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Subject[PATCH 4.9 60/96] usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit b78d830f0049ef1966dc1e0ebd1ec2a594e2cf25 upstream.

Harden CMD_SUBMIT path to handle malicious input that could trigger
large memory allocations. Add checks to validate transfer_buffer_length
and number_of_packets to protect against bad input requesting for
unbounded memory allocations.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/usbip/vudc_rx.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

--- a/drivers/usb/usbip/vudc_rx.c
+++ b/drivers/usb/usbip/vudc_rx.c
@@ -132,6 +132,25 @@ static int v_recv_cmd_submit(struct vudc
urb_p->new = 1;
urb_p->seqnum = pdu->base.seqnum;

+ if (urb_p->ep->type == USB_ENDPOINT_XFER_ISOC) {
+ /* validate packet size and number of packets */
+ unsigned int maxp, packets, bytes;
+
+ maxp = usb_endpoint_maxp(urb_p->ep->desc);
+ maxp *= usb_endpoint_maxp_mult(urb_p->ep->desc);
+ bytes = pdu->u.cmd_submit.transfer_buffer_length;
+ packets = DIV_ROUND_UP(bytes, maxp);
+
+ if (pdu->u.cmd_submit.number_of_packets < 0 ||
+ pdu->u.cmd_submit.number_of_packets > packets) {
+ dev_err(&udc->gadget.dev,
+ "CMD_SUBMIT: isoc invalid num packets %d\n",
+ pdu->u.cmd_submit.number_of_packets);
+ ret = -EMSGSIZE;
+ goto free_urbp;
+ }
+ }
+
ret = alloc_urb_from_cmd(&urb_p->urb, pdu, urb_p->ep->type);
if (ret) {
usbip_event_add(&udc->ud, VUDC_EVENT_ERROR_MALLOC);

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