oss-sec mailing list archives
Re: filesystem capabilities
From: Kees Cook <kees () ubuntu com>
Date: Wed, 10 Nov 2010 10:06:29 -0800
On Mon, Nov 08, 2010 at 12:01:29PM -0500, Steve Grubb wrote:
While in general this is a good idea, there are issues with it, in arbitrary order: - Some currently-SUID programs are aware of them being (potentially) SUID, and will drop the "more privileged" euid when it is no longer needed, but they will probably not be aware of them possessing capabilities.This is an artifact of having a capabilities library that takes several lines of code to do anything. It is more correct to check for capabilities that trusting that euid means that you have certain powers. In my opinion, a lot of this code should be cleaned up so that its correct.
Right, it's not just a matter of dropping setuid bits and adding fscaps; these tools each need to be changed to understand fscaps and correctly drop privs. Which is especially true for "mixed" environments where the code could run _either_ as setuid or with fscaps. Building that logic into the cap library (which ever one) is the plan, as I understand.
The intent of this project is to get the patches and user space work done. We know that just setting the bit is not all that has to be done.
Yup, and Debian and Ubuntu have even further to go since their userspace and package manager don't even handle xattrs. It would be nice if upstream tar took the xattr patches. Steve, are there any plans to make that happen? -Kees -- Kees Cook Ubuntu Security Team
Current thread:
- filesystem capabilities Solar Designer (Nov 07)
- Re: filesystem capabilities Ludwig Nussel (Nov 08)
- Re: filesystem capabilities Sebastian Krahmer (Nov 08)
- Re: filesystem capabilities Kees Cook (Nov 10)
- Re: filesystem capabilities Sebastian Krahmer (Nov 08)
- Re: filesystem capabilities yersinia (Nov 08)
- Re: filesystem capabilities James Morris (Nov 08)
- <Possible follow-ups>
- Re: filesystem capabilities Steve Grubb (Nov 08)
- Re: filesystem capabilities Steve Grubb (Nov 08)
- Re: filesystem capabilities Kees Cook (Nov 10)
- Re: filesystem capabilities Steve Grubb (Nov 10)
- Re: filesystem capabilities Kees Cook (Nov 10)
- Re: filesystem capabilities Steve Grubb (Nov 10)
- Re: filesystem capabilities Kees Cook (Nov 18)
- Re: filesystem capabilities Daniel J Walsh (Nov 18)
- Re: filesystem capabilities Kees Cook (Nov 10)
- Re: filesystem capabilities Ludwig Nussel (Nov 08)