diff options
| author | Phil Sutter <phil@nwl.cc> | 2019-07-23 15:27:52 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2019-07-25 08:37:20 +0200 |
| commit | cb81572e8cb50c5fb98b0b962cdfe48fff71fd37 (patch) | |
| tree | a6d4fa40c2d04babdc5fd076295d0144f664979d /net/bridge | |
| parent | 15a78ba1844a8e052c1226f930133de4cef4e7ad (diff) | |
netfilter: nf_tables: Make nft_meta expression more robust
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>
Diffstat (limited to 'net/bridge')
| -rw-r--r-- | net/bridge/netfilter/nft_meta_bridge.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/net/bridge/netfilter/nft_meta_bridge.c b/net/bridge/netfilter/nft_meta_bridge.c index bed66f536b34..a98dec2cf0cf 100644 --- a/net/bridge/netfilter/nft_meta_bridge.c +++ b/net/bridge/netfilter/nft_meta_bridge.c @@ -30,13 +30,9 @@ static void nft_meta_bridge_get_eval(const struct nft_expr *expr, 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; @@ -64,7 +60,7 @@ static void nft_meta_bridge_get_eval(const struct nft_expr *expr, 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); |