[PATCH 3.18 030/120] usb: wusbcore: security: cast sizeof to int for comparison

Greg Kroah-Hartman
2018-10-11T15:36:58Z

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 = f(...);
... when != x = e1
when != 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/wusbcore/security.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/wusbcore/security.c
+++ b/drivers/usb/wusbcore/security.c
@@ -230,7 +230,7 @@ int wusb_dev_sec_add(struct wusbhc *wusb

result = 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;