Re: A small bug in file access control that all have neglected

On Tue, 15 Aug 2023 at 06:11, Xuancong Wang xuancong84@gmail.com wrote:

Yes, by "full access", I mean `chmod 777`. You can easily reproduce this bug on any Linux machine by typing the following commands:

This is how things are supposed to work. The 0777 permissions mean that you can read, write and execute the file. They do not mean that you own the file.

As a non-owner, you can set the access and modification times the same way you could by just reading and writing to the file. So if you set mtime, you have to set ctime ("change time") too.

To actually change times arbitrarily and with other patterns, you need to actually own the file.

Linus