From nobody Wed Nov 5 15:01:44 2025 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 1534958198851731.7942538163486; Wed, 22 Aug 2018 10:16:38 -0700 (PDT) Received: from localhost ([::1]:60101 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsWkH-0000Ne-Lv for importer@patchew.org; Wed, 22 Aug 2018 13:16:37 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42833) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsWgA-0004Vz-TK for qemu-devel@nongnu.org; Wed, 22 Aug 2018 13:12:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fsWX4-0005JT-Sw for qemu-devel@nongnu.org; Wed, 22 Aug 2018 13:03:02 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50282 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 1fsWX4-0005JF-Ov for qemu-devel@nongnu.org; Wed, 22 Aug 2018 13:02:58 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 709F14023ECB for ; Wed, 22 Aug 2018 17:02:58 +0000 (UTC) Received: from localhost (ovpn-112-25.ams2.redhat.com [10.36.112.25]) by smtp.corp.redhat.com (Postfix) with ESMTP id 185FAA9E93; Wed, 22 Aug 2018 17:02:57 +0000 (UTC) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= To: qemu-devel@nongnu.org Date: Wed, 22 Aug 2018 19:02:47 +0200 Message-Id: <20180822170250.29573-2-marcandre.lureau@redhat.com> In-Reply-To: <20180822170250.29573-1-marcandre.lureau@redhat.com> References: <20180822170250.29573-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Wed, 22 Aug 2018 17:02:58 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Wed, 22 Aug 2018 17:02:58 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'marcandre.lureau@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] [PATCH v4 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, Eduardo Otubo , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= 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" 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 2.18.0.547.g1d89318c48