[PATCH] smackfs: use netlbl_cfg_cipsov4_del() for deleting cipso_v4_doi

[Casey Schaufler]

On 10/19/2021 4:27 AM, Tetsuo Handa wrote:
> 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 at syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
> Fixes: 6c2e8ac0953fccdd ("netlabel: Update kernel configuration API")

Added to smack-next. Thank you.

> ---
>   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 3a75d2a8f517..83b90442f963 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -714,7 +714,7 @@ 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;
>   	}
>   }