4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold <johan@xxxxxxxxxx>
commit 8c76d7cd520ebffc1ea9ea0850d87a224a50c7f2 upstream.
Add missing sanity check to the bulk-in completion handler to avoid an
integer underflow that could be triggered by a malicious device.
This avoids leaking up to 56 bytes from after the URB transfer buffer to
user space.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/safe_serial.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/usb/serial/safe_serial.c
+++ b/drivers/usb/serial/safe_serial.c
@@ -205,6 +205,11 @@ static void safe_process_read_urb(struct
if (!safe)
goto out;
+ if (length < 2) {
+ dev_err(&port->dev, "malformed packet\n");
+ return;
+ }
+
fcs = fcs_compute10(data, length, CRC10_INITFCS);
if (fcs) {
dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);