[PATCH] smackfs: Added check catlen

[Casey Schaufler]

On 1/24/2023 2:50 AM, Denis Arefev wrote:
>   If the catlen is 0, the memory for the netlbl_lsm_catmap
>   structure must be allocated anyway, otherwise the check of
>   such rules is not completed correctly.
>
> Signed-off-by: Denis Arefev <arefev at swemel.ru>

Added to smack-next. Thank you.

> ---
>  security/smack/smackfs.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index 4b58526450d4..d45f4395a6ce 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -830,7 +830,7 @@ static int smk_open_cipso(struct inode *inode, struct file *file)
>  static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
>  				size_t count, loff_t *ppos, int format)
>  {
> -	struct netlbl_lsm_catmap *old_cat;
> +	struct netlbl_lsm_catmap *old_cat, *new_cat = NULL;
>  	struct smack_known *skp;
>  	struct netlbl_lsm_secattr ncats;
>  	char mapcatset[SMK_CIPSOLEN];
> @@ -917,8 +917,19 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
>  
>  		smack_catset_bit(cat, mapcatset);
>  	}
> -
> -	rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
> +	ncats.flags = 0;
> +	if (catlen == 0) {
> +		ncats.attr.mls.cat = NULL;
> +		ncats.attr.mls.lvl = maplevel;
> +		new_cat = netlbl_catmap_alloc(GFP_ATOMIC);
> +		if (new_cat)
> +			new_cat->next = ncats.attr.mls.cat;
> +		ncats.attr.mls.cat = new_cat;
> +		skp->smk_netlabel.flags &= ~(1U << 3);
> +		rc = 0;
> +	} else {
> +		rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
> +	}
>  	if (rc >= 0) {
>  		old_cat = skp->smk_netlabel.attr.mls.cat;
>  		skp->smk_netlabel.attr.mls.cat = ncats.attr.mls.cat;