From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8C9A3955C7 for ; Mon, 1 Jun 2026 10:29:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780309771; cv=none; b=ObHKBOTqGAR3b9C5gFmdzHkP4yzlCn/+1KB0bixNOVDGZffwB6YFXJagoMussY0/GbiLlD6z0NI4shKjhPzfy4gEkNoQchNhbS40/wRJmNZ0w3VJMYZ5hvrPoHphNPj4OuSHyLTeA5bBmpHbFHI2bOgRN0q1ijxiHO/y2sK08Xo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780309771; c=relaxed/simple; bh=fRMqCe8tnMgB4Ax5yI8s9QrIPh4Zo6Ottk//3i7c5iU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kIXdya48kJDXNtXqmm84Q9HmlR5HcGEd0n7c0qyTN7ZCVEF5mEkwztzwDo2EDjVrLykLraexiVIK6NEi9AJWa4KCQW6t36JDFHvCcSnxiwbYUrYtlOwMVRUYGy3m7/pRNrJOLhbzLxT6iZwE0cwCRaBJcXgmPnIRcX56bm+jt6s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=MC+awPPL; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="MC+awPPL" Received: from netfilter.org (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with UTF8SMTPSA id 2981260180; Mon, 1 Jun 2026 12:29:27 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1780309767; bh=jVSNYJXDkLh5iIZgFtyL2xgN9r1CdB6bhtLo/viKkj0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MC+awPPLvfAL3Twgh39HswuCGahoWLC9N1pww083r4A59dkEfY77tcbNTb53mVk53 A7Zmmf/Pl8o1ZNhTkIv+jV5Id1YG/9O0eTgat5rFCqLx9HMnIRoa8s2nlZrZuTyPSn BhtDH++aN/cha7Zm0ESI7FocPvzMutQf/6HaTe3662GhXtbfmCg8cf069icB7HvbE3 nS1gfP3Yh4yDthKTa+edCbfwUN3yhi3emdQfmfIbZfHvc2JwkYJe4fRQzprKm4yU2J gGclXjECwexjl6xOV8ull/DVVAex+p1/mOIU4Mn4X1I48Jye0jBKdp1/zJR+gBRqFA Zf6F3Iv9WbOfg== Date: Mon, 1 Jun 2026 12:29:24 +0200 From: Pablo Neira Ayuso To: Florian Westphal Cc: netfilter-devel@vger.kernel.org, Hacking Subject: Re: [PATCH nf] netfilter: bridge: ebt_redirect: don't assume bridge port exists Message-ID: References: <20260601095000.595383-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260601095000.595383-1-fw@strlen.de> Hi Florian, On Mon, Jun 01, 2026 at 11:50:00AM +0200, Florian Westphal wrote: > ebt_redirect_tg() dereferences br_port_get_rcu() return without a > NULL check, causing a kernel panic when the bridge port has been > removed between the original hook invocation and an NFQUEUE > reinject. Maybe more candidates for the same pattern? net/bridge/netfilter/nft_reject_bridge.c: br_forward(br_port_get_rcu(dev), nskb, false, true); net/bridge/netfilter/nft_reject_bridge.c: br_forward(br_port_get_rcu(dev), nskb, false, true); net/bridge/netfilter/nft_reject_bridge.c: br_forward(br_port_get_rcu(dev), nskb, false, true); net/bridge/netfilter/nft_reject_bridge.c: br_forward(br_port_get_rcu(dev), nskb, false, true); net/netfilter/nfnetlink_log.c: htonl(br_port_get_rcu(indev)->br->dev->ifindex))) net/netfilter/nfnetlink_log.c: htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) net/netfilter/nfnetlink_queue.c: htonl(br_port_get_rcu(indev)->br->dev->ifindex))) net/netfilter/nfnetlink_queue.c: htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) So this can be fix in one patch? Thanks > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Reported-by: Hacking > Signed-off-by: Florian Westphal > --- > net/bridge/netfilter/ebt_redirect.c | 21 +++++++++++++++------ > 1 file changed, 15 insertions(+), 6 deletions(-) > > diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c > index 307790562b49..379662961aeb 100644 > --- a/net/bridge/netfilter/ebt_redirect.c > +++ b/net/bridge/netfilter/ebt_redirect.c > @@ -20,16 +20,25 @@ static unsigned int > ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par) > { > const struct ebt_redirect_info *info = par->targinfo; > + const unsigned char *dev_addr; > > if (skb_ensure_writable(skb, 0)) > return EBT_DROP; > > - if (xt_hooknum(par) != NF_BR_BROUTING) > - /* rcu_read_lock()ed by nf_hook_thresh */ > - ether_addr_copy(eth_hdr(skb)->h_dest, > - br_port_get_rcu(xt_in(par))->br->dev->dev_addr); > - else > - ether_addr_copy(eth_hdr(skb)->h_dest, xt_in(par)->dev_addr); > + if (xt_hooknum(par) != NF_BR_BROUTING) { > + const struct net_bridge_port *port; > + > + port = br_port_get_rcu(xt_in(par)); > + if (!port) > + return EBT_DROP; > + > + dev_addr = port->br->dev->dev_addr; > + } else { > + dev_addr = xt_in(par)->dev_addr; > + } > + > + ether_addr_copy(eth_hdr(skb)->h_dest, dev_addr); > + > skb->pkt_type = PACKET_HOST; > return info->target; > } > -- > 2.54.0 > >