diff options
| author | Miklos Szeredi <mszeredi@redhat.com> | 2021-11-04 10:55:34 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-22 09:29:40 +0100 |
| commit | f9f300a92297be8250547347fd52216ef0177ae0 (patch) | |
| tree | 45401046aef29b3c2898e20f557ee52d48d5098e | |
| parent | ba2a9d8f8ef139c5782579dc87058d71a0393c7e (diff) | |
ovl: fix warning in ovl_create_real()
commit 1f5573cfe7a7056e80a92c7a037a3e69f3a13d1c upstream.
Syzbot triggered the following warning in ovl_workdir_create() ->
ovl_create_real():
if (!err && WARN_ON(!newdentry->d_inode)) {
The reason is that the cgroup2 filesystem returns from mkdir without
instantiating the new dentry.
Weird filesystems such as this will be rejected by overlayfs at a later
stage during setup, but to prevent such a warning, call ovl_mkdir_real()
directly from ovl_workdir_create() and reject this case early.
Reported-and-tested-by: syzbot+75eab84fd0af9e8bf66b@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/overlayfs/dir.c | 3 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 1 | ||||
| -rw-r--r-- | fs/overlayfs/super.c | 12 |
3 files changed, 10 insertions, 6 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 876de87f604c..8c89eaea1583 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -113,8 +113,7 @@ kill_whiteout: goto out; } -static int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, - umode_t mode) +int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode) { int err; struct dentry *d, *dentry = *newdentry; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 6934bcf030f0..a8e9da5f01eb 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -409,6 +409,7 @@ struct ovl_cattr { #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) +int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode); struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, struct ovl_cattr *attr); int ovl_cleanup(struct inode *dir, struct dentry *dentry); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index f036d7544d4a..f5cf0938f298 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -650,10 +650,14 @@ retry: goto retry; } - work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); - err = PTR_ERR(work); - if (IS_ERR(work)) - goto out_err; + err = ovl_mkdir_real(dir, &work, attr.ia_mode); + if (err) + goto out_dput; + + /* Weird filesystem returning with hashed negative (kernfs)? */ + err = -EINVAL; + if (d_really_is_negative(work)) + goto out_dput; /* * Try to remove POSIX ACL xattrs from workdir. We are good if: |