linux-kernel - Re: [PATCH v2] x86: Preserve iopl on fork and execve

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:	Tue, 12 May 2015 08:24:38 -0700
From:	Arjan van de Ven <arjanvandeven@...il.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Alex Henrie <alexhenrie24@...il.com>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	Kees Cook <keescook@...omium.org>,
	"H . Peter Anvin" <hpa@...or.com>, Doug Johnson <dougvj@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Tyler Hicks <tyhicks@...onical.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	LKML <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arjan van de Ven <arjan@...radead.org>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Brian Gerst <brgerst@...il.com>
Subject: Re: [PATCH v2] x86: Preserve iopl on fork and execve

On Mon, May 11, 2015 at 11:40 PM, Ingo Molnar <mingo@...nel.org> wrote:
>  - Nothing actually broke that people cared about in the last 2.5
>    years, thus this might be one of the (very very rare) cases where
>    preserving a breakage is the right thing to do.


>  - These syscalls are rarely used, and we could as well insist that
>    every new context should have the permissions to (re-)acquire them
>    and should actively seek them - instead of inheriting it to shells
>    via system(), etc. The best strategy with dangerous APIs is to make
>    it really, really explicit when they are used.

since nothing really broke and its a "nasty either way" regression
wise, picking the more secure path looks the most sane.

the most likely impact path is in the X world, where X normally gets
iopl type permissions (even thought it doesn't need
them anymore nowadays).. reverting this behavior would give all the
processes X spawns off those perms as well...

also the interesting question is:
can a process give up these perms?
otherwise it becomes a "once given, never gotten rid of" hell hole.
--
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/