[PATCH AUTOSEL 4.19 10/49] usb: xhci: Fix a potential null pointer dereference in xhci_debugfs_create_endpoint()

Sasha Levin
2019-06-08T11:43:17Z

From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit 5bce256f0b528624a34fe907db385133bb7be33e ]

In xhci_debugfs_create_slot(), kzalloc() can fail and
dev->debugfs_private will be NULL.
In xhci_debugfs_create_endpoint(), dev->debugfs_private is used without
any null-pointer check, and can cause a null pointer dereference.

To fix this bug, a null-pointer check is added in
xhci_debugfs_create_endpoint().

This bug is found by a runtime fuzzing tool named FIZZER written by us.

[subjet line change change, add potential -Mathais]
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/xhci-debugfs.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/usb/host/xhci-debugfs.c b/drivers/usb/host/xhci-debugfs.c
index cadc01336bf8..7ba6afc7ef23 100644
--- a/drivers/usb/host/xhci-debugfs.c
+++ b/drivers/usb/host/xhci-debugfs.c
@@ -440,6 +440,9 @@ void xhci_debugfs_create_endpoint(struct xhci_hcd *xhci,
struct xhci_ep_priv *epriv;
struct xhci_slot_priv *spriv = dev->debugfs_private;

+ if (!spriv)
+ return;
+
if (spriv->eps[ep_index])
return;

--
2.20.1