From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13DFCC43603 for ; Thu, 19 Dec 2019 19:10:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6314227BF for ; Thu, 19 Dec 2019 19:10:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576782620; bh=CqvtxM5wQOaMFWkK5dFmK0FDjGmValcb6z/pJpqMHoA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MOSETFTu9fIQX7NaBAH8gLyuEodL3yH2sSKvCuaQ04O3XNJDLBpJVMr26nh7Q9IRQ b8w9fHHVx4vBwjmGNpQU3nZykmebBkksoSzrhD4aoIGF4GXVBz4nUjjIChop4XHS/V QpDDQG8LZ2sTZuyPZ+qkNq4N02MN5d+6QlJhBKDI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728510AbfLSTKP (ORCPT ); Thu, 19 Dec 2019 14:10:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:58192 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728271AbfLSSjp (ORCPT ); Thu, 19 Dec 2019 13:39:45 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7281D2467F; Thu, 19 Dec 2019 18:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780784; bh=CqvtxM5wQOaMFWkK5dFmK0FDjGmValcb6z/pJpqMHoA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aRgheYh9TaazUcYMW+nV+JjLrJ7fNO9snKT+36l85gGZvf9m1E1I+cT6+JxienyyP 6eSdqjBSUBYBUqEzvsLkKrDmeEFxPNzrflhtWvsuL1E79B0u32QZllQUwUiLGyL7Ms itZYmDEHRI7uQeyWbFN1or8utrheZ9ZaxHPzh9l0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jann Horn , Andy Lutomirski , Thomas Gleixner , Al Viro , Andrew Morton , Borislav Petkov , Brian Gerst , Kees Cook , Linus Torvalds , Linux API , Peter Zijlstra , Tetsuo Handa , Tycho Andersen , Ingo Molnar , "zhangyi (F)" Subject: [PATCH 4.4 078/162] fs/proc: Stop reporting eip and esp in /proc/PID/stat Date: Thu, 19 Dec 2019 19:33:06 +0100 Message-Id: <20191219183212.539842175@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183150.477687052@linuxfoundation.org> References: <20191219183150.477687052@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andy Lutomirski commit 0a1eb2d474edfe75466be6b4677ad84e5e8ca3f5 upstream. Reporting these fields on a non-current task is dangerous. If the task is in any state other than normal kernel code, they may contain garbage or even kernel addresses on some architectures. (x86_64 used to do this. I bet lots of architectures still do.) With CONFIG_THREAD_INFO_IN_TASK=y, it can OOPS, too. As far as I know, there are no use programs that make any material use of these fields, so just get rid of them. Reported-by: Jann Horn Signed-off-by: Andy Lutomirski Acked-by: Thomas Gleixner Cc: Al Viro Cc: Andrew Morton Cc: Borislav Petkov Cc: Brian Gerst Cc: Kees Cook Cc: Linus Torvalds Cc: Linux API Cc: Peter Zijlstra Cc: Tetsuo Handa Cc: Tycho Andersen Link: http://lkml.kernel.org/r/a5fed4c3f4e33ed25d4bb03567e329bc5a712bcc.1475257877.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: zhangyi (F) Signed-off-by: Greg Kroah-Hartman --- fs/proc/array.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -425,10 +425,11 @@ static int do_task_stat(struct seq_file mm = get_task_mm(task); if (mm) { vsize = task_vsize(mm); - if (permitted) { - eip = KSTK_EIP(task); - esp = KSTK_ESP(task); - } + /* + * esp and eip are intentionally zeroed out. There is no + * non-racy way to read them without freezing the task. + * Programs that need reliable values can use ptrace(2). + */ } get_task_comm(tcomm, task);