From patchwork Sat Dec 16 01:07:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 13495305 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DA6D5110E for ; Sat, 16 Dec 2023 01:07:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="V3FEDbdT" Received: from tushar-HP-Pavilion-Laptop-15-eg0xxx.lan (unknown [50.46.228.62]) by linux.microsoft.com (Postfix) with ESMTPSA id 30F9C20B3CC2; Fri, 15 Dec 2023 17:07:40 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 30F9C20B3CC2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1702688860; bh=2IOw2XXOJ/lRQNX6HMUntrseQX7ML13OzSk1lyP6kFQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V3FEDbdTk51T+KVYtJxwjl13Kg8iXAPKVPl3td9AhQHoPc/OE4TEWuzeLyvMEHQOz PhqkdxOePFRhhx466L0EOOEhMU+5aNfgfXcQWxk68Q9fGhunFEwqVr4Iw27NefnU9T Ue/UZEnfo15HpXR2GvKuE5bECHHxBeraTWqNMjn0= From: Tushar Sugandhi To: zohar@linux.ibm.com, 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 Subject: [PATCH v3 5/7] ima: suspend measurements during buffer copy at kexec execute Date: Fri, 15 Dec 2023 17:07:27 -0800 Message-Id: <20231216010729.2904751-6-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231216010729.2904751-1-tusharsu@linux.microsoft.com> References: <20231216010729.2904751-1-tusharsu@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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) {