From patchwork Mon Jun 8 21:53:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11594073 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 1004792A for ; Mon, 8 Jun 2020 21:53:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D76DA20760 for ; Mon, 8 Jun 2020 21:53:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="VSpg9qrB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726827AbgFHVxt (ORCPT ); Mon, 8 Jun 2020 17:53:49 -0400 Received: from linux.microsoft.com ([13.77.154.182]:41658 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726789AbgFHVxt (ORCPT ); Mon, 8 Jun 2020 17:53:49 -0400 Received: from localhost.localdomain (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 2885D20B717B; Mon, 8 Jun 2020 14:53:48 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 2885D20B717B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1591653228; bh=xc2Cr5Aohy9MgGfLPpnVpGSQbatWni8qwfQ89wE0oIM=; h=From:To:Cc:Subject:Date:From; b=VSpg9qrBKfCgAMHGahpi4/S7yxgM50HxOkFqUt8A36BBQXm2iuiMrWeiLqr0o0i/J 7a2voa1QrwWey/8Q7acuzusWc/dgJ1hvYbid5bOel0EibtPvnlDJ9xGDi40dZJPdDN 31tHWyOAcGAd4AeoUCwS/5qaR8Gwz0ulb2UdgNH0= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, paul@paul-moore.com Cc: linux-integrity@vger.kernel.org, linux-audit@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH v3] IMA: Add audit log for failure conditions Date: Mon, 8 Jun 2020 14:53:43 -0700 Message-Id: <20200608215343.4491-1-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The final log statement in process_buffer_measurement() for failure condition is at debug level. This does not log the message unless the system log level is raised which would significantly increase the messages in the system log. Change this log message to an audit message for better triaging failures in the function. ima_alloc_key_entry() does not log a message for failure condition. Add an audit message for failure condition in this function. Sample audit messages: [ 8.051937] audit: type=1804 audit(1591633422.365:8): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_keys cause=hashing_error(-22) comm="systemd" name=".builtin_trusted_keys" res=0 [ 8.063218] audit: type=1804 audit(1591633422.377:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=alloc_entry(-12) comm="systemd" name="kexec-cmdline" res=0 Signed-off-by: Lakshmi Ramasubramanian Reviewed-by: Richard Guy Briggs --- security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_main.c | 37 +++++++++++++++++++++---- security/integrity/ima/ima_queue.c | 2 -- security/integrity/ima/ima_queue_keys.c | 4 +++ 4 files changed, 37 insertions(+), 8 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index df93ac258e01..8a47249c6238 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -47,6 +47,8 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 }; #define NR_BANKS(chip) ((chip != NULL) ? chip->nr_allocated_banks : 0) +#define AUDIT_CAUSE_LEN_MAX 32 + /* current content of the policy */ extern int ima_policy_flag; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 800fb3bba418..b10f09bc7eca 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -739,6 +739,9 @@ void process_buffer_measurement(const void *buf, int size, int pcr, const char *keyring) { int ret = 0; + const char *audit_cause = "ENOMEM"; + const char *op = "measuring_keys"; + char measurement_audit_cause[AUDIT_CAUSE_LEN_MAX]; struct ima_template_entry *entry = NULL; struct integrity_iint_cache iint = {}; struct ima_event_data event_data = {.iint = &iint, @@ -793,21 +796,43 @@ void process_buffer_measurement(const void *buf, int size, iint.ima_hash->length = hash_digest_size[ima_hash_algo]; ret = ima_calc_buffer_hash(buf, size, iint.ima_hash); - if (ret < 0) + if (ret < 0) { + audit_cause = "hashing_error"; goto out; + } ret = ima_alloc_init_template(&event_data, &entry, template); - if (ret < 0) + if (ret < 0) { + audit_cause = "alloc_entry"; goto out; + } ret = ima_store_template(entry, violation, NULL, buf, pcr); - - if (ret < 0) + if (ret < 0) { + audit_cause = "store_entry"; ima_free_template_entry(entry); + } out: - if (ret < 0) - pr_devel("%s: failed, result: %d\n", __func__, ret); + if (ret < 0) { + snprintf(measurement_audit_cause, AUDIT_CAUSE_LEN_MAX, + "%s(%d)", audit_cause, ret); + + switch (func) { + case KEXEC_CMDLINE: + op = "measuring_kexec_cmdline"; + break; + case KEY_CHECK: + op = "measuring_keys"; + break; + default: + op = "measuring_blacklisted_hash"; + break; + } + + integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, eventname, + op, measurement_audit_cause, ret, 0); + } return; } diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index fb4ec270f620..4a761d765c6c 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -19,8 +19,6 @@ #include #include "ima.h" -#define AUDIT_CAUSE_LEN_MAX 32 - /* pre-allocated array of tpm_digest structures to extend a PCR */ static struct tpm_digest *digests; diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c index cb3e3f501593..4de31ff172aa 100644 --- a/security/integrity/ima/ima_queue_keys.c +++ b/security/integrity/ima/ima_queue_keys.c @@ -68,6 +68,7 @@ static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring, size_t payload_len) { int rc = 0; + const char *audit_cause = "ENOMEM"; struct ima_key_entry *entry; entry = kzalloc(sizeof(*entry), GFP_KERNEL); @@ -88,6 +89,9 @@ static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring, out: if (rc) { + integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, + keyring->description, "measuring_keys", + audit_cause, rc, 0); ima_free_key_entry(entry); entry = NULL; }