From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 C8D27F8FA6D for ; Tue, 21 Apr 2026 12:50:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2o9jc+HWTpkdKWNYfnzkn/Sp9eGYz5SD/ShIOBFzj/w=; b=wpTiaCt3npd4h8+sXrJyy+m6XO HGzi1F+bRtGZxNCBA/xSjEV8O1HBQ7rBjnTB3w24TxPwIRDvqgal0N24ZdXV3H9Ejmi1BN0OZnIxi bv/KhOvcNc4IwjqYX5FWIzjSoDCZKL9COp4B72IFCvL3aeucKaW73wZVVtTZndPhLzo90bEtPZoEO ySVjdr9i0E7t3lRmdn3zwSiBtT615C7mST2hU0zBX5SJjKvJjoPlYhE78PaW2dM+MmVeXyhtsUpZO Bj1qNDgzkpKlVKiULRUgsGfhJQ3DKq44Pww70OLy7ibycnrG+gNC0URTgEonMml0HjQZLXmOCyBuz ft1TCHhg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFAYd-00000008bsA-0P3D; Tue, 21 Apr 2026 12:50:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFAYZ-00000008brf-49rT for linux-arm-kernel@lists.infradead.org; Tue, 21 Apr 2026 12:50:25 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0685F2454; Tue, 21 Apr 2026 05:50:16 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6A3013FE76; Tue, 21 Apr 2026 05:50:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776775821; bh=MIBNdfn2tTRK5iTJfoWsKX9aUYA34uCXEBimixXhsiU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=S+rH//yEb9awLsr3u7V247G6FaCBB1GziF7HlaD/iWBJd4BSks2CbYdDNqX2gTOiU Zje7bwvTfSh7N5Nhxmxwc7e/Dx85jW0hrMVKWxEohJorUob8GlZWwnKmKNvI/RpnOG mZsj8F52vSUnbYpj3LuQvU5NT6UcCZ364QN5Hk9A= Date: Tue, 21 Apr 2026 13:50:15 +0100 From: Yeoreum Yun To: Mimi Zohar Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, roberto.sassu@huawei.com, dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com, peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca, sudeep.holla@kernel.org, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org Subject: Re: [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync Message-ID: References: <20260417175759.3191279-1-yeoreum.yun@arm.com> <20260417175759.3191279-2-yeoreum.yun@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260421_055024_192667_AD62BC50 X-CRM114-Status: GOOD ( 40.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mimi, > On Fri, 2026-04-17 at 18:57 +0100, Yeoreum Yun wrote: > > To generate the boot_aggregate log in the IMA subsystem with TPM PCR values, > > the TPM driver must be built as built-in and > > must be probed before the IMA subsystem is initialized. > > > > However, when the TPM device operates over the FF-A protocol using > > the CRB interface, probing fails and returns -EPROBE_DEFER if > > the tpm_crb_ffa device — an FF-A device that provides the communication > > interface to the tpm_crb driver — has not yet been probed. > > > > To ensure the TPM device operating over the FF-A protocol with > > the CRB interface is probed before IMA initialization, > > the following conditions must be met: > > > > 1. The corresponding ffa_device must be registered, > > which is done via ffa_init(). > > > > 2. The tpm_crb_driver must successfully probe this device via > > tpm_crb_ffa_init(). > > > > 3. The tpm_crb driver using CRB over FF-A can then > > be probed successfully. (See crb_acpi_add() and > > tpm_crb_ffa_init() for reference.) > > > > Unfortunately, ffa_init(), tpm_crb_ffa_init(), and crb_acpi_driver_init() are > > all registered with device_initcall, which means crb_acpi_driver_init() may > > be invoked before ffa_init() and tpm_crb_ffa_init() are completed. > > > > When this occurs, probing the TPM device is deferred. > > However, the deferred probe can happen after the IMA subsystem > > has already been initialized, since IMA initialization is performed > > during late_initcall, and deferred_probe_initcall() is performed > > at the same level. > > > > To resolve this, move ima_init() into late_inicall_sync level > > so that let IMA not miss TPM PCR value when generating boot_aggregate > > log though TPM device presents in the system. > > > > Signed-off-by: Yeoreum Yun > > IMA should be initialized as early as possible. I'm really hesitant to defer > ima_init() to late_initcall_sync() for systems that the TPM is currently > initialized in time. For these systems, continue initializing IMA at > late_initcall(). As a compromise for those systems that the TPM isn't properly > initialized in time, define and instantiate the late_initcall_sync(). > > ima_init() would need to differentiate between the late_initcall and > late_initcall_sync. On late_initcall(), instead of saying "No TPM chip found, > activating TPM-bypass!", it should say "No TPM chip found, deferring to > late_initcall_sync" or something similar. But can we really move those initialisations to be called again? I am referring to functions such as ima_init_crypto(), ima_add_boot_aggregate(), and ima_measure_critical_data() in ima_init()— first without TPM, and then a second time once TPM becomes available. I don’t think that approach would work. In other words, unless tpm_default_chip() can differentiate between a TPM device that is deferred and one that does not exist, we cannot distinguish between the “defer” case and “-EEXIST”. It might be possible if the TPM core tracked the state when a driver returns -EPROBE_DEFER, but I am not sure that is the right approach. For deferred probe cases, the “device initialised in time” check should likely be done at late_initcall_sync, rather than late_initcall. This implies that any such check performed before late_initcall_sync does not reflect a valid state, as it cannot distinguish between “not present” and “deferred”. Therefore, I think the TPM check in IMA should be performed at late_initcall_sync. Am I missing something? Thanks. > > > --- > > include/linux/lsm_hooks.h | 2 ++ > > security/integrity/ima/ima_main.c | 2 +- > > security/lsm_init.c | 13 +++++++++++-- > > 3 files changed, 14 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index d48bf0ad26f4..88fe105b7f00 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -166,6 +166,7 @@ enum lsm_order { > > * @initcall_fs: LSM callback for fs_initcall setup, optional > > * @initcall_device: LSM callback for device_initcall() setup, optional > > * @initcall_late: LSM callback for late_initcall() setup, optional > > + * @initcall_late_sync: LSM callback for late_initcall_sync() setup, optional > > */ > > struct lsm_info { > > const struct lsm_id *id; > > @@ -181,6 +182,7 @@ struct lsm_info { > > int (*initcall_fs)(void); > > int (*initcall_device)(void); > > int (*initcall_late)(void); > > + int (*initcall_late_sync)(void); > > }; > > > > #define DEFINE_LSM(lsm) \ > > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > > index 1d6229b156fb..ace280fa3212 100644 > > --- a/security/integrity/ima/ima_main.c > > +++ b/security/integrity/ima/ima_main.c > > @@ -1320,5 +1320,5 @@ DEFINE_LSM(ima) = { > > .order = LSM_ORDER_LAST, > > .blobs = &ima_blob_sizes, > > /* Start IMA after the TPM is available */ > > - .initcall_late = init_ima, > > + .initcall_late_sync = init_ima, > > }; > > diff --git a/security/lsm_init.c b/security/lsm_init.c > > index 573e2a7250c4..4e5c59beb82a 100644 > > --- a/security/lsm_init.c > > +++ b/security/lsm_init.c > > @@ -547,13 +547,22 @@ device_initcall(security_initcall_device); > > * security_initcall_late - Run the LSM late initcalls > > */ > > static int __init security_initcall_late(void) > > +{ > > + return lsm_initcall(late); > > +} > > +late_initcall(security_initcall_late); > > + > > +/** > > + * security_initcall_late_sync - Run the LSM late initcalls sync > > + */ > > +static int __init security_initcall_late_sync(void) > > { > > int rc; > > > > - rc = lsm_initcall(late); > > + rc = lsm_initcall(late_sync); > > lsm_pr_dbg("all enabled LSMs fully activated\n"); > > call_blocking_lsm_notifier(LSM_STARTED_ALL, NULL); > > > > return rc; > > } > > -late_initcall(security_initcall_late); > > +late_initcall_sync(security_initcall_late_sync); > > -- > > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7} > > -- Sincerely, Yeoreum Yun