regulator: core: Use different devices for resource allocation and DT lookup

[ Upstream commit 8f3cbcd6b440032ebc7f7d48a1689dcc70a4eb98 ]

Following by the below discussion, there's the potential UAF issue
between regulator and mfd.
https://lore.kernel.org/all/20221128143601.1698148-1-yangyingliang@huawei.com/

From the analysis of Yingliang

CPU A				|CPU B
mt6370_probe()			|
  devm_mfd_add_devices()	|
				|mt6370_regulator_probe()
				|  regulator_register()
				|    //allocate init_data and add it to devres
				|    regulator_of_get_init_data()
i2c_unregister_device()		|
  device_del()			|
    devres_release_all()	|
      // init_data is freed	|
      release_nodes()		|
				|  // using init_data causes UAF
				|  regulator_register()

It's common to use mfd core to create child device for the regulator.
In order to do the DT lookup for init data, the child that registered
the regulator would pass its parent as the parameter. And this causes
init data resource allocated to its parent, not itself. The issue happen
when parent device is going to release and regulator core is still doing
some operation of init data constraint for the regulator of child device.

To fix it, this patch expand 'regulator_register' API to use the
different devices for init data allocation and DT lookup.

Reported-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/1670311341-32664-1-git-send-email-u0084500@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
index 1cf958983e8680565d407c4b094b9c1d2505a833..b2342b3d78c7234303bb6155005f00b82c797cea 100644 (file)
--- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
+++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
@@ -185,7 +185,8 @@ int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
        cfg.init_data = &init_data;
        cfg.ena_gpiod = int3472->regulator.gpio;
 
-       int3472->regulator.rdev = regulator_register(&int3472->regulator.rdesc,
+       int3472->regulator.rdev = regulator_register(int3472->dev,
+                                                    &int3472->regulator.rdesc,
                                                     &cfg);
        if (IS_ERR(int3472->regulator.rdev)) {
                ret = PTR_ERR(int3472->regulator.rdev);

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1c1710d367d301d865afbaa6fa8d99bf34c8fa55..c095ca9f01e88e773cc9c682018601bd56a16c60 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -5388,6 +5388,7 @@ static struct regulator_coupler generic_regulator_coupler = {
 
 /**
  * regulator_register - register regulator
+ * @dev: the device that drive the regulator
  * @regulator_desc: regulator to register
  * @cfg: runtime configuration for regulator
  *
@@ -5396,7 +5397,8 @@ static struct regulator_coupler generic_regulator_coupler = {
  * or an ERR_PTR() on error.
  */
 struct regulator_dev *
-regulator_register(const struct regulator_desc *regulator_desc,
+regulator_register(struct device *dev,
+                  const struct regulator_desc *regulator_desc,
                   const struct regulator_config *cfg)
 {
        const struct regulator_init_data *init_data;
@@ -5405,7 +5407,6 @@ regulator_register(const struct regulator_desc *regulator_desc,
        struct regulator_dev *rdev;
        bool dangling_cfg_gpiod = false;
        bool dangling_of_gpiod = false;
-       struct device *dev;
        int ret, i;
 
        if (cfg == NULL)
@@ -5417,8 +5418,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
                goto rinse;
        }
 
-       dev = cfg->dev;
-       WARN_ON(!dev);
+       WARN_ON(!dev || !cfg->dev);
 
        if (regulator_desc->name == NULL || regulator_desc->ops == NULL) {
                ret = -EINVAL;

diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c
index 32823a87fd409a310ddd0417ee4af41869271ce7..d94db64cd490c4da4471a65c30c3f832c440c83a 100644 (file)
--- a/drivers/regulator/devres.c
+++ b/drivers/regulator/devres.c
@@ -221,7 +221,7 @@ struct regulator_dev *devm_regulator_register(struct device *dev,
        if (!ptr)
                return ERR_PTR(-ENOMEM);
 
-       rdev = regulator_register(regulator_desc, config);
+       rdev = regulator_register(dev, regulator_desc, config);
        if (!IS_ERR(rdev)) {
                *ptr = rdev;
                devres_add(dev, ptr);

diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index e12b681c72e5ebfd8d68d2b4365fe74d0abfa7b0..bd0c5d1fd647c80550d3a7b87d8776180040cc05 100644 (file)
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -505,7 +505,7 @@ struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
        struct device_node *child;
        struct regulator_init_data *init_data = NULL;
 
-       child = regulator_of_get_init_node(dev, desc);
+       child = regulator_of_get_init_node(config->dev, desc);
        if (!child)
                return NULL;
 

diff --git a/drivers/regulator/stm32-vrefbuf.c b/drivers/regulator/stm32-vrefbuf.c
index 30ea3bc8ca1921ced12c21c8c418475e6864db1b..7a454b7b6eab9958ad28ef2ba09739f3b893ce2c 100644 (file)
--- a/drivers/regulator/stm32-vrefbuf.c
+++ b/drivers/regulator/stm32-vrefbuf.c
@@ -210,7 +210,7 @@ static int stm32_vrefbuf_probe(struct platform_device *pdev)
                                                      pdev->dev.of_node,
                                                      &stm32_vrefbuf_regu);
 
-       rdev = regulator_register(&stm32_vrefbuf_regu, &config);
+       rdev = regulator_register(&pdev->dev, &stm32_vrefbuf_regu, &config);
        if (IS_ERR(rdev)) {
                ret = PTR_ERR(rdev);
                dev_err(&pdev->dev, "register failed with error %d\n", ret);

diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index f9a7461e72b80ef345ef3165262ac82bce201ed7..d3b4a3d4514aba340650c673b8a34c05132cb348 100644 (file)
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -687,7 +687,8 @@ static inline int regulator_err2notif(int err)
 
 
 struct regulator_dev *
-regulator_register(const struct regulator_desc *regulator_desc,
+regulator_register(struct device *dev,
+                  const struct regulator_desc *regulator_desc,
                   const struct regulator_config *config);
 struct regulator_dev *
 devm_regulator_register(struct device *dev,