patch "staging: ks7010: prevent buffer overflow in ks_wlan_set_scan()" added to staging-linus

This is a note to let you know that I've just added the patch titled

staging: ks7010: prevent buffer overflow in ks_wlan_set_scan()

to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 651652def082ef79ea85ad2ca4f19167d927e330 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <[email protected]>
Date: Tue, 2 Mar 2021 14:19:39 +0300
Subject: staging: ks7010: prevent buffer overflow in ks_wlan_set_scan()

The user can specify a "req->essid_len" of up to 255 but if it's over IW_ESSID_MAX_SIZE (32) that can lead to memory corruption.

---
 drivers/staging/ks7010/ks_wlan_net.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

index dc09cc6e1c47..09e7b4cd0138 100644
@@ -1120,6 +1120,7 @@ static int ks_wlan_set_scan(struct net_device *dev,
 {
 	struct ks_wlan_private *priv = netdev_priv(dev);
 	struct iw_scan_req *req = NULL;
+	int len;
 
 	if (priv->sleep_mode == SLP_SLEEP)
 		return -EPERM;

@@ -1129,8 +1130,9 @@ static int ks_wlan_set_scan(struct net_device *dev,
 	if (wrqu->data.length == sizeof(struct iw_scan_req) &&
 	    wrqu->data.flags & IW_SCAN_THIS_ESSID) {
 		req = (struct iw_scan_req *)extra;
-		priv->scan_ssid_len = req->essid_len;
-		memcpy(priv->scan_ssid, req->essid, priv->scan_ssid_len);
+		len = min_t(int, req->essid_len, IW_ESSID_MAX_SIZE);
+		priv->scan_ssid_len = len;
+		memcpy(priv->scan_ssid, req->essid, len);
 	} else {
 		priv->scan_ssid_len = 0;
 	}

2.30.1