From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66F4B3932C6 for ; Wed, 4 Mar 2026 08:43:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772613832; cv=none; b=mWyV4Q5WV0bxuVl0iJCBJhsDUbomMTsaLoVvmBWHvnWUL8m9fSybKSJKALmYthbOyN7z24XgKV0faTwsxRzG6wbWz3z0m4wFjiL/JDWxKZYyRLTrODi/EGpxjaSFyJPHjneFV+jE12ad+foDhjI87kC0kpYM2OZbazudjV9npIE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772613832; c=relaxed/simple; bh=VIJxBhv7XGCFbPbdOeAB7Qdcmzlygb76zrm9jwwzsOA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=DqYbqtrXzktc148h5Q5c5hdrgtnK1J4YJflcAAuiLJfIYs1kTLZo8zgKG6UBzybzcoej0W7kQWLmsy9vognNtMD4uE5Zpe0q9eNDjIVnStQ/QkkXZddUMNBYyEh0Z62nGqc2hIDvhqD9E9xh5QCIQloM5DhQD8Y+KkQMys6e/Uc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=RLVQiFvT; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RLVQiFvT" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-c70ea677571so4007206a12.0 for ; Wed, 04 Mar 2026 00:43:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772613830; x=1773218630; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=E3vMQO/IQoYaKESJWlFHP+qMU8qosPwTVj93SXFE13Y=; b=RLVQiFvT6sJ/P5I+bpFCEWEUsXmIpCPKMODFKfSa3ClISRLGGNP6+WXqe2hnZ7pee9 br/024vPcTglhUKNbgy2Bkqrp03LeVZexAZc5L3RACLr9gdMbh7lMAuq8q9ZpxgnZxM3 9qRi2vY9FueJKRiw9ajtI5oBYwWQoufnbMYyKDB3gluqBSfmKQIratAvyqIVc5gs4LTE RWUTVPKySt3coo+6Npmf/rw0TcUi0W/+pDsYmQRchRZ8HK2nLTAlegDvGMzx5lUOUcfx 6r358bsGfwwvy7fjFuf4a3HkEUs9J6ATTcOCL4tOPWNZRVYPKUCf1tmSvk80JdrUiL4x wsGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772613830; x=1773218630; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=E3vMQO/IQoYaKESJWlFHP+qMU8qosPwTVj93SXFE13Y=; b=DrfOm228iIJEuR8QxiCqiGATDuzQyKG0oU6LL18lhGjTqfetNZpIP59t1zk/Gwyc1r DDizWLwzOK0XKOsIxw1UjdlcXtBnczziie82EZrbR6O+Wgv8158AwFYv5oAsUHWNBhZj SqWcvTyFNAYnOm9gfw6CaxJTZP8PEw6QSvhNXXSf7qZ/yRSn+IGJ8KP2oay8AOya/WrL sBJF4FsgJL1dNG2X/AzigoZWH3gRhXBQPErflDqaUtN77EKikPVynL/ak/f8VAG9pRoq OdomYKuKPOaSm13hvPfATJhUrERTIgq6lzAuteMFftjHdzujZR9KUQxf/xzZUNME5Gh/ Xwlw== X-Forwarded-Encrypted: i=1; AJvYcCVg1eQzDRI4wjK7VqVhkZhz0bWEyQL/FYIbJ7xlW3wTAPqfQJhuZnZOD2TtUIqY/zVlPVXwWGKTZqwdw3A=@vger.kernel.org X-Gm-Message-State: AOJu0YzcX36/gRmSIDopRVBxUoSCVsqT1fgJlfkfMekqRsxRpVxZox2q FnEPibdolxxVW8jhw0918wKZL/uJgvj9EcfoPgPK6R4g8ahW5fdRb9EmG4KJ89X+fw5bt+avbRq datMhHQ== X-Received: from pfbbj10.prod.google.com ([2002:a05:6a00:318a:b0:7cf:2dad:ff87]) (user=kuniyu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:438f:b0:827:2ee0:411f with SMTP id d2e1a72fcca58-82972b61332mr1138758b3a.4.1772613829535; Wed, 04 Mar 2026 00:43:49 -0800 (PST) Date: Wed, 4 Mar 2026 08:42:57 +0000 In-Reply-To: <20260304-br-nd-suppress-ipv6-null-fix-v1-1-084356ba8257@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260304-br-nd-suppress-ipv6-null-fix-v1-1-084356ba8257@gmail.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260304084348.1075022-1-kuniyu@google.com> Subject: Re: [PATCH] net: bridge: fix NULL dereference in br_do_suppress_nd when ipv6.disable=1 From: Kuniyuki Iwashima To: devnull+maximilianpezzullo.gmail.com@kernel.org Cc: bridge@lists.linux.dev, davem@davemloft.net, edumazet@google.com, gurucp2005@bugzilla.kernel.org, horms@kernel.org, idosch@nvidia.com, kuba@kernel.org, linux-kernel@vger.kernel.org, maximilianpezzullo@gmail.com, netdev@vger.kernel.org, pabeni@redhat.com, razor@blackwall.org Content-Type: text/plain; charset="UTF-8" From: Maximilian Pezzullo via B4 Relay Date: Wed, 04 Mar 2026 09:20:23 +0100 > From: Maximilian Pezzullo > > When the kernel is booted with ipv6.disable=1, the IPv6 module loads > but skips full initialization, leaving ipv6_stub as NULL. If the bridge > neigh_suppress feature is enabled on a port and an ICMPv6 Neighbor > Solicitation arrives, br_do_suppress_nd() calls neigh_lookup() via > ipv6_stub->nd_tbl without first checking whether ipv6_stub is valid, > causing a kernel panic. > > Fix this by returning early if ipv6_stub or its nd_tbl pointer is NULL. > > Reported-by: Guruprasad C P > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221143 > Signed-off-by: Maximilian Pezzullo > --- > net/bridge/br_arp_nd_proxy.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c > index 1e2b51769eec..0b1b9ba29b7d 100644 > --- a/net/bridge/br_arp_nd_proxy.c > +++ b/net/bridge/br_arp_nd_proxy.c > @@ -455,6 +455,9 @@ void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br, > return; > } > > + if (!ipv6_stub || !ipv6_stub->nd_tbl) > + return; ipv6_stub is never be NULL. Also, Fernando is already working on the fix. https://lore.kernel.org/netdev/20260226234059.19402-1-fmancera@suse.de/ https://lore.kernel.org/netdev/20260302140847.5941-1-fmancera@suse.de/ > + > n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev); > if (n) { > struct net_bridge_fdb_entry *f; > > --- > base-commit: af4e9ef3d78420feb8fe58cd9a1ab80c501b3c08 > change-id: 20260304-br-nd-suppress-ipv6-null-fix-0a516fc27f1a > > Best regards, > -- > Maximilian Pezzullo