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Smith" X-Patchwork-Id: 12933980 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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 47B30C00144 for ; Mon, 1 Aug 2022 18:50:06 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.379030.612300 (Exim 4.92) (envelope-from ) id 1oIaUF-0001Xj-Hb; Mon, 01 Aug 2022 18:49:55 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 379030.612300; Mon, 01 Aug 2022 18:49:55 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oIaUF-0001Xc-EW; Mon, 01 Aug 2022 18:49:55 +0000 Received: by outflank-mailman (input) for mailman id 379030; Mon, 01 Aug 2022 18:49:54 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oIaUD-0001HC-T9 for xen-devel@lists.xenproject.org; Mon, 01 Aug 2022 18:49:54 +0000 Received: from sender4-of-o51.zoho.com (sender4-of-o51.zoho.com [136.143.188.51]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id b993c8fe-11ca-11ed-bd2d-47488cf2e6aa; Mon, 01 Aug 2022 20:49:52 +0200 (CEST) Received: from sisyou.hme. (static-72-81-132-2.bltmmd.fios.verizon.net [72.81.132.2]) by mx.zohomail.com with SMTPS id 1659379780263279.82479886226827; Mon, 1 Aug 2022 11:49:40 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: b993c8fe-11ca-11ed-bd2d-47488cf2e6aa ARC-Seal: i=1; a=rsa-sha256; t=1659379785; cv=none; d=zohomail.com; s=zohoarc; b=Mie+QNw3tw5TnxhdWrG/p2uk5jrUanzZ0YMZc/paAI9lkcZoWcVzikjAGNUTWouz50TDZS78X9Xphmj2XIGYv3VYcb2nA+p5cEX5j/TLCDlPTrVWfczcBhpObHRd4xl4N3QK+jbyeerOksc0CdMrPM9ZSl8L+ZX5USEv2e1o0DU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1659379785; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=5Ty85HsajPA+R434u8DJBEiLXdypLYNOpYAB9hFvXvo=; b=RiaRXRKY8UMOzxSEA8cn+rw9GI7wK3AiuEWnarPN2hgjDoUiRlgzz1WC5BKE0u5WMhWfRhPIJHvCf/orqHPda1N8BOMr52k9b8s5fPi5tiCqiLrw3k3Qc5fC1FaiIsYaTNIs8jJ+DDR6MpfOtqckC5pbXzSopvGYJ401fFkD/vc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=apertussolutions.com; spf=pass smtp.mailfrom=dpsmith@apertussolutions.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1659379785; s=zoho; d=apertussolutions.com; i=dpsmith@apertussolutions.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-Id:Message-Id:In-Reply-To:References:MIME-Version:Content-Type:Content-Transfer-Encoding:Reply-To; bh=5Ty85HsajPA+R434u8DJBEiLXdypLYNOpYAB9hFvXvo=; b=riFy6BHh/ho68y/c4Z43+ypH9qLotM5U3DE3iiriae4NT3lIGxt90jTOZSkewZYz oHMPnzY7+Ec8BhHWYgYwYekMLsIIEIBhSN5dxCsPl9bPlDLZ1i41Mu8NU5TifxoCEUL qzdq6xTzwE6oEBD+iTLJY9bPkv4inw6wLe7FoddA= From: "Daniel P. Smith" To: xen-devel@lists.xenproject.org, Volodymyr Babchuk , Wei Liu , "Daniel P. Smith" Cc: jandryuk@gmail.com, Luca Fancellu , Julien Grall , Rahul Singh , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Henry Wang , Stefano Stabellini , Julien Grall , Bertrand Marquis , Jan Beulich , Andrew Cooper , George Dunlap , Dario Faggioli , Daniel De Graaf Subject: [PATCH v10 1/3] xsm: create idle domain privileged and demote after setup Date: Mon, 1 Aug 2022 14:49:26 -0400 Message-Id: <20220801184928.28522-2-dpsmith@apertussolutions.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220801184928.28522-1-dpsmith@apertussolutions.com> References: <20220801184928.28522-1-dpsmith@apertussolutions.com> MIME-Version: 1.0 X-ZohoMailClient: External There are new capabilities, dom0less and hyperlaunch, that introduce internal hypervisor logic, which needs to make resource allocation calls that are protected by XSM access checks. The need for these resource allocations are necessary for dom0less and hyperlaunch when they are constructing the initial domain(s).  This creates an issue as a subset of the hypervisor code is executed under a system domain, the idle domain, that is represented by a per-CPU non-privileged struct domain. To enable these new capabilities to function correctly but in a controlled manner, this commit changes the idle system domain to be created as a privileged domain under the default policy and demoted before transitioning to running. A new XSM hook, xsm_set_system_active(), is introduced to allow each XSM policy type to demote the idle domain appropriately for that policy type. In the case of SILO, it inherits the default policy's hook for xsm_set_system_active(). For flask, a stub is added to ensure that flask policy system will function correctly with this patch until flask is extended with support for starting the idle domain privileged and properly demoting it on the call to xsm_set_system_active(). Signed-off-by: Daniel P. Smith Reviewed-by: Jason Andryuk Reviewed-by: Luca Fancellu Acked-by: Julien Grall # arm Reviewed-by: Rahul Singh Tested-by: Rahul Singh Acked-by: Roger Pau Monné Tested-by: Henry Wang --- xen/arch/arm/setup.c | 3 +++ xen/arch/x86/setup.c | 4 ++++ xen/common/sched/core.c | 7 ++++++- xen/include/xsm/dummy.h | 17 +++++++++++++++++ xen/include/xsm/xsm.h | 6 ++++++ xen/xsm/dummy.c | 1 + xen/xsm/flask/hooks.c | 23 +++++++++++++++++++++++ 7 files changed, 60 insertions(+), 1 deletion(-) diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index 577c54e6fb..85ff956ec2 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -1063,6 +1063,9 @@ void __init start_xen(unsigned long boot_phys_offset, /* Hide UART from DOM0 if we're using it */ serial_endboot(); + if ( (rc = xsm_set_system_active()) != 0 ) + panic("xsm: unable to switch to SYSTEM_ACTIVE privilege: %d\n", rc); + system_state = SYS_STATE_active; for_each_domain( d ) diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index 53a73010e0..f08b07b8de 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -619,6 +619,10 @@ static void noreturn init_done(void) { void *va; unsigned long start, end; + int err; + + if ( (err = xsm_set_system_active()) != 0 ) + panic("xsm: unable to switch to SYSTEM_ACTIVE privilege: %d\n", err); system_state = SYS_STATE_active; diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c index 8c73489654..250207038e 100644 --- a/xen/common/sched/core.c +++ b/xen/common/sched/core.c @@ -3033,7 +3033,12 @@ void __init scheduler_init(void) sched_ratelimit_us = SCHED_DEFAULT_RATELIMIT_US; } - idle_domain = domain_create(DOMID_IDLE, NULL, 0); + /* + * The idle dom is created privileged to ensure unrestricted access during + * setup and will be demoted by xsm_set_system_active() when setup is + * complete. + */ + idle_domain = domain_create(DOMID_IDLE, NULL, CDF_privileged); BUG_ON(IS_ERR(idle_domain)); BUG_ON(nr_cpu_ids > ARRAY_SIZE(idle_vcpu)); idle_domain->vcpu = idle_vcpu; diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h index 58afc1d589..77f27e7163 100644 --- a/xen/include/xsm/dummy.h +++ b/xen/include/xsm/dummy.h @@ -101,6 +101,23 @@ static always_inline int xsm_default_action( } } +static XSM_INLINE int cf_check xsm_set_system_active(void) +{ + struct domain *d = current->domain; + + ASSERT(d->is_privileged); + + if ( d->domain_id != DOMID_IDLE ) + { + printk("%s: should only be called by idle domain\n", __func__); + return -EPERM; + } + + d->is_privileged = false; + + return 0; +} + static XSM_INLINE void cf_check xsm_security_domaininfo( struct domain *d, struct xen_domctl_getdomaininfo *info) { diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h index 3e2b7fe3db..8dad03fd3d 100644 --- a/xen/include/xsm/xsm.h +++ b/xen/include/xsm/xsm.h @@ -52,6 +52,7 @@ typedef enum xsm_default xsm_default_t; * !!! WARNING !!! */ struct xsm_ops { + int (*set_system_active)(void); void (*security_domaininfo)(struct domain *d, struct xen_domctl_getdomaininfo *info); int (*domain_create)(struct domain *d, uint32_t ssidref); @@ -208,6 +209,11 @@ extern struct xsm_ops xsm_ops; #ifndef XSM_NO_WRAPPERS +static inline int xsm_set_system_active(void) +{ + return alternative_call(xsm_ops.set_system_active); +} + static inline void xsm_security_domaininfo( struct domain *d, struct xen_domctl_getdomaininfo *info) { diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c index 8c044ef615..e6ffa948f7 100644 --- a/xen/xsm/dummy.c +++ b/xen/xsm/dummy.c @@ -14,6 +14,7 @@ #include static const struct xsm_ops __initconst_cf_clobber dummy_ops = { + .set_system_active = xsm_set_system_active, .security_domaininfo = xsm_security_domaininfo, .domain_create = xsm_domain_create, .getdomaininfo = xsm_getdomaininfo, diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c index 6ffafc2f44..c97c44f803 100644 --- a/xen/xsm/flask/hooks.c +++ b/xen/xsm/flask/hooks.c @@ -191,6 +191,28 @@ static int cf_check flask_domain_alloc_security(struct domain *d) return 0; } +static int cf_check flask_set_system_active(void) +{ + struct domain *d = current->domain; + + ASSERT(d->is_privileged); + + if ( d->domain_id != DOMID_IDLE ) + { + printk("%s: should only be called by idle domain\n", __func__); + return -EPERM; + } + + /* + * While is_privileged has no significant meaning under flask, set to false + * as is_privileged is not only used for a privilege check but also as a + * type of domain check, specifically if the domain is the control domain. + */ + d->is_privileged = false; + + return 0; +} + static void cf_check flask_domain_free_security(struct domain *d) { struct domain_security_struct *dsec = d->ssid; @@ -1774,6 +1796,7 @@ static int cf_check flask_argo_send( #endif static const struct xsm_ops __initconst_cf_clobber flask_ops = { + .set_system_active = flask_set_system_active, .security_domaininfo = flask_security_domaininfo, .domain_create = flask_domain_create, .getdomaininfo = flask_getdomaininfo, From patchwork Mon Aug 1 18:49:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Daniel P. Smith" X-Patchwork-Id: 12933982 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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 447E3C00144 for ; Mon, 1 Aug 2022 18:50:32 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.379039.612312 (Exim 4.92) (envelope-from ) id 1oIaUg-00036a-Ur; Mon, 01 Aug 2022 18:50:22 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 379039.612312; Mon, 01 Aug 2022 18:50:22 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oIaUg-00036P-RH; Mon, 01 Aug 2022 18:50:22 +0000 Received: by outflank-mailman (input) for mailman id 379039; Mon, 01 Aug 2022 18:50:22 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oIaUf-00033M-UQ for xen-devel@lists.xenproject.org; Mon, 01 Aug 2022 18:50:22 +0000 Received: from sender4-of-o51.zoho.com (sender4-of-o51.zoho.com [136.143.188.51]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id ca68af3f-11ca-11ed-924f-1f966e50362f; Mon, 01 Aug 2022 20:50:20 +0200 (CEST) Received: from sisyou.hme. (static-72-81-132-2.bltmmd.fios.verizon.net [72.81.132.2]) by mx.zohomail.com with SMTPS id 165937978515485.11645410728738; Mon, 1 Aug 2022 11:49:45 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: ca68af3f-11ca-11ed-924f-1f966e50362f ARC-Seal: i=1; a=rsa-sha256; t=1659379789; cv=none; d=zohomail.com; s=zohoarc; b=DxN0kxPhr5x3cABPIiCbkjAeSiDhcQYP4CrTPaDAzmwvFl8Zoz4gjYKMAA950oh/FcCh6XbL5eRPSDptH0pq54DjwodP7WR9t3VSTiABrkrj73wsmslqWxRDffOXjD39PtHK6gD9SX4TuilAeAG+zzPRyXCk44ygW+DQukQhujI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1659379789; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=cpjxkhtgIS46NAqzn+lFjzbvDxK+C/y4xCBDpUybEIY=; b=oAlFN9QvwQShmihItl6l7W/ILxT00mZiOI8ZS+T5BnInUamzEOPuQ6T/gw7tpTsxmoMM7PmbD8lsteCEelQoByDTpGKHY7QQreCkheAzLVMxBQMbq4VxGdjXSMZeFsealE2pXenybDZJ+BXX292kM1eDHl0GApguj5R0lp8qa0k= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=apertussolutions.com; spf=pass smtp.mailfrom=dpsmith@apertussolutions.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1659379789; s=zoho; d=apertussolutions.com; i=dpsmith@apertussolutions.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-Id:Message-Id:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Reply-To; bh=cpjxkhtgIS46NAqzn+lFjzbvDxK+C/y4xCBDpUybEIY=; b=eoNvb2GMcL0CnT61/Znvn9gJu1zkwmdm+qeqO80Wwta5cVU017osy8NRxzrIgxek IU6BSfxEKDLBLhexvD/TvcVteMw0mM70goGsVmPz5Y63RV+wnBi3TJm1Nzxx1R5Nm6h NEVWuMRODblPfmgk2F34I6ElFMKAWhIqO7tt5ass= From: "Daniel P. Smith" To: xen-devel@lists.xenproject.org, "Daniel P. Smith" Cc: jandryuk@gmail.com, Luca Fancellu , Rahul Singh , Henry Wang , Daniel De Graaf , Wei Liu , Anthony PERARD Subject: [PATCH v10 2/3] flask: implement xsm_set_system_active Date: Mon, 1 Aug 2022 14:49:27 -0400 Message-Id: <20220801184928.28522-3-dpsmith@apertussolutions.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220801184928.28522-1-dpsmith@apertussolutions.com> References: <20220801184928.28522-1-dpsmith@apertussolutions.com> MIME-Version: 1.0 X-ZohoMailClient: External This commit implements full support for starting the idle domain privileged by introducing a new flask label xenboot_t which the idle domain is labeled with at creation. It then provides the implementation for the XSM hook xsm_set_system_active to relabel the idle domain to the existing xen_t flask label. In the reference flask policy a new macro, xen_build_domain(target), is introduced for creating policies for dom0less/hyperlaunch allowing the hypervisor to create and assign the necessary resources for domain construction. Signed-off-by: Daniel P. Smith Reviewed-by: Jason Andryuk Reviewed-by: Luca Fancellu Tested-by: Luca Fancellu Reviewed-by: Rahul Singh Tested-by: Rahul Singh Tested-by: Henry Wang --- tools/flask/policy/modules/xen.if | 7 +++++++ tools/flask/policy/modules/xen.te | 1 + tools/flask/policy/policy/initial_sids | 1 + xen/xsm/flask/hooks.c | 9 ++++++++- xen/xsm/flask/policy/initial_sids | 1 + 5 files changed, 18 insertions(+), 1 deletion(-) diff --git a/tools/flask/policy/modules/xen.if b/tools/flask/policy/modules/xen.if index 5e2aa472b6..424daab6a0 100644 --- a/tools/flask/policy/modules/xen.if +++ b/tools/flask/policy/modules/xen.if @@ -62,6 +62,13 @@ define(`create_domain_common', ` setparam altp2mhvm altp2mhvm_op dm }; ') +# xen_build_domain(target) +# Allow a domain to be created at boot by the hypervisor +define(`xen_build_domain', ` + allow xenboot_t $1:domain create; + allow xenboot_t $1_channel:event create; +') + # create_domain(priv, target) # Allow a domain to be created directly define(`create_domain', ` diff --git a/tools/flask/policy/modules/xen.te b/tools/flask/policy/modules/xen.te index 3dbf93d2b8..de98206fdd 100644 --- a/tools/flask/policy/modules/xen.te +++ b/tools/flask/policy/modules/xen.te @@ -24,6 +24,7 @@ attribute mls_priv; ################################################################################ # The hypervisor itself +type xenboot_t, xen_type, mls_priv; type xen_t, xen_type, mls_priv; # Domain 0 diff --git a/tools/flask/policy/policy/initial_sids b/tools/flask/policy/policy/initial_sids index 6b7b7eff21..ec729d3ba3 100644 --- a/tools/flask/policy/policy/initial_sids +++ b/tools/flask/policy/policy/initial_sids @@ -2,6 +2,7 @@ # objects created before the policy is loaded or for objects that do not have a # label defined in some other manner. +sid xenboot gen_context(system_u:system_r:xenboot_t,s0) sid xen gen_context(system_u:system_r:xen_t,s0) sid dom0 gen_context(system_u:system_r:dom0_t,s0) sid domxen gen_context(system_u:system_r:domxen_t,s0) diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c index c97c44f803..8c9cd0f297 100644 --- a/xen/xsm/flask/hooks.c +++ b/xen/xsm/flask/hooks.c @@ -173,7 +173,7 @@ static int cf_check flask_domain_alloc_security(struct domain *d) switch ( d->domain_id ) { case DOMID_IDLE: - dsec->sid = SECINITSID_XEN; + dsec->sid = SECINITSID_XENBOOT; break; case DOMID_XEN: dsec->sid = SECINITSID_DOMXEN; @@ -193,9 +193,14 @@ static int cf_check flask_domain_alloc_security(struct domain *d) static int cf_check flask_set_system_active(void) { + struct domain_security_struct *dsec; struct domain *d = current->domain; + dsec = d->ssid; + ASSERT(d->is_privileged); + ASSERT(dsec->sid == SECINITSID_XENBOOT); + ASSERT(dsec->self_sid == SECINITSID_XENBOOT); if ( d->domain_id != DOMID_IDLE ) { @@ -210,6 +215,8 @@ static int cf_check flask_set_system_active(void) */ d->is_privileged = false; + dsec->self_sid = dsec->sid = SECINITSID_XEN; + return 0; } diff --git a/xen/xsm/flask/policy/initial_sids b/xen/xsm/flask/policy/initial_sids index 7eca70d339..e8b55b8368 100644 --- a/xen/xsm/flask/policy/initial_sids +++ b/xen/xsm/flask/policy/initial_sids @@ -3,6 +3,7 @@ # # Define initial security identifiers # +sid xenboot sid xen sid dom0 sid domio From patchwork Mon Aug 1 18:49:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Daniel P. 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(static-72-81-132-2.bltmmd.fios.verizon.net [72.81.132.2]) by mx.zohomail.com with SMTPS id 1659379787630270.7014982877881; Mon, 1 Aug 2022 11:49:47 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d4a36c28-11ca-11ed-924f-1f966e50362f ARC-Seal: i=1; a=rsa-sha256; t=1659379791; cv=none; d=zohomail.com; s=zohoarc; b=Q9mwUtvZGz/FCpcnMempPReZ50jrCpdFOBJC/fqJGT/hvjvdvJPBsEwb7S21NF15ACBe3+ZFaevzgdHFK45ZY5Kv25FKT/Vql9c/s2qFpRmI3MvJ4GBA67rhwm5YoLwhJS+8MUZ3PfP02IP/GS19zYDLE2Aub/SNHvQFtZlByEk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1659379791; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=gpmxoFgFxGv7Q9frig3z6tCtnPr6RMz7LbnBr0EPi6Y=; b=SfMbc3DIJbpF77aj9/X1g7sECo44vbAct3Njj8nxmeUHn//gXVHH8uu/lddgfIIS4kKDJ4Ol1v17sWsNsUqazQExQC3v2PflZ5jN1KMdqk27Pwqkx+vY8tKttAXB1Egon1b/Fq5f/6uMuMkwprhJo/JNpdgUKHYgRkeljP0iJao= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=apertussolutions.com; spf=pass smtp.mailfrom=dpsmith@apertussolutions.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1659379791; s=zoho; d=apertussolutions.com; i=dpsmith@apertussolutions.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-Id:Message-Id:In-Reply-To:References:MIME-Version:Content-Type:Content-Transfer-Encoding:Reply-To; bh=gpmxoFgFxGv7Q9frig3z6tCtnPr6RMz7LbnBr0EPi6Y=; b=TJvdTcoNsknYMQkGlJ32+5N9ZhTSJaCdXRcItSuTBKVVjKI+4FxfCKWuuzzcUs5U 4K/XSS/PNIiXFYl4kUkXeNRIlRr1u1UgZnEy5K1ohM6lNZXe5oKXA+yHEBP/3ZpXM4o 3XR1YZxrHnB7B8r80m0NPGE2R3Y2LwaDX9c/U8Kc= From: "Daniel P. Smith" To: xen-devel@lists.xenproject.org, "Daniel P. Smith" Cc: jandryuk@gmail.com, Daniel De Graaf , Wei Liu , Anthony PERARD Subject: [PATCH v10 3/3] xsm: refactor flask sid alloc and domain check Date: Mon, 1 Aug 2022 14:49:28 -0400 Message-Id: <20220801184928.28522-4-dpsmith@apertussolutions.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220801184928.28522-1-dpsmith@apertussolutions.com> References: <20220801184928.28522-1-dpsmith@apertussolutions.com> MIME-Version: 1.0 X-ZohoMailClient: External The function flask_domain_alloc_security() allocates the security context and assigns an initial SID for the domain under construction. When it came to SID assignment of the initial domain, flask_domain_alloc_security() would assign unlabeled_t. Then in flask_domain_create() it would be switched to dom0_t. This logic worked under the assumption that the first domain constructed would be the hypervisor constructing dom0 and all other domains would be constructed by a toolstack, which would provide a SID. The introduction of dom0less and subsequently hyperlaunch violates this assumption, as non-privileged domain may be constructed before the initial domain or no initial domain may be constructed at all. It is not possible currently for dom0less to express domain labels in the domain configuration, as such the FLASK policy must employ a sensible initial SID assignment that can differentiate between hypervisor and toolstack domain construction.  With the introduction of xenboot_t it is now possible to distinguish when the hypervisor is in the boot state, and thus any domain construction happening at this time is being initiated by the hypervisor. This commit addresses the above situation by using a check to confirm if the hypervisor is under the xenboot_t context in flask_domain_alloc_security(). When that is the case, it will inspect the domain's is_privileged field to determine whether an initial label of dom0_t or domU_t should be set for the domain. The logic for flask_domain_create() was changed to allow the incoming SID to override the initial label. The base policy was adjusted to allow the idle domain under the xenboot_t context the ability to construct domains of both types, dom0_t and domu_t. Signed-off-by: Daniel P. Smith --- tools/flask/policy/modules/dom0.te | 3 +++ tools/flask/policy/modules/domU.te | 3 +++ xen/xsm/flask/hooks.c | 35 +++++++++++++++++------------- 3 files changed, 26 insertions(+), 15 deletions(-) diff --git a/tools/flask/policy/modules/dom0.te b/tools/flask/policy/modules/dom0.te index 0a63ce15b6..f710ff9941 100644 --- a/tools/flask/policy/modules/dom0.te +++ b/tools/flask/policy/modules/dom0.te @@ -75,3 +75,6 @@ admin_device(dom0_t, ioport_t) admin_device(dom0_t, iomem_t) domain_comms(dom0_t, dom0_t) + +# Allow the hypervisor to build domains of type dom0_t +xen_build_domain(dom0_t) diff --git a/tools/flask/policy/modules/domU.te b/tools/flask/policy/modules/domU.te index b77df29d56..3f269018f9 100644 --- a/tools/flask/policy/modules/domU.te +++ b/tools/flask/policy/modules/domU.te @@ -13,6 +13,9 @@ domain_comms(domU_t, domU_t) migrate_domain_out(dom0_t, domU_t) domain_self_comms(domU_t) +# Allow the hypervisor to build domains of type domU_t +xen_build_domain(domU_t) + # Device model for domU_t. You can define distinct types for device models for # domains of other types, or add more make_device_model lines for this type. declare_domain(dm_dom_t) diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c index 8c9cd0f297..cb81e62c52 100644 --- a/xen/xsm/flask/hooks.c +++ b/xen/xsm/flask/hooks.c @@ -182,7 +182,15 @@ static int cf_check flask_domain_alloc_security(struct domain *d) dsec->sid = SECINITSID_DOMIO; break; default: - dsec->sid = SECINITSID_UNLABELED; + if ( domain_sid(current->domain) == SECINITSID_XENBOOT ) + { + if ( d->is_privileged ) + dsec->sid = SECINITSID_DOM0; + else + dsec->sid = SECINITSID_DOMU; + } + else + dsec->sid = SECINITSID_UNLABELED; } dsec->self_sid = dsec->sid; @@ -548,22 +556,19 @@ static int cf_check flask_domain_create(struct domain *d, uint32_t ssidref) { int rc; struct domain_security_struct *dsec = d->ssid; - static int dom0_created = 0; - if ( is_idle_domain(current->domain) && !dom0_created ) - { - dsec->sid = SECINITSID_DOM0; - dom0_created = 1; - } - else - { - rc = avc_current_has_perm(ssidref, SECCLASS_DOMAIN, - DOMAIN__CREATE, NULL); - if ( rc ) - return rc; + /* + * If the null label is passed, then use the label from security context + * allocation. + */ + if ( ssidref == 0 ) + ssidref = dsec->sid; - dsec->sid = ssidref; - } + rc = avc_current_has_perm(ssidref, SECCLASS_DOMAIN, DOMAIN__CREATE, NULL); + if ( rc ) + return rc; + + dsec->sid = ssidref; dsec->self_sid = dsec->sid; rc = security_transition_sid(dsec->sid, dsec->sid, SECCLASS_DOMAIN,