nft_meta_get_eval()'s tendency to bail out setting NFT_BREAK verdict in
situations where required data is missing leads to unexpected behaviour
with inverted checks like so:
| meta iifname != eth0 accept
This rule will never match if there is no input interface (or it is not
known) which is not intuitive and, what's worse, breaks consistency of
iptables-nft with iptables-legacy.
Fix this by falling back to placing a value in dreg which never matches
(avoiding accidental matches), i.e. zero for interface index and an
empty string for interface name.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
switch (priv->key) {
case NFT_META_BRI_IIFNAME:
br_dev = nft_meta_get_bridge(in);
- if (!br_dev)
- goto err;
break;
case NFT_META_BRI_OIFNAME:
br_dev = nft_meta_get_bridge(out);
- if (!br_dev)
- goto err;
break;
case NFT_META_BRI_IIFPVID: {
u16 p_pvid;
goto out;
}
- strncpy((char *)dest, br_dev->name, IFNAMSIZ);
+ strncpy((char *)dest, br_dev ? br_dev->name : "", IFNAMSIZ);
return;
out:
return nft_meta_get_eval(expr, regs, pkt);
*dest = skb->mark;
break;
case NFT_META_IIF:
- if (in == NULL)
- goto err;
- *dest = in->ifindex;
+ *dest = in ? in->ifindex : 0;
break;
case NFT_META_OIF:
- if (out == NULL)
- goto err;
- *dest = out->ifindex;
+ *dest = out ? out->ifindex : 0;
break;
case NFT_META_IIFNAME:
- if (in == NULL)
- goto err;
- strncpy((char *)dest, in->name, IFNAMSIZ);
+ strncpy((char *)dest, in ? in->name : "", IFNAMSIZ);
break;
case NFT_META_OIFNAME:
- if (out == NULL)
- goto err;
- strncpy((char *)dest, out->name, IFNAMSIZ);
+ strncpy((char *)dest, out ? out->name : "", IFNAMSIZ);
break;
case NFT_META_IIFTYPE:
if (in == NULL)