Timeline for Is Unix "permission model" conceptually broken?
Current License: CC BY-SA 4.0
23 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 9, 2022 at 2:42 | review | Close votes | |||
| May 28, 2022 at 3:01 | |||||
| Apr 15, 2022 at 10:11 | comment | added | Scrooge McDuck | @ilkkachu the question needs to be rephrased to better reflect what I find counterintuitive on the euristic verbal description of the permissions. | |
| Apr 15, 2022 at 10:07 | history | edited | Scrooge McDuck | CC BY-SA 4.0 | edited body |
| Apr 14, 2022 at 13:02 | answer | added | waltinator | timeline score: -3 | |
| Apr 14, 2022 at 11:18 | comment | added | ilkkachu | This post reads more like it's trying to prove a point already decided, and less like a genuine question. There's one situation, which honestly looks tailor-made to prove how the permission model is wrong. No comparison to other situations, no consideration on if the same goals could be achieved by other means. (like just copying the files to the student-accessible directory when they should get to see the file, or using email, or...). It's a bit like asking if knives are useless since yours doesn't cut and your hand hurts when using it, but neglecting to think about holding it the right way. | |
| Apr 14, 2022 at 10:20 | review | Close votes | |||
| Apr 20, 2022 at 3:08 | |||||
| Apr 14, 2022 at 10:12 | comment | added | muru | "Is X broken?" for models can often be answered with "It's not broken, it's limited." What's important is knowing the limitations and then either reworking the situation to fit them or using another model. The answerable question is: "Is model X usable for scenario Y?" Is Newtonian physics broken? It works well enough for a lot of things outside relativistic scenarios. Is the use of Euclidean geometry in the real world broken? It works well enough when spacetime curvature isn't significant enough to be relevant. Is the POSIX permissions model broken? Works well enough for a lot of use cases. | |
| Apr 14, 2022 at 9:47 | history | edited | Scrooge McDuck | CC BY-SA 4.0 | 77* instead of 66* on dirs |
| Nov 27, 2021 at 15:25 | comment | added | user313992 | @Scrooge "intuitively" Intuition sucks. Use your reason, not your intuition. Don't add the the x permission for everybody to a directory if you don't want to let everybody access the files within it. | |
| Nov 27, 2021 at 14:41 | comment | added | Chris Davies | @HaukeLaging +rx or -rx would still make more sense IMO. Without x on a directory it doesn't matter whether a file exists or not; I still can't get to it. mkdir x; touch x/y; chmod a-x x now we can cat x/y or cat x/z and in both cases we still get permission denied | |
| Nov 27, 2021 at 14:17 | comment | added | Hauke Laging | @roaima You might want to allow someone to know when a certain file is available without allowing access to the file. By taking away x you can enforce that access is not possible no matter what the creator of the file does to its permissions. | |
| Nov 27, 2021 at 12:44 | comment | added | Chris Davies | Setting r or rw permission on a directory makes no sense without x. You should have either (a) no access, or (b) x optionally with other permission bits | |
| Nov 27, 2021 at 12:37 | comment | added | user10489 | Your scenario is broken, not unix permissions. Also, you should never use 6 as a permission on a directory. +r,-x makes very little sense on a directory. +w,-x makes no sense. | |
| Nov 27, 2021 at 11:56 | review | Close votes | |||
| Dec 16, 2021 at 3:05 | |||||
| Nov 27, 2021 at 11:31 | comment | added | Scrooge McDuck | @nog642 nah, I meant the teacher setup the directories for the test. With 110 they couldn't read nor edit it. | |
| Nov 27, 2021 at 11:28 | comment | added | Scrooge McDuck | Intuitively one is brought to think that not being able to read is the same as covering your eyes and that being able to transverse is the same as to be given the exit path to a labyrinth, while reality is that the combination of the two is you're free to roam in a dark room and touch everything. | |
| Nov 27, 2021 at 11:20 | comment | added | Scrooge McDuck | to @francoisP and "they" (can't tag more than one user): I'm not judging nor what the teacher has done nor his reasons here; the example is just an ad-hoc plot device made to show that not being able to read but being able to transverse doesn't imply not being able to know what there is in the directory and that a more coherent behaviour would be to just say no to everything, like when you try to connect to an ssh host you don't have credentials for. | |
| Nov 27, 2021 at 10:45 | comment | added | Kamil Maciorowski | More general view: for each permission bit you can find a scenario where this bit is useful; still some combinations of permissions may make little or no sense. Just don't use these exact combinations. Similarly some sequences of bytes are invalid in Unicode, so they shouldn't appear in Unicode text. If you deliberately create such a sequence and interpret as Unicode, it's your problem. If anyone sets permissions that make no sense, it's their problem. | |
| Nov 27, 2021 at 10:37 | comment | added | nog642 | Pretty sure "so that next day the students will be able to access the test only after he will have told them the path" means you'd need to set 110 permissions on subject1, not 660. | |
| Nov 27, 2021 at 10:29 | comment | added | Kusalananda♦ | The issue is primarily the fact that the teacher manages files in the students' home directories. That should not be possible on any sanely set up system (where teachers are not admins), and is totally unnecessary for the purpose of what the teacher(s) are trying to do. Why manage more than a single copy of the tests? What if students already have directories with the same names (e.g. ~/tests)? | |
| Nov 27, 2021 at 10:22 | comment | added | francois P | 1st question : you just don't understand the unix permissions, it just does what it has to do in current description of the issue. 2cd one : for the same reason, in fact it is not a second error bet consequence of the 1st one. | |
| Nov 27, 2021 at 10:16 | comment | added | francois P | It is not related to permissions issues, but on method issues here. The approach of the problem/organization, just a mess out of sens in my opinion. Never a teacher directory have to be changed (permissions) it just has to be copied or linked on the pertinent date to students work directories. Or better, students just pull exercises/tests from a git repo opened special for the test/exam on the chosen date. (here teachers have permissions on gitlab of course) etc...etc.... there are so many methods & tools to do that, no ready-to-give answer is really possible. | |
| Nov 27, 2021 at 10:10 | history | asked | Scrooge McDuck | CC BY-SA 4.0 |