From 35927d7509ab9bf41896b7e44f639504eae08af7 Mon Sep 17 00:00:00 2001 From: Xu Wang Date: Fri, 27 Dec 2019 09:34:32 +0000 Subject: [PATCH] i2c: Fix a potential use after free [ Upstream commit e4c72c06c367758a14f227c847f9d623f1994ecf ] Free the adap structure only after we are done using it. This patch just moves the put_device() down a bit to avoid the use after free. Fixes: 611e12ea0f12 ("i2c: core: manage i2c bus device refcount in i2c_[get|put]_adapter") Signed-off-by: Xu Wang [wsa: added comment to the code, added Fixes tag] Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/i2c-core-base.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index cfbef70..8fb065ca 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -2464,8 +2464,9 @@ void i2c_put_adapter(struct i2c_adapter *adap) if (!adap) return; - put_device(&adap->dev); module_put(adap->owner); + /* Should be last, otherwise we risk use-after-free with 'adap' */ + put_device(&adap->dev); } EXPORT_SYMBOL(i2c_put_adapter); -- 2.7.4