This is a note to let you know that I've just added the patch titled regulator: core: Use different devices for resource allocation and DT lookup to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: regulator-core-use-different-devices-for-resource-al.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3f7be3b657947ff6e56afeed6199a2d4f45de9a3 Author: ChiYuan Huang <cy_huang@xxxxxxxxxxx> Date: Tue Dec 6 15:22:21 2022 +0800 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@xxxxxxxxxx/ 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@xxxxxxxxxx> Signed-off-by: ChiYuan Huang <cy_huang@xxxxxxxxxxx> Link: https://lore.kernel.org/r/1670311341-32664-1-git-send-email-u0084500@xxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c index 1cf958983e86..b2342b3d78c7 100644 --- 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 15677f5dcd99..8b567664f812 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5404,6 +5404,7 @@ 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 * @@ -5412,7 +5413,8 @@ 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; @@ -5421,7 +5423,6 @@ 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; bool resolved_early = false; @@ -5434,8 +5435,7 @@ 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 3265e75e97ab..5c7ff9b3e8a7 100644 --- a/drivers/regulator/devres.c +++ b/drivers/regulator/devres.c @@ -385,7 +385,7 @@ 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 0aff1c2886b5..cd726d4e8fbf 100644 --- 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 30ea3bc8ca19..7a454b7b6eab 100644 --- 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 f9a7461e72b8..d3b4a3d4514a 100644 --- 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,