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authorOliver Neukum <oneukum@suse.com>2019-11-07 09:48:01 +0100
committerDavid S. Miller <davem@davemloft.net>2019-11-07 15:27:06 -0800
commit332f989a3b0041b810836c5c3747e59aad7e9d0b (patch)
tree412b95932374b9675b47915972fef54c0907d685
parent025ec40b81d785a98f76b8bdb509ac10773b4f12 (diff)
CDC-NCM: handle incomplete transfer of MTU
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>
-rw-r--r--drivers/net/usb/cdc_ncm.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 00cab3f43a4c..a245597a3902 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -578,8 +578,8 @@ static void cdc_ncm_set_dgram_size(struct usbnet *dev, int new_size)
/* 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;
}
@@ -590,7 +590,7 @@ static void cdc_ncm_set_dgram_size(struct usbnet *dev, int new_size)
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");