From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 5 Nov 2013 05:55:21 +0000 (+1100)
Subject: anon_inodefs: forbid open via /proc
X-Git-Tag: next-20131105~2^2~276
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2051a80c88b54a3254b867b110b54a578011cf77;p=karo-tx-linux.git

anon_inodefs: forbid open via /proc

open("/proc/pid/$anon-fd") should fail, we can't create the new file with
correct f_op/etc correctly.  Currently this creates the bogus file with
the empty anon_inode_fops, this is harmless but still wrong and
misleading.

Add anon_inode_fops->anon_open() which simply returns ENXIO like
sock_no_open() does in this case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 85c961849953..0cfbe066a00e 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -24,7 +24,15 @@
 
 static struct vfsmount *anon_inode_mnt __read_mostly;
 static struct inode *anon_inode_inode;
-static const struct file_operations anon_inode_fops;
+
+static int anon_open(struct inode *inode, struct file *file)
+{
+	return -ENXIO;
+}
+
+static const struct file_operations anon_inode_fops = {
+	.open = anon_open,
+};
 
 /*
  * anon_inodefs_dname() is called from d_path().