Patch "fs: completely ignore unknown open flags" has been added to the 4.4-stable tree

Patch "fs: completely ignore unknown open flags" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fs: completely ignore unknown open flags

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fs-completely-ignore-unknown-open-flags.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 629e014bb8349fcf7c1e4df19a842652ece1c945 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 27 Apr 2017 09:42:25 +0200
Subject: fs: completely ignore unknown open flags

From: Christoph Hellwig <hch@lst.de>

commit 629e014bb8349fcf7c1e4df19a842652ece1c945 upstream.

Currently we just stash anything we got into file->f_flags, and the
report it in fcntl(F_GETFD).  This patch just clears out all unknown
flags so that we don't pass them to the fs or report them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/open.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/open.c
+++ b/fs/open.c
@@ -885,6 +885,12 @@ static inline int build_open_flags(int f
 	int lookup_flags = 0;
 	int acc_mode;
 
+	/*
+	 * Clear out all open flags we don't know about so that we don't report
+	 * them in fcntl(F_GETFD) or similar interfaces.
+	 */
+	flags &= VALID_OPEN_FLAGS;
+
 	if (flags & (O_CREAT | __O_TMPFILE))
 		op->mode = (mode & S_IALLUGO) | S_IFREG;
 	else


Patches currently in stable-queue which might be from hch@lst.de are

queue-4.4/fs-add-a-valid_open_flags.patch
queue-4.4/fs-completely-ignore-unknown-open-flags.patch