[NETFILTER]: nfnetlink_queue: don't unregister handler of other subsystem
The queue handlers registered by ip[6]_queue.ko at initialization should
not be unregistered according to requests from userland program
using nfnetlink_queue. If we allow that, there is no way to register
the handlers of built-in ip[6]_queue again.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 10b5c62..0eed0b7 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -275,7 +275,8 @@
};
extern int nf_register_queue_handler(int pf,
struct nf_queue_handler *qh);
-extern int nf_unregister_queue_handler(int pf);
+extern int nf_unregister_queue_handler(int pf,
+ struct nf_queue_handler *qh);
extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
extern void nf_reinject(struct sk_buff *skb,
struct nf_info *info,
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index b1f2ace..f402894 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -44,12 +44,17 @@
EXPORT_SYMBOL(nf_register_queue_handler);
/* The caller must flush their queue before this */
-int nf_unregister_queue_handler(int pf)
+int nf_unregister_queue_handler(int pf, struct nf_queue_handler *qh)
{
if (pf >= NPROTO)
return -EINVAL;
write_lock_bh(&queue_handler_lock);
+ if (queue_handler[pf] != qh) {
+ write_unlock_bh(&queue_handler_lock);
+ return -EINVAL;
+ }
+
queue_handler[pf] = NULL;
write_unlock_bh(&queue_handler_lock);
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 7a97bec..7d47fc4 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -913,9 +913,7 @@
case NFQNL_CFG_CMD_PF_UNBIND:
QDEBUG("unregistering queue handler for pf=%u\n",
ntohs(cmd->pf));
- /* This is a bug and a feature. We can unregister
- * other handlers(!) */
- ret = nf_unregister_queue_handler(ntohs(cmd->pf));
+ ret = nf_unregister_queue_handler(ntohs(cmd->pf), &nfqh);
break;
default:
ret = -EINVAL;