Messages in this thread | | | Date | Fri, 7 Apr 2006 12:45:45 -0700 | From | Chris Wright <> | Subject | Re: [RFC][PATCH 0/7] fireflier LSM for labeling sockets based on its creator (owner) |
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* Török Edwin (edwin@gurde.com) wrote: > The purpose of the fireflier LSM is to "label" each socket with a context, > where the context is a (list of) the program(s) that has/have access to it. > > I've written fireflier LSM to allow filtering packets "per application". It is > meant to be used only when SELinux is not available (not available/disabled > at boot). For more details, see the initial discussion [1]
There is so much SELinux code in here, it's really not making sense to do this as separate work.
> Summary of how fireflier LSM works: > - each program is associated a sid, depending on its mountpoint+inode, i.e. 2 > processes launched from the same program have the same sid
That sounds like a problem. Ptrace can undermine that really easily. Also bind mounts will give you a different sid for same exectuable, with a possible way to get into interesting 'group' situation.
> - each socket created by a processis labeled with the process's sid > - if 2 or more programs have access to the socket, it is labeled with a "group > sid". A group sid contains a list of the sids of programs having access > - userspace, or iptables module can match packets on this "fireflier context"
How do you keep from joining the group?
> As I stated in my previous mail, I intend to write a userspace policy module > generator, that is to be used when selinux is enabled. > When it is disabled, then only would the fireflier lsm be used. > > I am asking for your comments/suggestions on the following issues: > - security/correctness of the LSM (is there a way for a program to have access > to a socket, and escaping the labeling?)
what do you do about ptrace, /proc/[pid]/mem, fd passing, bind mounts, /proc/self/mem, etc.
> - how do I generate an SELinux policy, that does what this LSM module does?
Sounds like the best solution.
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