[PATCH 4.4 12/25] USB: serial: mos7840: fix another NULL-deref at open
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2017-02-24 08:37:22
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4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold <johan@kernel.org>
commit 5182c2cf2a9bfb7f066ef0bdd2bb6330b94dd74e upstream.
Fix another NULL-pointer dereference at open should a malicious device
lack an interrupt-in endpoint.
Note that the driver has a broken check for an interrupt-in endpoint
which means that an interrupt URB has never even been submitted.
Fixes: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/serial/mos7840.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c@@ -1024,6 +1024,7 @@ static int mos7840_open(struct tty_struc * (can't set it up in mos7840_startup as the structures * * were not set up at that time.) */ if (port0->open_ports == 1) { + /* FIXME: Buffer never NULL, so URB is not submitted. */ if (serial->port[0]->interrupt_in_buffer == NULL) { /* set up interrupt urb */ usb_fill_int_urb(serial->port[0]->interrupt_in_urb,
@@ -2119,7 +2120,8 @@ static int mos7840_calc_num_ports(struct static int mos7840_attach(struct usb_serial *serial) { if (serial->num_bulk_in < serial->num_ports || - serial->num_bulk_out < serial->num_ports) { + serial->num_bulk_out < serial->num_ports || + serial->num_interrupt_in < 1) { dev_err(&serial->interface->dev, "missing endpoints\n"); return -ENODEV; }