From 5f4b204b6b8153923d5be8002c5f7082985d153f Mon Sep 17 00:00:00 2001 From: Zeng Heng Date: Wed, 16 Nov 2022 15:43:39 +0800 Subject: regulator: core: fix kobject release warning and memory leak in regulator_register() Here is a warning report about lack of registered release() from kobject lib: Device '(null)' does not have a release() function, it is broken and must be fixed. WARNING: CPU: 0 PID: 48430 at drivers/base/core.c:2332 device_release+0x104/0x120 Call Trace: kobject_put+0xdc/0x180 put_device+0x1b/0x30 regulator_register+0x651/0x1170 devm_regulator_register+0x4f/0xb0 When regulator_register() returns fail and directly goto `clean` symbol, rdev->dev has not registered release() function yet (which is registered by regulator_class in the following), so rdev needs to be freed manually. If rdev->dev.of_node is not NULL, which means the of_node has gotten by regulator_of_get_init_data(), it needs to call of_node_put() to avoid refcount leak. Otherwise, only calling put_device() would lead memory leak of rdev in further: unreferenced object 0xffff88810d0b1000 (size 2048): comm "107-i2c-rtq6752", pid 48430, jiffies 4342258431 (age 1341.780s) backtrace: kmalloc_trace+0x22/0x110 regulator_register+0x184/0x1170 devm_regulator_register+0x4f/0xb0 When regulator_register() returns fail and goto `wash` symbol, rdev->dev has registered release() function, so directly call put_device() to cleanup everything. Fixes: d3c731564e09 ("regulator: plug of_node leak in regulator_register()'s error path") Signed-off-by: Zeng Heng Link: https://lore.kernel.org/r/20221116074339.1024240-1-zengheng4@huawei.com Signed-off-by: Mark Brown --- drivers/regulator/core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/regulator/core.c') diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 28879f8974d9..b3a0f6df91c0 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5639,11 +5639,15 @@ wash: mutex_lock(®ulator_list_mutex); regulator_ena_gpio_free(rdev); mutex_unlock(®ulator_list_mutex); + put_device(&rdev->dev); + rdev = NULL; clean: if (dangling_of_gpiod) gpiod_put(config->ena_gpiod); + if (rdev && rdev->dev.of_node) + of_node_put(rdev->dev.of_node); + kfree(rdev); kfree(config); - put_device(&rdev->dev); rinse: if (dangling_cfg_gpiod) gpiod_put(cfg->ena_gpiod); -- cgit v1.2.3-58-ga151 From 1f386d6894d0f1b7de8ef640c41622ddd698e7ab Mon Sep 17 00:00:00 2001 From: Yang Yingliang Date: Wed, 16 Nov 2022 11:37:06 +0800 Subject: regulator: core: fix UAF in destroy_regulator() I got a UAF report as following: ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x935/0x2060 Read of size 8 at addr ffff88810e838220 by task python3/268 Call Trace: dump_stack_lvl+0x67/0x83 print_report+0x178/0x4b0 kasan_report+0x90/0x190 __lock_acquire+0x935/0x2060 lock_acquire+0x156/0x400 _raw_spin_lock+0x2a/0x40 lockref_get+0x11/0x30 simple_recursive_removal+0x41/0x440 debugfs_remove.part.12+0x32/0x50 debugfs_remove+0x29/0x30 _regulator_put.cold.54+0x3e/0x27f regulator_put+0x1f/0x30 release_nodes+0x6a/0xa0 devres_release_all+0xf8/0x150 Allocated by task 37: kasan_save_stack+0x1c/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x5d/0x70 slab_post_alloc_hook+0x62/0x510 kmem_cache_alloc_lru+0x222/0x5a0 __d_alloc+0x31/0x440 d_alloc+0x30/0xf0 d_alloc_parallel+0xc4/0xd20 __lookup_slow+0x15e/0x2f0 lookup_one_len+0x13a/0x150 start_creating+0xea/0x190 debugfs_create_dir+0x1e/0x210 create_regulator+0x254/0x4e0 _regulator_get+0x2a1/0x467 _devm_regulator_get+0x5a/0xb0 regulator_virtual_probe+0xb9/0x1a0 Freed by task 30: kasan_save_stack+0x1c/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x50 __kasan_slab_free+0x102/0x190 kmem_cache_free+0xf6/0x600 rcu_core+0x54c/0x12b0 __do_softirq+0xf2/0x5e3 Last potentially related work creation: kasan_save_stack+0x1c/0x40 __kasan_record_aux_stack+0x98/0xb0 call_rcu+0x42/0x700 dentry_free+0x6c/0xd0 __dentry_kill+0x23b/0x2d0 dput.part.31+0x431/0x780 simple_recursive_removal+0xa9/0x440 debugfs_remove.part.12+0x32/0x50 debugfs_remove+0x29/0x30 regulator_unregister+0xe3/0x230 release_nodes+0x6a/0xa0 ================================================================== Here is how happened: processor A processor B regulator_register() rdev_init_debugfs() rdev->debugfs = debugfs_create_dir() devm_regulator_get() rdev = regulator_dev_lookup() create_regulator(rdev) // using rdev->debugfs as parent debugfs_create_dir(rdev->debugfs) mfd_remove_devices_fn() release_nodes() regulator_unregister() // free rdev->debugfs debugfs_remove_recursive(rdev->debugfs) release_nodes() destroy_regulator() debugfs_remove_recursive() <- causes UAF In devm_regulator_get(), after getting rdev, the refcount is get, so fix this by moving debugfs_remove_recursive() to regulator_dev_release(), then it can be proctected by the refcount, the 'rdev->debugfs' can not be freed until the refcount is 0. Fixes: 5de705194e98 ("regulator: Add basic per consumer debugfs") Signed-off-by: Yang Yingliang Link: https://lore.kernel.org/r/20221116033706.3595812-1-yangyingliang@huawei.com Signed-off-by: Mark Brown --- drivers/regulator/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/regulator/core.c') diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index b3a0f6df91c0..ec626bda79d6 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5149,6 +5149,7 @@ static void regulator_dev_release(struct device *dev) { struct regulator_dev *rdev = dev_get_drvdata(dev); + debugfs_remove_recursive(rdev->debugfs); kfree(rdev->constraints); of_node_put(rdev->dev.of_node); kfree(rdev); @@ -5676,7 +5677,6 @@ void regulator_unregister(struct regulator_dev *rdev) mutex_lock(®ulator_list_mutex); - debugfs_remove_recursive(rdev->debugfs); WARN_ON(rdev->open_count); regulator_remove_coupling(rdev); unset_regulator_supplies(rdev); -- cgit v1.2.3-58-ga151