From 78ebff828a33c3f14ce8765040f117da1f750a6c Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 27 Oct 2021 10:08:19 +0200 Subject: [PATCH] mwifiex: fix division by zero in fw download path commit 89f8765a11d8df49296d92c404067f9b5c58ee26 upstream. Add the missing endpoint sanity checks to probe() to avoid division by zero in mwifiex_write_data_sync() in case a malicious device has broken descriptors (or when doing descriptor fuzz testing). Only add checks for the firmware-download boot stage, which require both command endpoints, for now. The driver looks like it will handle a missing endpoint during normal operation without oopsing, albeit not very gracefully as it will try to submit URBs to the default pipe and fail. 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: 4daffe354366 ("mwifiex: add support for Marvell USB8797 chipset") Cc: stable@vger.kernel.org # 3.5 Cc: Amitkumar Karwar Signed-off-by: Johan Hovold Reviewed-by: Brian Norris Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20211027080819.6675-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/marvell/mwifiex/usb.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/net/wireless/marvell/mwifiex/usb.c b/drivers/net/wireless/marvell/mwifiex/usb.c index 528107d70c1c..cb8a9ad40cfe 100644 --- a/drivers/net/wireless/marvell/mwifiex/usb.c +++ b/drivers/net/wireless/marvell/mwifiex/usb.c @@ -505,6 +505,22 @@ static int mwifiex_usb_probe(struct usb_interface *intf, } } + switch (card->usb_boot_state) { + case USB8XXX_FW_DNLD: + /* Reject broken descriptors. */ + if (!card->rx_cmd_ep || !card->tx_cmd_ep) + return -ENODEV; + if (card->bulk_out_maxpktsize == 0) + return -ENODEV; + break; + case USB8XXX_FW_READY: + /* Assume the driver can handle missing endpoints for now. */ + break; + default: + WARN_ON(1); + return -ENODEV; + } + usb_set_intfdata(intf, card); ret = mwifiex_add_card(card, &card->fw_done, &usb_ops,