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(static-72-81-132-2.bltmmd.fios.verizon.net [72.81.132.2]) by mx.zohomail.com with SMTPS id 1656555681174357.5298548276269; Wed, 29 Jun 2022 19:21:21 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version 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: 5987cd99-f81b-11ec-bdce-3d151da133c5 ARC-Seal: i=1; a=rsa-sha256; t=1656555683; cv=none; d=zohomail.com; s=zohoarc; b=KkZjrAWhyCzxuaTfk4HyOQcABlZH9V2u2VGeNfUtgSBEPaiW8EcX25QVk+aThyW9bcgg3bJqrM95slVa9TIxdA4h+yGvABsf5rTdS/k22BZQLN2GL90Gzdtwy9/U2MuPUzn9sbVwTZPi39AjjdcwEZpgv4QXQOXCjwozdBvFwbw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1656555683; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=Y1u1KN5rb+4xb8wageG1qE7t6SXe6Jl3PmiVFY61+kE=; b=Zn8YMEOXaaK+TNIthX1/WdUBSMd7zWqTnMRnbG1IGteneXA8OGbhNdOL9NTDN/Nf2Gy13oA4JkaVf03ejogINWyH479y/V9pPQmPUIai1km+MjHkC0YYMLxa9scilQzKOPwhGWD/KJRfPh7p6rZJ2bBiIhbICD35UUoPRRGsdDw= 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=1656555683; 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=Y1u1KN5rb+4xb8wageG1qE7t6SXe6Jl3PmiVFY61+kE=; b=CDFj8biAa4oX+RJ4/e8TqpgpEsW22yRnV8rI/aB9bOpWv1qSh0wC7xxo1sEJfX76 5CJOpU4FvTl4JNGrYX6Yswzl6qAaIJr8hTww9bPjv1nCyoy2+AHp67JNaL3OpfDPZ9G 51UOBOTGIiXMDRkpj3Xs8gI2OrqMKnFrBz+WfYA8= From: "Daniel P. Smith" To: xen-devel@lists.xenproject.org, Volodymyr Babchuk , Wei Liu , "Daniel P. Smith" Cc: scott.davis@starlab.io, jandryuk@gmail.com, christopher.clark@starlab.io, Luca Fancellu , Julien Grall , Rahul Singh , Stefano Stabellini , Julien Grall , Bertrand Marquis , Jan Beulich , Andrew Cooper , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , George Dunlap , Dario Faggioli , Daniel De Graaf Subject: [PATCH v9 1/3] xsm: create idle domain privileged and demote after setup Date: Wed, 29 Jun 2022 22:21:08 -0400 Message-Id: <20220630022110.31555-2-dpsmith@apertussolutions.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220630022110.31555-1-dpsmith@apertussolutions.com> References: <20220630022110.31555-1-dpsmith@apertussolutions.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External X-ZohoMail-DKIM: pass (identity dpsmith@apertussolutions.com) X-ZM-MESSAGEID: 1656555714221100003 There are new capabilities, dom0less and hyperlaunch, that introduce intern= al 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 initi= al domain(s). =C2=A0This 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 dem= ote 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 Monn=C3=A9 --- 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(); =20 + if ( (rc =3D xsm_set_system_active()) !=3D 0 ) + panic("xsm: unable to switch to SYSTEM_ACTIVE privilege: %d\n", rc= ); + system_state =3D SYS_STATE_active; =20 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 =3D xsm_set_system_active()) !=3D 0 ) + panic("xsm: unable to switch to SYSTEM_ACTIVE privilege: %d\n", er= r); =20 system_state =3D SYS_STATE_active; =20 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 =3D SCHED_DEFAULT_RATELIMIT_US; } =20 - idle_domain =3D domain_create(DOMID_IDLE, NULL, 0); + /* + * The idle dom is created privileged to ensure unrestricted access du= ring + * setup and will be demoted by xsm_set_system_active() when setup is + * complete. + */ + idle_domain =3D 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 =3D 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( } } =20 +static XSM_INLINE int cf_check xsm_set_system_active(void) +{ + struct domain *d =3D current->domain; + + ASSERT(d->is_privileged); + + if ( d->domain_id !=3D DOMID_IDLE ) + { + printk("%s: should only be called by idle domain\n", __func__); + return -EPERM; + } + + d->is_privileged =3D 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; =20 #ifndef XSM_NO_WRAPPERS =20 +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 =20 static const struct xsm_ops __initconst_cf_clobber dummy_ops =3D { + .set_system_active =3D xsm_set_system_active, .security_domaininfo =3D xsm_security_domaininfo, .domain_create =3D xsm_domain_create, .getdomaininfo =3D 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; } =20 +static int cf_check flask_set_system_active(void) +{ + struct domain *d =3D current->domain; + + ASSERT(d->is_privileged); + + if ( d->domain_id !=3D 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 dom= ain. + */ + d->is_privileged =3D false; + + return 0; +} + static void cf_check flask_domain_free_security(struct domain *d) { struct domain_security_struct *dsec =3D d->ssid; @@ -1774,6 +1796,7 @@ static int cf_check flask_argo_send( #endif =20 static const struct xsm_ops __initconst_cf_clobber flask_ops =3D { + .set_system_active =3D flask_set_system_active, .security_domaininfo =3D flask_security_domaininfo, .domain_create =3D flask_domain_create, .getdomaininfo =3D flask_getdomaininfo, --=20 2.20.1