netfilter: nf_queue: fix possible use-after-free

stable inclusion
from stable-v5.10.104
commit 4d05239203fa38ea8a6f31e228460da4cb17a71a
bugzilla: https://gitee.com/openeuler/kernel/issues/I56XAC

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4d05239203fa38ea8a6f31e228460da4cb17a71a

--------------------------------

commit c3873070 upstream.

Eric Dumazet says:
  The sock_hold() side seems suspect, because there is no guarantee
  that sk_refcnt is not already 0.

On failure, we cannot queue the packet and need to indicate an
error.  The packet will be dropped by the caller.

v2: split skb prefetch hunk into separate change

Fixes: 271b72c7 ("udp: RCU handling for Unicast packets.")
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/net/netfilter/nf_queue.h

@@ -37,7 +37,7 @@ void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *q
 void nf_unregister_queue_handler(struct net *net);
 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
 
-void nf_queue_entry_get_refs(struct nf_queue_entry *entry);
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry);
 void nf_queue_entry_free(struct nf_queue_entry *entry);
 
 static inline void init_hashrandom(u32 *jhash_initval)

net/netfilter/nf_queue.c

@@ -100,16 +100,17 @@ static void __nf_queue_entry_init_physdevs(struct nf_queue_entry *entry)
 }
 
 /* Bump dev refs so they don't vanish while packet is out */
-void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
+bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
 {
 	struct nf_hook_state *state = &entry->state;
 
+	if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt))
+		return false;
+
 	if (state->in)
 		dev_hold(state->in);
 	if (state->out)
 		dev_hold(state->out);
-	if (state->sk)
-		sock_hold(state->sk);
 
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	if (entry->physin)
@@ -117,6 +118,7 @@ void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
 	if (entry->physout)
 		dev_hold(entry->physout);
 #endif
+	return true;
 }
 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
 
@@ -205,7 +207,10 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
 
 	__nf_queue_entry_init_physdevs(entry);
 
-	nf_queue_entry_get_refs(entry);
+	if (!nf_queue_entry_get_refs(entry)) {
+		kfree(entry);
+		return -ENOTCONN;
+	}
 
 	switch (entry->state.pf) {
 	case AF_INET:

net/netfilter/nfnetlink_queue.c

@@ -712,9 +712,15 @@ static struct nf_queue_entry *
 nf_queue_entry_dup(struct nf_queue_entry *e)
 {
 	struct nf_queue_entry *entry = kmemdup(e, e->size, GFP_ATOMIC);
-	if (entry)
-		nf_queue_entry_get_refs(entry);
-	return entry;
+
+	if (!entry)
+		return NULL;
+
+	if (nf_queue_entry_get_refs(entry))
+		return entry;
+
+	kfree(entry);
+	return NULL;
 }
 
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)