From: Florian Westphal <fw@strlen.de> mainline inclusion from mainline-v7.2-rc1 commit ccb9fd4b87538ccf19ccff78ee26700526d94867 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15906 CVE: CVE-2026-53220 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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 <eilaimemedsnaimel@gmail.com> Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- 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 | 60 +++++++++++++++++++++++++++-- 4 files changed, 89 insertions(+), 14 deletions(-) diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c index 3fda71a8579d..73f185cccd63 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 307790562b49..83486cd4d564 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 3da32d2f68e0..cfd68bc005d2 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 38ab16b71c21..574c62a451ce 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -255,11 +255,48 @@ 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; int err; + if (!nf_bridge_ports_valid(entry)) + verdict = NF_DROP; + if (verdict == NF_ACCEPT || verdict == NF_REPEAT || verdict == NF_STOP) { @@ -434,6 +471,23 @@ static int nfqnl_put_bridge(struct nf_queue_entry *entry, struct sk_buff *skb) return -1; } +#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, @@ -569,8 +623,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, 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; @@ -603,8 +656,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, 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; -- 2.43.0