Messages in this thread Patch in this message | | | From | Johan Hovold <> | Subject | [PATCH 3/3] mwifiex: fix division by zero in fw download path | Date | Tue, 26 Oct 2021 11:52:14 +0200 |
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Add the missing endpoint max-packet sanity check 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).
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 <akarwar@marvell.com> Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/net/wireless/marvell/mwifiex/usb.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/net/wireless/marvell/mwifiex/usb.c b/drivers/net/wireless/marvell/mwifiex/usb.c index 426e39d4ccf0..2826654907d9 100644 --- a/drivers/net/wireless/marvell/mwifiex/usb.c +++ b/drivers/net/wireless/marvell/mwifiex/usb.c @@ -502,6 +502,9 @@ static int mwifiex_usb_probe(struct usb_interface *intf, atomic_set(&card->tx_cmd_urb_pending, 0); card->bulk_out_maxpktsize = le16_to_cpu(epd->wMaxPacketSize); + /* Reject broken descriptors. */ + if (card->bulk_out_maxpktsize == 0) + return -ENODEV; } } -- 2.32.0
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