[PATCH 4.19 60/85] usb: gadget: udc: renesas_usb3: Fix sysfs interface of "role"

Greg Kroah-Hartman
2019-08-22T17:31:11Z

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

commit 5dac665cf403967bb79a7aeb8c182a621fe617ff upstream.

Since the role_store() uses strncmp(), it's possible to refer
out-of-memory if the sysfs data size is smaller than strlen("host").
This patch fixes it by using sysfs_streq() instead of strncmp().

Fixes: cc995c9ec118 ("usb: gadget: udc: renesas_usb3: add support for usb role swap")
Cc: <stable@vger.kernel.org> # v4.12+
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/gadget/udc/renesas_usb3.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -19,6 +19,7 @@
#include <linux/pm_runtime.h>
#include <linux/sizes.h>
#include <linux/slab.h>
+#include <linux/string.h>
#include <linux/sys_soc.h>
#include <linux/uaccess.h>
#include <linux/usb/ch9.h>
@@ -2378,9 +2379,9 @@ static ssize_t role_store(struct device
if (usb3->forced_b_device)
return -EBUSY;

- if (!strncmp(buf, "host", strlen("host")))
+ if (sysfs_streq(buf, "host"))
new_mode_is_host = true;
- else if (!strncmp(buf, "peripheral", strlen("peripheral")))
+ else if (sysfs_streq(buf, "peripheral"))
new_mode_is_host = false;
else
return -EINVAL;