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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Julia Lawall <Julia.Lawall@lip6.fr>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.14 38/87] usb: wusbcore: security: cast sizeof to
 int for comparison
Thread-Topic: [PATCH AUTOSEL 4.14 38/87] usb: wusbcore: security: cast sizeof
 to int for comparison
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Date:   Mon, 17 Sep 2018 03:02:47 +0000
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From: Julia Lawall <Julia.Lawall@lip6.fr>

[ Upstream commit d3ac5598c5010a8999978ebbcca3b1c6188ca36b ]

Comparing an int to a size, which is unsigned, causes the int to become
unsigned, giving the wrong result.  usb_get_descriptor can return a
negative error code.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
int x;
expression e,e1;
identifier f;
@@

*x =3D f(...);
... when !=3D x =3D e1
    when !=3D if (x < 0 || ...) { ... return ...; }
*x < sizeof(e)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/usb/wusbcore/security.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/wusbcore/security.c b/drivers/usb/wusbcore/securit=
y.c
index 170f2c38de9b..5274aa7339b8 100644
--- a/drivers/usb/wusbcore/security.c
+++ b/drivers/usb/wusbcore/security.c
@@ -230,7 +230,7 @@ int wusb_dev_sec_add(struct wusbhc *wusbhc,
=20
 	result =3D usb_get_descriptor(usb_dev, USB_DT_SECURITY,
 				    0, secd, sizeof(*secd));
-	if (result < sizeof(*secd)) {
+	if (result < (int)sizeof(*secd)) {
 		dev_err(dev, "Can't read security descriptor or "
 			"not enough data: %d\n", result);
 		goto out;
--=20
2.17.1