From 1ee34b2e09c21efdf8e9f96610f6a7b8fc458064 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 26 Oct 2021 12:36:17 +0200 Subject: net: lan78xx: fix division by zero in send path commit db6c3c064f5d55fa9969f33eafca3cdbefbb3541 upstream. Add the missing endpoint max-packet sanity check to probe() to avoid division by zero in lan78xx_tx_bh() in case a malicious device has broken descriptors (or when doing descriptor fuzz testing). Note that USB core will reject URBs submitted for endpoints with zero wMaxPacketSize but that drivers doing packet-size calculations still need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip endpoint descriptors with maxpacket=0")). Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver") Cc: stable@vger.kernel.org # 4.3 Cc: Woojung.Huh@microchip.com Signed-off-by: Johan Hovold Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/lan78xx.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/net/usb/lan78xx.c') diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index 1439863e9061..324e2e15092f 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2956,6 +2956,12 @@ static int lan78xx_probe(struct usb_interface *intf, dev->maxpacket = usb_maxpacket(dev->udev, dev->pipe_out, 1); + /* Reject broken descriptors. */ + if (dev->maxpacket == 0) { + ret = -ENODEV; + goto out3; + } + /* driver requires remote-wakeup capability during autosuspend. */ intf->needs_remote_wakeup = 1; -- cgit v1.2.3