# \[PATCH 4.9 108/207\] smackfs: use netlbl\_cfg\_cipsov4\_del() for deleting cipso\_v4\_doi

- From: Greg Kroah-Hartman \<gregkh@linuxfoundation.org\>
- Date: 2021-11-24 12:21:39 
- List: stable
- Page: https://ratatoskr.run/stable/2021/11/1584026
- Thread: https://ratatoskr.run/stable/2021/11/1583929/t/2.md

```text
From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>

[ Upstream commit 0934ad42bb2c5df90a1b9de690f93de735b622fe ]

syzbot is reporting UAF at cipso_v4_doi_search() [1], for smk_cipso_doi()
is calling kfree() without removing from the cipso_v4_doi_list list after
netlbl_cfg_cipsov4_map_add() returned an error. We need to use
netlbl_cfg_cipsov4_del() in order to remove from the list and wait for
RCU grace period before kfree().

Link: https://syzkaller.appspot.com/bug?extid=93dba5b91f0fed312cbd [1]
Reported-by: syzbot <redacted>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 6c2e8ac0953fccdd ("netlabel: Update kernel configuration API")
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 security/smack/smackfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index cf1f92a04359a..ed5b89fbbd96f 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -735,7 +735,7 @@ static void smk_cipso_doi(void)
 	if (rc != 0) {
 		printk(KERN_WARNING "%s:%d map add rc = %d\n",
 		       __func__, __LINE__, rc);
-		kfree(doip);
+		netlbl_cfg_cipsov4_del(doip->doi, &nai);
 		return;
 	}
 }
-- 
2.33.0



```