From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752597Ab1LKXUl (ORCPT ); Sun, 11 Dec 2011 18:20:41 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:55207 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751972Ab1LKXUk (ORCPT ); Sun, 11 Dec 2011 18:20:40 -0500 Date: Sun, 11 Dec 2011 15:20:29 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly To: Vasiliy Kulikov cc: Andrew Morton , Al Viro , Alexey Dobriyan , kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] proc: fix task_struct infoleak In-Reply-To: <20111211182821.GA2853@albatros> Message-ID: References: <20111211182821.GA2853@albatros> User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 11 Dec 2011, Vasiliy Kulikov wrote: > proc_pid_permission() doesn't put task_struct on every /proc/$pid/ > access. A demo from Hugh Dickins: > > while :; do ps; grep KernelStack /proc/meminfo; sleep 1; done > > Reported-by: Hugh Dickins > Signed-off-by: Vasiliy Kulikov Thank you, yes, that fixes it for me: Tested-by: Hugh Dickins but hopefully akpm will just fold this into the original patch. Hmm, tiny niggle, but I notice that has_pid_permissions() is declared, reasonably, as bool; so wouldn't it be better for has_perms to be declared as bool instead of int? Hardly worth bothering about, but if you've a mind to respin with a corrected Subject as Al rightly suggests. > --- > This is a patch against a hidepid patchset from -mm. > > fs/proc/base.c | 9 +++++++-- > 1 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 8caf5cb..0e5c577 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -646,9 +646,14 @@ static bool has_pid_permissions(struct pid_namespace *pid, > static int proc_pid_permission(struct inode *inode, int mask) > { > struct pid_namespace *pid = inode->i_sb->s_fs_info; > - struct task_struct *task = get_proc_task(inode); > + struct task_struct *task; > + int has_perms; > + > + task = get_proc_task(inode); > + has_perms = has_pid_permissions(pid, task, 1); > + put_task_struct(task); > > - if (!has_pid_permissions(pid, task, 1)) { > + if (!has_perms) { > if (pid->hide_pid == 2) { > /* > * Let's make getdents(), stat(), and open() > -- > 1.7.0.4