4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 2035f3ff8eaa29cfb5c8e2160b0f6e85eeb21a95 ]
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 3f1e53abff84 ("netfilter: ebtables: don't attempt to allocate 0-sized compat array").
Fixes: 7d7d7e02111e9 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/netfilter/ebtables.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 5e55cef0cec3..6693e209efe8 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -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;