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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 43403C761A6 for ; Mon, 27 Mar 2023 09:15:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pgiwf-00037i-Ob; Mon, 27 Mar 2023 05:15:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pgiwd-00037I-Jj for qemu-devel@nongnu.org; Mon, 27 Mar 2023 05:15:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pgiwb-000100-Lw for qemu-devel@nongnu.org; Mon, 27 Mar 2023 05:15:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679908512; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jXRsBTxAMpae02Fl8JHlmQYQEXrTXhCun5JjyBJjFiQ=; b=HLrVQFny6F3gejGo/dcOlIF2mm7/3CSvk/NXorQNLKHWv8lv5mxthaXoPQP2TzSXjSIgKz 7ylbV2LfJ6iz3nvhJwVJv7F3h7upVVZVc/105IM+baVOpvIQyp6BkDqZdm9Xf2PP4uC+JF g98rQZ6zu7FrWGK+FQN2MnAPNh029f8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-168-f_IE3EzGPoOHLJxzOV2OMA-1; Mon, 27 Mar 2023 05:15:10 -0400 X-MC-Unique: f_IE3EzGPoOHLJxzOV2OMA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 486DB85530C for ; Mon, 27 Mar 2023 09:15:10 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.173]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B0A8F492B01; Mon, 27 Mar 2023 09:15:09 +0000 (UTC) Date: Mon, 27 Mar 2023 10:15:06 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Blake Cc: qemu-devel@nongnu.org Subject: Re: [PATCH] systemd: Also clear LISTEN_FDNAMES during systemd socket activation Message-ID: References: <20230324153349.1123774-1-eblake@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230324153349.1123774-1-eblake@redhat.com> User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Mar 24, 2023 at 10:33:49AM -0500, Eric Blake wrote: > Some time after systemd documented LISTEN_PID and LISTEN_FDS for > socket activation, they later added LISTEN_FDNAMES; now documented at: > https://www.freedesktop.org/software/systemd/man/sd_listen_fds.html > > In particular, look at the implementation of sd_listen_fds_with_names(): > https://github.com/systemd/systemd/blob/main/src/libsystemd/sd-daemon/sd-daemon.c > > If we ever pass LISTEN_PID=xxx and LISTEN_FDS=n to a child process, > but leave LISTEN_FDNAMES=... unchanged as inherited from our parent > process, then our child process using sd_listen_fds_with_names() might > see a mismatch in the number of names (unexpected -EINVAL failure), or > even if the number of names matches the values of those names may be > unexpected (with even less predictable results). > > Usually, this is not an issue - the point of LISTEN_PID is to tell > systemd socket activation to ignore all other LISTEN_* if they were > not directed to this particular pid. But if we end up consuming a > socket directed to this qemu process, and later decide to spawn a > child process that also needs systemd socket activation, we must > ensure we are not leaking any stale systemd variables through to that > child. The easiest way to do this is to wipe ALL LISTEN_* variables > at the time we consume a socket, even if we do not yet care about a > LISTEN_FDNAMES passed in from the parent process. > > See also https://lists.freedesktop.org/archives/systemd-devel/2023-March/048920.html > > Thanks: Laszlo Ersek > Signed-off-by: Eric Blake > --- > util/systemd.c | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|