From nobody Wed Nov 5 02:32:59 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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1500641688507946.4945865431746; Fri, 21 Jul 2017 05:54:48 -0700 (PDT) Received: from localhost ([::1]:42967 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dYXSB-0002Dd-5w for importer@patchew.org; Fri, 21 Jul 2017 08:54:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57609) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dYXQA-0000qJ-UL for qemu-devel@nongnu.org; Fri, 21 Jul 2017 08:52:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dYXQA-0000bL-0K for qemu-devel@nongnu.org; Fri, 21 Jul 2017 08:52:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46106) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dYXQ9-0000b4-NH for qemu-devel@nongnu.org; Fri, 21 Jul 2017 08:52:41 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A7A84461D6 for ; Fri, 21 Jul 2017 12:52:40 +0000 (UTC) Received: from vader.redhat.com (ovpn-116-236.ams2.redhat.com [10.36.116.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0FDCE8B30B for ; Fri, 21 Jul 2017 12:52:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A7A84461D6 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=otubo@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com A7A84461D6 From: Eduardo Otubo To: qemu-devel@nongnu.org Date: Fri, 21 Jul 2017 14:52:31 +0200 Message-Id: <20170721125235.11939-3-otubo@redhat.com> In-Reply-To: <20170721125235.11939-1-otubo@redhat.com> References: <20170721125235.11939-1-otubo@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 21 Jul 2017 12:52:40 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 2/6] seccomp: add obsolete argument to command line 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This patch introduces the argument [,obsolete=3Dallow] to the `-sandbox on' option. It allows Qemu to run safely on old system that still relies on old system calls. Signed-off-by: Eduardo Otubo --- include/sysemu/seccomp.h | 4 +++- qemu-options.hx | 9 +++++++-- qemu-seccomp.c | 32 +++++++++++++++++++++++++++++++- vl.c | 16 +++++++++++++++- 4 files changed, 56 insertions(+), 5 deletions(-) diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h index cfc06008cb..7a7bde246b 100644 --- a/include/sysemu/seccomp.h +++ b/include/sysemu/seccomp.h @@ -15,7 +15,9 @@ #ifndef QEMU_SECCOMP_H #define QEMU_SECCOMP_H =20 +#define OBSOLETE 0x0001 + #include =20 -int seccomp_start(void); +int seccomp_start(uint8_t seccomp_opts); #endif diff --git a/qemu-options.hx b/qemu-options.hx index 746b5fa75d..54e492f36a 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4004,13 +4004,18 @@ Old param mode (ARM only). ETEXI =20 DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ - "-sandbox Enable seccomp mode 2 system call filter (default 'of= f').\n", + "-sandbox on[,obsolete=3Dallow] Enable seccomp mode 2 system call fil= ter (default 'off').\n" \ + " obsolete: Allow obsolete system calls\n", QEMU_ARCH_ALL) STEXI -@item -sandbox @var{arg} +@item -sandbox @var{arg}[,obsolete=3D@var{string}] @findex -sandbox Enable Seccomp mode 2 system call filter. 'on' will enable syscall filteri= ng and 'off' will disable it. The default is 'off'. +@table @option +@item obsolete=3D@var{string} +Enable Obsolete system calls +@end table ETEXI =20 DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, diff --git a/qemu-seccomp.c b/qemu-seccomp.c index f8877b07b5..c6a8b28260 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -31,6 +31,20 @@ struct QemuSeccompSyscall { uint8_t priority; }; =20 +static const struct QemuSeccompSyscall obsolete[] =3D { + { SCMP_SYS(readdir), 255 }, + { SCMP_SYS(_sysctl), 255 }, + { SCMP_SYS(bdflush), 255 }, + { SCMP_SYS(create_module), 255 }, + { SCMP_SYS(get_kernel_syms), 255 }, + { SCMP_SYS(query_module), 255 }, + { SCMP_SYS(sgetmask), 255 }, + { SCMP_SYS(ssetmask), 255 }, + { SCMP_SYS(sysfs), 255 }, + { SCMP_SYS(uselib), 255 }, + { SCMP_SYS(ustat), 255 }, +}; + static const struct QemuSeccompSyscall blacklist[] =3D { { SCMP_SYS(reboot), 255 }, { SCMP_SYS(swapon), 255 }, @@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] =3D { { SCMP_SYS(vserver), 255 }, }; =20 -int seccomp_start(void) +static int is_obsolete(int syscall) +{ + unsigned int i =3D 0; + + for (i =3D 0; i < ARRAY_SIZE(obsolete); i++) { + if (syscall =3D=3D obsolete[i].num) { + return 1; + } + } + + return 0; +} + +int seccomp_start(uint8_t seccomp_opts) { int rc =3D 0; unsigned int i =3D 0; @@ -69,6 +96,9 @@ int seccomp_start(void) } =20 for (i =3D 0; i < ARRAY_SIZE(blacklist); i++) { + if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) { + continue; + } rc =3D seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0); if (rc < 0) { goto seccomp_return; diff --git a/vl.c b/vl.c index 15b98800e9..cbe09c94af 100644 --- a/vl.c +++ b/vl.c @@ -271,6 +271,10 @@ static QemuOptsList qemu_sandbox_opts =3D { .name =3D "enable", .type =3D QEMU_OPT_BOOL, }, + { + .name =3D "obsolete", + .type =3D QEMU_OPT_STRING, + }, { /* end of list */ } }, }; @@ -1032,7 +1036,17 @@ static int parse_sandbox(void *opaque, QemuOpts *opt= s, Error **errp) { if (qemu_opt_get_bool(opts, "enable", false)) { #ifdef CONFIG_SECCOMP - if (seccomp_start() < 0) { + uint8_t seccomp_opts =3D 0x0000; + const char *value =3D NULL; + + value =3D qemu_opt_get(opts, "obsolete"); + if (value) { + if (strcmp(value, "allow") =3D=3D 0) { + seccomp_opts |=3D OBSOLETE; + } + } + + if (seccomp_start(seccomp_opts) < 0) { error_report("failed to install seccomp syscall filter " "in the kernel"); return -1; --=20 2.13.3