[PATCH 5.4 017/165] regulator: core: fix regulator_register() error paths to properly release rdev

Greg Kroah-Hartman
2020-01-11T10:21:04Z

From: Wen Yang <wenyang@linux.alibaba.com>

[ Upstream commit a3cde9534ebdafe18a9bbab208df724c57e6c8e8 ]

There are several issues with the error handling code of
the regulator_register() function:
ret = device_register(&rdev->dev);
if (ret != 0) {
put_device(&rdev->dev); --> rdev released
goto unset_supplies;
}
...
unset_supplies:
...
unset_regulator_supplies(rdev); --> use-after-free
...
clean:
if (dangling_of_gpiod)
gpiod_put(config->ena_gpiod);
kfree(rdev); --> double free

We add a variable to record the failure of device_register() and
move put_device() down a bit to avoid the above issues.

Fixes: c438b9d01736 ("regulator: core: Move registration of regulator device")
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20191201030250.38074-1-wenyang@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/regulator/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index d66404920976..1dba0bdf3762 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4992,6 +4992,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
struct regulator_dev *rdev;
bool dangling_cfg_gpiod = false;
bool dangling_of_gpiod = false;
+ bool reg_device_fail = false;
struct device *dev;
int ret, i;

@@ -5177,7 +5178,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
dev_set_drvdata(&rdev->dev, rdev);
ret = device_register(&rdev->dev);
if (ret != 0) {
- put_device(&rdev->dev);
+ reg_device_fail = true;
goto unset_supplies;
}

@@ -5208,7 +5209,10 @@ regulator_register(const struct regulator_desc *regulator_desc,
clean:
if (dangling_of_gpiod)
gpiod_put(config->ena_gpiod);
- kfree(rdev);
+ if (reg_device_fail)
+ put_device(&rdev->dev);
+ else
+ kfree(rdev);
kfree(config);
rinse:
if (dangling_cfg_gpiod)
--
2.20.1