From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E51F53A8746; Tue, 16 Jun 2026 16:24:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781627069; cv=none; b=dIzmSAlc/NlBlp8M6ntnd/1z1X2YhYnZsPiflZC2MCrs8fnARwnTV4gZvhsXz3WGWbdAyIzHoou3EWgxjdFjz1RD51X/1TfQDICIRXTVoiGeu6bnWIoLJV1daz5we5DV9dzz9ymaJKE+bGia7wJbn2oR+69ydVL+tEPR7WKjpd4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781627069; c=relaxed/simple; bh=uO0KvMVUSYKsJ4ISK3bVyrbV0gCqicZIF79vQ4O4Kd0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AXYEkEMb26NgRBZV2JmWtUNXReEhS4DnBchcCy7n1oBVSXmOyqXwU56HMk+b9tVEHdupr1/3PV+L7KOChd0sstybx61SBkYKHAC8NkJmQJ0OvujE0dK34U0ERhbXmJ8hQ9v62w7fraI0sRpGq5aqDLQHu90yxtfBTatqgHGxiVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kiL0W4w8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kiL0W4w8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F420D1F000E9; Tue, 16 Jun 2026 16:24:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781627067; bh=2GjyZCyVf7iO96XdjM8uY2uzTYZdASwpzObOeQh5J5c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kiL0W4w8H9HvCHkopgHX1tBJiNDrN9d5xUeDsy/3M8+/6RCk9RaPrk19ko2dOhCK+ O2LqOudmEx2zI1B/hOFz8XjtF7HIOqJc6SrjoUG2JMsSGqvD4vagIZsPxR7AjvYeM/ Q3FJ1mA1FNSMG5BRByE/5cgwxbuoMjlnAbOggTag= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jian Zhou , Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 6.12 097/261] netfilter: revalidate bridge ports Date: Tue, 16 Jun 2026 20:28:55 +0530 Message-ID: <20260616145049.534848482@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145044.869532709@linuxfoundation.org> References: <20260616145044.869532709@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit ccb9fd4b87538ccf19ccff78ee26700526d94867 ] 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. A mere NULL check isn't sufficient, however. As sashiko review points out userspace can not only remove the port from the bridge, it could also place the device in a different virtual device, e.g. macvlan. If this happens, we must drop the packet, there is no way for us to reinject it into the bridge path. Switch to _upper API, we don't need the bridge port structure. Also, this fix keeps another bug intact: Both nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER too aggressive, which prevents certain logging features when queueing in bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old CONFIG_BRIDGE_NETFILTER cruft is off. Fixes tag is a common ancestor, this was always broken. Fixes: f350a0a87374 ("bridge: use rx_handler_data pointer to store net_bridge_port pointer") Reported-by: Ji'an Zhou Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/bridge/netfilter/ebt_dnat.c | 4 +- net/bridge/netfilter/ebt_redirect.c | 16 +++++--- net/netfilter/nfnetlink_log.c | 23 +++++++++-- net/netfilter/nfnetlink_queue.c | 64 +++++++++++++++++++++++++---- 4 files changed, 89 insertions(+), 18 deletions(-) diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c index 3fda71a8579d13..73f185cccd63df 100644 --- a/net/bridge/netfilter/ebt_dnat.c +++ b/net/bridge/netfilter/ebt_dnat.c @@ -39,7 +39,9 @@ ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par) dev = xt_in(par); break; case NF_BR_PRE_ROUTING: - dev = br_port_get_rcu(xt_in(par))->br->dev; + dev = netdev_master_upper_dev_get_rcu(xt_in(par)); + if (!dev) /* bridge port removed? */ + return EBT_DROP; break; default: dev = NULL; diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c index 307790562b4929..83486cd4d564b1 100644 --- a/net/bridge/netfilter/ebt_redirect.c +++ b/net/bridge/netfilter/ebt_redirect.c @@ -24,12 +24,18 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par) 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 + if (xt_hooknum(par) != NF_BR_BROUTING) { + const struct net_device *dev; + + dev = netdev_master_upper_dev_get_rcu(xt_in(par)); + if (!dev) + return EBT_DROP; + + ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr); + } else { ether_addr_copy(eth_hdr(skb)->h_dest, xt_in(par)->dev_addr); + } + skb->pkt_type = PACKET_HOST; return info->target; } diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index 3da32d2f68e092..cfd68bc005d26b 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -450,6 +450,23 @@ static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff return -1; } +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) +static int nflog_put_master_ifindex(struct sk_buff *nlskb, int attr, + const struct net_device *dev) +{ + const struct net_device *upper; + + if (dev && !netif_is_bridge_port(dev)) + return 0; + + upper = netdev_master_upper_dev_get_rcu((struct net_device *)dev); + if (upper && nla_put_be32(nlskb, attr, htonl(upper->ifindex))) + return -EMSGSIZE; + + return 0; +} +#endif + /* This is an inline function, we don't really care about a long * list of arguments */ static inline int @@ -504,8 +521,7 @@ __build_packet_message(struct nfnl_log_net *log, /* rcu_read_lock()ed by nf_hook_thresh or * nf_log_packet. */ - nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, - htonl(br_port_get_rcu(indev)->br->dev->ifindex))) + nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_INDEV, indev)) goto nla_put_failure; } else { int physinif; @@ -541,8 +557,7 @@ __build_packet_message(struct nfnl_log_net *log, /* rcu_read_lock()ed by nf_hook_thresh or * nf_log_packet. */ - nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, - htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) + nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_OUTDEV, outdev)) goto nla_put_failure; } else { struct net_device *physoutdev; diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 8518b620ae50ed..1b517cd2bb58cc 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -426,10 +426,47 @@ static bool nf_ct_drop_unconfirmed(const struct nf_queue_entry *entry, bool *is_ return false; } +static bool nf_bridge_port_valid(const struct net_device *dev) +{ + if (!dev) + return true; + + return netif_is_bridge_port(dev); +} + +/* queued skbs leave rcu protection. We bump device refcount so that + * the device cannot go away. However, while packet was out the port + * could have been removed from the bridge. + * + * Ensure in+outdev are still part of a bridge at reinject time. + * + * The device rx_handler_data could even be pointing at data that is + * not a net_bridge_port structure. + */ +static bool nf_bridge_ports_valid(const struct nf_queue_entry *entry) +{ +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) + if (!nf_bridge_port_valid(entry->physin) || + !nf_bridge_port_valid(entry->physout)) + return false; +#endif + if (entry->state.pf != PF_BRIDGE) + return true; + + if (!nf_bridge_port_valid(entry->state.in) || + !nf_bridge_port_valid(entry->state.out)) + return false; + + return true; +} + static void nfqnl_reinject(struct nf_queue_entry *entry, unsigned int verdict) { const struct nf_ct_hook *ct_hook; + if (!nf_bridge_ports_valid(entry)) + verdict = NF_DROP; + if (verdict == NF_ACCEPT || verdict == NF_REPEAT || verdict == NF_STOP) { @@ -622,6 +659,23 @@ static int nf_queue_checksum_help(struct sk_buff *entskb) return skb_checksum_help(entskb); } +#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) +static int nfqnl_put_master_ifindex(struct sk_buff *nlskb, int attr, + const struct net_device *dev) +{ + const struct net_device *upper; + + if (dev && !netif_is_bridge_port(dev)) + return 0; + + upper = netdev_master_upper_dev_get_rcu((struct net_device *)dev); + if (upper && nla_put_be32(nlskb, attr, htonl(upper->ifindex))) + return -EMSGSIZE; + + return 0; +} +#endif + static struct sk_buff * nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, struct nf_queue_entry *entry, @@ -755,10 +809,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, * netfilter_bridge) */ if (nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV, htonl(indev->ifindex)) || - /* this is the bridge group "brX" */ - /* rcu_read_lock()ed by __nf_queue */ - nla_put_be32(skb, NFQA_IFINDEX_INDEV, - htonl(br_port_get_rcu(indev)->br->dev->ifindex))) + nfqnl_put_master_ifindex(skb, NFQA_IFINDEX_INDEV, indev)) goto nla_put_failure; } else { int physinif; @@ -789,10 +840,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, * netfilter_bridge) */ if (nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV, htonl(outdev->ifindex)) || - /* this is the bridge group "brX" */ - /* rcu_read_lock()ed by __nf_queue */ - nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, - htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) + nfqnl_put_master_ifindex(skb, NFQA_IFINDEX_OUTDEV, outdev)) goto nla_put_failure; } else { int physoutif; -- 2.53.0