From nobody Wed Apr 24 23:45:56 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1535036917963255.04816367856063; Thu, 23 Aug 2018 08:08:37 -0700 (PDT) Received: from localhost ([::1]:37094 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsrDw-0005XT-FF for importer@patchew.org; Thu, 23 Aug 2018 11:08:36 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48439) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsqyV-0003xd-M6 for qemu-devel@nongnu.org; Thu, 23 Aug 2018 10:52:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fsqyU-0008D9-EG for qemu-devel@nongnu.org; Thu, 23 Aug 2018 10:52:39 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55746 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fsqyU-0008CZ-8k for qemu-devel@nongnu.org; Thu, 23 Aug 2018 10:52:38 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DB018804BAAC; Thu, 23 Aug 2018 14:52:37 +0000 (UTC) Received: from vader.redhat.com (ovpn-117-73.ams2.redhat.com [10.36.117.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id A86602156701; Thu, 23 Aug 2018 14:52:36 +0000 (UTC) From: Eduardo Otubo To: qemu-devel@nongnu.org Date: Thu, 23 Aug 2018 16:52:27 +0200 Message-Id: <20180823145230.13183-2-otubo@redhat.com> In-Reply-To: <20180823145230.13183-1-otubo@redhat.com> References: <20180823145230.13183-1-otubo@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 23 Aug 2018 14:52:37 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 23 Aug 2018 14:52:37 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'otubo@redhat.com' RCPT:'' Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PULL 1/4] seccomp: use SIGSYS signal instead of killing the thread X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pmoore@redhat.com, peter.maydell@linaro.org, marcandre.lureau@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" From: Marc-Andr=C3=A9 Lureau The seccomp action SCMP_ACT_KILL results in immediate termination of the thread that made the bad system call. However, qemu being multi-threaded, it keeps running. There is no easy way for parent process / management layer (libvirt) to know about that situation. Instead, the default SIGSYS handler when invoked with SCMP_ACT_TRAP will terminate the program and core dump. This may not be the most secure solution, but probably better than just killing the offending thread. SCMP_ACT_KILL_PROCESS has been added in Linux 4.14 to improve the situation, which I propose to use by default if available in the next patch. Related to: https://bugzilla.redhat.com/show_bug.cgi?id=3D1594456 Signed-off-by: Marc-Andr=C3=A9 Lureau Reviewed-by: Daniel P. Berrang=C3=A9 Acked-by: Eduardo Otubo --- qemu-seccomp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qemu-seccomp.c b/qemu-seccomp.c index 9cd8eb9499..b117a92559 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -125,7 +125,7 @@ static int seccomp_start(uint32_t seccomp_opts) continue; } =20 - rc =3D seccomp_rule_add_array(ctx, SCMP_ACT_KILL, blacklist[i].num, + rc =3D seccomp_rule_add_array(ctx, SCMP_ACT_TRAP, blacklist[i].num, blacklist[i].narg, blacklist[i].arg_cm= p); if (rc < 0) { goto seccomp_return; --=20 2.17.1