From e4c72c06c367758a14f227c847f9d623f1994ecf Mon Sep 17 00:00:00 2001
From: Xu Wang <vulab@iscas.ac.cn>
Date: Fri, 27 Dec 2019 09:34:32 +0000
Subject: [PATCH] i2c: Fix a potential use after free
Git-commit: e4c72c06c367758a14f227c847f9d623f1994ecf
Patch-mainline: v6.0-rc1
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 8ae47e0bbd67..10f35f942066 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2461,8 +2461,9 @@ 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);
--
2.35.3