[PATCH 4.4 16/46] staging: wlan-ng: fix out of bounds read in prism2sta_probe_usb()

Greg Kroah-Hartman
2020-09-21T16:32:06Z

From: Rustam Kovhaev <rkovhaev@gmail.com>

commit fea22e159d51c766ba70473f473a0ec914cc7e92 upstream.

let's use usb_find_common_endpoints() to discover endpoints, it does all
necessary checks for type and xfer direction

remove memset() in hfa384x_create(), because we now assign endpoints in
prism2sta_probe_usb() and because create_wlan() uses kzalloc() to
allocate hfa384x struct before calling hfa384x_create()

Fixes: faaff9765664 ("staging: wlan-ng: properly check endpoint types")
Reported-and-tested-by: syzbot+22794221ab96b0bab53a@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=22794221ab96b0bab53a
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200804145614.104320-1-rkovhaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/wlan-ng/hfa384x_usb.c | 5 -----
drivers/staging/wlan-ng/prism2usb.c | 19 ++++++-------------
2 files changed, 6 insertions(+), 18 deletions(-)

--- a/drivers/staging/wlan-ng/hfa384x_usb.c
+++ b/drivers/staging/wlan-ng/hfa384x_usb.c
@@ -530,13 +530,8 @@ static void hfa384x_usb_defer(struct wor
----------------------------------------------------------------*/
void hfa384x_create(hfa384x_t *hw, struct usb_device *usb)
{
- memset(hw, 0, sizeof(hfa384x_t));
hw->usb = usb;

- /* set up the endpoints */
- hw->endp_in = usb_rcvbulkpipe(usb, 1);
- hw->endp_out = usb_sndbulkpipe(usb, 2);
-
/* Set up the waitq */
init_waitqueue_head(&hw->cmdq);

--- a/drivers/staging/wlan-ng/prism2usb.c
+++ b/drivers/staging/wlan-ng/prism2usb.c
@@ -60,23 +60,14 @@ static int prism2sta_probe_usb(struct us
const struct usb_device_id *id)
{
struct usb_device *dev;
- const struct usb_endpoint_descriptor *epd;
- const struct usb_host_interface *iface_desc = interface->cur_altsetting;
+ struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+ struct usb_host_interface *iface_desc = interface->cur_altsetting;
wlandevice_t *wlandev = NULL;
hfa384x_t *hw = NULL;
int result = 0;

- if (iface_desc->desc.bNumEndpoints != 2) {
- result = -ENODEV;
- goto failed;
- }
-
- result = -EINVAL;
- epd = &iface_desc->endpoint[1].desc;
- if (!usb_endpoint_is_bulk_in(epd))
- goto failed;
- epd = &iface_desc->endpoint[2].desc;
- if (!usb_endpoint_is_bulk_out(epd))
+ result = usb_find_common_endpoints(iface_desc, &bulk_in, &bulk_out, NULL, NULL);
+ if (result)
goto failed;

dev = interface_to_usbdev(interface);
@@ -95,6 +86,8 @@ static int prism2sta_probe_usb(struct us
}

/* Initialize the hw data */
+ hw->endp_in = usb_rcvbulkpipe(dev, bulk_in->bEndpointAddress);
+ hw->endp_out = usb_sndbulkpipe(dev, bulk_out->bEndpointAddress);
hfa384x_create(hw, dev);
hw->wlandev = wlandev;