linux-kernel - Re: [PATCH v2] ipc/shm: fix the historical/wrong mm->start

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: <20140826193709.GB26576@redhat.com>
Date:	Tue, 26 Aug 2014 21:37:09 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Cyrill Gorcunov <gorcunov@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>,
	Manfred Spraul <manfred@...orfullife.com>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	Kees Cook <keescook@...omium.org>, Tejun Heo <tj@...nel.org>,
	Andrew Vagin <avagin@...nvz.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	Vasiliy Kulikov <segoon@...nwall.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Michael Kerrisk <mtk.manpages@...il.com>,
	Julien Tinnes <jln@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ipc/shm: fix the historical/wrong mm->start_stack
	check

On 08/26, Cyrill Gorcunov wrote:
>
> On Mon, Aug 25, 2014 at 09:12:07PM +0200, Oleg Nesterov wrote:
> > +		vma = find_vma(current->mm, addr);
> > +		if (vma) {
> > +			unsigned long end = addr + size;
> > +
> > +			if (vma->vm_flags & VM_GROWSDOWN)
> > +				end += PAGE_SIZE * 5;
> > +
> > +			if (end < addr || end > vma->vm_start)
> > +				goto invalid;
>
> Looks good to me, but I somehow missed in first version of the patch
> too the following aspect -- end > vma->vm_start? Maybe end >= vma->vm_end?

I think ">" is correct, the last byte is "addr + size - 1". Otherwise,
say, find_vma_intersection() is buggy. But this doesn't matter, please
see v3.

Oleg.

--
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/