ovl: Copy up underlying inode's ->i_mode to overlay inode
Right now when a new overlay inode is created, we initialize overlay
inode's ->i_mode from underlying inode ->i_mode but we retain only
file type bits (S_IFMT) and discard permission bits.
This patch changes it and retains permission bits too. This should allow
overlay to do permission checks on overlay inode itself in task context.
[SzM] It also fixes clearing suid/sgid bits on write.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Cc: <stable@vger.kernel.org>
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 1233992..d1cdc60 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -413,12 +413,11 @@
if (!inode)
return NULL;
- mode &= S_IFMT;
-
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_flags |= S_NOATIME | S_NOCMTIME;
+ mode &= S_IFMT;
switch (mode) {
case S_IFDIR:
inode->i_private = oe;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 4bd9b5b..cfbca53 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -187,6 +187,7 @@
{
to->i_uid = from->i_uid;
to->i_gid = from->i_gid;
+ to->i_mode = from->i_mode;
}
/* dir.c */
