From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot <syzbot+93dba5b91f0fed312cbd@syzkaller.appspotmail.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 238/355] smackfs: use netlbl_cfg_cipsov4_del() for deleting cipso_v4_doi
Date:   Mon, 15 Nov 2021 18:02:42 +0100
Message-Id: <20211115165321.447839089@linuxfoundation.org>
In-Reply-To: <20211115165313.549179499@linuxfoundation.org>
References: <20211115165313.549179499@linuxfoundation.org>
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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 <syzbot+93dba5b91f0fed312cbd@syzkaller.appspotmail.com>
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 fdf5f336f834a..6b6fec04c412b 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -712,7 +712,7 @@ 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