[PATCH 5.10.y 2/2] netfilter: nf_queue: hold bridge skb->dev while queued

[Sasha Levin <sashal@kernel.org>]

From: Haoze Xie <royenheart@gmail.com>

[ Upstream commit e196115ec330a18de415bdb9f5071aa9f08e53ce ]

br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge
master before queueing bridge LOCAL_IN packets. NFQUEUE only holds
references on state.in/out and bridge physdevs, so a queued bridge
packet can retain a freed bridge master in skb->dev until reinjection.

When the verdict is reinjected later, br_netif_receive_skb() re-enters
the receive path with skb->dev still pointing at the freed bridge master,
triggering a use-after-free.

Store skb->dev in the queue entry, hold a reference on it for the queue
lifetime, and use the saved device when dropping queued packets during
NETDEV_DOWN handling.

Fixes: ac2863445686 ("netfilter: bridge: add nf_afinfo to enable queuing to userspace")
Cc: stable@kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Haoze Xie <royenheart@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/netfilter/nf_queue.h | 1 +
 net/netfilter/nf_queue.c         | 4 +++-
 net/netfilter/nfnetlink_queue.c  | 2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h
index b1d43894296a6..6b4de68a762e3 100644
--- a/include/net/netfilter/nf_queue.h
+++ b/include/net/netfilter/nf_queue.h
@@ -12,6 +12,7 @@
 struct nf_queue_entry {
 	struct list_head	list;
 	struct sk_buff		*skb;
+	struct net_device	*skb_dev;
 	unsigned int		id;
 	unsigned int		hook_index;	/* index in hook_entries->hook[] */
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index d7542c5c4ae61..d9d35658a357c 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -60,6 +60,7 @@ static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
 	struct nf_hook_state *state = &entry->state;
 
 	/* Release those devices we held, or Alexey will kill me. */
+	dev_put(entry->skb_dev);
 	dev_put(state->in);
 	dev_put(state->out);
 	if (state->sk)
@@ -103,6 +104,7 @@ bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
 	if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
 		return false;
 
+	dev_hold(entry->skb_dev);
 	dev_hold(state->in);
 	dev_hold(state->out);
 
@@ -204,11 +206,11 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
 
 	*entry = (struct nf_queue_entry) {
 		.skb	= skb,
+		.skb_dev = skb->dev,
 		.state	= *state,
 		.hook_index = index,
 		.size	= sizeof(*entry) + route_key_size,
 	};
-
 	__nf_queue_entry_init_physdevs(entry);
 
 	if (!nf_queue_entry_get_refs(entry)) {
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index bfe909267c9d9..1541d6801001c 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -911,6 +911,8 @@ dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
 	if (physinif == ifindex || physoutif == ifindex)
 		return 1;
 #endif
+	if (entry->skb_dev && entry->skb_dev->ifindex == ifindex)
+		return 1;
 	if (entry->state.in)
 		if (entry->state.in->ifindex == ifindex)
 			return 1;
-- 
2.53.0