linux

iv/linux

History

Zheng Liang a295aef603 ovl: fix missing negative dentry check in ovl_rename()

The following reproducer

  mkdir lower upper work merge
  touch lower/old
  touch lower/new
  mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge
  rm merge/new
  mv merge/old merge/new & unlink upper/new

may result in this race:

PROCESS A:
  rename("merge/old", "merge/new");
  overwrite=true,ovl_lower_positive(old)=true,
  ovl_dentry_is_whiteout(new)=true -> flags |= RENAME_EXCHANGE

PROCESS B:
  unlink("upper/new");

PROCESS A:
  lookup newdentry in new_upperdir
  call vfs_rename() with negative newdentry and RENAME_EXCHANGE

Fix by adding the missing check for negative newdentry.

Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
Fixes: e9be9d5e76e3 ("overlay filesystem")
Cc: <stable@vger.kernel.org> # v3.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

2021-09-24 21:00:31 +02:00

copy_up.c

ovl: use kvalloc in xattr copy-up

2021-08-17 11:47:45 +02:00

dir.c

ovl: fix missing negative dentry check in ovl_rename()

2021-09-24 21:00:31 +02:00

export.c

ovl: fix uninitialized pointer read in ovl_lookup_real_one()

2021-08-10 10:21:30 +02:00

file.c

ovl: fix deadlock in splice write