From: trix@redhat.com
To: jacmet@sunsite.dk, gregkh@linuxfoundation.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Tom Rix <trix@redhat.com>
Subject: [PATCH] USB: c67x00: fix use after free in c67x00_giveback_urb
Date: Wed, 8 Jul 2020 06:12:43 -0700 [thread overview]
Message-ID: <20200708131243.24336-1-trix@redhat.com> (raw)
From: Tom Rix <trix@redhat.com>
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@redhat.com>
---
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
reply other threads:[~2020-07-08 13:12 UTC|newest]
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