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    Subject[PATCH 4.14 097/125] USB: c67x00: fix use after free in c67x00_giveback_urb
    Date
    From: Tom Rix <trix@redhat.com>

    commit 211f08347355cba1f769bbf3355816a12b3ddd55 upstream.

    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>
    Cc: stable <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/20200708131243.24336-1-trix@redhat.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/usb/c67x00/c67x00-sched.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/usb/c67x00/c67x00-sched.c
    +++ b/drivers/usb/c67x00/c67x00-sched.c
    @@ -500,7 +500,7 @@ c67x00_giveback_urb(struct c67x00_hcd *c
    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);
    }


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