syzbot reports following splat:
BUG: KMSAN: uninit-value in ebt_stp_mt_check+0x24b/0x450
net/bridge/netfilter/ebt_stp.c:162
ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162
xt_check_match+0x1438/0x1650 net/netfilter/x_tables.c:506
ebt_check_match net/bridge/netfilter/ebtables.c:372 [inline]
ebt_check_entry net/bridge/netfilter/ebtables.c:702 [inline]
The uninitialised access is
xt_mtchk_param->nft_compat
... which should be set to 0.
Fix it by zeroing the struct beforehand, same for tgchk.
ip(6)tables targetinfo uses c99-style initialiser, so no change
needed there.
Reported-by: syzbot+da4494182233c23a5fcf@syzkaller.appspotmail.com
Fixes: 55917a21d0cc0 ("netfilter: x_tables: add context to know if extension runs from nft_compat")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
c568503ef0