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regulator: core: Fix slab-out-of-bounds in regulator_unlock_recursive() 

The recent commit 7d8196641e ("regulator: Remove pointer table
overallocation") changed the size of coupled_rdevs and now KASAN is able
to detect slab-out-of-bounds problem in regulator_unlock_recursive(),
which is a legit problem caused by a typo in the code. The recursive
unlock function uses n_coupled value of a parent regulator for unlocking
supply regulator, while supply's n_coupled should be used. In practice
problem may only affect platforms that use coupled regulators.

Cc: stable@vger.kernel.org # 5.0+
Fixes: f8702f9e4a ("regulator: core: Use ww_mutex for regulators locking")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200831204335.19489-1-digetx@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Dmitry Osipenko 2020-08-31 23:43:35 +03:00 committed by Mark Brown
parent 3bec5b6aae
commit 0a7416f947
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 9 additions and 6 deletions
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15
drivers/regulator/core.c
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@ -236,8 +236,8 @@ static bool regulator_supply_is_couple(struct regulator_dev *rdev)
static void regulator_unlock_recursive(struct regulator_dev *rdev,
unsigned int n_coupled)
{
struct regulator_dev *c_rdev;
int i;
struct regulator_dev *c_rdev, *supply_rdev;
int i, supply_n_coupled;
for (i = n_coupled; i > 0; i--) {
c_rdev = rdev->coupling_desc.coupled_rdevs[i - 1];
@ -245,10 +245,13 @@ static void regulator_unlock_recursive(struct regulator_dev *rdev,
if (!c_rdev)
continue;
if (c_rdev->supply && !regulator_supply_is_couple(c_rdev))
regulator_unlock_recursive(
c_rdev->supply->rdev,
c_rdev->coupling_desc.n_coupled);
if (c_rdev->supply && !regulator_supply_is_couple(c_rdev)) {
supply_rdev = c_rdev->supply->rdev;
supply_n_coupled = supply_rdev->coupling_desc.n_coupled;
regulator_unlock_recursive(supply_rdev,
supply_n_coupled);
}
regulator_unlock(c_rdev);
}