Messages in this thread | | | Date | Tue, 23 Feb 1999 22:17:37 +0200 (IST) | From | Alon Ziv <> | Subject | Re: RFC: Security feature: partly prohibit process uid-changing |
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On Tue, 23 Feb 1999, Ph. Marek wrote:
> How about implementing a new field in the process structure, which gives > the SMALLEST possible uid for this process? standard would be 0, but could > be raised by all|root to any other value, maybe root could want lower it too. > Limiting set(re)uid seems like a nice extension, but I think the proposed mechanism is wrong. I had an idea, a while back, to change the setuid / setgid semantics a bit when using ACLs (which are themselves still a future idea...); my idea is to move the two bits indicating setuid and setgid to *each* entry in the ACL. This way, I can set- for each program- not just *who* can use it, but *what permissions* they'll get when they do. (In a similar vein, if we ever add support for forced capability sets to the filesystem, we can use a similar idea and give varying capabilities to each user).
This also solves the server situation- simply set the set[ug]id bits only in ACLs, and only for users / groups that aren't restricted. Then the more `restricted' users won't see the programs as setuid at all.
-az
------------------------+---------------------------------------------------- . __ | Phone: +972 3 5340753 (home), +972 3 9685882 (work) _| / | email: alonz@usa.net / | /_ Alon Ziv | smail: 33 Ha-Rama St., Ganey Tiqwah 55900, Israel ------------------------+---------------------------------------------------- <<<(((this place reserved for that ultra-wise oneliner I haven't found.)))>>>
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