From patchwork Mon Feb 3 18:42:55 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 13958022 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7159919938D; Mon, 3 Feb 2025 18:43:06 +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=1738608188; cv=none; b=SDMmGS15bmPyIfvxSvCRFQuzb+xhdv1y6KSl9OBW63GetkKq5QESoacmXNgh9P5J+ZRAzclF9Iw0exqNqXguddLXsXl0OE41IlUt+l1cutewOhCtMD9O13vIsQZJxFXSMQAfQAafCYDtIqaNYRCUEFeJyeVRrek6BzwkcxFRgS8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738608188; c=relaxed/simple; bh=ZV4vYEbQIpjD72/RY85S+Dgnqd0a77LyHi+94XZNKi0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WzCukXwhd6Ry+FmBKDVDvbgpPNCLUacDvIGMJkQx8kWD3eB+GOVFVdvscmXCV1oiGTI7jtaV78SZTWF8/3OvL4NInd1Et9i1inJiGlsXFDQrBlYb0sNQgv0KrCBtfzdpcfT3Jm7+op/tEThpHA0KoJqBSohLxYVDnDIoACOBELU= 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=bNj80hcA; 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="bNj80hcA" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id 09A19205493C; Mon, 3 Feb 2025 10:43:05 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 09A19205493C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1738608185; bh=KbbzVWtcOJ7Gt1QLNcb0WLEL7b64gQxfibl1JZ8EMTM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bNj80hcAhiATBlbzHimaIioftHHv3CwJh7ZMwrB+kcXp6Oy2x/dt0hf/677kesmU2 NnHosZZl8RgyT32j/3taEM3mkTC11LVrBx+2fz8IRL3fDTzf3oVkTYrfZQT6xHxQQw 0/rWVXvWmkNUtTEvZWc/q5tt2g8wyQtcgw8p/uiM= 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, inux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, chenste@linux.microsoft.com Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com Subject: [PATCH v7 6/7] ima: make the kexec extra memory configurable Date: Mon, 3 Feb 2025 10:42:55 -0800 Message-Id: <20250203184256.61285-7-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250203184256.61285-1-chenste@linux.microsoft.com> References: <20250203184256.61285-1-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. From: Tushar Sugandhi Author: Tushar Sugandhi Suggested-by: Stefan Berger Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen --- 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..54b145ae6096 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, an extra half a 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 d5f004cfeaec..c9c916f69ca7 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -128,22 +128,26 @@ 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_size; /* 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_size = PAGE_SIZE / 2; + else + extra_size = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; + binary_runtime_size = ima_get_binary_runtime_size() + extra_size; + 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");