[PATCH 1/1] anon_inodefs: forbid open via /proc

[Oleg Nesterov <oleg@redhat.com>]

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>
---
 fs/anon_inodes.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 47a65df..af25036 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().
-- 
1.5.5.1