USB: fix linked-list corruption in rh_call_control()

commit 1633682053a7ee8058e10c76722b9b28e97fb73f upstream.

Using KASAN, Dmitry found a bug in the rh_call_control() routine: If
buffer allocation fails, the routine returns immediately without
unlinking its URB from the control endpoint, eventually leading to
linked-list corruption.

This patch fixes the problem by jumping to the end of the routine
(where the URB is unlinked) when an allocation failure occurs.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 7f2144eb58d93c1bd636c83482c27390b24c9737..66f513398d28ff1b7afabe0f06321ff1b9a03fe8 100644 (file)
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -497,8 +497,10 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
         */
        tbuf_size =  max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
        tbuf = kzalloc(tbuf_size, GFP_KERNEL);
-       if (!tbuf)
-               return -ENOMEM;
+       if (!tbuf) {
+               status = -ENOMEM;
+               goto err_alloc;
+       }
 
        bufp = tbuf;
 
@@ -701,6 +703,7 @@ error:
        }
 
        kfree(tbuf);
+ err_alloc:
 
        /* any errors get returned through the urb completion */
        spin_lock_irq(&hcd_root_hub_lock);