[PATCH 5.4 063/177] phy: renesas: rcar-gen3-usb2: Fix sysfs interface of "role"

Greg Kroah-Hartman
2019-12-16T18:26:29Z

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

commit 4bd5ead82d4b877ebe41daf95f28cda53205b039 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().

Reported-by: Pavel Machek <pavel@denx.de>
Fixes: 9bb86777fb71 ("phy: rcar-gen3-usb2: add sysfs for usb role swap")
Cc: <stable@vger.kernel.org> # v4.10+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/phy/renesas/phy-rcar-gen3-usb2.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
@@ -21,6 +21,7 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
+#include <linux/string.h>
#include <linux/usb/of.h>
#include <linux/workqueue.h>

@@ -320,9 +321,9 @@ static ssize_t role_store(struct device
if (!ch->is_otg_channel || !rcar_gen3_is_any_rphy_initialized(ch))
return -EIO;

- if (!strncmp(buf, "host", strlen("host")))
+ if (sysfs_streq(buf, "host"))
new_mode = PHY_MODE_USB_HOST;
- else if (!strncmp(buf, "peripheral", strlen("peripheral")))
+ else if (sysfs_streq(buf, "peripheral"))
new_mode = PHY_MODE_USB_DEVICE;
else
return -EINVAL;