From: Oliver Neukum oneukum@suse.com
[ Upstream commit 332f989a3b0041b810836c5c3747e59aad7e9d0b ]
A malicious device may give half an answer when asked for its MTU. The driver will proceed after this with a garbage MTU. Anything but a complete answer must be treated as an error.
V2: used sizeof as request by Alexander
Reported-and-tested-by: syzbot+0631d878823ce2411636@syzkaller.appspotmail.com Signed-off-by: Oliver Neukum oneukum@suse.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/cdc_ncm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -576,8 +576,8 @@ static void cdc_ncm_set_dgram_size(struc /* read current mtu value from device */ err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE, USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE, - 0, iface_no, &max_datagram_size, 2); - if (err < 0) { + 0, iface_no, &max_datagram_size, sizeof(max_datagram_size)); + if (err < sizeof(max_datagram_size)) { dev_dbg(&dev->intf->dev, "GET_MAX_DATAGRAM_SIZE failed\n"); goto out; } @@ -588,7 +588,7 @@ static void cdc_ncm_set_dgram_size(struc max_datagram_size = cpu_to_le16(ctx->max_datagram_size); err = usbnet_write_cmd(dev, USB_CDC_SET_MAX_DATAGRAM_SIZE, USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE, - 0, iface_no, &max_datagram_size, 2); + 0, iface_no, &max_datagram_size, sizeof(max_datagram_size)); if (err < 0) dev_dbg(&dev->intf->dev, "SET_MAX_DATAGRAM_SIZE failed\n");