Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755886Ab1F1BO5 (ORCPT ); Mon, 27 Jun 2011 21:14:57 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:40646 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755843Ab1F1BNz convert rfc822-to-8bit (ORCPT ); Mon, 27 Jun 2011 21:13:55 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=KtLp3E0H8DWBaqMp02yco3+aRMl16RSLfMr0gz8XzUewVhuh4uIUmthQQTOOQPbBFY VpbTu5FU8FFMMnjG2JmIqjmwtrfNfY5IDdPT/Ek9zNoYBj7uMtda+6CzoFezDWwep2Gm AktvjQrqGPWfXHBvUu7Z7zr4UYmYaABehAWCk= MIME-Version: 1.0 In-Reply-To: <1308917318-4749-1-git-send-email-segoon@openwall.com> References: <1308917318-4749-1-git-send-email-segoon@openwall.com> Date: Tue, 28 Jun 2011 06:43:54 +0530 X-Google-Sender-Auth: 7_Iu00vuSryIOOAF9xD5IDUk5KU Message-ID: Subject: Re: [PATCH 1/2] proc: restrict access to /proc/PID/io From: Balbir Singh To: Vasiliy Kulikov Cc: linux-kernel@vger.kernel.org, Andrew Morton , Al Viro , David Rientjes , Stephen Wilson , KOSAKI Motohiro , security@kernel.org, Eric Paris , Solar Designer Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 863 Lines: 20 On Fri, Jun 24, 2011 at 5:38 PM, Vasiliy Kulikov wrote: > /proc/PID/io may be used for gathering private information. ?E.g. for > openssh and vsftpd daemons wchars/rchars may be used to learn the > precise password length. ?Restrict it to processes being able to ptrace > the target process. > Hmm.. How do I reproduce this, won't they be enough randomness around rchar/wchar by the time the attacker reads it? > ptrace_may_access() is needed to prevent keeping open file descriptor of > "io" file, executing setuid binary and gathering io information of the > setuid'ed process. Balbir Singh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/