[PATCH v2] ar5523: check endpoints type and direction in probe()

From: Mazin Al Haddad
Date: Tue Aug 23 2022 - 18:58:23 EST


Fixes a bug reported by syzbot, where a warning occurs in usb_submit_urb()
due to the wrong endpoint type. There is no check for both the number
of endpoints and the type which causes an error as the code tries to
send a URB to the wrong endpoint.

Fix it by adding a check for the number of endpoints and the
direction/type of the endpoints. If the endpoints do not match the
expected configuration -ENODEV is returned.

Syzkaller report:

usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 1 PID: 71 at drivers/usb/core/urb.c:502 usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
Modules linked in:
CPU: 1 PID: 71 Comm: kworker/1:2 Not tainted 5.19.0-rc7-syzkaller-00150-g32f02a211b0a #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
ar5523_cmd+0x420/0x790 drivers/net/wireless/ath/ar5523/ar5523.c:275
ar5523_cmd_read drivers/net/wireless/ath/ar5523/ar5523.c:302 [inline]
ar5523_host_available drivers/net/wireless/ath/ar5523/ar5523.c:1376 [inline]
ar5523_probe+0xc66/0x1da0 drivers/net/wireless/ath/ar5523/ar5523.c:1655

Link: https://syzkaller.appspot.com/bug?extid=1bc2c2afd44f820a669f
Reported-and-tested-by: syzbot+1bc2c2afd44f820a669f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Mazin Al Haddad <mazinalhaddad05@xxxxxxxxx>
---
v1->v2 changes:
- Fix incorrect check in if statement within switch case (was missing
a "!" operator).
- Added comments explaining the code.

drivers/net/wireless/ath/ar5523/ar5523.c | 33 ++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
index 6f937d2cc126..d7e86dc4c293 100644
--- a/drivers/net/wireless/ath/ar5523/ar5523.c
+++ b/drivers/net/wireless/ath/ar5523/ar5523.c
@@ -1581,8 +1581,41 @@ static int ar5523_probe(struct usb_interface *intf,
struct usb_device *dev = interface_to_usbdev(intf);
struct ieee80211_hw *hw;
struct ar5523 *ar;
+ struct usb_host_interface *host = intf->cur_altsetting;
int error = -ENOMEM;

+ if (host->desc.bNumEndpoints != 4) {
+ dev_err(&dev->dev, "Wrong number of endpoints\n");
+ return -ENODEV;
+ }
+
+ // Check for type of endpoint and direction.
+ for (int i = 0; i < host->desc.bNumEndpoints; ++i) {
+ struct usb_endpoint_descriptor *ep = &host->endpoint[i].desc;
+
+ switch (i) {
+ case 0:
+ case 1:
+ // if endpoint direction and type does not match
+ if (!((ep->bEndpointAddress & USB_DIR_OUT) &&
+ ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
+ == USB_ENDPOINT_XFER_BULK))){
+ dev_err(&dev->dev, "Wrong type of endpoints\n");
+ return -ENODEV;
+ }
+ break;
+ case 2:
+ case 3:
+ if (!((ep->bEndpointAddress & USB_DIR_IN) &&
+ ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
+ == USB_ENDPOINT_XFER_BULK))){
+ dev_err(&dev->dev, "Wrong type of endpoints\n");
+ return -ENODEV;
+ }
+ break;
+ }
+ }
+
/*
* Load firmware if the device requires it. This will return
* -ENXIO on success and we'll get called back afer the usb
--
2.37.2