[PATCH 4.9 02/41] fs: completely ignore unknown open flags
From: Greg Kroah-Hartman
Date: Mon Jul 10 2017 - 13:21:29 EST
4.9-stable review patch. If anyone has any objections, please let me know.
From: Christoph Hellwig <hch@xxxxxx>
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@xxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
fs/open.c | 6 ++++++
1 file changed, 6 insertions(+)
@@ -902,6 +902,12 @@ static inline int build_open_flags(int f
int lookup_flags = 0;
int acc_mode = ACC_MODE(flags);
+ * 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;