Commit 9f3ee8e7 authored by Johan Hovold's avatar Johan Hovold Committed by Ben Hutchings

USB: serial: digi_acceleport: fix OOB data sanity check

commit 2d380889 upstream.

Make sure to check for short transfers to avoid underflow in a loop
condition when parsing the receive buffer.

Also fix an off-by-one error in the incomplete sanity check which could
lead to invalid data being parsed.

Fixes: 8c209e67 ("USB: make actual_length in struct urb field u32")
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 8602693a
......@@ -1484,16 +1484,20 @@ static int digi_read_oob_callback(struct urb *urb)
struct usb_serial *serial = port->serial;
struct tty_struct *tty;
struct digi_port *priv = usb_get_serial_port_data(port);
unsigned char *buf = urb->transfer_buffer;
int opcode, line, status, val;
int i;
unsigned int rts;
if (urb->actual_length < 4)
return -1;
/* handle each oob command */
for (i = 0; i < urb->actual_length - 3;) {
opcode = ((unsigned char *)urb->transfer_buffer)[i++];
line = ((unsigned char *)urb->transfer_buffer)[i++];
status = ((unsigned char *)urb->transfer_buffer)[i++];
val = ((unsigned char *)urb->transfer_buffer)[i++];
for (i = 0; i < urb->actual_length - 4; i += 4) {
opcode = buf[i];
line = buf[i + 1];
status = buf[i + 2];
val = buf[i + 3];
dev_dbg(&port->dev, "digi_read_oob_callback: opcode=%d, line=%d, status=%d, val=%d\n",
opcode, line, status, val);
......
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