[PATCH] usbip: vhci_hcd: check port number before using

From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
To: Valentina Manea <valentina.manea.m@gmail.com>,
	Shuah Khan <shuah@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	syzbot+600b03e0cf1b73bb23c4@syzkaller.appspotmail.com,
	Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
	stable <stable@vger.kernel.org>
Subject: [PATCH] usbip: vhci_hcd: check port number before using
Date: Mon,  8 Oct 2018 20:19:13 +0100	[thread overview]
Message-ID: <20181008191913.11527-1-sudip.mukherjee@codethink.co.uk> (raw)

From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>

The port number is checked and it just prints an error message but it
still continues to use the invalid port. And as a result it accesses
memory which is not its resulting in  BUG report from KASAN.

Reported-by: syzbot+600b03e0cf1b73bb23c4@syzkaller.appspotmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
 drivers/usb/usbip/vhci_hcd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index d11f3f8dad40..71883aa788ac 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -334,8 +334,10 @@ static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 	usbip_dbg_vhci_rh("typeReq %x wValue %x wIndex %x\n", typeReq, wValue,
 			  wIndex);
 
-	if (wIndex > VHCI_HC_PORTS)
+	if (wIndex > VHCI_HC_PORTS) {
 		pr_err("invalid port number %d\n", wIndex);
+		return -ENODEV;
+	}
 	rhport = wIndex - 1;
 
 	vhci_hcd = hcd_to_vhci_hcd(hcd);
-- 
2.11.0

