HID: corsair: fix control-transfer error handling

Make sure to check for short control transfers in order to avoid parsing
uninitialised buffer data and leaking it to user space.

Note that the backlight and macro-mode buffer constraints are kept as
loose as possible in order to avoid any regressions should the current
buffer sizes be larger than necessary.

Fixes: 6f78193ee9ea ("HID: corsair: Add Corsair Vengeance K90 driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-corsair.c b/drivers/hid/hid-corsair.c
index 5971907a23b13db1250264f8a26c214e3c9b748a..c0303f61c26a94f1998f6883d42a0fc8cb41f432 100644 (file)
--- a/drivers/hid/hid-corsair.c
+++ b/drivers/hid/hid-corsair.c
@@ -159,7 +159,7 @@ static enum led_brightness k90_backlight_get(struct led_classdev *led_cdev)
                              USB_DIR_IN | USB_TYPE_VENDOR |
                              USB_RECIP_DEVICE, 0, 0, data, 8,
                              USB_CTRL_SET_TIMEOUT);
-       if (ret < 0) {
+       if (ret < 5) {
                dev_warn(dev, "Failed to get K90 initial state (error %d).\n",
                         ret);
                ret = -EIO;
@@ -274,7 +274,7 @@ static ssize_t k90_show_macro_mode(struct device *dev,
                              USB_DIR_IN | USB_TYPE_VENDOR |
                              USB_RECIP_DEVICE, 0, 0, data, 2,
                              USB_CTRL_SET_TIMEOUT);
-       if (ret < 0) {
+       if (ret < 1) {
                dev_warn(dev, "Failed to get K90 initial mode (error %d).\n",
                         ret);
                ret = -EIO;
@@ -351,7 +351,7 @@ static ssize_t k90_show_current_profile(struct device *dev,
                              USB_DIR_IN | USB_TYPE_VENDOR |
                              USB_RECIP_DEVICE, 0, 0, data, 8,
                              USB_CTRL_SET_TIMEOUT);
-       if (ret < 0) {
+       if (ret < 8) {
                dev_warn(dev, "Failed to get K90 initial state (error %d).\n",
                         ret);
                ret = -EIO;