netfilter: ebtables: compat: un-break 32bit setsockopt when no rules are present

Unlike ip(6)tables ebtables only counts user-defined chains.

The effect is that a 32bit ebtables binary on a 64bit kernel can do
'ebtables -N FOO' only after adding at least one rule, else the request
fails with -EINVAL.

This is a similar fix as done in
3f1e53abff ("netfilter: ebtables: don't attempt to allocate 0-sized compat array").

Fixes: 7d7d7e0211 ("netfilter: compat: reject huge allocation requests")
Reported-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2019-01-21 21:54:36 +01:00 коммит произвёл Pablo Neira Ayuso
Родитель 53ab60baa1
Коммит 2035f3ff8e
1 изменённых файлов: 6 добавлений и 3 удалений

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@ -2293,9 +2293,12 @@ static int compat_do_replace(struct net *net, void __user *user,
xt_compat_lock(NFPROTO_BRIDGE);
ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
if (ret < 0)
goto out_unlock;
if (tmp.nentries) {
ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
if (ret < 0)
goto out_unlock;
}
ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
if (ret < 0)
goto out_unlock;