From patchwork Wed Feb 5 10:33:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 11366067 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 EF984112B for ; Wed, 5 Feb 2020 10:36:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEE872085B for ; Wed, 5 Feb 2020 10:36:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728142AbgBEKgO (ORCPT ); Wed, 5 Feb 2020 05:36:14 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2372 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727562AbgBEKgO (ORCPT ); Wed, 5 Feb 2020 05:36:14 -0500 Received: from lhreml702-cah.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 5C31088D2955EFC409B0; Wed, 5 Feb 2020 10:36:12 +0000 (GMT) Received: from roberto-HP-EliteDesk-800-G2-DM-65W.huawei.com (10.204.65.160) by smtpsuk.huawei.com (10.201.108.43) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 5 Feb 2020 10:36:05 +0000 From: Roberto Sassu To: , , CC: , , , , Roberto Sassu Subject: [PATCH v2 7/8] ima: Calculate and extend PCR with digests in ima_template_entry Date: Wed, 5 Feb 2020 11:33:16 +0100 Message-ID: <20200205103317.29356-8-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200205103317.29356-1-roberto.sassu@huawei.com> References: <20200205103317.29356-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.65.160] X-CFilter-Loop: Reflected Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: This patch modifies ima_calc_field_array_hash() to calculate a template digest for each allocated PCR bank and SHA1. It also passes the tpm_digest array of the template entry to ima_pcr_extend() or in case of a violation, the pre-initialized digests array filled with 0xff. Padding with zeros is still done if the mapping between TPM algorithm ID and crypto ID is unknown. This patch calculates again the template digest when a measurement list is restored. Copying only the SHA1 digest (due to the limitation of the current measurement list format) is not sufficient, as hash collision detection will be done on the digest calculated with the default IMA hash algorithm. Changelog v1: - replace ima_tpm_chip->nr_allocated_banks with ima_num_template_digests (suggested by Mimi) - retrieve alg_id only if i < ima_tpm_chip->nr_allocated_banks - check if ima_tpm_chip is NULL Signed-off-by: Roberto Sassu --- security/integrity/ima/ima_crypto.c | 32 ++++++++++++++++++++++++++- security/integrity/ima/ima_queue.c | 30 +++++++++++++++---------- security/integrity/ima/ima_template.c | 14 ++++++++++-- 3 files changed, 61 insertions(+), 15 deletions(-) diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 3101c343f963..1ee813d33bdc 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -615,9 +615,39 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, int ima_calc_field_array_hash(struct ima_field_data *field_data, struct ima_template_entry *entry) { - int rc; + u16 alg_id; + int rc, i, nr_allocated_banks = 0; rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx); + if (rc) + return rc; + + entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1; + + if (ima_tpm_chip) + nr_allocated_banks = ima_tpm_chip->nr_allocated_banks; + + for (i = 0; i < ima_num_template_digests; i++) { + if (i == ima_sha1_idx) + continue; + + if (i < nr_allocated_banks) { + alg_id = ima_tpm_chip->allocated_banks[i].alg_id; + entry->digests[i].alg_id = alg_id; + } + + /* for unmapped TPM algorithms digest is still a padded SHA1 */ + if (!ima_algo_array[i].tfm) { + memcpy(entry->digests[i].digest, + entry->digests[ima_sha1_idx].digest, + TPM_DIGEST_SIZE); + continue; + } + + rc = ima_calc_field_array_hash_tfm(field_data, entry, i); + if (rc) + return rc; + } return rc; } diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index bcd99db9722c..7f7509774b85 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -137,18 +137,14 @@ unsigned long ima_get_binary_runtime_size(void) return binary_runtime_size + sizeof(struct ima_kexec_hdr); }; -static int ima_pcr_extend(const u8 *hash, int pcr) +static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr) { int result = 0; - int i; if (!ima_tpm_chip) return result; - for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) - memcpy(digests[i].digest, hash, TPM_DIGEST_SIZE); - - result = tpm_pcr_extend(ima_tpm_chip, pcr, digests); + result = tpm_pcr_extend(ima_tpm_chip, pcr, digests_arg); if (result != 0) pr_err("Error Communicating to TPM chip, result: %d\n", result); return result; @@ -166,7 +162,8 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation, const char *op, struct inode *inode, const unsigned char *filename) { - u8 digest[TPM_DIGEST_SIZE]; + u8 *digest = entry->digests[ima_sha1_idx].digest; + struct tpm_digest *digests_arg = entry->digests; const char *audit_cause = "hash_added"; char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX]; int audit_info = 1; @@ -174,8 +171,6 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation, mutex_lock(&ima_extend_list_mutex); if (!violation) { - memcpy(digest, entry->digests[ima_sha1_idx].digest, - sizeof(digest)); if (ima_lookup_digest_entry(digest, entry->pcr)) { audit_cause = "hash_exists"; result = -EEXIST; @@ -191,9 +186,9 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation, } if (violation) /* invalidate pcr */ - memset(digest, 0xff, sizeof(digest)); + digests_arg = digests; - tpmresult = ima_pcr_extend(digest, entry->pcr); + tpmresult = ima_pcr_extend(digests_arg, entry->pcr); if (tpmresult != 0) { snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)", tpmresult); @@ -219,6 +214,8 @@ int ima_restore_measurement_entry(struct ima_template_entry *entry) int __init ima_init_digests(void) { + u16 digest_size; + u16 crypto_id; int i; if (!ima_tpm_chip) @@ -229,8 +226,17 @@ int __init ima_init_digests(void) if (!digests) return -ENOMEM; - for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) + for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) { digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id; + digest_size = ima_tpm_chip->allocated_banks[i].digest_size; + crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id; + + /* for unmapped TPM algorithms digest is still a padded SHA1 */ + if (crypto_id == HASH_ALGO__LAST) + digest_size = SHA1_DIGEST_SIZE; + + memset(digests[i].digest, 0xff, digest_size); + } return 0; } diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index 751f101ae927..dae6aab8d0bd 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -356,6 +356,7 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc, int ima_restore_measurement_list(loff_t size, void *buf) { char template_name[MAX_TEMPLATE_NAME_LEN]; + unsigned char zero[TPM_DIGEST_SIZE] = { 0 }; struct ima_kexec_hdr *khdr = buf; struct ima_field_data hdr[HDR__LAST] = { @@ -455,8 +456,17 @@ int ima_restore_measurement_list(loff_t size, void *buf) if (ret < 0) break; - memcpy(entry->digests[ima_sha1_idx].digest, - hdr[HDR_DIGEST].data, hdr[HDR_DIGEST].len); + if (memcmp(hdr[HDR_DIGEST].data, zero, sizeof(zero))) { + ret = ima_calc_field_array_hash( + &entry->template_data[0], + entry); + if (ret < 0) { + pr_err("cannot calculate template digest\n"); + ret = -EINVAL; + break; + } + } + entry->pcr = !ima_canonical_fmt ? *(hdr[HDR_PCR].data) : le32_to_cpu(*(hdr[HDR_PCR].data)); ret = ima_restore_measurement_entry(entry);