[PATCH] USB: c67x00: fix use after free in c67x00_giveback_urb
From: trix
Date: Wed Jul 08 2020 - 09:12:55 EST
From: Tom Rix <trix@xxxxxxxxxx>
clang static analysis flags this error
c67x00-sched.c:489:55: warning: Use of memory after it is freed [unix.Malloc]
usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);
^~~~~~~~~~~~
Problem happens in this block of code
c67x00_release_urb(c67x00, urb);
usb_hcd_unlink_urb_from_ep(c67x00_hcd_to_hcd(c67x00), urb);
spin_unlock(&c67x00->lock);
usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);
In the call to c67x00_release_urb has this freeing of urbp
urbp = urb->hcpriv;
urb->hcpriv = NULL;
list_del(&urbp->hep_node);
kfree(urbp);
And so urbp is freed before usb_hcd_giveback_urb uses it as its 3rd
parameter.
Since all is required is the status, pass the status directly as is
done in c64x00_urb_dequeue
Fixes: e9b29ffc519b ("USB: add Cypress c67x00 OTG controller HCD driver")
Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
drivers/usb/c67x00/c67x00-sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/c67x00/c67x00-sched.c b/drivers/usb/c67x00/c67x00-sched.c
index ef1e4ecaee99..f7f6229082ca 100644
--- a/drivers/usb/c67x00/c67x00-sched.c
+++ b/drivers/usb/c67x00/c67x00-sched.c
@@ -486,7 +486,7 @@ c67x00_giveback_urb(struct c67x00_hcd *c67x00, struct urb *urb, int status)
c67x00_release_urb(c67x00, urb);
usb_hcd_unlink_urb_from_ep(c67x00_hcd_to_hcd(c67x00), urb);
spin_unlock(&c67x00->lock);
- usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);
+ usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, status);
spin_lock(&c67x00->lock);
}
--
2.18.1