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| author | Zheng Liang <zhengliang6@huawei.com> | 2021-09-24 09:16:27 +0800 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2021-09-24 21:00:31 +0200 |
| commit | a295aef603e109a47af355477326bd41151765b6 (patch) | |
| tree | 6c51213e683f2e13c04ec7ff7348695e86568fc4 /fs/overlayfs/file.c | |
| parent | 6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff) | |
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>
Diffstat (limited to 'fs/overlayfs/file.c')
0 files changed, 0 insertions, 0 deletions