vfs: canonicalize create mode in build_open_flags()
Userspace can pass weird create mode in open(2) that we canonicalize to
"(mode & S_IALLUGO) | S_IFREG" in vfs_create().
The problem is that we use the uncanonicalized mode before calling vfs_create()
with unforseen consequences.
So do the canonicalization early in build_open_flags().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
CC: stable@vger.kernel.org
diff --git a/fs/open.c b/fs/open.c
index bc132e1..e1f2cdb 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -852,9 +852,10 @@
int lookup_flags = 0;
int acc_mode;
- if (!(flags & O_CREAT))
- mode = 0;
- op->mode = mode;
+ if (flags & O_CREAT)
+ op->mode = (mode & S_IALLUGO) | S_IFREG;
+ else
+ op->mode = 0;
/* Must never be set by userspace */
flags &= ~FMODE_NONOTIFY;