linux-kernel - Re: [PATCH] signal: Make the si_code check in rt

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]

Message-ID: <CA+y5pbRq8Fbt8HUuDEJGOi4i4fa2RLfF1Rt-O7GHYpOhL6tD=Q@mail.gmail.com>
Date:	Mon, 12 Oct 2015 17:37:09 +0100
From:	"Amanieu d'Antras" <amanieu@...il.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: Re: [PATCH] signal: Make the si_code check in rt_[tg]sigqueueinfo stricter

On Mon, Oct 12, 2015 at 4:54 PM, Oleg Nesterov <oleg@...hat.com> wrote:
> Yes, copy_siginfo_to_user() does __put_user((short)from->si_code).
> But SI_FROMUSER/SI_FROMKERNEL are internal kernel checks, we mostly
> use them in copy_siginfo_to_user().
>
> And note that if ->si_code < 0 we simply do __copy_to_user(), so
> userspace can't see something which looks like "from kernel", in
> this case we do not truncate ->si_code.

Ah my bad, I seem to have missed that case. So copy_siginfo_to_user
seems to be safe, but it is still an issue for copy_siginfo_to_user32
which doesn't have this check.

Maybe this should be fixed in the compat code instead?
--
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/