From 6756af923e06aa33ad8894aaecbf9060953ba00f Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 26 Nov 2024 12:55:12 +0100 Subject: [PATCH] udf: Verify inode link counts before performing rename During rename, we are updating link counts of various inodes either when rename deletes target or when moving directory across directories. Verify involved link counts are sane so that we don't trip warnings in VFS. Reported-by: syzbot+3ff7365dc04a6bcafa66@syzkaller.appspotmail.com Signed-off-by: Jan Kara --- fs/udf/namei.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 2be775d30ac1..2cb49b6b0716 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -791,8 +791,18 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir, retval = -ENOTEMPTY; if (!empty_dir(new_inode)) goto out_oiter; + retval = -EFSCORRUPTED; + if (new_inode->i_nlink != 2) + goto out_oiter; } + retval = -EFSCORRUPTED; + if (old_dir->i_nlink < 3) + goto out_oiter; is_dir = true; + } else if (new_inode) { + retval = -EFSCORRUPTED; + if (new_inode->i_nlink < 1) + goto out_oiter; } if (is_dir && old_dir != new_dir) { retval = udf_fiiter_find_entry(old_inode, &dotdot_name,