linux-kernel - Re: [PATCH] audit: clear thread flag for new children

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Mon, 29 Oct 2007 18:04:31 -0400
From:	Steve Grubb <sgrubb@...hat.com>
To:	Tony Jones <tonyj@...e.de>
Cc:	linux-audit@...hat.com, linux-kernel@...r.kernel.org,
	chrisw@...s-sol.org, viro@....linux.org.uk
Subject: Re: [PATCH] audit: clear thread flag for new children

On Monday 29 October 2007 01:20:58 pm Tony Jones wrote:
> > The problem is that removing that flag makes the children unauditable in
> > the future. The only place that flag gets set is during fork.
>
> I don't see this.

If the child does not have the TIF_SYSCALL_AUDIT flag, it never goes into 
audit_syscall_entry. It becomes unauditable.


> The case that would be undesirable would be for a task to have an audit
> context but to not have the thread flag enabled.

That would just be a small allocation of memory that will be returned when the 
process exits. From an auditing PoV, something that is undesirable is the 
inability to audit a process that you want to audit.


> > Unless I'm missing something, to make all children auditable again would
> > mean stopping all processes and or'ing that flag into all thread info
> > areas.
>
> I think you are.  Or maybe the code was different two years ago so that the
> above made sense.  
>
> In the above scenario, audit is disabled, a new child is forked, we bail
> early so there is no audit context (and now there is no flag in the thread
> area).   Currently there is no way this task is ever going to be audited as
> there is no audit context. 

So when audit is re-enabled, how do you make that task auditable?


> If this task forks a new child, at this point the value of audit enabled
> will determine if there should be a context allocated and it will allocate
> the TIF flag also.

In the new child, but not the parent.


> I don't see your stopping all processes scenario. 

That is so you can walk the process table and "or" the bit in unconditionally. 
All processes need to be auditable or you've got a security hole.

-Steve
-
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/