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From:   Lee Gibson <leegib@gmail.com>
To:     kvalo@codeaurora.org
Cc:     davem@davemloft.net, kuba@kernel.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Lee Gibson <leegib@gmail.com>
Subject: [PATCH] wl1251: Fix possible buffer overflow in wl1251_cmd_scan
Date:   Wed, 17 Mar 2021 12:18:07 +0000
Message-Id: <20210317121807.389169-1-leegib@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Function wl1251_cmd_scan calls memcpy without checking the length.
A user could control that length and trigger a buffer overflow.
Fix by checking the length is within the maximum allowed size.

Signed-off-by: Lee Gibson <leegib@gmail.com>
---
 drivers/net/wireless/ti/wl1251/cmd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ti/wl1251/cmd.c b/drivers/net/wireless/ti/wl1251/cmd.c
index 498c8db2eb48..e4d028a53d91 100644
--- a/drivers/net/wireless/ti/wl1251/cmd.c
+++ b/drivers/net/wireless/ti/wl1251/cmd.c
@@ -455,8 +455,11 @@ int wl1251_cmd_scan(struct wl1251 *wl, u8 *ssid, size_t ssid_len,
 	}
 
 	cmd->params.ssid_len = ssid_len;
-	if (ssid)
-		memcpy(cmd->params.ssid, ssid, ssid_len);
+	if (ssid) {
+		int len = min_t(int, ssid_len, IEEE80211_MAX_SSID_LEN);
+
+		memcpy(cmd->params.ssid, ssid, len);
+	}
 
 	ret = wl1251_cmd_send(wl, CMD_SCAN, cmd, sizeof(*cmd));
 	if (ret < 0) {
-- 
2.25.1