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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Denis Efremov <denis.e.efremov@oracle.com>
Subject: [PATCH 5.17 656/772] staging: r8188eu: prevent ->Ssid overflow in rtw_wx_set_scan()
Date:   Tue,  7 Jun 2022 19:04:08 +0200
Message-Id: <20220607165008.394000471@linuxfoundation.org>
In-Reply-To: <20220607164948.980838585@linuxfoundation.org>
References: <20220607164948.980838585@linuxfoundation.org>
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From: Denis Efremov <denis.e.efremov@oracle.com>

commit bc10916e890948d8927a5c8c40fb5dc44be5e1b8 upstream.

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: 2b42bd58b321 ("staging: r8188eu: introduce new os_dep dir for RTL8188eu driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Denis Efremov <denis.e.efremov@oracle.com>
Link: https://lore.kernel.org/r/20220518070052.108287-1-denis.e.efremov@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/r8188eu/os_dep/ioctl_linux.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
@@ -1181,9 +1181,11 @@ static int rtw_wx_set_scan(struct net_de
 						break;
 					}
 					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);
 						ssid_index++;
 					}
 					pos += sec_len;