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 24C2AC3DA6E for ; Fri, 5 Jan 2024 19:51:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=QXLGS8s+GkKKoOV1WWnuJMOJ2Pr4vsG4GKDI6Eo9WXw=; b=4pVl/7KIv+VcMv dYTAwCyeaaDu/vKg5eCfPYEqFg5MR9lq734Jn4b8kdVZKRtrmjyJcPuacIfipT5zLcCwNrH3gXIpU 4KrnWD370qXg8UG5vv7r4JRnbcxsbXhoH+pcatuxwrqOFj/kLvBppszz8YXbY1NMjqMS45hFQD1Ax AmzcxJwZmWalgaN47EIcUv+3hlpVR7F9Wfe/Mm4CS/zGCf4gmX5IncJdlyNxPr2CJk8SSYTaXfSwf OTgN1SAqcmzFavZTLWsv3rdJcbJgdQBFacqGNOWdUO+MXO5GtRcAJU9egNxRbusLx5LHeFda+qy7f ln86CDuA8f95xpdImlvA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rLqDf-0008Bj-0E; Fri, 05 Jan 2024 19:51:03 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rLqDc-0008BO-1B for kexec@lists.infradead.org; Fri, 05 Jan 2024 19:51:01 +0000 Received: from [192.168.86.69] (unknown [50.46.228.62]) by linux.microsoft.com (Postfix) with ESMTPSA id D249A20ACF29; Fri, 5 Jan 2024 11:50:58 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D249A20ACF29 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1704484259; bh=Ql4Awcr9cJ6en22RzD+jHkpP0ibJROvhwbc9bt1K8pk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gO2OaLNCtWWy1nnG/3fhPaCRUgIkpL9T4IN95OCptxklMH14CiTqEC/ghmOV5iJv0 4jIVPzYCl43LiX+MzT7UU5ljJGP1clUCwFre7UoqFbdkMrQUzZ4W5SFVNwDagEJHOl xTZFuTxQhRIcj5hcOwNgmSKr6iIvHv3LA7G53gmA= Message-ID: <7ed7dccf-8482-4285-b21e-d518cb20d9e9@linux.microsoft.com> Date: Fri, 5 Jan 2024 11:50:58 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/7] ima: suspend measurements during buffer copy at kexec execute Content-Language: en-US To: Mimi Zohar , roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, stefanb@linux.ibm.com, ebiederm@xmission.com, noodles@fb.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org Cc: code@tyhicks.com, nramas@linux.microsoft.com, paul@paul-moore.com References: <20231216010729.2904751-1-tusharsu@linux.microsoft.com> <20231216010729.2904751-6-tusharsu@linux.microsoft.com> From: Tushar Sugandhi In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240105_115100_467399_0926114E X-CRM114-Status: GOOD ( 22.61 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 12/20/23 12:44, Mimi Zohar wrote: > On Fri, 2023-12-15 at 17:07 -0800, Tushar Sugandhi wrote: >> If the new measurements are added to the IMA log while it is being >> being copied to the kexec buffer during kexec 'execute', it can miss >> copying those new measurements to the kexec buffer, and the buffer can go >> out of sync with TPM PCRs. This could result in breaking the integrity >> of the measurements after the kexec soft reboot to the new Kernel. >> >> Add a check in the ima_add_template_entry() function not to measure >> events and return from the function early when 'suspend_ima_measurements' >> flag is set. >> >> This ensures the consistency of the IMA measurement list while copying >> them to the kexec buffer. When the 'suspend_ima_measurements' flag is >> set, any new measurements will be ignored until the flag is unset. This >> allows the buffer to be safely copied without worrying about concurrent >> modifications to the measurement list. This is crucial for maintaining >> the integrity of the measurements during a kexec soft reboot. >> >> Signed-off-by: Tushar Sugandhi >> --- >> security/integrity/ima/ima_queue.c | 13 +++++++++++++ >> 1 file changed, 13 insertions(+) >> >> diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c >> index cb9abc02a304..5946a26a2849 100644 >> --- a/security/integrity/ima/ima_queue.c >> +++ b/security/integrity/ima/ima_queue.c >> @@ -195,6 +195,19 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation, >> } >> } >> >> + /* >> + * suspend_ima_measurements will be set if the system is >> + * undergoing kexec soft boot to a new kernel. >> + * suspending measurements in this short window ensures the >> + * consistency of the IMA measurement list during copying >> + * of the kexec buffer. >> + */ >> + if (atomic_read(&suspend_ima_measurements)) { >> + audit_cause = "measurements_suspended"; >> + audit_info = 0; >> + goto out; >> + } >> + >> result = ima_add_digest_entry(entry, >> !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE)); >> if (result < 0) { > > I assume you meant to include the suspend/resume code in "ima: kexec: > move ima log copy from kexec load to execute" in this patch. > Sure, I can move the suspend/resume code from Patch 2/7 of this series to this patch (5/7). Earlier I introduced the suspend/resume functionality in patch 2 because it was used in the functions in that patch. But shifting it hear will make the patches cleaner. ~Tushar _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec