Re: [PATCH 4.4 133/146] ovl: Copy up underlying inodes ->i_mode to overlay inode
From: Eryu Guan <hidden>
Date: 2016-08-03 07:37:05
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On Mon, Jul 25, 2016 at 01:56:28PM -0700, Greg Kroah-Hartman wrote:
4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vivek Goyal <vgoyal@redhat.com> commit 07a2daab49c549a37b5b744cbebb6e3f445f12bc upstream. 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.
This patch introduced a hang when writing to suid file, fstests generic/355 could reproduce the hang easily, it only failed the test without this patch and didn't hang the kernel. Should we skip it for now and wait for a further fix? (The 4.6-stable tree faces the same question) Thanks, Eryu
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Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reported-by: Eryu Guan <redacted> Signed-off-by: Miklos Szeredi <redacted> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/overlayfs/inode.c | 3 +-- fs/overlayfs/overlayfs.h | 1 + 2 files changed, 2 insertions(+), 2 deletions(-)--- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c@@ -412,12 +412,11 @@ struct inode *ovl_new_inode(struct super 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; --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h@@ -181,6 +181,7 @@ static inline void ovl_copyattr(struct i { to->i_uid = from->i_uid; to->i_gid = from->i_gid; + to->i_mode = from->i_mode; } /* dir.c */