net: Add module reference to FIB notifiers
When a listener registers to the FIB notification chain it receives a
dump of the FIB entries and rules from existing address families by
invoking their dump operations.
While we call into these modules we need to make sure they aren't
removed. Do that by increasing their reference count before invoking
their dump operations and decrease it afterwards.
Fixes: 04b1d4e50e82 ("net: core: Make the FIB notification chain generic")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/fib_notifier.h b/include/net/fib_notifier.h
index 2414752..669b971 100644
--- a/include/net/fib_notifier.h
+++ b/include/net/fib_notifier.h
@@ -2,6 +2,7 @@
#define __NET_FIB_NOTIFIER_H
#include <linux/types.h>
+#include <linux/module.h>
#include <linux/notifier.h>
#include <net/net_namespace.h>
@@ -26,6 +27,7 @@
struct list_head list;
unsigned int (*fib_seq_read)(struct net *net);
int (*fib_dump)(struct net *net, struct notifier_block *nb);
+ struct module *owner;
struct rcu_head rcu;
};
diff --git a/net/core/fib_notifier.c b/net/core/fib_notifier.c
index 292aab8..4fc202d 100644
--- a/net/core/fib_notifier.c
+++ b/net/core/fib_notifier.c
@@ -2,6 +2,7 @@
#include <linux/notifier.h>
#include <linux/rcupdate.h>
#include <linux/kernel.h>
+#include <linux/module.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/fib_notifier.h>
@@ -33,8 +34,12 @@
rtnl_lock();
for_each_net(net) {
- list_for_each_entry(ops, &net->fib_notifier_ops, list)
+ list_for_each_entry(ops, &net->fib_notifier_ops, list) {
+ if (!try_module_get(ops->owner))
+ continue;
fib_seq += ops->fib_seq_read(net);
+ module_put(ops->owner);
+ }
}
rtnl_unlock();
@@ -46,8 +51,12 @@
struct fib_notifier_ops *ops;
list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) {
- int err = ops->fib_dump(net, nb);
+ int err;
+ if (!try_module_get(ops->owner))
+ continue;
+ err = ops->fib_dump(net, nb);
+ module_put(ops->owner);
if (err)
return err;
}
diff --git a/net/ipv4/fib_notifier.c b/net/ipv4/fib_notifier.c
index 5d7afb1..cfd420b0 100644
--- a/net/ipv4/fib_notifier.c
+++ b/net/ipv4/fib_notifier.c
@@ -2,6 +2,7 @@
#include <linux/notifier.h>
#include <linux/socket.h>
#include <linux/kernel.h>
+#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/fib_notifier.h>
#include <net/netns/ipv4.h>
@@ -49,6 +50,7 @@
.family = AF_INET,
.fib_seq_read = fib4_seq_read,
.fib_dump = fib4_dump,
+ .owner = THIS_MODULE,
};
int __net_init fib4_notifier_init(struct net *net)
diff --git a/net/ipv6/fib6_notifier.c b/net/ipv6/fib6_notifier.c
index 66a103e..05f82ba 100644
--- a/net/ipv6/fib6_notifier.c
+++ b/net/ipv6/fib6_notifier.c
@@ -1,6 +1,7 @@
#include <linux/notifier.h>
#include <linux/socket.h>
#include <linux/kernel.h>
+#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/fib_notifier.h>
#include <net/netns/ipv6.h>
@@ -41,6 +42,7 @@
.family = AF_INET6,
.fib_seq_read = fib6_seq_read,
.fib_dump = fib6_dump,
+ .owner = THIS_MODULE,
};
int __net_init fib6_notifier_init(struct net *net)