Will I break things if I use "sudo chmod -R u=wrx {user}"?

apmech707

6/5/23, 9:14 PM

I am new to linux and Ubuntu. I am learning the terminal and want to set up my userspace as secure as possible. I have multiple users and some have access to files of other users. I want to make sure they can only access the files and folders I set up. So I gave certain folders a public subgroup " chown {usergroup}:{publicgroup} {folder} ", and set that group permission to read and execute " chmod g+rx {folder} ". The group {publicgroup} already contains the necessary users.

BUT, I am concerned that the others and group part of the permissions still says r-x on many files/folders. I was thinking of taking the rwx permissions away from everyting excecpt the few folders and files that I want the group access to using the above command and going back throught to add some rx permissions. Will executing the above chmod command break things? How would you-the community- recommend setting up secure, isolated userspaces while still sharing files. Thanks for helping me! I am still a linux newbe.

0 + 0

permissions

command-line

chmod

waltinator

6/5/23, 9:35 PM

If you make a global permissions change to any system directory, you will break your system unrecoverably. System permissions are carefully set, and shouldn't be messed with. What you're trying to do is unclear. Are you familiar with the Owner/Group/World, Read/Write/Execute access scheme used by Unix/Linux? Read `man -a chmod`.

apmech707

6/5/23, 9:39 PM

Thanks fo the man page hint. I'll read through that. Yes, I am sorta familiar with the owner/group/world and read/write/execute scheme but it is still confusing me a little. I just what to have a guest user that can access one folder. But not let any other folders or user access anything else.

apmech707

6/5/23, 9:43 PM

Also, I realize using that command on root or like /bin would certainly break things. But I was talking about /home/me folder

Score:1

Ubuntu

Tilman

6/6/23, 2:04 AM

First, the command chmod u=rwx will not do what you intend. It will set the owner permissions to read+write+execute but will leave the group and world permissions untouched. What you want is chmod go-rwx.

Second, you do not want to set the execute permission bit indiscriminately on all files as described in your question. The execute permission should only be set on files that are intended to be executed as programs.

Third, it's never a good idea to sweepingly change the permissions on other users' files without asking them first whether they had a good reason to set the permissions as they are. You have a high chance of breaking things like that.

And finally, if you take away group and world execute permission on a user's home directory then other users cannot access any file or directory within that home directory, even if the permissions on that file or directory itself would allow it.

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Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Will I break things if I use "sudo chmod -R u=wrx {user}"?

TH: ฉันจะทำลายสิ่งต่าง ๆ หรือไม่ถ้าฉันใช้ "sudo chmod -R u=wrx {user}"

RO: Voi sparge lucrurile dacă folosesc „sudo chmod -R u=wrx {user}”?

RU: Сломаю ли я что-нибудь, если использую «sudo chmod -R u=wrx {user}»?

VI: Tôi sẽ làm hỏng mọi thứ nếu tôi sử dụng "sudo chmod -R u=wrx {user}"?

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