linux-kernel - Re: [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm

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: <20100525123027.GA29883@redhat.com>
Date:	Tue, 25 May 2010 14:30:27 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	David Howells <dhowells@...hat.com>
Cc:	Roland McGrath <roland@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mike Frysinger <vapier@...too.org>, linux-sh@...r.kernel.org,
	Paul Mundt <lethal@...ux-sh.org>,
	uclinux-dist-devel@...ckfin.uclinux.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage
	of child->mm

On 05/25, David Howells wrote:
>
> Oleg Nesterov <oleg@...hat.com> wrote:
>
> > > Like PEEKTEXT and POKETEXT?
> >
> > They use access_process_vm().
>
> Which needs to get the mm:
>
> 	int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> 	{
> 		struct vm_area_struct *vma;
> 		struct mm_struct *mm;
>
> 		if (addr + len < addr)
> 			return 0;
>
> 		mm = get_task_mm(tsk);

Yes sure,

But I do not think it makes any sense to change the signature of
access_process_vm() as well, it has a lot of callers. And it is
complex, it does get_user_pages(). Compared to that get_task_mm()
inside of access_process_vm() is nothing.

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/