From patchwork Fri Sep 8 11:44:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eduardo Otubo X-Patchwork-Id: 811546 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3xpb9S661Dz9s83 for ; Fri, 8 Sep 2017 21:45:32 +1000 (AEST) Received: from localhost ([::1]:44851 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqHj1-0001WA-0J for incoming@patchwork.ozlabs.org; Fri, 08 Sep 2017 07:45:31 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59309) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqHiK-0001TT-Go for qemu-devel@nongnu.org; Fri, 08 Sep 2017 07:44:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dqHiJ-0006kg-3s for qemu-devel@nongnu.org; Fri, 08 Sep 2017 07:44:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38253) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dqHiI-0006iq-RC for qemu-devel@nongnu.org; Fri, 08 Sep 2017 07:44:47 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id CFE347EA84 for ; Fri, 8 Sep 2017 11:44:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CFE347EA84 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=otubo@redhat.com Received: from vader.redhat.com (ovpn-117-226.ams2.redhat.com [10.36.117.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id B82F460605; Fri, 8 Sep 2017 11:44:44 +0000 (UTC) From: Eduardo Otubo To: qemu-devel@nongnu.org Date: Fri, 8 Sep 2017 13:44:04 +0200 Message-Id: <20170908114407.25906-3-otubo@redhat.com> In-Reply-To: <20170908114407.25906-1-otubo@redhat.com> References: <20170908114407.25906-1-otubo@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 08 Sep 2017 11:44:45 +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] [PATCHv6 2/5] 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: , Cc: thuth@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This patch introduces the argument [,obsolete=allow] 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 Reviewed-by: Thomas Huth Reviewed-by: Daniel P. Berrange --- include/sysemu/seccomp.h | 3 ++- qemu-options.hx | 12 ++++++++++-- qemu-seccomp.c | 19 ++++++++++++++++++- vl.c | 23 ++++++++++++++++++++++- 4 files changed, 52 insertions(+), 5 deletions(-) diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h index 23b9c3c789..215138a372 100644 --- a/include/sysemu/seccomp.h +++ b/include/sysemu/seccomp.h @@ -16,8 +16,9 @@ #define QEMU_SECCOMP_H #define QEMU_SECCOMP_SET_DEFAULT (1 << 0) +#define QEMU_SECCOMP_SET_OBSOLETE (1 << 1) #include -int seccomp_start(void); +int seccomp_start(uint32_t seccomp_opts); #endif diff --git a/qemu-options.hx b/qemu-options.hx index 9f6e2adfff..72150c6b84 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4017,13 +4017,21 @@ Old param mode (ARM only). ETEXI DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ - "-sandbox Enable seccomp mode 2 system call filter (default 'off').\n", + "-sandbox on[,obsolete=allow|deny]\n" \ + " Enable seccomp mode 2 system call filter (default 'off').\n" \ + " use 'obsolete' to allow obsolete system calls that are provided\n" \ + " by the kernel, but typically no longer used by modern\n" \ + " C library implementations.\n", QEMU_ARCH_ALL) STEXI -@item -sandbox @var{arg} +@item -sandbox @var{arg}[,obsolete=@var{string}] @findex -sandbox Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will disable it. The default is 'off'. +@table @option +@item obsolete=@var{string} +Enable Obsolete system calls +@end table ETEXI DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, diff --git a/qemu-seccomp.c b/qemu-seccomp.c index f66613fc71..8a5fbd2ff1 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -55,9 +55,22 @@ static const struct QemuSeccompSyscall blacklist[] = { { SCMP_SYS(tuxcall), QEMU_SECCOMP_SET_DEFAULT }, { SCMP_SYS(ulimit), QEMU_SECCOMP_SET_DEFAULT }, { SCMP_SYS(vserver), QEMU_SECCOMP_SET_DEFAULT }, + /* obsolete */ + { SCMP_SYS(readdir), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(_sysctl), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(bdflush), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(create_module), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(get_kernel_syms), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(query_module), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(sgetmask), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(ssetmask), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(sysfs), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(uselib), QEMU_SECCOMP_SET_OBSOLETE }, + { SCMP_SYS(ustat), QEMU_SECCOMP_SET_OBSOLETE }, }; -int seccomp_start(void) + +int seccomp_start(uint32_t seccomp_opts) { int rc = 0; unsigned int i = 0; @@ -70,6 +83,10 @@ int seccomp_start(void) } for (i = 0; i < ARRAY_SIZE(blacklist); i++) { + if (!(seccomp_opts & blacklist[i].set)) { + continue; + } + rc = 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 76e0b3a946..62b71dd529 100644 --- a/vl.c +++ b/vl.c @@ -271,6 +271,10 @@ static QemuOptsList qemu_sandbox_opts = { .name = "enable", .type = QEMU_OPT_BOOL, }, + { + .name = "obsolete", + .type = QEMU_OPT_STRING, + }, { /* end of list */ } }, }; @@ -1034,7 +1038,24 @@ static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) { if (qemu_opt_get_bool(opts, "enable", false)) { #ifdef CONFIG_SECCOMP - if (seccomp_start() < 0) { + uint32_t seccomp_opts = QEMU_SECCOMP_SET_DEFAULT + | QEMU_SECCOMP_SET_OBSOLETE; + const char *value = NULL; + + value = qemu_opt_get(opts, "obsolete"); + if (value) { + if (g_str_equal(value, "allow")) { + seccomp_opts &= ~QEMU_SECCOMP_SET_OBSOLETE; + } else if (g_str_equal(value, "deny")) { + /* this is the default option, this if is here + * to provide a little bit of consistency for + * the command line */ + } else { + error_report("invalid argument for obsolete"); + } + } + + if (seccomp_start(seccomp_opts) < 0) { error_report("failed to install seccomp syscall filter " "in the kernel"); return -1;