From: Bjørn Mork bjorn@mork.no
[ Upstream commit 3fe4b3351301660653a2bc73f2226da0ebd2b95e ]
Endpoints with zero wMaxPacketSize are not usable for transferring data. Ignore such endpoints when looking for valid in, out and status pipes, to make the driver more robust against invalid and meaningless descriptors.
The wMaxPacketSize of the out pipe is used as divisor. So this change fixes a divide-by-zero bug.
Reported-by: syzbot+ce366e2b8296e25d84f5@syzkaller.appspotmail.com Signed-off-by: Bjørn Mork bjorn@mork.no Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/cdc_ncm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -636,8 +636,12 @@ cdc_ncm_find_endpoints(struct usbnet *de u8 ep;
for (ep = 0; ep < intf->cur_altsetting->desc.bNumEndpoints; ep++) { - e = intf->cur_altsetting->endpoint + ep; + + /* ignore endpoints which cannot transfer data */ + if (!usb_endpoint_maxp(&e->desc)) + continue; + switch (e->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) { case USB_ENDPOINT_XFER_INT: if (usb_endpoint_dir_in(&e->desc)) {