Re: Status of capabilities?

From: Dax Kelson (
Date: Thu Jun 27 2002 - 01:05:25 EST

On Wed, 2002-06-26 at 06:40, Michael Kerrisk wrote:

> What's still missing in 2.4, as far as I can see after reading the sources,
> is the ability to set capabilities on executable files so that a process
> gains those privileges when executing the file. I recall seeing some
> information somewhere saying this wasn't possible / wasn't going to happen
> for ext2. Is it on the drawing board for any file system?

The 2.5 VFS supports Extended Attributes (since 2.5.3). I think the plan
was use EAs to store capabilities. So I believe that the infrastructure
is in place, someone with the proper skills just needs to:

1. Define how capabilities will be stored as a EA
2. Teach fs/exec.c to use the capabilities stored with the file
3. Write lscap(1)
4. Write chcap(1)
5. Audit/fix all SUID root binaries to use capabilities
6. Set appropriate capabilities with for each with chcap(1) and then:
   # find / -type f -perm -4000 -user root -exec chmod u-s {} \;
7. Party and snicker in the general direction of that OS with the slogan
"One remote hole in the default install, in nearly 6 years!"

Dax Kelson
Guru Labs

Disclaimer: I could be completely wrong on any or all of the above

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