linux.git/fs/overlayfs, branch v3.18.72

ovl: fsync after copy-up

2016-11-24T04:09:18+00:00

[ Upstream commit 641089c1549d8d3df0b047b5de7e9a111362cdce ]

Make sure the copied up file hits the disk before renaming to the final
destination.  If this is not done then the copy-up may corrupt the data in
the file in case of a crash.

Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin

ovl: fix workdir creation

2016-09-22T17:25:10+00:00

[ Upstream commit e1ff3dd1ae52cef5b5373c8cc4ad949c2c25a71c ]

Workdir creation fails in latest kernel.

Fix by allowing EOPNOTSUPP as a valid return value from
vfs_removexattr(XATTR_NAME_POSIX_ACL_*).  Upper filesystem may not support
ACL and still be perfectly able to support overlayfs.

Reported-by: Martin Ziegler 
Signed-off-by: Miklos Szeredi 
Fixes: c11b9fdd6a61 ("ovl: remove posix_acl_default from workdir")
Cc: 
Signed-off-by: Sasha Levin

ovl: listxattr: use strnlen()

2016-09-15T22:54:06+00:00

[ Upstream commit 7cb35119d067191ce9ebc380a599db0b03cbd9d9 ]

Be defensive about what underlying fs provides us in the returned xattr
list buffer.  If it's not properly null terminated, bail out with a warning
insead of BUG.

Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin

ovl: remove posix_acl_default from workdir

2016-09-15T22:54:06+00:00

[ Upstream commit c11b9fdd6a612f376a5e886505f1c54c16d8c380 ]

Clear out posix acl xattrs on workdir and also reset the mode after
creation so that an inherited sgid bit is cleared.

Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin

ovl: don't copy up opaqueness

2016-09-12T18:53:02+00:00

[ Upstream commit 0956254a2d5b9e2141385514553aeef694dfe3b5 ]

When a copy up of a directory occurs which has the opaque xattr set, the
xattr remains in the upper directory. The immediate behavior with overlayfs
is that the upper directory is not treated as opaque, however after a
remount the opaque flag is used and upper directory is treated as opaque.
This causes files created in the lower layer to be hidden when using
multiple lower directories.

Fix by not copying up the opaque flag.

To reproduce:

 ----8<---------8<---------8<---------8<---------8<---------8<----
mkdir -p l/d/s u v w mnt
mount -t overlay overlay -olowerdir=l,upperdir=u,workdir=w mnt
rm -rf mnt/d/
mkdir -p mnt/d/n
umount mnt
mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
touch mnt/d/foo
umount mnt
mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
ls mnt/d
 ----8<---------8<---------8<---------8<---------8<---------8<----

output should be:  "foo  n"

Reported-by: Derek McGowan 
Link: https://bugzilla.kernel.org/show_bug.cgi?id=151291
Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin

ovl: verify upper dentry in ovl_remove_and_whiteout()

2016-08-08T01:59:02+00:00

[ Upstream commit cfc9fde0b07c3b44b570057c5f93dda59dca1c94 ]

The upper dentry may become stale before we call ovl_lock_rename_workdir.
For example, someone could (mistakenly or maliciously) manually unlink(2)
it directly from upperdir.

To ensure it is not stale, let's lookup it after ovl_lock_rename_workdir
and and check if it matches the upper dentry.

Essentially, it is the same problem and similar solution as in
commit 11f3710417d0 ("ovl: verify upper dentry before unlink and rename").

Signed-off-by: Maxim Patlasov 
Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin

ovl: Copy up underlying inode's ->i_mode to overlay inode

2016-08-08T01:44:56+00:00

[ Upstream commit 07a2daab49c549a37b5b744cbebb6e3f445f12bc ]

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: 
Signed-off-by: Sasha Levin

ovl: handle ATTR_KILL*

2016-08-08T01:44:50+00:00

[ Upstream commit b99c2d913810e56682a538c9f2394d76fca808f8 ]

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: 
Signed-off-by: Sasha Levin

ovl: fix permission checking for setattr

2016-04-12T13:09:32+00:00

[ Upstream commit acff81ec2c79492b180fade3c2894425cd35a545 ]

[Al Viro] The bug is in being too enthusiastic about optimizing ->setattr()
away - instead of "copy verbatim with metadata" + "chmod/chown/utimes"
(with the former being always safe and the latter failing in case of
insufficient permissions) it tries to combine these two.  Note that copyup
itself will have to do ->setattr() anyway; _that_ is where the elevated
capabilities are right.  Having these two ->setattr() (one to set verbatim
copy of metadata, another to do what overlayfs ->setattr() had been asked
to do in the first place) combined is where it breaks.

Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

ovl: copy new uid/gid into overlayfs runtime inode

2016-03-22T15:11:10+00:00

[ Upstream commit b81de061fa59f17d2730aabb1b84419ef3913810 ]

Overlayfs must update uid/gid after chown, otherwise functions
like inode_owner_or_capable() will check user against stale uid.
Catched by xfstests generic/087, it chowns file and calls utimes.

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Sasha Levin