smackfs: use netlbl_cfg_cipsov4_del() for deleting cipso_v4_doi

[ 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
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>

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 89989d2..658eab0 100644 (file)
--- 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;
        }
 }