linux.git/fs/overlayfs, branch v5.4.64

ovl: fix unneeded call to ovl_change_flags()

2020-07-22T07:33:12+00:00

commit 81a33c1ee941c3bb9ffc6bac8f676be13351344e upstream.

The check if user has changed the overlay file was wrong, causing unneeded
call to ovl_change_flags() including taking f_lock on every file access.

Fixes: d989903058a8 ("ovl: do not generate duplicate fsnotify events for "fake" path")
Cc:  # v4.19+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: relax WARN_ON() when decoding lower directory file handle

2020-07-22T07:33:12+00:00

commit 124c2de2c0aee96271e4ddab190083d8aa7aa71a upstream.

Decoding a lower directory file handle to overlay path with cold
inode/dentry cache may go as follows:

1. Decode real lower file handle to lower dir path
2. Check if lower dir is indexed (was copied up)
3. If indexed, get the upper dir path from index
4. Lookup upper dir path in overlay
5. If overlay path found, verify that overlay lower is the lower dir
   from step 1

On failure to verify step 5 above, user will get an ESTALE error and a
WARN_ON will be printed.

A mismatch in step 5 could be a result of lower directory that was renamed
while overlay was offline, after that lower directory has been copied up
and indexed.

This is a scripted reproducer based on xfstest overlay/052:

  # Create lower subdir
  create_dirs
  create_test_files $lower/lowertestdir/subdir
  mount_dirs
  # Copy up lower dir and encode lower subdir file handle
  touch $SCRATCH_MNT/lowertestdir
  test_file_handles $SCRATCH_MNT/lowertestdir/subdir -p -o $tmp.fhandle
  # Rename lower dir offline
  unmount_dirs
  mv $lower/lowertestdir $lower/lowertestdir.new/
  mount_dirs
  # Attempt to decode lower subdir file handle
  test_file_handles $SCRATCH_MNT -p -i $tmp.fhandle

Since this WARN_ON() can be triggered by user we need to relax it.

Fixes: 4b91c30a5a19 ("ovl: lookup connected ancestor of dir in inode cache")
Cc:  # v4.16+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: inode reference leak in ovl_is_inuse true case.

2020-07-22T07:33:11+00:00

commit 24f14009b8f1754ec2ae4c168940c01259b0f88a upstream.

When "ovl_is_inuse" true case, trap inode reference not put.  plus adding
the comment explaining sequence of ovl_is_inuse after ovl_setup_trap.

Fixes: 0be0bfd2de9d ("ovl: fix regression caused by overlapping layers detection")
Cc:  # v4.19+
Reviewed-by: Amir Goldstein 
Signed-off-by: youngjun 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: fix regression with re-formatted lower squashfs

2020-07-22T07:33:11+00:00

commit a888db310195400f050b89c47673f0f8babfbb41 upstream.

Commit 9df085f3c9a2 ("ovl: relax requirement for non null uuid of lower
fs") relaxed the requirement for non null uuid with single lower layer to
allow enabling index and nfs_export features with single lower squashfs.

Fabian reported a regression in a setup when overlay re-uses an existing
upper layer and re-formats the lower squashfs image.  Because squashfs
has no uuid, the origin xattr in upper layer are decoded from the new
lower layer where they may resolve to a wrong origin file and user may
get an ESTALE or EIO error on lookup.

To avoid the reported regression while still allowing the new features
with single lower squashfs, do not allow decoding origin with lower null
uuid unless user opted-in to one of the new features that require
following the lower inode of non-dir upper (index, xino, metacopy).

Reported-by: Fabian 
Link: https://lore.kernel.org/linux-unionfs/32532923.JtPX5UtSzP@fgdesktop/
Fixes: 9df085f3c9a2 ("ovl: relax requirement for non null uuid of lower fs")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: initialize error in ovl_copy_xattr

2020-06-17T14:40:32+00:00

commit 520da69d265a91c6536c63851cbb8a53946974f0 upstream.

In ovl_copy_xattr, if all the xattrs to be copied are overlayfs private
xattrs, the copy loop will terminate without assigning anything to the
error variable, thus returning an uninitialized value.

If ovl_copy_xattr is called from ovl_clear_empty, this uninitialized error
value is put into a pointer by ERR_PTR(), causing potential invalid memory
accesses down the line.

This commit initialize error with 0. This is the correct value because when
there's no xattr to copy, because all xattrs are private, ovl_copy_xattr
should succeed.

This bug is discovered with the help of INIT_STACK_ALL and clang.

Signed-off-by: Yuxuan Shui 
Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1050405
Fixes: 0956254a2d5b ("ovl: don't copy up opaqueness")
Cc: stable@vger.kernel.org # v4.8
Signed-off-by: Alexander Potapenko 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: fix value of i_ino for lower hardlink corner case

2020-04-21T07:04:50+00:00

commit 300b124fcf6ad2cd99a7b721e0f096785e0a3134 upstream.

Commit 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more
cases"), relaxed the condition nfs_export=on in order to set the value of
i_ino to xino map of real ino.

Specifically, it also relaxed the pre-condition that index=on for
consistent i_ino. This opened the corner case of lower hardlink in
ovl_get_inode(), which calls ovl_fill_inode() with ino=0 and then
ovl_init_inode() is called to set i_ino to lower real ino without the xino
mapping.

Pass the correct values of ino;fsid in this case to ovl_fill_inode(), so it
can initialize i_ino correctly.

Fixes: 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more ...")
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: fix lseek overflow on 32bit

2020-02-11T12:35:24+00:00

commit a4ac9d45c0cd14a2adc872186431c79804b77dbf upstream.

ovl_lseek() is using ssize_t to return the value from vfs_llseek().  On a
32-bit kernel ssize_t is a 32-bit signed int, which overflows above 2 GB.

Assign the return value of vfs_llseek() to loff_t to fix this.

Reported-by: Boris Gjenero 
Fixes: 9e46b840c705 ("ovl: support stacked SEEK_HOLE/SEEK_DATA")
Cc:  # v4.19
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

2020-02-11T12:35:24+00:00

commit 4c37e71b713ecffe81f8e6273c6835e54306d412 upstream.

The WARN_ON() that child entry is always on overlay st_dev became wrong
when we allowed this function to update d_ino in non-samefs setup with xino
enabled.

It is not true in case of xino bits overflow on a non-dir inode.  Leave the
WARN_ON() only for directories, where assertion is still true.

Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
Cc:  # v4.17+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: relax WARN_ON() on rename to self

2019-12-17T18:56:11+00:00

commit 6889ee5a53b8d969aa542047f5ac8acdc0e79a91 upstream.

In ovl_rename(), if new upper is hardlinked to old upper underneath
overlayfs before upper dirs are locked, user will get an ESTALE error
and a WARN_ON will be printed.

Changes to underlying layers while overlayfs is mounted may result in
unexpected behavior, but it shouldn't crash the kernel and it shouldn't
trigger WARN_ON() either, so relax this WARN_ON().

Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com
Fixes: 804032fabb3b ("ovl: don't check rename to self")
Cc:  # v4.9+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

ovl: fix corner case of non-unique st_dev;st_ino

2019-12-17T18:56:10+00:00

commit 9c6d8f13e9da10a26ad7f0a020ef86e8ef142835 upstream.

On non-samefs overlay without xino, non pure upper inodes should use a
pseudo_dev assigned to each unique lower fs and pure upper inodes use the
real upper st_dev.

It is fine for an overlay pure upper inode to use the same st_dev;st_ino
values as the real upper inode, because the content of those two different
filesystem objects is always the same.

In this case, however:
 - two filesystems, A and B
 - upper layer is on A
 - lower layer 1 is also on A
 - lower layer 2 is on B

Non pure upper overlay inode, whose origin is in layer 1 will have the same
st_dev;st_ino values as the real lower inode. This may result with a false
positive results of 'diff' between the real lower and copied up overlay
inode.

Fix this by using the upper st_dev;st_ino values in this case.  This breaks
the property of constant st_dev;st_ino across copy up of this case. This
breakage will be fixed by a later patch.

Fixes: 5148626b806a ("ovl: allocate anon bdev per unique lower fs")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman