From b99c2d913810e56682a538c9f2394d76fca808f8 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 4 Jul 2016 16:49:48 +0200 Subject: ovl: handle ATTR_KILL* Before 4bacc9c9234c ("overlayfs: Make f_path...") file->f_path pointed to the underlying file, hence suid/sgid removal on write worked fine. After that patch file->f_path pointed to the overlay file, and the file mode bits weren't copied to overlay_inode->i_mode. So the suid/sgid removal simply stopped working. The fix is to copy the mode bits, but then ovl_setattr() needs to clear ATTR_MODE to avoid the BUG() in notify_change(). So do this first, then in the next patch copy the mode. Reported-by: Eryu Guan Signed-off-by: Miklos Szeredi Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: --- fs/overlayfs/inode.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/overlayfs/inode.c') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index c831c2e5f803..1233992a7c47 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -80,6 +80,9 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) goto out_drop_write; } + if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) + attr->ia_valid &= ~ATTR_MODE; + inode_lock(upperdentry->d_inode); err = notify_change(upperdentry, attr, NULL); if (!err) -- cgit v1.2.3 From 07a2daab49c549a37b5b744cbebb6e3f445f12bc Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Fri, 1 Jul 2016 16:34:25 -0400 Subject: 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 Reported-by: Eryu Guan Signed-off-by: Miklos Szeredi Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: --- fs/overlayfs/inode.c | 3 +-- fs/overlayfs/overlayfs.h | 1 + 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/overlayfs/inode.c') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 1233992a7c47..d1cdc60dd68f 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -413,12 +413,11 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, 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 4bd9b5ba8f42..cfbca53590d0 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -187,6 +187,7 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to) { to->i_uid = from->i_uid; to->i_gid = from->i_gid; + to->i_mode = from->i_mode; } /* dir.c */ -- cgit v1.2.3