[{"id":1764626,"web_url":"http://patchwork.ozlabs.org/comment/1764626/","msgid":"<20170907095851.GG30609@redhat.com>","list_archive_url":null,"date":"2017-09-07T09:58:51","subject":"Re: [Qemu-devel] [PATCHv4 3/6] seccomp: add elevateprivileges\n\targument to command line","submitter":{"id":2694,"url":"http://patchwork.ozlabs.org/api/people/2694/","name":"Daniel P. Berrangé","email":"berrange@redhat.com"},"content":"On Fri, Sep 01, 2017 at 12:58:15PM +0200, Eduardo Otubo wrote:\n> This patch introduces the new argument\n> [,elevateprivileges=allow|deny|children] to the `-sandbox on'. It allows\n> or denies Qemu process to elevate its privileges by blacklisting all\n> set*uid|gid system calls. The 'children' option will let forks and\n> execves run unprivileged.\n> \n> Signed-off-by: Eduardo Otubo \n> ---\n> include/sysemu/seccomp.h | 1 +\n> qemu-options.hx | 12 +++++++++---\n> qemu-seccomp.c | 29 ++++++++++++++++++-----------\n> vl.c | 27 +++++++++++++++++++++++++++\n> 4 files changed, 55 insertions(+), 14 deletions(-)\n\n\n> diff --git a/vl.c b/vl.c\n> index ca267f9918..1d44b05772 100644\n> --- a/vl.c\n> +++ b/vl.c\n> @@ -29,6 +29,7 @@\n> \n> #ifdef CONFIG_SECCOMP\n> #include \"sysemu/seccomp.h\"\n> +#include \"sys/prctl.h\"\n> #endif\n> \n> #if defined(CONFIG_VDE)\n> @@ -275,6 +276,10 @@ static QemuOptsList qemu_sandbox_opts = {\n> .name = \"obsolete\",\n> .type = QEMU_OPT_STRING,\n> },\n> + {\n> + .name = \"elevateprivileges\",\n> + .type = QEMU_OPT_STRING,\n> + },\n> { /* end of list */ }\n> },\n> };\n> @@ -1052,6 +1057,28 @@ static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)\n> \t }\n> }\n> \n> + value = qemu_opt_get(opts, \"elevateprivileges\");\n> + if (value) {\n> + if (strcmp(value, \"deny\") == 0) {\n> + seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED;\n> + } else if (strcmp(value, \"children\") == 0) {\n> + seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED;\n> +\n> + /* calling prctl directly because we're\n> + * not sure if host has CAP_SYS_ADMIN set*/\n> + if (prctl(PR_SET_NO_NEW_PRIVS, 1)) {\n> + error_report(\"failed to set no_new_privs \"\n> + \"aborting\");\n> + return -1;\n> + }\n> + } else if (strcmp(value, \"allow\") == 0) {\n> + /* default value */\n\nAgain slight preference for g_str_equal() in all these checks.\n\n\n> + } else {\n> + error_report(\"invalid argument for elevateprivileges\");\n> + return -1;\n> + }\n> + }\n> +\n> if (seccomp_start(seccomp_opts) < 0) {\n> error_report(\"failed to install seccomp syscall filter \"\n> \"in the kernel\");\n\nRegards,\nDaniel","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ext-mx07.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx07.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=berrange@redhat.com"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xnwsZ4Y68z9t2R\n\tfor ;\n\tThu, 7 Sep 2017 19:59:30 +1000 (AEST)","from localhost ([::1]:39616 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dptaq-0002fv-QG\n\tfor incoming@patchwork.ozlabs.org; Thu, 07 Sep 2017 05:59:28 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:43487)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dptaP-0002fa-Qc\n\tfor qemu-devel@nongnu.org; Thu, 07 Sep 2017 05:59:07 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dptaL-0007gl-41\n\tfor qemu-devel@nongnu.org; Thu, 07 Sep 2017 05:59:01 -0400","from mx1.redhat.com ([209.132.183.28]:41004)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from ) id 1dptaK-0007gC-Ri\n\tfor qemu-devel@nongnu.org; Thu, 07 Sep 2017 05:58:57 -0400","from smtp.corp.redhat.com\n\t(int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id DE069C047B67\n\tfor ; Thu, 7 Sep 2017 09:58:55 +0000 (UTC)","from redhat.com (unknown [10.33.36.82])\n\tby smtp.corp.redhat.com (Postfix) with ESMTPS id E21734DC6B;\n\tThu, 7 Sep 2017 09:58:53 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com DE069C047B67","Date":"Thu, 7 Sep 2017 10:58:51 +0100","From":"\"Daniel P. Berrange\" ","To":"Eduardo Otubo ","Message-ID":"<20170907095851.GG30609@redhat.com>","References":"<20170901105818.31956-1-otubo@redhat.com>\n\t<20170901105818.31956-4-otubo@redhat.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20170901105818.31956-4-otubo@redhat.com>","User-Agent":"Mutt/1.8.3 (2017-05-23)","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.14","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.31]);\n\tThu, 07 Sep 2017 09:58:56 +0000 (UTC)","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]","X-Received-From":"209.132.183.28","Subject":"Re: [Qemu-devel] [PATCHv4 3/6] seccomp: add elevateprivileges\n\targument to command line","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Reply-To":"\"Daniel P. Berrange\" ","Cc":"thuth@redhat.com, qemu-devel@nongnu.org","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"}}]