Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752813AbbF2B1R (ORCPT ); Sun, 28 Jun 2015 21:27:17 -0400 Received: from mail-yk0-f177.google.com ([209.85.160.177]:35012 "EHLO mail-yk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753149AbbF2B1I (ORCPT ); Sun, 28 Jun 2015 21:27:08 -0400 MIME-Version: 1.0 In-Reply-To: <55901BB2.8030808@hurleysoftware.com> References: <1435439824-3975-1-git-send-email-batrick@batbytes.com> <1435452689-25390-1-git-send-email-batrick@batbytes.com> <1435452689-25390-2-git-send-email-batrick@batbytes.com> <55901BB2.8030808@hurleysoftware.com> Date: Sun, 28 Jun 2015 21:27:07 -0400 Message-ID: Subject: Re: [PATCH v2 2/2] tty: check tcsetpgrp p is a process group From: Patrick Donnelly To: Peter Hurley Cc: Greg Kroah-Hartman , Jiri Slaby , open list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1789 Lines: 49 On Sun, Jun 28, 2015 at 12:07 PM, Peter Hurley wrote: > On 06/27/2015 08:51 PM, Patrick Donnelly wrote: >> This fixes a bug where a process can set the foreground process group to its >> pid even if its pid is not a valid pgrp. >> >> Signed-off-by: Patrick Donnelly >> --- >> drivers/tty/tty_io.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c >> index fbb55db..01b4769 100644 >> --- a/drivers/tty/tty_io.c >> +++ b/drivers/tty/tty_io.c >> @@ -2579,6 +2579,9 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t >> retval = -ESRCH; >> if (!pgrp) >> goto out_unlock; >> + retval = -EINVAL; >> + if (!pid_task(pgrp, PIDTYPE_PGID)) >> + goto out_unlock; > > This change implies that the sequence in session_of_pgrp() that specifically > checks for pid_task(pgrp, PIDTYPE_PGID) == NULL is not doing anything > useful. However, that hypothesis is directly contradicted by the > comment above session_of_pgrp() > > "* This checks not only the pgrp, but falls back on the pid if no > * satisfactory pgrp is found. I dunno - gdb doesn't work correctly > * without this..." > > Regards, > Peter Hurley > >> retval = -EPERM; >> if (session_of_pgrp(pgrp) != task_session(current)) >> goto out_unlock; >> Ah, missed that. Good catch! I guess this patch is no good since it was already accounted for and it breaks gdb. -- Patrick Donnelly -- 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/