linux-kernel - Re: sys_chroot+sys

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 25 Sep 2007 23:28:47 +0930
From:	David Newall <david@...idnewall.com>
To:	"Serge E. Hallyn" <serge@...lyn.com>
CC:	Bill Davidsen <davidsen@....com>,
	Philipp Marek <philipp@...ek.priv.at>, 7eggert@....de,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	majkls <majkls@...pere.com>, bunk@...tum.de,
	linux-kernel@...r.kernel.org
Subject: Re: sys_chroot+sys_fchdir Fix

Serge E. Hallyn wrote:
> Quoting David Newall (david@...idnewall.com):
>   
>> Serge E. Hallyn wrote:
>>     
>>> Quoting David Newall (david@...idnewall.com):
>>>   
>>>       
>>>> It might be tidy if pivot_root could be used (instead of a hack based on 
>>>> a chroot bug), but it'd still be unportable.
>>>>     
>>>>         
>>> It can.
>>>
>>> Please re-read my previous msg.
>>>       
>> I read it.  Currently pivot_root can't be used to affect a single process.  
>>     
>
> No.  If you unshare your mounts namespace immediately before pivot_root,
> then pivot_root will only affect that single process.
>   

Bugger.  You're right, I didn't read your previous message; I thought I 
had but I was wrong.

>>	unshare(CLONE_NEWNS);
>> 	chdir(new_dir);
>> 	pivot_root(new_dir, oldroot);

After further RTFMing, and assuming "any processes or threads which  
use  the  old  root directory" means what you imply, and surely it does, 
then I agree: pivot_root already does the job.  Does anybody still need 
to use a bug in chroot?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/