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authorJia-Ju Bai <baijiaju1990@gmail.com>2018-12-18 15:04:25 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-12-19 10:13:26 +0300
commitc85400f886e3d41e69966470879f635a2b50084c (patch)
treec567f6146fb5ff13a0ed311085cf6ac622f7e189 /drivers/usb/host/r8a66597-hcd.c
parentc710d0bb76ff0795d8b6c1cda1e01e6e1e661a4a (diff)
downloadlinux-c85400f886e3d41e69966470879f635a2b50084c.tar.xz
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>
Diffstat (limited to 'drivers/usb/host/r8a66597-hcd.c')
-rw-r--r--drivers/usb/host/r8a66597-hcd.c5
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);