This is a note to let you know that I've just added the patch titled
USB: c67x00: fix use after free in c67x00_giveback_urb
to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 211f08347355cba1f769bbf3355816a12b3ddd55 Mon Sep 17 00:00:00 2001
From: Tom Rix trix@redhat.com Date: Wed, 8 Jul 2020 06:12:43 -0700 Subject: USB: c67x00: fix use after free in c67x00_giveback_urb
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(-)
diff --git a/drivers/usb/c67x00/c67x00-sched.c b/drivers/usb/c67x00/c67x00-sched.c index 633c52de3bb3..9865750bc31e 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); }