From: Xu Wang vulab@iscas.ac.cn
stable inclusion from stable-v4.19.307 commit 23a191b132cd87f746c62f3dc27da33683d85829 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I946KM CVE: CVE-2019-25162
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[ 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 vulab@iscas.ac.cn [wsa: added comment to the code, added Fixes tag] Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 2a43f4e46af0..9079be0d51d1 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -2273,8 +2273,9 @@ 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);