kernel.git/fs/overlayfs/dir.c, branch linux-6.4.y

ovl: update of dentry revalidate flags after copy up

2023-07-19T14:36:07Z

[ Upstream commit b07d5cc93e1b28df47a72c519d09d0a836043613 ] After copy up, we may need to update d_flags if upper dentry is on a remote fs and lower dentries are not. Add helpers to allow incremental update of the revalidate flags. Fixes: bccece1ead36 ("ovl: allow remote upper") Reviewed-by: Gao Xiang Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fs: port inode_init_owner() to mnt_idmap

2023-01-19T08:24:28Z

Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft)

fs: port ->rename() to pass mnt_idmap

2023-01-19T08:24:26Z

fs: port ->mknod() to pass mnt_idmap

2023-01-19T08:24:26Z

fs: port ->mkdir() to pass mnt_idmap

2023-01-19T08:24:26Z

fs: port ->symlink() to pass mnt_idmap

2023-01-19T08:24:25Z

fs: port ->create() to pass mnt_idmap

2023-01-19T08:24:25Z

Merge tag 'ovl-update-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2022-12-13T04:18:26Z

Pull overlayfs update from Miklos Szeredi: - Fix a couple of bugs found by syzbot - Don't ingore some open flags set by fcntl(F_SETFL) - Fix failure to create a hard link in certain cases - Use type safe helpers for some mnt_userns transformations - Improve performance of mount - Misc cleanups * tag 'ovl-update-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: Kconfig: Fix spelling mistake "undelying" -> "underlying" ovl: use inode instead of dentry where possible ovl: Add comment on upperredirect reassignment ovl: use plain list filler in indexdir and workdir cleanup ovl: do not reconnect upper index records in ovl_indexdir_cleanup() ovl: fix comment typos ovl: port to vfs{g,u}id_t and associated helpers ovl: Use ovl mounter's fsuid and fsgid in ovl_link() ovl: Use "buf" flexible array for memcpy() destination ovl: update ->f_iocb_flags when ovl_change_flags() modifies ->f_flags ovl: fix use inode directly in rcu-walk mode

ovl: Use ovl mounter's fsuid and fsgid in ovl_link()

2022-12-08T09:49:46Z

There is a wrong case of link() on overlay: $ mkdir /lower /fuse /merge $ mount -t fuse /fuse $ mkdir /fuse/upper /fuse/work $ mount -t overlay /merge -o lowerdir=/lower,upperdir=/fuse/upper,\ workdir=work $ touch /merge/file $ chown bin.bin /merge/file // the file's caller becomes "bin" $ ln /merge/file /merge/lnkfile Then we will get an error(EACCES) because fuse daemon checks the link()'s caller is "bin", it denied this request. In the changing history of ovl_link(), there are two key commits: The first is commit bb0d2b8ad296 ("ovl: fix sgid on directory") which overrides the cred's fsuid/fsgid using the new inode. The new inode's owner is initialized by inode_init_owner(), and inode->fsuid is assigned to the current user. So the override fsuid becomes the current user. We know link() is actually modifying the directory, so the caller must have the MAY_WRITE permission on the directory. The current caller may should have this permission. This is acceptable to use the caller's fsuid. The second is commit 51f7e52dc943 ("ovl: share inode for hard link") which removed the inode creation in ovl_link(). This commit move inode_init_owner() into ovl_create_object(), so the ovl_link() just give the old inode to ovl_create_or_link(). Then the override fsuid becomes the old inode's fsuid, neither the caller nor the overlay's mounter! So this is incorrect. Fix this bug by using ovl mounter's fsuid/fsgid to do underlying fs's link(). Link: https://lore.kernel.org/all/20220817102952.xnvesg3a7rbv576x@wittgenstein/T Link: https://lore.kernel.org/lkml/20220825130552.29587-1-zhangtianci.1997@bytedance.com/t Signed-off-by: Zhang Tianci Signed-off-by: Jiachen Zhang Reviewed-by: Christian Brauner (Microsoft) Fixes: 51f7e52dc943 ("ovl: share inode for hard link") Cc: # v4.8 Signed-off-by: Miklos Szeredi

ovl: use posix acl api

2022-10-20T08:13:31Z

Now that posix acls have a proper api us it to copy them. All filesystems that can serve as lower or upper layers for overlayfs have gained support for the new posix acl api in previous patches. So switch all internal overlayfs codepaths for copying posix acls to the new posix acl api. Acked-by: Miklos Szeredi Signed-off-by: Christian Brauner (Microsoft)