Ensure that the lookup operation is present for the inode in the overlay filesystem. If the operation is missing, log a warning and return an EIO error to prevent further issues in the lookup process. Reported-by: syzbot+a8c9d476508bd14a90e5@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://syzkaller.appspot.com/bug?extid=a8c9d476508bd14a90e5 Signed-off-by: Vasiliy Kovalev <kovalev@xxxxxxxxxxxx> --- fs/overlayfs/namei.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 5764f91d283e7..a73f37e401cf0 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -1115,6 +1115,13 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, for (i = 0; !d.stop && i < ovl_numlower(poe); i++) { struct ovl_path lower = ovl_lowerstack(poe)[i]; + if (!lower.dentry->d_inode->i_op->lookup) { + err = -EIO; + pr_warn_ratelimited("missing lookup operation for inode %p\n", + lower.dentry->d_inode); + goto out_put; + } + if (!ovl_redirect_follow(ofs)) d.last = i == ovl_numlower(poe) - 1; else if (d.is_dir || !ofs->numdatalayer) -- 2.33.8
