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-rw-r--r--fs/proc/proc_net.c6
-rw-r--r--include/linux/proc_fs.h5
-rw-r--r--include/net/net_namespace.h12
-rw-r--r--net/core/dev.c6
-rw-r--r--net/core/dev_mcast.c6
-rw-r--r--net/netlink/af_netlink.c6
-rw-r--r--net/wireless/wext.c6
7 files changed, 39 insertions, 8 deletions
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 358930a3142a..85cc8e8bb862 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -51,6 +51,12 @@ void proc_net_remove(struct net *net, const char *name)
 }
 EXPORT_SYMBOL_GPL(proc_net_remove);
 
+struct net *get_proc_net(const struct inode *inode)
+{
+	return maybe_get_net(PDE_NET(PDE(inode)));
+}
+EXPORT_SYMBOL_GPL(get_proc_net);
+
 static struct proc_dir_entry *proc_net_shadow;
 
 static struct dentry *proc_net_shadow_dentry(struct dentry *parent,
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 59646705f151..20741f668f7b 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -270,10 +270,7 @@ static inline struct net *PDE_NET(struct proc_dir_entry *pde)
 	return pde->parent->data;
 }
 
-static inline struct net *PROC_NET(const struct inode *inode)
-{
-	return PDE_NET(PDE(inode));
-}
+struct net *get_proc_net(const struct inode *inode);
 
 struct proc_maps_private {
 	struct pid *pid;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 3081b6ed35fe..ac8f8304094e 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -46,6 +46,18 @@ static inline struct net *get_net(struct net *net)
 	return net;
 }
 
+static inline struct net *maybe_get_net(struct net *net)
+{
+	/* Used when we know struct net exists but we
+	 * aren't guaranteed a previous reference count
+	 * exists.  If the reference count is zero this
+	 * function fails and returns NULL.
+	 */
+	if (!atomic_inc_not_zero(&net->count))
+		net = NULL;
+	return net;
+}
+
 static inline void put_net(struct net *net)
 {
 	if (atomic_dec_and_test(&net->count))
diff --git a/net/core/dev.c b/net/core/dev.c
index d16dcab49c60..666c112efb55 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2464,7 +2464,11 @@ static int dev_seq_open(struct inode *inode, struct file *file)
 	res =  seq_open(file, &dev_seq_ops);
 	if (!res) {
 		seq = file->private_data;
-		seq->private = get_net(PROC_NET(inode));
+		seq->private = get_proc_net(inode);
+		if (!seq->private) {
+			seq_release(inode, file);
+			res = -ENXIO;
+		}
 	}
 	return res;
 }
diff --git a/net/core/dev_mcast.c b/net/core/dev_mcast.c
index 1c4f6198459b..896b0ca5aed7 100644
--- a/net/core/dev_mcast.c
+++ b/net/core/dev_mcast.c
@@ -246,7 +246,11 @@ static int dev_mc_seq_open(struct inode *inode, struct file *file)
 	res = seq_open(file, &dev_mc_seq_ops);
 	if (!res) {
 		seq = file->private_data;
-		seq->private = get_net(PROC_NET(inode));
+		seq->private = get_proc_net(inode);
+		if (!seq->private) {
+			seq_release(inode, file);
+			res = -ENXIO;
+		}
 	}
 	return res;
 }
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3029f865cd61..dc9f8c2ab1d5 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1859,7 +1859,11 @@ static int netlink_seq_open(struct inode *inode, struct file *file)
 
 	seq = file->private_data;
 	seq->private = iter;
-	iter->net = get_net(PROC_NET(inode));
+	iter->net = get_proc_net(inode);
+	if (!iter->net) {
+		seq_release_private(inode, file);
+		return -ENXIO;
+	}
 	return 0;
 }
 
diff --git a/net/wireless/wext.c b/net/wireless/wext.c
index e8b3409d6c8b..85e5f9dd0d8e 100644
--- a/net/wireless/wext.c
+++ b/net/wireless/wext.c
@@ -678,7 +678,11 @@ static int wireless_seq_open(struct inode *inode, struct file *file)
 	res = seq_open(file, &wireless_seq_ops);
 	if (!res) {
 		seq = file->private_data;
-		seq->private = get_net(PROC_NET(inode));
+		seq->private = get_proc_net(inode);
+		if (!seq->private) {
+			seq_release(inode, file);
+			res = -ENXIO;
+		}
 	}
 	return res;
 }