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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 839A8C54FC9 for ; Tue, 21 Apr 2020 09:04:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6270A20CC7 for ; Tue, 21 Apr 2020 09:04:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MKwRAESw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728397AbgDUJEz (ORCPT ); Tue, 21 Apr 2020 05:04:55 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:52757 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726052AbgDUJEx (ORCPT ); Tue, 21 Apr 2020 05:04:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587459892; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Jiq5vxLEVOIwG9hr0wweOUq8q9Kc0ppf4k/26mm9nI0=; b=MKwRAESwgOjoQ/t//ugozYJo2EZUoxkRxBm3CY1KoFafEhbb/10B2ysMpaMjGREMy+3fgO 8fmEg8tAaI45a0xsO3Dml8fbKHbKXJADgDXA6bc89Zp/X4WVjnZEPSXz8d5a3N/R7ogyYZ bdAHj64luipLgcu7GyDUBH+Gs4Rskkg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-401-zvLOlh2NMJOWjtqGbie_IQ-1; Tue, 21 Apr 2020 05:04:31 -0400 X-MC-Unique: zvLOlh2NMJOWjtqGbie_IQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2198B107ACC9; Tue, 21 Apr 2020 09:04:30 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.195.130]) by smtp.corp.redhat.com (Postfix) with SMTP id CC2C85DA66; Tue, 21 Apr 2020 09:04:28 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 21 Apr 2020 11:04:29 +0200 (CEST) Date: Tue, 21 Apr 2020 11:04:27 +0200 From: Oleg Nesterov To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, Christof Meerwald , Linux Containers Subject: Re: [PATCH] signal: Avoid corrupting si_pid and si_uid in do_notify_parent Message-ID: <20200421090426.GA6787@redhat.com> References: <20200419201336.GI22017@edge.cmeerw.net> <87sggyytnh.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87sggyytnh.fsf@x220.int.ebiederm.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/20, Eric W. Biederman wrote: > > The immediate problem is as Christof noticed that "pid_alive(current) == false". this is slightly offtopic, but we can probably remove this "pid_alive" check, pid_nr_ns() checks pid != NULL anyway. > Inspecting the code it appears this problem has existed since the pid > namespace support started handling this case Agreed... > @@ -1993,8 +1993,12 @@ bool do_notify_parent(struct task_struct *tsk, int sig) > if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) > sig = 0; > } > + /* > + * Bypass send_signal as the si_pid and si_uid values have > + * been generated in the parent's namespaces. > + */ > if (valid_signal(sig) && sig) > - __group_send_sig_info(sig, &info, tsk->parent); > + __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false); Acked-by: Oleg Nesterov