mpls: fix possible use after free of device
The mpls device is used in an RCU read context without a lock being
held. As the memory is freed without waiting for the RCU grace period
to elapse, the freed memory could still be in use.
Address this by using kfree_rcu to free the memory for the mpls device
after the RCU grace period has elapsed.
Fixes: 03c57747a702 ("mpls: Per-device MPLS state")
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 7b3f732..bff427f 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -541,7 +541,7 @@
RCU_INIT_POINTER(dev->mpls_ptr, NULL);
- kfree(mdev);
+ kfree_rcu(mdev, rcu);
}
static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index b064c34..8cabeb5 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -16,6 +16,7 @@
int input_enabled;
struct ctl_table_header *sysctl;
+ struct rcu_head rcu;
};
struct sk_buff;