4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold <jo...@kernel.org>
commit 654b404f2a222f918af9b0cd18ad469d0c941a8e upstream.
Add missing sanity check to the bulk-in completion handler to avoid an
integer underflow that can be triggered by a malicious device.
This avoids leaking 128 kB of memory content from after the URB transfer
buffer to user space.
Fixes: 8c209e6782ca ("USB: make actual_length in struct urb field u32")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <jo...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/usb/serial/io_ti.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -1761,7 +1761,7 @@ static void edge_bulk_in_callback(struct
port_number = edge_port->port->port_number;
- if (edge_port->lsr_event) {
+ if (urb->actual_length > 0 && edge_port->lsr_event) {
edge_port->lsr_event = 0;
dev_dbg(dev, "%s ===== Port %u LSR Status = %02x, Data = %02x
======\n",
__func__, port_number, edge_port->lsr_mask, *data);
