[PATCH 4.9 51/72] USB: fix linked-list corruption in rh_call_control()

Greg Kroah-Hartman
2017-04-06T09:19:39Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 1633682053a7ee8058e10c76722b9b28e97fb73f upstream.

Using KASAN, Dmitry found a bug in the rh_call_control() routine: If
buffer allocation fails, the routine returns immediately without
unlinking its URB from the control endpoint, eventually leading to
linked-list corruption.

This patch fixes the problem by jumping to the end of the routine
(where the URB is unlinked) when an allocation failure occurs.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/core/hcd.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -520,8 +520,10 @@ static int rh_call_control (struct usb_h
*/
tbuf_size = max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
tbuf = kzalloc(tbuf_size, GFP_KERNEL);
- if (!tbuf)
- return -ENOMEM;
+ if (!tbuf) {
+ status = -ENOMEM;
+ goto err_alloc;
+ }

bufp = tbuf;

@@ -734,6 +736,7 @@ error:
}

kfree(tbuf);
+ err_alloc:

/* any errors get returned through the urb completion */
spin_lock_irq(&hcd_root_hub_lock);