linux-kernel - Re: RT scheduling and a way to make a process hang, unkillable

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, 16 Feb 2009 14:19:31 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Dhaval Giani <dhaval@...ux.vnet.ibm.com>
Cc:	Corey Hickey <bugfood-ml@...ooh.org>, linux-kernel@...r.kernel.org,
	Bharata B Rao <bharata@...ux.vnet.ibm.com>,
	Balbir Singh <balbir@...ibm.com>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>, mtk.manpages@...il.com
Subject: Re: RT scheduling and a way to make a process hang, unkillable

On Mon, 2009-02-16 at 18:44 +0530, Dhaval Giani wrote:
>  (This is not a good day!)

Monday strikes again ;-)

> @@ -572,6 +572,9 @@ static int set_user(struct cred *new)
>  	if (!new_user)
>  		return -EAGAIN;

So here we just allocated new_user and made sure we didn't fail that
allocation.

> +	if (!task_can_switch_user(new->uid, current))
> +		return -EAGAIN;

And here you bail, without freeing new_user. The idea was to do this
check before alloc_uid().

>  	if (atomic_read(&new_user->processes) >=
>  				current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
>  			new_user != INIT_USER) {

--
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/