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/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 @@ static unsigned int fib_seq_sum(void)
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 @@ static int fib_net_dump(struct net *net, struct notifier_block *nb)
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 @@ static const struct fib_notifier_ops fib4_notifier_ops_template = {
.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 @@ static const struct fib_notifier_ops fib6_notifier_ops_template = {
.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)