From patchwork Tue Feb 18 22:55:01 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 13981019 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 391A21DE2C0; Tue, 18 Feb 2025 22:55:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739919313; cv=none; b=Zk+DcgxRteVDfNqFSM6/nSW0vX9Lw9jVILd13wBHHrNv6OsnSnqhMkC5UrVgYIa77Q8W316fxMsnAnHcdTrr4X1yGqYuYgNUxFO86W+7xLulJhoqdTYBU3mRAvjPPNGEP1BPLhZ2YJFQ7YH4Mij0tLYd4DV/TITNh3W4DuiYfFU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739919313; c=relaxed/simple; bh=NdY41Q3mngnUO3C8+zd11cU9JLxscu+ZNFL+kW2yufk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ZsER8NV9LQBArTti1GRmPuk0rIh/5reHkz/qJWHAqI5jiOs0NvDq6/B0pU1rX0iAvVP0ZmQ5nzwP1TJZIAw1qh1GmBpKWFpcqNGrohm+7pqUbAFnenpjiS3rjZaIifJIvmyhZF63zHhMdz2Mg1RGR2v/p4Wu9FLtfVRysQEqcrQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=qW0JCrzC; arc=none smtp.client-ip=13.77.154.182 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="qW0JCrzC" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id C7E1F20376F2; Tue, 18 Feb 2025 14:55:10 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C7E1F20376F2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1739919310; bh=m5XSyV5sl/OO048Kq+/HhIgyzDGnEXapm0HPn0O8xYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qW0JCrzC8y6bmwIoagtpf2t/tuRUd3AKlbz8MlS8OeESk9Rh9y1gnPF8cOcdcw2Tr 9YvAcXdDq/ejrS9KbWicsnXaXTwfpzVDp9tJTuZVhjbUDehaVZzW22iIDXrxz3mR7k SCFZrcESBBU6peRjmpvSAClKBQ2rnEIk96wkzCXY= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v8 6/7] ima: make the kexec extra memory configurable Date: Tue, 18 Feb 2025 14:55:01 -0800 Message-Id: <20250218225502.747963-7-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250218225502.747963-1-chenste@linux.microsoft.com> References: <20250218225502.747963-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The extra memory allocated for carrying the IMA measurement list across kexec is hard-coded as half a PAGE. Make it configurable. Define a Kconfig option, IMA_KEXEC_EXTRA_MEMORY_KB, to configure the extra memory (in kb) to be allocated for IMA measurements added during kexec soft reboot. Ensure the default value of the option is set such that extra half a page of memory for additional measurements is allocated for the additional measurements. Update ima_add_kexec_buffer() function to allocate memory based on the Kconfig option value, rather than the currently hard-coded one. Suggested-by: Stefan Berger Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar --- security/integrity/ima/Kconfig | 10 ++++++++++ security/integrity/ima/ima_kexec.c | 16 ++++++++++------ 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 475c32615006..d73c96c3c1c9 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -321,4 +321,14 @@ config IMA_DISABLE_HTABLE help This option disables htable to allow measurement of duplicate records. +config IMA_KEXEC_EXTRA_MEMORY_KB + int "Extra memory for IMA measurements added during kexec soft reboot" + depends on IMA_KEXEC + default 0 + help + IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be + allocated (in kb) for IMA measurements added during kexec soft reboot. + If set to the default value of 0, an extra half page of memory for those + additional measurements will be allocated. + endif diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index f9dd7ff95b84..6c8c203ad81e 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -126,22 +126,26 @@ void ima_add_kexec_buffer(struct kimage *image) .buf_min = 0, .buf_max = ULONG_MAX, .top_down = true }; unsigned long binary_runtime_size; - + unsigned long extra_memory; /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; size_t kexec_buffer_size = 0; int ret; /* - * Reserve an extra half page of memory for additional measurements - * added during the kexec load. + * Reserve extra memory for measurements added during kexec. */ - binary_runtime_size = ima_get_binary_runtime_size(); + if (CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB <= 0) + extra_memory = PAGE_SIZE / 2; + else + extra_memory = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; + binary_runtime_size = ima_get_binary_runtime_size() + extra_memory; + if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) kexec_segment_size = ULONG_MAX; else - kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + - PAGE_SIZE / 2, PAGE_SIZE); + kexec_segment_size = ALIGN(binary_runtime_size, PAGE_SIZE); + if ((kexec_segment_size == ULONG_MAX) || ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { pr_err("Binary measurement list too large.\n");