linux-toradex.git/fs/overlayfs, branch v4.4.73

ovl: fsync after copy-up

2016-11-10T15:36:34+00:00

commit 641089c1549d8d3df0b047b5de7e9a111362cdce upstream.

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 
Signed-off-by: Greg Kroah-Hartman

ovl: copy_up_xattr(): use strnlen

2016-10-28T07:01:30+00:00

commit 8b326c61de08f5ca4bc454a168f19e7e43c4cc2a upstream.

Be defensive about what underlying fs provides us in the returned xattr
list buffer.  strlen() may overrun the buffer, so use strnlen() and WARN if
the contents are not properly null terminated.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: Fix info leak in ovl_lookup_temp()

2016-10-28T07:01:30+00:00

commit 6a45b3628ce4dcf7498b39c87d475bab6e2a9b24 upstream.

The function uses the memory address of a struct dentry as unique id.
While the address-based directory entry is only visible to root it is IMHO
still worth fixing since the temporary name does not have to be a kernel
address.  It can be any unique number.  Replace it by an atomic integer
which is allowed to wrap around.

Signed-off-by: Richard Weinberger 
Reviewed-by: Kees Cook 
Signed-off-by: Miklos Szeredi 
Fixes: e9be9d5e76e3 ("overlay filesystem")
Signed-off-by: Greg Kroah-Hartman

ovl: fix workdir creation

2016-09-15T06:27:52+00:00

commit e1ff3dd1ae52cef5b5373c8cc4ad949c2c25a71c upstream.

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")
Signed-off-by: Greg Kroah-Hartman

ovl: listxattr: use strnlen()

2016-09-15T06:27:52+00:00

commit 7cb35119d067191ce9ebc380a599db0b03cbd9d9 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

ovl: remove posix_acl_default from workdir

2016-09-15T06:27:52+00:00

commit c11b9fdd6a612f376a5e886505f1c54c16d8c380 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

ovl: don't copy up opaqueness

2016-09-15T06:27:52+00:00

commit 0956254a2d5b9e2141385514553aeef694dfe3b5 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

ovl: disallow overlayfs as upperdir

2016-08-20T16:09:19+00:00

commit 76bc8e2843b66f8205026365966b49ec6da39ae7 upstream.

This does not work and does not make sense.  So instead of fixing it
(probably not hard) just disallow.

Reported-by: Andrei Vagin 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: handle ATTR_KILL*

2016-08-10T09:49:28+00:00

commit b99c2d913810e56682a538c9f2394d76fca808f8 upstream.

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: Eric Schultz 
Cc: Eric Hameleers 
[backported by Eric Hameleers as seen in https://bugzilla.kernel.org/show_bug.cgi?id=150711]
Signed-off-by: Greg Kroah-Hartman

ovl: verify upper dentry before unlink and rename

2016-07-27T16:47:40+00:00

commit 11f3710417d026ea2f4fcf362d866342c5274185 upstream.

Unlink and rename in overlayfs checked the upper dentry for staleness by
verifying upper->d_parent against upperdir.  However the dentry can go
stale also by being unhashed, for example.

Expand the verification to actually look up the name again (under parent
lock) and check if it matches the upper dentry.  This matches what the VFS
does before passing the dentry to filesytem's unlink/rename methods, which
excludes any inconsistency caused by overlayfs.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman