
+					if (sec_len > 0 &&
+					    sec_len <= len &&
+					    sec_len <= 32) {
 						ssid[ssid_index].SsidLength = sec_len;
-						memcpy(ssid[ssid_index].Ssid, pos, ssid[ssid_index].SsidLength);
+						memcpy(ssid[ssid_index].Ssid, pos, sec_len);
 						/* DBG_871X("%s COMBO_SCAN with specific ssid:%s, %d\n", __func__ */
 						/* 	, ssid[ssid_index].Ssid, ssid[ssid_index].SsidLength); */
 						ssid_index++;
-- 
2.35.3