From patchwork Fri Dec 13 00:42:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11289613 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 71F8E1593 for ; Fri, 13 Dec 2019 00:43:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5134B2253D for ; Fri, 13 Dec 2019 00:43:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="CrHariPO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731609AbfLMAm5 (ORCPT ); Thu, 12 Dec 2019 19:42:57 -0500 Received: from linux.microsoft.com ([13.77.154.182]:49714 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731519AbfLMAmz (ORCPT ); Thu, 12 Dec 2019 19:42:55 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id 40BFC20B7189; Thu, 12 Dec 2019 16:42:54 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 40BFC20B7189 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1576197774; bh=FsYnq2HPcFYThd4TxlJ3uzA3ou60BVf/q7LsE01sWiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CrHariPOh0keCU3aW6T/egZNMGziTEKk4gq3pVXGU8oXvsp2ghwL+EVNfE3l7E/zN 5yZ+mNlW/MBm4oeT0k7jmzrhqCzPAcGCr9pAk+mBmqxAid2oo2oaaTFg6jJUCta4mB A89FpHzpk+1byDN4P/X5Fz0DwBuSmHmCGbKR4Tes= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.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 v3 1/2] IMA: Define workqueue for early boot "key" measurements Date: Thu, 12 Dec 2019 16:42:49 -0800 Message-Id: <20191213004250.21132-2-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191213004250.21132-1-nramas@linux.microsoft.com> References: <20191213004250.21132-1-nramas@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Measuring keys requires a custom IMA policy to be loaded. Keys created or updated before a custom IMA policy is loaded should be queued and the keys should be processed after a custom policy is loaded. This patch defines workqueue for queuing keys when a custom IMA policy has not yet been loaded. A flag namely ima_process_keys is used to check if the key should be queued or should be processed immediately. Signed-off-by: Lakshmi Ramasubramanian --- security/integrity/ima/ima.h | 15 +++ security/integrity/ima/ima_asymmetric_keys.c | 119 +++++++++++++++++++ 2 files changed, 134 insertions(+) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index f06238e41a7c..97f8a4078483 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -205,6 +205,21 @@ extern const char *const func_tokens[]; struct modsig; +#ifdef CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE +/* + * To track keys that need to be measured. + */ +struct ima_key_entry { + struct list_head list; + void *payload; + size_t payload_len; + char *keyring_name; +}; +void ima_process_queued_keys(void); +#else +static inline void ima_process_queued_keys(void) {} +#endif /* CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */ + /* LIM API function definitions */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index fea2e7dd3b09..a1781348ce69 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -14,6 +14,125 @@ #include #include "ima.h" +/* + * Flag to indicate whether a key can be processed + * right away or should be queued for processing later. + */ +static bool ima_process_keys; + +/* + * To synchronize access to the list of keys that need to be measured + */ +static DEFINE_MUTEX(ima_keys_mutex); +static LIST_HEAD(ima_keys); + +static void ima_free_key_entry(struct ima_key_entry *entry) +{ + if (entry) { + kfree(entry->payload); + kfree(entry->keyring_name); + kfree(entry); + } +} + +static struct ima_key_entry *ima_alloc_key_entry( + struct key *keyring, + const void *payload, size_t payload_len) +{ + int rc = 0; + struct ima_key_entry *entry; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (entry) { + entry->payload = kmemdup(payload, payload_len, GFP_KERNEL); + entry->keyring_name = kstrdup(keyring->description, + GFP_KERNEL); + entry->payload_len = payload_len; + } + + if ((entry == NULL) || (entry->payload == NULL) || + (entry->keyring_name == NULL)) { + rc = -ENOMEM; + goto out; + } + + INIT_LIST_HEAD(&entry->list); + +out: + if (rc) { + ima_free_key_entry(entry); + entry = NULL; + } + + return entry; +} + +bool ima_queue_key(struct key *keyring, const void *payload, + size_t payload_len) +{ + bool queued = false; + struct ima_key_entry *entry; + + entry = ima_alloc_key_entry(keyring, payload, payload_len); + if (!entry) + return false; + + mutex_lock(&ima_keys_mutex); + if (!ima_process_keys) { + list_add_tail(&entry->list, &ima_keys); + queued = true; + } + mutex_unlock(&ima_keys_mutex); + + if (!queued) + ima_free_key_entry(entry); + + return queued; +} + +/* + * ima_process_queued_keys() - process keys queued for measurement + * + * This function sets ima_process_keys to true and processes queued keys. + * From here on keys will be processed right away (not queued). + */ +void ima_process_queued_keys(void) +{ + struct ima_key_entry *entry, *tmp; + LIST_HEAD(temp_ima_keys); + + if (ima_process_keys) + return; + + /* + * To avoid holding the mutex when processing queued keys, + * transfer the queued keys with the mutex held to a temp list, + * release the mutex, and then process the queued keys from + * the temp list. + * + * Since ima_process_keys is set to true, any new key will be + * processed immediately and not be queued. + */ + INIT_LIST_HEAD(&temp_ima_keys); + + mutex_lock(&ima_keys_mutex); + + ima_process_keys = true; + + list_for_each_entry_safe(entry, tmp, &ima_keys, list) + list_move_tail(&entry->list, &temp_ima_keys); + + mutex_unlock(&ima_keys_mutex); + + list_for_each_entry_safe(entry, tmp, &temp_ima_keys, list) { + 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); + } +} + /** * ima_post_key_create_or_update - measure asymmetric keys * @keyring: keyring to which the key is linked to