Can chmod 777 ubituitously replace the need for chown ?

Question

Its clear to me that the

chmod 777

command will make any file, theoretically, accessible/readable/writeable/executable/ by any user.

But are there instances where, even with a world writable/readable file, we still need to implement CHOWN in order for the file to be used by system processes?

Or can we assume that, as long as permissions are wide open, the chown command has no impact on the access pattern behaviour of a file.

I ask this in relevance to some multithreaded/cluster processes which seem to fail when running as the wrong user due to ENOENT errors which appear to occur on a file which has wide open (777) permissions.

Answer 1

With a script which is setuid/setgid, meaning it executes as the user or group that owns the file this may be an issue.

Theoretically a program may check ownerships of a file before using them, secured tools such a ssh refuse to execute with global permissions, but afaik don't check ownerships. And it could also potentially be an issue with programs which set their own ownership, such as mail servers which also usually check for permissions before dropping to the mail user id.

Security wise it is considered very bad practice.