From patchwork Mon Dec 23 03:24:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11307761 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4E5A2109A for ; Mon, 23 Dec 2019 03:25:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 215A5206CB for ; Mon, 23 Dec 2019 03:25:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="CKUu7XIL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726564AbfLWDY7 (ORCPT ); Sun, 22 Dec 2019 22:24:59 -0500 Received: from linux.microsoft.com ([13.77.154.182]:42638 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726393AbfLWDY7 (ORCPT ); Sun, 22 Dec 2019 22:24:59 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id 927BC2010AEB; Sun, 22 Dec 2019 19:24:57 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 927BC2010AEB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1577071497; bh=yGKmhs9aMGkAz/y14zgjsApaSuYZENSdyxq6xKWHgWk=; h=From:To:Cc:Subject:Date:From; b=CKUu7XILT88WzBI/z7iJg4AwHIvmNiHCX6bUQyi7IRVoPXQG1iKOYhKB6brVU8QbQ FRqoPDY1aP9ROSGDjP60oBY0NJqS3TIK0P7yuTzj52034foI7ftYsWsR67b21pvWxj xzFrZUb8kX+hCvzCFXFt/TrwP4KPDTfTO/wwwO9g= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH v1] IMA: Defined timer to free queued keys Date: Sun, 22 Dec 2019 19:24:54 -0800 Message-Id: <20191223032454.2797-1-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org keys queued for measurement should still be processed even if a custom IMA policy was not loaded. Otherwise, the keys will remain queued forever consuming kernel memory. This patch defines a timer to handle the above scenario. The timer is setup to expire 5 minutes after IMA initialization is completed. If a custom IMA policy is loaded before the timer expires, the timer is removed and any queued keys are processed for measurement. But if a custom policy was not loaded, on timer expiration any queued keys are just freed. Signed-off-by: Lakshmi Ramasubramanian --- security/integrity/ima/ima.h | 2 + security/integrity/ima/ima_asymmetric_keys.c | 46 ++++++++++++++++++-- security/integrity/ima/ima_init.c | 8 +++- 3 files changed, 52 insertions(+), 4 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 97f8a4078483..c483215a9ee5 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -216,8 +216,10 @@ struct ima_key_entry { char *keyring_name; }; void ima_process_queued_keys(void); +void ima_init_key_queue(void); #else static inline void ima_process_queued_keys(void) {} +static inline void ima_init_key_queue(void) {} #endif /* CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */ /* LIM API function definitions */ diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index 4124f10ff0c2..e1c4e1e7d9a1 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -11,6 +11,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include "ima.h" @@ -26,6 +27,34 @@ static bool ima_process_keys; static DEFINE_MUTEX(ima_keys_mutex); static LIST_HEAD(ima_keys); +/* + * If custom IMA policy is not loaded then keys queued up + * for measurement should be freed. This timer is used + * for handling this scenario. + */ +static long ima_key_queue_timeout = 300000; /* 5 Minutes */ +static struct timer_list ima_key_queue_timer; + +/* + * This timer callback function processes keys that may still be + * queued up in case custom IMA policy was not loaded. + */ +static void ima_timer_handler(struct timer_list *timer) +{ + ima_process_queued_keys(); +} + +/* + * This function sets up a timer to process queued keys in case + * custom IMA policy was never loaded. + */ +void ima_init_key_queue(void) +{ + timer_setup(&ima_key_queue_timer, ima_timer_handler, 0); + mod_timer(&ima_key_queue_timer, + jiffies + msecs_to_jiffies(ima_key_queue_timeout)); +} + static void ima_free_key_entry(struct ima_key_entry *entry) { if (entry) { @@ -100,6 +129,7 @@ void ima_process_queued_keys(void) { struct ima_key_entry *entry, *tmp; bool process = false; + int timer_removed; if (ima_process_keys) return; @@ -120,10 +150,20 @@ void ima_process_queued_keys(void) if (!process) return; + /* + * Timer is no longer needed. If the timer was removed + * (i.e., the timer had not expired) the queued keys are + * processed for measurement. Else, the keys are just freed. + */ + timer_removed = del_timer(&ima_key_queue_timer); + list_for_each_entry_safe(entry, tmp, &ima_keys, list) { - process_buffer_measurement(entry->payload, entry->payload_len, - entry->keyring_name, KEY_CHECK, 0, - entry->keyring_name); + if (timer_removed) + process_buffer_measurement(entry->payload, + entry->payload_len, + entry->keyring_name, + KEY_CHECK, 0, + entry->keyring_name); list_del(&entry->list); ima_free_key_entry(entry); } diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 5d55ade5f3b9..195cb4079b2b 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -131,5 +131,11 @@ int __init ima_init(void) ima_init_policy(); - return ima_fs_init(); + rc = ima_fs_init(); + if (rc != 0) + return rc; + + ima_init_key_queue(); + + return rc; }