USB: usbip: fix null-ptr-deref in status_show_vhci()

Quoted 27 lines · Qasim Ijaz

If usb_add_hcd() fails in vhci_hcd_probe() (i.e., a probe failure), the error path calls usb_remove_hcd() and also sets pdev->dev.driver_data to NULL.

Consequently, any subsequent call to platform_get_drvdata(pdev) (which returns pdev->dev.driver_data) may yield NULL, causing a crash if that pointer is dereferenced.

Fix this by adding a sanity check to ensure "hcd" is non-NULL before proceeding with further operations.

Reported-by syzbot <[email protected]>

Closes https://syzkaller.appspot.com/bug?extid=83976e47ec1ef91e66f1

Tested-by syzbot <[email protected]>

Fixes 03cd00d538a6 ("usbip: vhci-hcd: Set the vhci structure up to work")

Signed-off-by Qasim Ijaz <[email protected]>

---
 drivers/usb/usbip/vhci_sysfs.c | 4 ++++
 1 file changed, 4 insertions(+)

drivers/usb/usbip/vhci_sysfs.c +0 -0

index d5865460e82d..a5e6c3c4af06 100644
@@ -76,6 +76,10 @@ static ssize_t status_show_vhci(int pdev_nr, char *out)
 	}
 

drivers/usb/usbip/vhci_sysfs.c static ssize_t status_show_vhci(int pdev_nr, char *out) · line 79

Quoted 2 lines

drivers/usb/usbip/vhci_sysfs.c +1 -0

 	hcd = platform_get_drvdata(pdev);
+

Empty line net really needed here...

drivers/usb/usbip/vhci_sysfs.c static ssize_t status_show_vhci(int pdev_nr, char *out) · line 85

Quoted 7 lines

drivers/usb/usbip/vhci_sysfs.c +3 -0

+	if (!hcd)
+		return 0;
+
 	vhci_hcd = hcd_to_vhci_hcd(hcd);
 	vhci = vhci_hcd->vhci;
 

MBR, Sergey