From patchwork Tue Oct 25 11:59:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michal Privoznik X-Patchwork-Id: 13019116 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0BFE1C04A95 for ; Tue, 25 Oct 2022 12:07:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1onIay-00025s-Tg; Tue, 25 Oct 2022 07:59:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onIax-00025J-2B for qemu-devel@nongnu.org; Tue, 25 Oct 2022 07:59:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1onIav-0002Hs-I8 for qemu-devel@nongnu.org; Tue, 25 Oct 2022 07:59:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666699184; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=VQSjSAA/ZBx8OwI0WsrM3x4EMtW7b6noxwgA4kzF1Lg=; b=UXrB3Q4dQzPbI5Lk3alP/86LoipBrMRQ0a/0rc/zUUugP2R/6Lz9gKbAgXgePJ1i+z78Rx p0MfJmTkfcDFogbdsRjODB5Y8A5AJgtuPlNphhElFFr9GWK00JGG1fzsrUFePbGt5AM4Rs lRf7/K+ceVWLTl6tktF6JKfzsjrBE6s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-99-RFVBDkVuPvGBnLxXMX2o0g-1; Tue, 25 Oct 2022 07:59:42 -0400 X-MC-Unique: RFVBDkVuPvGBnLxXMX2o0g-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 43CE085A59D for ; Tue, 25 Oct 2022 11:59:42 +0000 (UTC) Received: from maggie.redhat.com (unknown [10.43.2.39]) by smtp.corp.redhat.com (Postfix) with ESMTP id E07CD47505E for ; Tue, 25 Oct 2022 11:59:41 +0000 (UTC) From: Michal Privoznik To: qemu-devel@nongnu.org Subject: [PATCH] seccomp: Get actual errno value from failed seccomp functions Date: Tue, 25 Oct 2022 13:59:36 +0200 Message-Id: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=mprivozn@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.517, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Upon failure, a libseccomp API returns actual errno value very rarely. Fortunately, after its commit 34bf78ab (contained in 2.5.0 release), the SCMP_FLTATR_API_SYSRAWRC attribute can be set which makes subsequent APIs return true errno on failure. This is especially critical when seccomp_load() fails, because generic -ECANCELED says nothing. Signed-off-by: Michal Privoznik Reviewed-by: Philippe Mathieu-Daudé --- meson.build | 9 +++++++++ softmmu/qemu-seccomp.c | 9 +++++++++ 2 files changed, 18 insertions(+) diff --git a/meson.build b/meson.build index b686dfef75..5f114c89d9 100644 --- a/meson.build +++ b/meson.build @@ -636,10 +636,16 @@ if vmnet.found() and not cc.has_header_symbol('vmnet/vmnet.h', endif seccomp = not_found +seccomp_has_sysrawrc = false if not get_option('seccomp').auto() or have_system or have_tools seccomp = dependency('libseccomp', version: '>=2.3.0', required: get_option('seccomp'), method: 'pkg-config', kwargs: static_kwargs) + if seccomp.found() + seccomp_has_sysrawrc = cc.has_header_symbol('seccomp.h', + 'SCMP_FLTATR_API_SYSRAWRC', + dependencies: seccomp) + endif endif libcap_ng = not_found @@ -1849,6 +1855,9 @@ config_host_data.set('CONFIG_RDMA', rdma.found()) config_host_data.set('CONFIG_SDL', sdl.found()) config_host_data.set('CONFIG_SDL_IMAGE', sdl_image.found()) config_host_data.set('CONFIG_SECCOMP', seccomp.found()) +if seccomp.found() + config_host_data.set('CONFIG_SECCOMP_SYSRAWRC', seccomp_has_sysrawrc) +endif config_host_data.set('CONFIG_SNAPPY', snappy.found()) config_host_data.set('CONFIG_TPM', have_tpm) config_host_data.set('CONFIG_USB_LIBUSB', libusb.found()) diff --git a/softmmu/qemu-seccomp.c b/softmmu/qemu-seccomp.c index deaf8a4ef5..05abf257c4 100644 --- a/softmmu/qemu-seccomp.c +++ b/softmmu/qemu-seccomp.c @@ -312,6 +312,15 @@ static int seccomp_start(uint32_t seccomp_opts, Error **errp) goto seccomp_return; } +#if defined(CONFIG_SECCOMP_SYSRAWRC) + rc = seccomp_attr_set(ctx, SCMP_FLTATR_API_SYSRAWRC, 1); + if (rc != 0) { + error_setg_errno(errp, -rc, + "failed to set seccomp rawrc attribute"); + goto seccomp_return; + } +#endif + rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1); if (rc != 0) { error_setg_errno(errp, -rc,