diff options
| author | Jia-Ju Bai | 2018-12-18 20:04:25 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2018-12-19 08:13:26 +0100 |
| commit | c85400f886e3d41e69966470879f635a2b50084c (patch) | |
| tree | c567f6146fb5ff13a0ed311085cf6ac622f7e189 | |
| parent | c710d0bb76ff0795d8b6c1cda1e01e6e1e661a4a (diff) | |
usb: r8a66597: Fix a possible concurrency use-after-free bug in r8a66597_endpoint_disable()
The function r8a66597_endpoint_disable() and r8a66597_urb_enqueue() may
be concurrently executed.
The two functions both access a possible shared variable "hep->hcpriv".
This shared variable is freed by r8a66597_endpoint_disable() via the
call path:
r8a66597_endpoint_disable
kfree(hep->hcpriv) (line 1995 in Linux-4.19)
This variable is read by r8a66597_urb_enqueue() via the call path:
r8a66597_urb_enqueue
spin_lock_irqsave(&r8a66597->lock)
init_pipe_info
enable_r8a66597_pipe
pipe = hep->hcpriv (line 802 in Linux-4.19)
The read operation is protected by a spinlock, but the free operation
is not protected by this spinlock, thus a concurrency use-after-free bug
may occur.
To fix this bug, the spin-lock and spin-unlock function calls in
r8a66597_endpoint_disable() are moved to protect the free operation.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/host/r8a66597-hcd.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/host/r8a66597-hcd.c b/drivers/usb/host/r8a66597-hcd.c index 984892dd72f5..42668aeca57c 100644 --- a/drivers/usb/host/r8a66597-hcd.c +++ b/drivers/usb/host/r8a66597-hcd.c @@ -1979,6 +1979,8 @@ static int r8a66597_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, static void r8a66597_endpoint_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep) +__acquires(r8a66597->lock) +__releases(r8a66597->lock) { struct r8a66597 *r8a66597 = hcd_to_r8a66597(hcd); struct r8a66597_pipe *pipe = (struct r8a66597_pipe *)hep->hcpriv; @@ -1991,13 +1993,14 @@ static void r8a66597_endpoint_disable(struct usb_hcd *hcd, return; pipenum = pipe->info.pipenum; + spin_lock_irqsave(&r8a66597->lock, flags); if (pipenum == 0) { kfree(hep->hcpriv); hep->hcpriv = NULL; + spin_unlock_irqrestore(&r8a66597->lock, flags); return; } - spin_lock_irqsave(&r8a66597->lock, flags); pipe_stop(r8a66597, pipe); pipe_irq_disable(r8a66597, pipenum); disable_irq_empty(r8a66597, pipenum); |