Re: R: Linux kernel source archive vulnerable

[Kyle Moffett <mrmacman_g4@mac.com>]

On Sep 11, 2006, at 14:29:58, Jon Lewis wrote:
> On Fri, 8 Sep 2006, Perego Paolo Franco wrote:
>
> > Anyway just few considerations:
> > 2) a good sysadmin is aware that /usr/src is NOT supposed to be  
> > world writable
>
> For some reason (bug in how they're being checked out of git, I  
> assume), the latest kernel source tar files have all files and  
> directories world writable.  This is not how it's been in the past  
> and is not how it should be.

-ENOBUG

Please see these threads and quit bringing up this topic like crazy:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113304241100330&w=2
http://marc.theaimsgroup.com/?l=linux-kernel&m=114635639325551&w=2

To quote:
> Going over old ground again, any administrator a) compiling the  
> kernel as root or b) relying on GNU tar to make  
> _security_policy_decisions_ is completely insane.
>
> The only "trick" here is tar's decision not to apply umask, or root  
> uid/gid, to files in a tar when extracted as root.  This might make  
> sense for tars that you created and want to extract again (say  
> restoring a backup), but it certainly NEVER makes sense for files  
> downloaded off the Internet.

So if you must cause a senseless hubbub on securityfocus.com, please  
don't spill it over onto LKML.  This sort of thing is at _worst_ a  
bug in GNU tar that it's behavior is different when root.  I run a  
linux system with SELinux where user 0 is no different than any other  
user and has no special permissions at all, and this kind of  
stupidity bites me a lot.  My user 0 is "kyle" when I want to chown  
files I switch to the "sysadm" role, or if I absolutely need to  
override security policy for some reason I jump through hoops to get  
to the "root" role.  In neither of those cases do I care what UID I am.

So either deal insecure permissions when you can't be bothered to use  
GNU tar securely (easy), don't compile your kernel as root (easier)  
or fix GNU tar not to assume UID 0 is God in the first place.

Cheers,
Kyle Moffett
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/