Re: [PATCH net v2] netfilter: ipset: add missing range check in bitmap_ip_uadt

[Jozsef Kadlecsik <kadlec@netfilter.org>]

On Wed, 13 Nov 2024, Jeongjun Park wrote:

> When tb[IPSET_ATTR_IP_TO] is not present but tb[IPSET_ATTR_CIDR] exists,
> the values of ip and ip_to are slightly swapped. Therefore, the range check
> for ip should be done later, but this part is missing and it seems that the
> vulnerability occurs.
> 
> So we should add missing range checks and remove unnecessary range checks.
> 
> Cc: <stable@vger.kernel.org>
> Reported-by: syzbot+58c872f7790a4d2ac951@syzkaller.appspotmail.com
> Fixes: 72205fc68bd1 ("netfilter: ipset: bitmap:ip set type support")
> Signed-off-by: Jeongjun Park <aha310510@gmail.com>

Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>

The patch should be applied to the stable branches too. Thanks!

Best regards,
Jozsef

> ---
>  net/netfilter/ipset/ip_set_bitmap_ip.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c
> index e4fa00abde6a..5988b9bb9029 100644
> --- a/net/netfilter/ipset/ip_set_bitmap_ip.c
> +++ b/net/netfilter/ipset/ip_set_bitmap_ip.c
> @@ -163,11 +163,8 @@ bitmap_ip_uadt(struct ip_set *set, struct nlattr *tb[],
>  		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
>  		if (ret)
>  			return ret;
> -		if (ip > ip_to) {
> +		if (ip > ip_to)
>  			swap(ip, ip_to);
> -			if (ip < map->first_ip)
> -				return -IPSET_ERR_BITMAP_RANGE;
> -		}
>  	} else if (tb[IPSET_ATTR_CIDR]) {
>  		u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
>  
> @@ -178,7 +175,7 @@ bitmap_ip_uadt(struct ip_set *set, struct nlattr *tb[],
>  		ip_to = ip;
>  	}
>  
> -	if (ip_to > map->last_ip)
> +	if (ip < map->first_ip || ip_to > map->last_ip)
>  		return -IPSET_ERR_BITMAP_RANGE;
>  
>  	for (; !before(ip_to, ip); ip += map->hosts) {
> --
> 

-- 
E-mail : kadlec@netfilter.org, kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.hu
Address: Wigner Research Centre for Physics
         H-1525 Budapest 114, POB. 49, Hungary