linux-stable.git/fs/overlayfs, branch linux-4.8.y

ovl: fix d_real() for stacked fs

2016-12-08T06:16:18+00:00

commit c4fcfc1619ea43a8a89ad2f83ff23905eee088bd upstream.

Handling of recursion in d_real() is completely broken.  Recursion is only
done in the 'inode != NULL' case.  But when opening the file we have
'inode == NULL' hence d_real() will return an overlay dentry.  This won't
work since overlayfs doesn't define its own file operations, so all file
ops will fail.

Fix by doing the recursion first and the check against the inode second.

Bash script to reproduce the issue written by Quentin:

 - 8< - - - - - 8< - - - - - 8< - - - - - 8< - - - -
tmpdir=$(mktemp -d)
pushd ${tmpdir}

mkdir -p {upper,lower,work}
echo -n 'rocks' > lower/ksplice
mount -t overlay level_zero upper -o lowerdir=lower,upperdir=upper,workdir=work
cat upper/ksplice

tmpdir2=$(mktemp -d)
pushd ${tmpdir2}

mkdir -p {upper,work}
mount -t overlay level_one upper -o lowerdir=${tmpdir}/upper,upperdir=upper,workdir=work
ls -l upper/ksplice
cat upper/ksplice
 - 8< - - - - - 8< - - - - - 8< - - - - - 8< - - - -

Reported-by: Quentin Casasnovas 
Signed-off-by: Miklos Szeredi 
Fixes: 2d902671ce1c ("vfs: merge .d_select_inode() into .d_real()")
Signed-off-by: Greg Kroah-Hartman

ovl: fsync after copy-up

2016-11-10T15:38:51+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: update S_ISGID when setting posix ACLs

2016-11-10T15:38:51+00:00

commit fd3220d37b1f6f0cab6142d98b0e6c4082e63299 upstream.

This change fixes xfstest generic/375, which failed to clear the
setgid bit in the following test case on overlayfs:

  touch $testfile
  chown 100:100 $testfile
  chmod 2755 $testfile
  _runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile

Reported-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Tested-by: Amir Goldstein 
Fixes: d837a49bd57f ("ovl: fix POSIX ACL setting")
Signed-off-by: Greg Kroah-Hartman

ovl: fix get_acl() on tmpfs

2016-11-10T15:38:51+00:00

commit b93d4a0eb308d4400b84c8b24c1b80e09a9497d0 upstream.

tmpfs doesn't have ->get_acl() because it only uses cached acls.

This fixes the acl tests in pjdfstest when tmpfs is used as the upper layer
of the overlay.

Reported-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Fixes: 39a25b2b3762 ("ovl: define ->get_acl() for overlay inodes")
Signed-off-by: Greg Kroah-Hartman

ovl: copy_up_xattr(): use strnlen

2016-10-28T07:45:23+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()

2016-10-28T07:45:23+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

2016-09-05T11:55:20+00:00

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:

ovl: listxattr: use strnlen()

2016-09-01T09:12:00+00:00

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:

ovl: Switch to generic_getxattr

2016-09-01T09:12:00+00:00

Now that overlayfs has xattr handlers for iop->{set,remove}xattr, use
those same handlers for iop->getxattr as well.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Miklos Szeredi

ovl: copyattr after setting POSIX ACL

2016-09-01T09:12:00+00:00

Setting POSIX acl may also modify the file mode, so need to copy that up to
the overlay inode.

Reported-by: Eryu Guan 
Fixes: d837a49bd57f ("ovl: fix POSIX ACL setting")
Signed-off-by: Miklos Szeredi