linux/drivers/leds/leds-wm831x-status.c
Johan Hovold 47a459ecc8 leds: wm831x-status: fix use-after-free on unbind
Several MFD child drivers register their class devices directly under
the parent device. This means you cannot blindly do devres conversions
so that deregistration ends up being tied to the parent device,
something which leads to use-after-free on driver unbind when the class
device is released while still being registered.

Fixes: 8d3b6a4001 ("leds: wm831x-status: Use devm_led_classdev_register")
Cc: stable <stable@vger.kernel.org>     # 4.6
Cc: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
2020-06-22 10:38:00 +02:00

306 lines
6.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* LED driver for WM831x status LEDs
*
* Copyright(C) 2009 Wolfson Microelectronics PLC.
*/
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/status.h>
#include <linux/module.h>
struct wm831x_status {
struct led_classdev cdev;
struct wm831x *wm831x;
struct mutex mutex;
spinlock_t value_lock;
int reg; /* Control register */
int reg_val; /* Control register value */
int blink;
int blink_time;
int blink_cyc;
int src;
enum led_brightness brightness;
};
#define to_wm831x_status(led_cdev) \
container_of(led_cdev, struct wm831x_status, cdev)
static void wm831x_status_set(struct wm831x_status *led)
{
unsigned long flags;
mutex_lock(&led->mutex);
led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
spin_lock_irqsave(&led->value_lock, flags);
led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
if (led->blink) {
led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
led->reg_val |= led->blink_cyc;
} else {
if (led->brightness != LED_OFF)
led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
}
spin_unlock_irqrestore(&led->value_lock, flags);
wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
mutex_unlock(&led->mutex);
}
static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
struct wm831x_status *led = to_wm831x_status(led_cdev);
unsigned long flags;
spin_lock_irqsave(&led->value_lock, flags);
led->brightness = value;
if (value == LED_OFF)
led->blink = 0;
spin_unlock_irqrestore(&led->value_lock, flags);
wm831x_status_set(led);
return 0;
}
static int wm831x_status_blink_set(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off)
{
struct wm831x_status *led = to_wm831x_status(led_cdev);
unsigned long flags;
int ret = 0;
/* Pick some defaults if we've not been given times */
if (*delay_on == 0 && *delay_off == 0) {
*delay_on = 250;
*delay_off = 250;
}
spin_lock_irqsave(&led->value_lock, flags);
/* We only have a limited selection of settings, see if we can
* support the configuration we're being given */
switch (*delay_on) {
case 1000:
led->blink_time = 0;
break;
case 250:
led->blink_time = 1;
break;
case 125:
led->blink_time = 2;
break;
case 62:
case 63:
/* Actually 62.5ms */
led->blink_time = 3;
break;
default:
ret = -EINVAL;
break;
}
if (ret == 0) {
switch (*delay_off / *delay_on) {
case 1:
led->blink_cyc = 0;
break;
case 3:
led->blink_cyc = 1;
break;
case 4:
led->blink_cyc = 2;
break;
case 8:
led->blink_cyc = 3;
break;
default:
ret = -EINVAL;
break;
}
}
if (ret == 0)
led->blink = 1;
else
led->blink = 0;
spin_unlock_irqrestore(&led->value_lock, flags);
wm831x_status_set(led);
return ret;
}
static const char * const led_src_texts[] = {
"otp",
"power",
"charger",
"soft",
};
static ssize_t wm831x_status_src_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
struct wm831x_status *led = to_wm831x_status(led_cdev);
int i;
ssize_t ret = 0;
mutex_lock(&led->mutex);
for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
if (i == led->src)
ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
else
ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
mutex_unlock(&led->mutex);
ret += sprintf(&buf[ret], "\n");
return ret;
}
static ssize_t wm831x_status_src_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
struct wm831x_status *led = to_wm831x_status(led_cdev);
int i;
i = sysfs_match_string(led_src_texts, buf);
if (i >= 0) {
mutex_lock(&led->mutex);
led->src = i;
mutex_unlock(&led->mutex);
wm831x_status_set(led);
}
return size;
}
static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
static struct attribute *wm831x_status_attrs[] = {
&dev_attr_src.attr,
NULL
};
ATTRIBUTE_GROUPS(wm831x_status);
static int wm831x_status_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
struct wm831x_pdata *chip_pdata;
struct wm831x_status_pdata pdata;
struct wm831x_status *drvdata;
struct resource *res;
int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
int ret;
res = platform_get_resource(pdev, IORESOURCE_REG, 0);
if (res == NULL) {
dev_err(&pdev->dev, "No register resource\n");
return -EINVAL;
}
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
drvdata->wm831x = wm831x;
drvdata->reg = res->start;
if (dev_get_platdata(wm831x->dev))
chip_pdata = dev_get_platdata(wm831x->dev);
else
chip_pdata = NULL;
memset(&pdata, 0, sizeof(pdata));
if (chip_pdata && chip_pdata->status[id])
memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
else
pdata.name = dev_name(&pdev->dev);
mutex_init(&drvdata->mutex);
spin_lock_init(&drvdata->value_lock);
/* We cache the configuration register and read startup values
* from it. */
drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
if (drvdata->reg_val & WM831X_LED_MODE_MASK)
drvdata->brightness = LED_FULL;
else
drvdata->brightness = LED_OFF;
/* Set a default source if configured, otherwise leave the
* current hardware setting.
*/
if (pdata.default_src == WM831X_STATUS_PRESERVE) {
drvdata->src = drvdata->reg_val;
drvdata->src &= WM831X_LED_SRC_MASK;
drvdata->src >>= WM831X_LED_SRC_SHIFT;
} else {
drvdata->src = pdata.default_src - 1;
}
drvdata->cdev.name = pdata.name;
drvdata->cdev.default_trigger = pdata.default_trigger;
drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
drvdata->cdev.blink_set = wm831x_status_blink_set;
drvdata->cdev.groups = wm831x_status_groups;
ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, drvdata);
return 0;
}
static int wm831x_status_remove(struct platform_device *pdev)
{
struct wm831x_status *drvdata = platform_get_drvdata(pdev);
led_classdev_unregister(&drvdata->cdev);
return 0;
}
static struct platform_driver wm831x_status_driver = {
.driver = {
.name = "wm831x-status",
},
.probe = wm831x_status_probe,
.remove = wm831x_status_remove,
};
module_platform_driver(wm831x_status_driver);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("WM831x status LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-status");