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| author | Miklos Szeredi <mszeredi@redhat.com> | 2021-11-04 12:55:34 +0300 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2021-11-04 12:55:34 +0300 |
| commit | 1f5573cfe7a7056e80a92c7a037a3e69f3a13d1c (patch) | |
| tree | 529a98c4445e34dc1f806c760b2668f0b46ec27c /fs/overlayfs | |
| parent | 9a254403760041528bc8f69fe2f5e1ef86950991 (diff) | |
| download | linux-1f5573cfe7a7056e80a92c7a037a3e69f3a13d1c.tar.xz | |
ovl: fix warning in ovl_create_real()
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>
Diffstat (limited to 'fs/overlayfs')
| -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 93c7c267de93..f18490813170 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -137,8 +137,7 @@ 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 3894f3347955..2cd5741c873b 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -570,6 +570,7 @@ 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 178daa5e82c9..265181c110ae 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -787,10 +787,14 @@ 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: |