[PATCH 3.16 113/125] USB: whiteheat: Added bounds checking for bulk command response

Greg Kroah-Hartman
2014-09-03T23:02:12Z

From: James Forshaw <forshaw@google.com>

commit 6817ae225cd650fb1c3295d769298c38b1eba818 upstream.

This patch fixes a potential security issue in the whiteheat USB driver
which might allow a local attacker to cause kernel memory corrpution. This
is due to an unchecked memcpy into a fixed size buffer (of 64 bytes). On
EHCI and XHCI busses it's possible to craft responses greater than 64
bytes leading a buffer overflow.

Signed-off-by: James Forshaw <forshaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/serial/whiteheat.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/whiteheat.c
+++ b/drivers/usb/serial/whiteheat.c
@@ -514,6 +514,10 @@ static void command_port_read_callback(s
dev_dbg(&urb->dev->dev, "%s - command_info is NULL, exiting.\n", __func__);
return;
}
+ if (!urb->actual_length) {
+ dev_dbg(&urb->dev->dev, "%s - empty response, exiting.\n", __func__);
+ return;
+ }
if (status) {
dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", __func__, status);
if (status != -ENOENT)
@@ -534,7 +538,8 @@ static void command_port_read_callback(s
/* These are unsolicited reports from the firmware, hence no
waiting command to wakeup */
dev_dbg(&urb->dev->dev, "%s - event received\n", __func__);
- } else if (data[0] == WHITEHEAT_GET_DTR_RTS) {
+ } else if ((data[0] == WHITEHEAT_GET_DTR_RTS) &&
+ (urb->actual_length - 1 <= sizeof(command_info->result_buffer))) {
memcpy(command_info->result_buffer, &data[1],
urb->actual_length - 1);
command_info->command_finished = WHITEHEAT_CMD_COMPLETE;