From patchwork Thu Apr 16 16:49:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 284271 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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C427EC2BB85 for ; Thu, 16 Apr 2020 16:52:31 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 916842223E for ; Thu, 16 Apr 2020 16:52:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZEWZ38OM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 916842223E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37142 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jP7kc-0001aI-Po for qemu-devel@archiver.kernel.org; Thu, 16 Apr 2020 12:52:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:32955) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jP7hm-0006r1-Pn for qemu-devel@nongnu.org; Thu, 16 Apr 2020 12:49:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jP7hl-0000Pr-R4 for qemu-devel@nongnu.org; Thu, 16 Apr 2020 12:49:34 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:30846 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jP7hl-0000Pa-NE for qemu-devel@nongnu.org; Thu, 16 Apr 2020 12:49:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587055773; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OfPb5Xn/B/myf3QvtDqfsuKstRVK4hF/CQiBtI98nAY=; b=ZEWZ38OMEwm9w1EFgdOXtsAr4NbTtdjLZ6O9SrxsTQwATjEXfV5RfKYUy4JDLVBvfcrw26 /IRHulMzxz4fV7s4198t8qIOGHSEq0y1Eo0AtlMmNYVseBqDPfoYA8wNia3FO1gfidA06k XgrQJlorRnZLIAKYjAVaTgSIuhINfMI= 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-416-1r7NIdbSNDixjmlBnkk9qw-1; Thu, 16 Apr 2020 12:49:30 -0400 X-MC-Unique: 1r7NIdbSNDixjmlBnkk9qw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B2E58802683 for ; Thu, 16 Apr 2020 16:49:29 +0000 (UTC) Received: from localhost (ovpn-114-223.ams2.redhat.com [10.36.114.223]) by smtp.corp.redhat.com (Postfix) with ESMTP id EE0639A265; Thu, 16 Apr 2020 16:49:23 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 2/2] virtiofsd: drop all capabilities in the wait parent process Date: Thu, 16 Apr 2020 17:49:07 +0100 Message-Id: <20200416164907.244868-3-stefanha@redhat.com> In-Reply-To: <20200416164907.244868-1-stefanha@redhat.com> References: <20200416164907.244868-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, Stefan Hajnoczi , "Dr. David Alan Gilbert" , Vivek Goyal Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" All this process does is wait for its child. No capabilities are needed. Signed-off-by: Stefan Hajnoczi --- tools/virtiofsd/passthrough_ll.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index af97ba1c41..0c3f33b074 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -2530,6 +2530,17 @@ static void print_capabilities(void) printf("}\n"); } +/* + * Drop all Linux capabilities because the wait parent process only needs to + * sit in waitpid(2) and terminate. + */ +static void setup_wait_parent_capabilities(void) +{ + capng_setpid(syscall(SYS_gettid)); + capng_clear(CAPNG_SELECT_BOTH); + capng_apply(CAPNG_SELECT_BOTH); +} + /* * Move to a new mount, net, and pid namespaces to isolate this process. */ @@ -2561,6 +2572,8 @@ static void setup_namespaces(struct lo_data *lo, struct fuse_session *se) pid_t waited; int wstatus; + setup_wait_parent_capabilities(); + /* The parent waits for the child */ do { waited = waitpid(child, &wstatus, 0);