[PATCH 3.2 76/79] usbip: fix stub_send_ret_submit() vulnerability to null transfer_buffer

Ben Hutchings
2018-02-11T04:20:06Z

From: Shuah Khan <shuahkh@osg.samsung.com>

commit be6123df1ea8f01ee2f896a16c2b7be3e4557a5a upstream.

stub_send_ret_submit() handles urb with a potential null transfer_buffer,
when it replays a packet with potential malicious data that could contain
a null buffer. Add a check for the condition when actual_length > 0 and
transfer_buffer is null.

Reported-by: Secunia Research <vuln@secunia.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
- Device for logging purposes is &sdev->interface->dev
- Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/staging/usbip/stub_tx.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/drivers/staging/usbip/stub_tx.c
+++ b/drivers/staging/usbip/stub_tx.c
@@ -178,6 +178,13 @@ static int stub_send_ret_submit(struct s
memset(&pdu_header, 0, sizeof(pdu_header));
memset(&msg, 0, sizeof(msg));

+ if (urb->actual_length > 0 && !urb->transfer_buffer) {
+ dev_err(&sdev->interface->dev,
+ "urb: actual_length %d transfer_buffer null\n",
+ urb->actual_length);
+ return -1;
+ }
+
if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
iovnum = 2 + urb->number_of_packets;
else