From patchwork Tue Jun 23 00:32:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tyler Hicks X-Patchwork-Id: 11619499 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 7C2076C1 for ; Tue, 23 Jun 2020 00:34:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61238207DD for ; Tue, 23 Jun 2020 00:34:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="ZMJQIK5k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731920AbgFWAeU (ORCPT ); Mon, 22 Jun 2020 20:34:20 -0400 Received: from linux.microsoft.com ([13.77.154.182]:47458 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731908AbgFWAeR (ORCPT ); Mon, 22 Jun 2020 20:34:17 -0400 Received: from sequoia.work.tihix.com (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id 6AF7320B7192; Mon, 22 Jun 2020 17:34:16 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 6AF7320B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1592872457; bh=MjvOfyC6Kyxg10ZaMXyzh7KFkvoHbtJZoncaooevfJo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZMJQIK5k+SfaBZZH7Dc85cfB2xfcW5vhv9kMZtgIOrFC3fbI7kiTZI8aY5jeTgYWV r5aGhGDwBRHwyCwLooaDvqj8I2M9Mv2VOcjvwfo7nav/A/dD8ftKyJPSpffky6KOKN cuvl5LehN0NUd1D7o1SHs5uvyHlcx5X60fnG8Gyw= From: Tyler Hicks To: Mimi Zohar , Dmitry Kasatkin Cc: James Morris , "Serge E . Hallyn" , Lakshmi Ramasubramanian , Prakhar Srivastava , linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH 05/12] ima: Fail rule parsing when buffer hook functions have an invalid action Date: Mon, 22 Jun 2020 19:32:29 -0500 Message-Id: <20200623003236.830149-6-tyhicks@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200623003236.830149-1-tyhicks@linux.microsoft.com> References: <20200623003236.830149-1-tyhicks@linux.microsoft.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Buffer based hook functions, such as KEXEC_CMDLINE and KEY_CHECK, can only measure. The process_buffer_measurement() function quietly ignores all actions except measure so make this behavior clear at the time of policy load. The parsing of the keyrings conditional had a check to ensure that it was only specified with measure actions but the check should be on the hook function and not the keyrings conditional since "appraise func=KEY_CHECK" is not a valid rule. Fixes: b0935123a183 ("IMA: Define a new hook to measure the kexec boot command line arguments") Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys") Signed-off-by: Tyler Hicks --- security/integrity/ima/ima_policy.c | 36 +++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index ee5152ecd3d9..ecc234b956a2 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -979,6 +979,39 @@ static void check_template_modsig(const struct ima_template_desc *template) #undef MSG } +static bool ima_validate_rule(struct ima_rule_entry *entry) +{ + if (entry->action == UNKNOWN) + return false; + + if (entry->flags & IMA_FUNC) { + switch (entry->func) { + case NONE: + case FILE_CHECK: + case MMAP_CHECK: + case BPRM_CHECK: + case CREDS_CHECK: + case POST_SETATTR: + case MODULE_CHECK: + case FIRMWARE_CHECK: + case KEXEC_KERNEL_CHECK: + case KEXEC_INITRAMFS_CHECK: + case POLICY_CHECK: + break; + case KEXEC_CMDLINE: + case KEY_CHECK: + if (entry->action & ~(MEASURE | DONT_MEASURE)) + return false; + + break; + default: + return false; + } + } + + return true; +} + static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) { struct audit_buffer *ab; @@ -1156,7 +1189,6 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) keyrings_len = strlen(args[0].from) + 1; if ((entry->keyrings) || - (entry->action != MEASURE) || (entry->func != KEY_CHECK) || (keyrings_len < 2)) { result = -EINVAL; @@ -1362,7 +1394,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; } } - if (!result && (entry->action == UNKNOWN)) + if (!result && !ima_validate_rule(entry)) result = -EINVAL; else if (entry->action == APPRAISE) temp_ima_appraise |= ima_appraise_flag(entry->func);