Subject: chown of coreutils may delete the suid of file

From: "21625039" <[email-masked]>
Date: Tue, 14 Dec 2021 10:49:37 +0800

I encountered a problem with chown on my fedora34 as the version of
coreutils is 8.32.

The reproduce process could see the steps blow:

[root@fedora ~]# ll test.txt

-rw-r--r--. 1 root root 0 Dec 13 21:13 test.txt

[root@fedora ~]# chmod 4750 test.txt

[root@fedora ~]# ll test.txt

-rwsr-x---. 1 root root 0 Dec 13 21:13 test.txt

[root@fedora ~]# chown root:root test.txt

[root@fedora ~]# ll test.txt

-rwxr-x---. 1 root root 0 Dec 13 21:13 test.txt

[root@fedora ~]# rpm -qa coreutils

coreutils-8.32-19.fc34.x86_64

[root@fedora ~]# cat /etc/fedora-release

Fedora release 34 (Thirty Four)

Looking forward to hearing from you!

Thanks.