From: Pablo Neira Ayuso Subject: [PATCH 04/15] netfilter: bridge: stp fix reference to uninitialized data Date: Mon, 14 May 2018 00:36:45 +0200 Message-ID: <20180513223656.10077-5-pablo@netfilter.org> References: <20180513223656.10077-1-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: In-Reply-To: <20180513223656.10077-1-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org From: Stephen Hemminger The destination mac (destmac) is only valid if EBT_DESTMAC flag is set. Fix by changing the order of the comparison to look for the flag first. Reported-by: syzbot+5c06e318fc558cc27823@syzkaller.appspotmail.com Signed-off-by: Stephen Hemminger Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebt_stp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bridge/netfilter/ebt_stp.c b/net/bridge/netfilter/ebt_stp.c index 47ba98db145d..46c1fe7637ea 100644 --- a/net/bridge/netfilter/ebt_stp.c +++ b/net/bridge/netfilter/ebt_stp.c @@ -161,8 +161,8 @@ static int ebt_stp_mt_check(const struct xt_mtchk_param *par) /* Make sure the match only receives stp frames */ if (!par->nft_compat && (!ether_addr_equal(e->destmac, eth_stp_addr) || - !is_broadcast_ether_addr(e->destmsk) || - !(e->bitmask & EBT_DESTMAC))) + !(e->bitmask & EBT_DESTMAC) || + !is_broadcast_ether_addr(e->destmsk))) return -EINVAL; return 0; -- 2.11.0