From patchwork Thu Sep 17 13:46:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sumit Garg X-Patchwork-Id: 11782617 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 83B7F14F6 for ; Thu, 17 Sep 2020 14:19:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CD9A21974 for ; Thu, 17 Sep 2020 14:19:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="CYS1L/eI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727280AbgIQOMj (ORCPT ); Thu, 17 Sep 2020 10:12:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727238AbgIQN6i (ORCPT ); Thu, 17 Sep 2020 09:58:38 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D28CC0611BD for ; Thu, 17 Sep 2020 06:47:16 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id e4so1145850pln.10 for ; Thu, 17 Sep 2020 06:47:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=sHmkwc1IEt5uhNq3ZTTT253WhE5FWjqQoBIr/mPKXTw=; b=CYS1L/eILGc3sY/EfqUl9GQ0N4Kf5jWArABkP0EyIJNq1974J9yQT1DebLoQWngXjz hAd7uMcxDrr2/VL9F+MLhsO9EkrPZ00Iz1A9Odl41g7NFRXSK1xHmshoI0tgVOZUnK12 u23s64HeYb/q5Q6cqcmWgSGQTaQ4XLme+Syv6dKzm+ZkygxxEkwUMIi/DqthDsp5y01l 8GlA2nGiiHmfrWxWkzVu2IIn6vJwUHiHsqPbQ+DW1R3i5qwfEyrLBcO9jJviqaUlFuTK JFlkgvmlYD3bDLtkceFGe+QS0GDs2bwR/pthyxR8GD5e7gMNqffcAxHjxo7Ml6Wcg0Bs EkaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=sHmkwc1IEt5uhNq3ZTTT253WhE5FWjqQoBIr/mPKXTw=; b=sVly7Poqkd+R4kxMiUK+a8Ol8XvkvGgsCNv7OcqvnwWCP8qmMKxePaoCBERC4CXp5q 5dVlqEXdlU7PzjJhpusDZ/hQx267vyaKo3oUh5kyum4MBIbu/RaXO61Y+7ZbBPi9UQm1 XLQF0h/na+cJwXbYSMzS2kqAyuNsU5466c3lfaEiT4O802sBEVVNK2VklORqNMidF+BX 8tGMAziJ5qj2pcUWWme4SE9AqpwZXjVyx/8xQ2JY1Hb/MyUSTE2mlfKHCmYz8COF7Y6C cE1dpHuAq11lQ+Y6sw7ps9YwDkUmzw6a9J2Wn3X5xqxu5iRnZIJPasGCZNp8ibFt4FAE LYVg== X-Gm-Message-State: AOAM531nbO5Gnm/cF5j0ToWtEHdqk1hqQsdv32z79ETmjry//XB8AhbD fop3WwT29PzXi7I5chl0mB8QBA== X-Google-Smtp-Source: ABdhPJwxQVtt4v228fRD0XKWdqSZIxyK+cWpwqFQD/Mw4fAWLYkgja+pLDwxPZk1b+/8iEP0JD+p3g== X-Received: by 2002:a17:90b:4ac4:: with SMTP id mh4mr8832809pjb.224.1600350435811; Thu, 17 Sep 2020 06:47:15 -0700 (PDT) Received: from localhost.localdomain ([117.252.66.163]) by smtp.gmail.com with ESMTPSA id i73sm6821120pfe.67.2020.09.17.06.47.07 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Sep 2020 06:47:15 -0700 (PDT) From: Sumit Garg To: jarkko.sakkinen@linux.intel.com, zohar@linux.ibm.com, jejb@linux.ibm.com Cc: dhowells@redhat.com, jens.wiklander@linaro.org, corbet@lwn.net, jmorris@namei.org, serge@hallyn.com, casey@schaufler-ca.com, janne.karhunen@gmail.com, daniel.thompson@linaro.org, Markus.Wamser@mixed-mode.de, lhinds@redhat.com, keyrings@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org, Sumit Garg Subject: [PATCH v6 1/4] KEYS: trusted: Add generic trusted keys framework Date: Thu, 17 Sep 2020 19:16:35 +0530 Message-Id: <1600350398-4813-2-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> References: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> Precedence: bulk List-ID: Current trusted keys framework is tightly coupled to use TPM device as an underlying implementation which makes it difficult for implementations like Trusted Execution Environment (TEE) etc. to provide trusted keys support in case platform doesn't posses a TPM device. So this patch tries to add generic trusted keys framework where underlying implementations like TPM, TEE etc. could be easily plugged-in. Suggested-by: Jarkko Sakkinen Signed-off-by: Sumit Garg --- include/keys/trusted-type.h | 42 ++++ include/keys/trusted_tpm.h | 17 +- security/keys/trusted-keys/Makefile | 1 + security/keys/trusted-keys/trusted_core.c | 321 ++++++++++++++++++++++++++++ security/keys/trusted-keys/trusted_tpm1.c | 336 +++++------------------------- 5 files changed, 422 insertions(+), 295 deletions(-) create mode 100644 security/keys/trusted-keys/trusted_core.c diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index a94c03a..edd635a 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -40,6 +40,48 @@ struct trusted_key_options { uint32_t policyhandle; }; +struct trusted_key_ops { + /* + * flag to indicate if trusted key implementation supports migration + * or not. + */ + unsigned char migratable; + + /* Initialize key interface. */ + int (*init)(void); + + /* Seal a key. */ + int (*seal)(struct trusted_key_payload *p, char *datablob); + + /* Unseal a key. */ + int (*unseal)(struct trusted_key_payload *p, char *datablob); + + /* Get a randomized key. */ + int (*get_random)(unsigned char *key, size_t key_len); + + /* Exit key interface. */ + void (*exit)(void); +}; + extern struct key_type key_type_trusted; +#define TRUSTED_DEBUG 0 + +#if TRUSTED_DEBUG +static inline void dump_payload(struct trusted_key_payload *p) +{ + pr_info("trusted_key: key_len %d\n", p->key_len); + print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, + 16, 1, p->key, p->key_len, 0); + pr_info("trusted_key: bloblen %d\n", p->blob_len); + print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, + 16, 1, p->blob, p->blob_len, 0); + pr_info("trusted_key: migratable %d\n", p->migratable); +} +#else +static inline void dump_payload(struct trusted_key_payload *p) +{ +} +#endif + #endif /* _KEYS_TRUSTED_TYPE_H */ diff --git a/include/keys/trusted_tpm.h b/include/keys/trusted_tpm.h index a56d8e1..fb3280a 100644 --- a/include/keys/trusted_tpm.h +++ b/include/keys/trusted_tpm.h @@ -16,6 +16,8 @@ #define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset]) #define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset])) +extern struct trusted_key_ops tpm_trusted_key_ops; + struct osapsess { uint32_t handle; unsigned char secret[SHA1_DIGEST_SIZE]; @@ -60,17 +62,6 @@ static inline void dump_options(struct trusted_key_options *o) 16, 1, o->pcrinfo, o->pcrinfo_len, 0); } -static inline void dump_payload(struct trusted_key_payload *p) -{ - pr_info("trusted_key: key_len %d\n", p->key_len); - print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, - 16, 1, p->key, p->key_len, 0); - pr_info("trusted_key: bloblen %d\n", p->blob_len); - print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, - 16, 1, p->blob, p->blob_len, 0); - pr_info("trusted_key: migratable %d\n", p->migratable); -} - static inline void dump_sess(struct osapsess *s) { print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE, @@ -96,10 +87,6 @@ static inline void dump_options(struct trusted_key_options *o) { } -static inline void dump_payload(struct trusted_key_payload *p) -{ -} - static inline void dump_sess(struct osapsess *s) { } diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index 7b73ceb..49e3bcf 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -4,5 +4,6 @@ # obj-$(CONFIG_TRUSTED_KEYS) += trusted.o +trusted-y += trusted_core.o trusted-y += trusted_tpm1.o trusted-y += trusted_tpm2.o diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c new file mode 100644 index 0000000..4ae3fb4 --- /dev/null +++ b/security/keys/trusted-keys/trusted_core.c @@ -0,0 +1,321 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2010 IBM Corporation + * Copyright (c) 2019-2020, Linaro Limited + * + * See Documentation/security/keys/trusted-encrypted.rst + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static struct trusted_key_ops *available_trusted_key_ops[] = { +#if defined(CONFIG_TCG_TPM) + &tpm_trusted_key_ops, +#endif +}; +static struct trusted_key_ops *trusted_key_ops; + +enum { + Opt_err, + Opt_new, Opt_load, Opt_update, +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_err, NULL} +}; + +/* + * datablob_parse - parse the keyctl data and fill in the + * payload structure + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, struct trusted_key_payload *p) +{ + substring_t args[MAX_OPT_ARGS]; + long keylen; + int ret = -EINVAL; + int key_cmd; + char *c; + + /* main command */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + key_cmd = match_token(c, key_tokens, args); + switch (key_cmd) { + case Opt_new: + /* first argument is key size */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + ret = kstrtol(c, 10, &keylen); + if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) + return -EINVAL; + p->key_len = keylen; + ret = Opt_new; + break; + case Opt_load: + /* first argument is sealed blob */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + p->blob_len = strlen(c) / 2; + if (p->blob_len > MAX_BLOB_SIZE) + return -EINVAL; + ret = hex2bin(p->blob, c, p->blob_len); + if (ret < 0) + return -EINVAL; + ret = Opt_load; + break; + case Opt_update: + ret = Opt_update; + break; + case Opt_err: + return -EINVAL; + } + return ret; +} + +static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +{ + struct trusted_key_payload *p = NULL; + int ret; + + ret = key_payload_reserve(key, sizeof(*p)); + if (ret < 0) + return p; + p = kzalloc(sizeof(*p), GFP_KERNEL); + + p->migratable = trusted_key_ops->migratable; + + return p; +} + +/* + * trusted_instantiate - create a new trusted key + * + * Unseal an existing trusted blob or, for a new key, get a + * random key, then seal and create a trusted key-type key, + * adding it to the specified keyring. + * + * On success, return 0. Otherwise return errno. + */ +static int trusted_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *payload = NULL; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + int key_cmd; + size_t key_len; + + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + + payload = trusted_payload_alloc(key); + if (!payload) { + ret = -ENOMEM; + goto out; + } + + key_cmd = datablob_parse(datablob, payload); + if (key_cmd < 0) { + ret = key_cmd; + goto out; + } + + dump_payload(payload); + + switch (key_cmd) { + case Opt_load: + ret = trusted_key_ops->unseal(payload, datablob); + dump_payload(payload); + if (ret < 0) + pr_info("trusted_key: key_unseal failed (%d)\n", ret); + break; + case Opt_new: + key_len = payload->key_len; + ret = trusted_key_ops->get_random(payload->key, key_len); + if (ret != key_len) { + pr_info("trusted_key: key_create failed (%d)\n", ret); + goto out; + } + + ret = trusted_key_ops->seal(payload, datablob); + if (ret < 0) + pr_info("trusted_key: key_seal failed (%d)\n", ret); + break; + default: + ret = -EINVAL; + } +out: + kfree_sensitive(datablob); + if (!ret) + rcu_assign_keypointer(key, payload); + else + kfree_sensitive(payload); + return ret; +} + +static void trusted_rcu_free(struct rcu_head *rcu) +{ + struct trusted_key_payload *p; + + p = container_of(rcu, struct trusted_key_payload, rcu); + kfree_sensitive(p); +} + +/* + * trusted_update - reseal an existing key with new PCR values + */ +static int trusted_update(struct key *key, struct key_preparsed_payload *prep) +{ + struct trusted_key_payload *p; + struct trusted_key_payload *new_p; + size_t datalen = prep->datalen; + char *datablob; + int ret = 0; + + if (key_is_negative(key)) + return -ENOKEY; + p = key->payload.data[0]; + if (!p->migratable) + return -EPERM; + if (datalen <= 0 || datalen > 32767 || !prep->data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + + new_p = trusted_payload_alloc(key); + if (!new_p) { + ret = -ENOMEM; + goto out; + } + + memcpy(datablob, prep->data, datalen); + datablob[datalen] = '\0'; + ret = datablob_parse(datablob, new_p); + if (ret != Opt_update) { + ret = -EINVAL; + kfree_sensitive(new_p); + goto out; + } + + /* copy old key values, and reseal with new pcrs */ + new_p->migratable = p->migratable; + new_p->key_len = p->key_len; + memcpy(new_p->key, p->key, p->key_len); + dump_payload(p); + dump_payload(new_p); + + ret = trusted_key_ops->seal(new_p, datablob); + if (ret < 0) { + pr_info("trusted_key: key_seal failed (%d)\n", ret); + kfree_sensitive(new_p); + goto out; + } + + rcu_assign_keypointer(key, new_p); + call_rcu(&p->rcu, trusted_rcu_free); +out: + kfree_sensitive(datablob); + return ret; +} + +/* + * trusted_read - copy the sealed blob data to userspace in hex. + * On success, return to userspace the trusted key datablob size. + */ +static long trusted_read(const struct key *key, char *buffer, + size_t buflen) +{ + const struct trusted_key_payload *p; + char *bufp; + int i; + + p = dereference_key_locked(key); + if (!p) + return -EINVAL; + + if (buffer && buflen >= 2 * p->blob_len) { + bufp = buffer; + for (i = 0; i < p->blob_len; i++) + bufp = hex_byte_pack(bufp, p->blob[i]); + } + return 2 * p->blob_len; +} + +/* + * trusted_destroy - clear and free the key's payload + */ +static void trusted_destroy(struct key *key) +{ + kfree_sensitive(key->payload.data[0]); +} + +struct key_type key_type_trusted = { + .name = "trusted", + .instantiate = trusted_instantiate, + .update = trusted_update, + .destroy = trusted_destroy, + .describe = user_describe, + .read = trusted_read, +}; +EXPORT_SYMBOL_GPL(key_type_trusted); + +static int __init init_trusted(void) +{ + int i, ret = 0; + + for (i = 0; i < sizeof(available_trusted_key_ops); i++) { + trusted_key_ops = available_trusted_key_ops[i]; + + ret = trusted_key_ops->init(); + if (!ret) + break; + } + + /* + * encrypted_keys.ko depends on successful load of this module even if + * trusted key implementation is not found. + */ + if (ret == -ENODEV) + return 0; + + return ret; +} + +static void __exit cleanup_trusted(void) +{ + trusted_key_ops->exit(); +} + +late_initcall(init_trusted); +module_exit(cleanup_trusted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index b9fe02e..1c5df77 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -1,29 +1,22 @@ // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2010 IBM Corporation - * - * Author: - * David Safford + * Copyright (c) 2019-2020, Linaro Limited * * See Documentation/security/keys/trusted-encrypted.rst */ #include -#include -#include #include #include #include #include #include -#include #include #include -#include #include #include #include -#include #include #include @@ -703,7 +696,6 @@ static int key_unseal(struct trusted_key_payload *p, enum { Opt_err, - Opt_new, Opt_load, Opt_update, Opt_keyhandle, Opt_keyauth, Opt_blobauth, Opt_pcrinfo, Opt_pcrlock, Opt_migratable, Opt_hash, @@ -712,9 +704,6 @@ enum { }; static const match_table_t key_tokens = { - {Opt_new, "new"}, - {Opt_load, "load"}, - {Opt_update, "update"}, {Opt_keyhandle, "keyhandle=%s"}, {Opt_keyauth, "keyauth=%s"}, {Opt_blobauth, "blobauth=%s"}, @@ -841,71 +830,6 @@ static int getoptions(char *c, struct trusted_key_payload *pay, return 0; } -/* - * datablob_parse - parse the keyctl data and fill in the - * payload and options structures - * - * On success returns 0, otherwise -EINVAL. - */ -static int datablob_parse(char *datablob, struct trusted_key_payload *p, - struct trusted_key_options *o) -{ - substring_t args[MAX_OPT_ARGS]; - long keylen; - int ret = -EINVAL; - int key_cmd; - char *c; - - /* main command */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - key_cmd = match_token(c, key_tokens, args); - switch (key_cmd) { - case Opt_new: - /* first argument is key size */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - ret = kstrtol(c, 10, &keylen); - if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) - return -EINVAL; - p->key_len = keylen; - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_new; - break; - case Opt_load: - /* first argument is sealed blob */ - c = strsep(&datablob, " \t"); - if (!c) - return -EINVAL; - p->blob_len = strlen(c) / 2; - if (p->blob_len > MAX_BLOB_SIZE) - return -EINVAL; - ret = hex2bin(p->blob, c, p->blob_len); - if (ret < 0) - return -EINVAL; - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_load; - break; - case Opt_update: - /* all arguments are options */ - ret = getoptions(datablob, p, o); - if (ret < 0) - return ret; - ret = Opt_update; - break; - case Opt_err: - return -EINVAL; - break; - } - return ret; -} - static struct trusted_key_options *trusted_options_alloc(void) { struct trusted_key_options *options; @@ -926,248 +850,99 @@ static struct trusted_key_options *trusted_options_alloc(void) return options; } -static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +static int tpm_trusted_seal(struct trusted_key_payload *p, char *datablob) { - struct trusted_key_payload *p = NULL; - int ret; - - ret = key_payload_reserve(key, sizeof *p); - if (ret < 0) - return p; - p = kzalloc(sizeof *p, GFP_KERNEL); - if (p) - p->migratable = 1; /* migratable by default */ - return p; -} - -/* - * trusted_instantiate - create a new trusted key - * - * Unseal an existing trusted blob or, for a new key, get a - * random key, then seal and create a trusted key-type key, - * adding it to the specified keyring. - * - * On success, return 0. Otherwise return errno. - */ -static int trusted_instantiate(struct key *key, - struct key_preparsed_payload *prep) -{ - struct trusted_key_payload *payload = NULL; struct trusted_key_options *options = NULL; - size_t datalen = prep->datalen; - char *datablob; int ret = 0; - int key_cmd; - size_t key_len; int tpm2; tpm2 = tpm_is_tpm2(chip); if (tpm2 < 0) return tpm2; - if (datalen <= 0 || datalen > 32767 || !prep->data) - return -EINVAL; - - datablob = kmalloc(datalen + 1, GFP_KERNEL); - if (!datablob) - return -ENOMEM; - memcpy(datablob, prep->data, datalen); - datablob[datalen] = '\0'; - options = trusted_options_alloc(); - if (!options) { - ret = -ENOMEM; - goto out; - } - payload = trusted_payload_alloc(key); - if (!payload) { - ret = -ENOMEM; - goto out; - } + if (!options) + return -ENOMEM; - key_cmd = datablob_parse(datablob, payload, options); - if (key_cmd < 0) { - ret = key_cmd; + ret = getoptions(datablob, p, options); + if (ret < 0) goto out; - } + dump_options(options); if (!options->keyhandle) { ret = -EINVAL; goto out; } - dump_payload(payload); - dump_options(options); + if (tpm2) + ret = tpm2_seal_trusted(chip, p, options); + else + ret = key_seal(p, options); + if (ret < 0) { + pr_info("tpm_trusted_key: key_seal failed (%d)\n", ret); + goto out; + } - switch (key_cmd) { - case Opt_load: - if (tpm2) - ret = tpm2_unseal_trusted(chip, payload, options); - else - ret = key_unseal(payload, options); - dump_payload(payload); - dump_options(options); - if (ret < 0) - pr_info("trusted_key: key_unseal failed (%d)\n", ret); - break; - case Opt_new: - key_len = payload->key_len; - ret = tpm_get_random(chip, payload->key, key_len); - if (ret != key_len) { - pr_info("trusted_key: key_create failed (%d)\n", ret); + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); + if (ret < 0) { + pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret); goto out; } - if (tpm2) - ret = tpm2_seal_trusted(chip, payload, options); - else - ret = key_seal(payload, options); - if (ret < 0) - pr_info("trusted_key: key_seal failed (%d)\n", ret); - break; - default: - ret = -EINVAL; - goto out; } - if (!ret && options->pcrlock) - ret = pcrlock(options->pcrlock); out: - kfree_sensitive(datablob); kfree_sensitive(options); - if (!ret) - rcu_assign_keypointer(key, payload); - else - kfree_sensitive(payload); return ret; } -static void trusted_rcu_free(struct rcu_head *rcu) -{ - struct trusted_key_payload *p; - - p = container_of(rcu, struct trusted_key_payload, rcu); - kfree_sensitive(p); -} - -/* - * trusted_update - reseal an existing key with new PCR values - */ -static int trusted_update(struct key *key, struct key_preparsed_payload *prep) +static int tpm_trusted_unseal(struct trusted_key_payload *p, char *datablob) { - struct trusted_key_payload *p; - struct trusted_key_payload *new_p; - struct trusted_key_options *new_o; - size_t datalen = prep->datalen; - char *datablob; + struct trusted_key_options *options = NULL; int ret = 0; + int tpm2; - if (key_is_negative(key)) - return -ENOKEY; - p = key->payload.data[0]; - if (!p->migratable) - return -EPERM; - if (datalen <= 0 || datalen > 32767 || !prep->data) - return -EINVAL; + tpm2 = tpm_is_tpm2(chip); + if (tpm2 < 0) + return tpm2; - datablob = kmalloc(datalen + 1, GFP_KERNEL); - if (!datablob) + options = trusted_options_alloc(); + if (!options) return -ENOMEM; - new_o = trusted_options_alloc(); - if (!new_o) { - ret = -ENOMEM; - goto out; - } - new_p = trusted_payload_alloc(key); - if (!new_p) { - ret = -ENOMEM; - goto out; - } - memcpy(datablob, prep->data, datalen); - datablob[datalen] = '\0'; - ret = datablob_parse(datablob, new_p, new_o); - if (ret != Opt_update) { - ret = -EINVAL; - kfree_sensitive(new_p); + ret = getoptions(datablob, p, options); + if (ret < 0) goto out; - } + dump_options(options); - if (!new_o->keyhandle) { + if (!options->keyhandle) { ret = -EINVAL; - kfree_sensitive(new_p); goto out; } - /* copy old key values, and reseal with new pcrs */ - new_p->migratable = p->migratable; - new_p->key_len = p->key_len; - memcpy(new_p->key, p->key, p->key_len); - dump_payload(p); - dump_payload(new_p); + if (tpm2) + ret = tpm2_unseal_trusted(chip, p, options); + else + ret = key_unseal(p, options); + if (ret < 0) + pr_info("tpm_trusted_key: key_unseal failed (%d)\n", ret); - ret = key_seal(new_p, new_o); - if (ret < 0) { - pr_info("trusted_key: key_seal failed (%d)\n", ret); - kfree_sensitive(new_p); - goto out; - } - if (new_o->pcrlock) { - ret = pcrlock(new_o->pcrlock); + if (options->pcrlock) { + ret = pcrlock(options->pcrlock); if (ret < 0) { - pr_info("trusted_key: pcrlock failed (%d)\n", ret); - kfree_sensitive(new_p); + pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret); goto out; } } - rcu_assign_keypointer(key, new_p); - call_rcu(&p->rcu, trusted_rcu_free); out: - kfree_sensitive(datablob); - kfree_sensitive(new_o); + kfree_sensitive(options); return ret; } -/* - * trusted_read - copy the sealed blob data to userspace in hex. - * On success, return to userspace the trusted key datablob size. - */ -static long trusted_read(const struct key *key, char *buffer, - size_t buflen) -{ - const struct trusted_key_payload *p; - char *bufp; - int i; - - p = dereference_key_locked(key); - if (!p) - return -EINVAL; - - if (buffer && buflen >= 2 * p->blob_len) { - bufp = buffer; - for (i = 0; i < p->blob_len; i++) - bufp = hex_byte_pack(bufp, p->blob[i]); - } - return 2 * p->blob_len; -} - -/* - * trusted_destroy - clear and free the key's payload - */ -static void trusted_destroy(struct key *key) +static int tpm_trusted_get_random(unsigned char *key, size_t key_len) { - kfree_sensitive(key->payload.data[0]); + return tpm_get_random(chip, key, key_len); } -struct key_type key_type_trusted = { - .name = "trusted", - .instantiate = trusted_instantiate, - .update = trusted_update, - .destroy = trusted_destroy, - .describe = user_describe, - .read = trusted_read, -}; - -EXPORT_SYMBOL_GPL(key_type_trusted); - static void trusted_shash_release(void) { if (hashalg) @@ -1182,14 +957,14 @@ static int __init trusted_shash_alloc(void) hmacalg = crypto_alloc_shash(hmac_alg, 0, 0); if (IS_ERR(hmacalg)) { - pr_info("trusted_key: could not allocate crypto %s\n", + pr_info("tpm_trusted_key: could not allocate crypto %s\n", hmac_alg); return PTR_ERR(hmacalg); } hashalg = crypto_alloc_shash(hash_alg, 0, 0); if (IS_ERR(hashalg)) { - pr_info("trusted_key: could not allocate crypto %s\n", + pr_info("tpm_trusted_key: could not allocate crypto %s\n", hash_alg); ret = PTR_ERR(hashalg); goto hashalg_fail; @@ -1217,16 +992,13 @@ static int __init init_digests(void) return 0; } -static int __init init_trusted(void) +static int __init init_tpm_trusted(void) { int ret; - /* encrypted_keys.ko depends on successful load of this module even if - * TPM is not used. - */ chip = tpm_default_chip(); if (!chip) - return 0; + return -ENODEV; ret = init_digests(); if (ret < 0) @@ -1247,7 +1019,7 @@ static int __init init_trusted(void) return ret; } -static void __exit cleanup_trusted(void) +static void __exit exit_tpm_trusted(void) { if (chip) { put_device(&chip->dev); @@ -1257,7 +1029,11 @@ static void __exit cleanup_trusted(void) } } -late_initcall(init_trusted); -module_exit(cleanup_trusted); - -MODULE_LICENSE("GPL"); +struct trusted_key_ops tpm_trusted_key_ops = { + .migratable = 1, /* migratable by default */ + .init = init_tpm_trusted, + .seal = tpm_trusted_seal, + .unseal = tpm_trusted_unseal, + .get_random = tpm_trusted_get_random, + .exit = exit_tpm_trusted, +}; 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Refer to Documentation/tee.txt for detailed information about TEE. Signed-off-by: Sumit Garg --- include/keys/trusted_tee.h | 55 ++++++ security/keys/trusted-keys/Makefile | 1 + security/keys/trusted-keys/trusted_core.c | 4 + security/keys/trusted-keys/trusted_tee.c | 278 ++++++++++++++++++++++++++++++ 4 files changed, 338 insertions(+) create mode 100644 include/keys/trusted_tee.h create mode 100644 security/keys/trusted-keys/trusted_tee.c diff --git a/include/keys/trusted_tee.h b/include/keys/trusted_tee.h new file mode 100644 index 0000000..2e2bb15 --- /dev/null +++ b/include/keys/trusted_tee.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019-2020 Linaro Ltd. + * + * Author: + * Sumit Garg + */ + +#ifndef __TEE_TRUSTED_KEY_H +#define __TEE_TRUSTED_KEY_H + +#include + +#define DRIVER_NAME "tee-trusted-key" + +/* + * Get random data for symmetric key + * + * [out] memref[0] Random data + */ +#define TA_CMD_GET_RANDOM 0x0 + +/* + * Seal trusted key using hardware unique key + * + * [in] memref[0] Plain key + * [out] memref[1] Sealed key datablob + */ +#define TA_CMD_SEAL 0x1 + +/* + * Unseal trusted key using hardware unique key + * + * [in] memref[0] Sealed key datablob + * [out] memref[1] Plain key + */ +#define TA_CMD_UNSEAL 0x2 + +/** + * struct trusted_key_private - TEE Trusted key private data + * @dev: TEE based Trusted key device. + * @ctx: TEE context handler. + * @session_id: Trusted key TA session identifier. + * @shm_pool: Memory pool shared with TEE device. + */ +struct trusted_key_private { + struct device *dev; + struct tee_context *ctx; + u32 session_id; + struct tee_shm *shm_pool; +}; + +extern struct trusted_key_ops tee_trusted_key_ops; + +#endif diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile index 49e3bcf..012dd78 100644 --- a/security/keys/trusted-keys/Makefile +++ b/security/keys/trusted-keys/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_TRUSTED_KEYS) += trusted.o trusted-y += trusted_core.o trusted-y += trusted_tpm1.o trusted-y += trusted_tpm2.o +trusted-y += trusted_tee.o diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c index 4ae3fb4..83a6a15 100644 --- a/security/keys/trusted-keys/trusted_core.c +++ b/security/keys/trusted-keys/trusted_core.c @@ -8,6 +8,7 @@ #include #include +#include #include #include #include @@ -24,6 +25,9 @@ static struct trusted_key_ops *available_trusted_key_ops[] = { #if defined(CONFIG_TCG_TPM) &tpm_trusted_key_ops, #endif +#if defined(CONFIG_TEE) + &tee_trusted_key_ops, +#endif }; static struct trusted_key_ops *trusted_key_ops; diff --git a/security/keys/trusted-keys/trusted_tee.c b/security/keys/trusted-keys/trusted_tee.c new file mode 100644 index 0000000..b414d52 --- /dev/null +++ b/security/keys/trusted-keys/trusted_tee.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019-2020 Linaro Ltd. + * + * Author: + * Sumit Garg + */ + +#include +#include +#include +#include +#include + +#include +#include + +static struct trusted_key_private pvt_data; + +/* + * Have the TEE seal(encrypt) the symmetric key + */ +static int tee_trusted_seal(struct trusted_key_payload *p, char *datablob) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm_in = tee_shm_register(pvt_data.ctx, (unsigned long)p->key, + p->key_len, TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_in)) { + dev_err(pvt_data.dev, "key shm register failed\n"); + return PTR_ERR(reg_shm_in); + } + + reg_shm_out = tee_shm_register(pvt_data.ctx, (unsigned long)p->blob, + sizeof(p->blob), TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_out)) { + dev_err(pvt_data.dev, "blob shm register failed\n"); + ret = PTR_ERR(reg_shm_out); + goto out; + } + + inv_arg.func = TA_CMD_SEAL; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT; + param[0].u.memref.shm = reg_shm_in; + param[0].u.memref.size = p->key_len; + param[0].u.memref.shm_offs = 0; + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[1].u.memref.shm = reg_shm_out; + param[1].u.memref.size = sizeof(p->blob); + param[1].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_SEAL invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + p->blob_len = param[1].u.memref.size; + } + +out: + if (reg_shm_out) + tee_shm_free(reg_shm_out); + if (reg_shm_in) + tee_shm_free(reg_shm_in); + + return ret; +} + +/* + * Have the TEE unseal(decrypt) the symmetric key + */ +static int tee_trusted_unseal(struct trusted_key_payload *p, char *datablob) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm_in = tee_shm_register(pvt_data.ctx, (unsigned long)p->blob, + p->blob_len, TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_in)) { + dev_err(pvt_data.dev, "blob shm register failed\n"); + return PTR_ERR(reg_shm_in); + } + + reg_shm_out = tee_shm_register(pvt_data.ctx, (unsigned long)p->key, + sizeof(p->key), TEE_SHM_DMA_BUF | + TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm_out)) { + dev_err(pvt_data.dev, "key shm register failed\n"); + ret = PTR_ERR(reg_shm_out); + goto out; + } + + inv_arg.func = TA_CMD_UNSEAL; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT; + param[0].u.memref.shm = reg_shm_in; + param[0].u.memref.size = p->blob_len; + param[0].u.memref.shm_offs = 0; + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[1].u.memref.shm = reg_shm_out; + param[1].u.memref.size = sizeof(p->key); + param[1].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_UNSEAL invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + p->key_len = param[1].u.memref.size; + } + +out: + if (reg_shm_out) + tee_shm_free(reg_shm_out); + if (reg_shm_in) + tee_shm_free(reg_shm_in); + + return ret; +} + +/* + * Have the TEE generate random symmetric key + */ +static int tee_trusted_get_random(unsigned char *key, size_t key_len) +{ + int ret = 0; + struct tee_ioctl_invoke_arg inv_arg; + struct tee_param param[4]; + struct tee_shm *reg_shm = NULL; + + memset(&inv_arg, 0, sizeof(inv_arg)); + memset(¶m, 0, sizeof(param)); + + reg_shm = tee_shm_register(pvt_data.ctx, (unsigned long)key, key_len, + TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED); + if (IS_ERR(reg_shm)) { + dev_err(pvt_data.dev, "key shm register failed\n"); + return PTR_ERR(reg_shm); + } + + inv_arg.func = TA_CMD_GET_RANDOM; + inv_arg.session = pvt_data.session_id; + inv_arg.num_params = 4; + + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT; + param[0].u.memref.shm = reg_shm; + param[0].u.memref.size = key_len; + param[0].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + dev_err(pvt_data.dev, "TA_CMD_GET_RANDOM invoke err: %x\n", + inv_arg.ret); + ret = -EFAULT; + } else { + ret = param[0].u.memref.size; + } + + tee_shm_free(reg_shm); + + return ret; +} + +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) +{ + if (ver->impl_id == TEE_IMPL_ID_OPTEE) + return 1; + else + return 0; +} + +static int trusted_key_probe(struct device *dev) +{ + struct tee_client_device *rng_device = to_tee_client_device(dev); + int ret = 0, err = -ENODEV; + struct tee_ioctl_open_session_arg sess_arg; + + memset(&sess_arg, 0, sizeof(sess_arg)); + + pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, + NULL); + if (IS_ERR(pvt_data.ctx)) + return -ENODEV; + + memcpy(sess_arg.uuid, rng_device->id.uuid.b, TEE_IOCTL_UUID_LEN); + sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL; + sess_arg.num_params = 0; + + ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL); + if ((ret < 0) || (sess_arg.ret != 0)) { + dev_err(dev, "tee_client_open_session failed, err: %x\n", + sess_arg.ret); + err = -EINVAL; + goto out_ctx; + } + pvt_data.session_id = sess_arg.session; + + ret = register_key_type(&key_type_trusted); + if (ret < 0) + goto out_sess; + + pvt_data.dev = dev; + + return 0; + +out_sess: + tee_client_close_session(pvt_data.ctx, pvt_data.session_id); +out_ctx: + tee_client_close_context(pvt_data.ctx); + + return err; +} + +static int trusted_key_remove(struct device *dev) +{ + unregister_key_type(&key_type_trusted); + tee_client_close_session(pvt_data.ctx, pvt_data.session_id); + tee_client_close_context(pvt_data.ctx); + + return 0; +} + +static const struct tee_client_device_id trusted_key_id_table[] = { + {UUID_INIT(0xf04a0fe7, 0x1f5d, 0x4b9b, + 0xab, 0xf7, 0x61, 0x9b, 0x85, 0xb4, 0xce, 0x8c)}, + {} +}; +MODULE_DEVICE_TABLE(tee, trusted_key_id_table); + +static struct tee_client_driver trusted_key_driver = { + .id_table = trusted_key_id_table, + .driver = { + .name = DRIVER_NAME, + .bus = &tee_bus_type, + .probe = trusted_key_probe, + .remove = trusted_key_remove, + }, +}; + +static int __init init_tee_trusted(void) +{ + return driver_register(&trusted_key_driver.driver); +} + +static void __exit exit_tee_trusted(void) +{ + driver_unregister(&trusted_key_driver.driver); +} + +struct trusted_key_ops tee_trusted_key_ops = { + .migratable = 0, /* non-migratable */ + .init = init_tee_trusted, + .seal = tee_trusted_seal, + .unseal = tee_trusted_unseal, + .get_random = tee_trusted_get_random, + .exit = exit_tee_trusted, +}; 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Thu, 17 Sep 2020 06:47:33 -0700 (PDT) From: Sumit Garg To: jarkko.sakkinen@linux.intel.com, zohar@linux.ibm.com, jejb@linux.ibm.com Cc: dhowells@redhat.com, jens.wiklander@linaro.org, corbet@lwn.net, jmorris@namei.org, serge@hallyn.com, casey@schaufler-ca.com, janne.karhunen@gmail.com, daniel.thompson@linaro.org, Markus.Wamser@mixed-mode.de, lhinds@redhat.com, keyrings@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org, Sumit Garg Subject: [PATCH v6 3/4] doc: trusted-encrypted: updates with TEE as a new trust source Date: Thu, 17 Sep 2020 19:16:37 +0530 Message-Id: <1600350398-4813-4-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> References: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: Update documentation for Trusted and Encrypted Keys with TEE as a new trust source. Following is brief description of updates: - Add a section to demostrate a list of supported devices along with their security properties/guarantees. - Add a key generation section. - Updates for usage section including differences specific to a trust source. Signed-off-by: Sumit Garg Reviewed-by: Jarkko Sakkinen --- Documentation/security/keys/trusted-encrypted.rst | 203 ++++++++++++++++++---- 1 file changed, 171 insertions(+), 32 deletions(-) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 9483a74..a355045 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -6,30 +6,161 @@ Trusted and Encrypted Keys are two new key types added to the existing kernel key ring service. Both of these new types are variable length symmetric keys, and in both cases all keys are created in the kernel, and user space sees, stores, and loads only encrypted blobs. Trusted Keys require the availability -of a Trusted Platform Module (TPM) chip for greater security, while Encrypted -Keys can be used on any system. All user level blobs, are displayed and loaded -in hex ascii for convenience, and are integrity verified. +of a Trust Source for greater security, while Encrypted Keys can be used on any +system. All user level blobs, are displayed and loaded in hex ascii for +convenience, and are integrity verified. -Trusted Keys use a TPM both to generate and to seal the keys. Keys are sealed -under a 2048 bit RSA key in the TPM, and optionally sealed to specified PCR -(integrity measurement) values, and only unsealed by the TPM, if PCRs and blob -integrity verifications match. A loaded Trusted Key can be updated with new -(future) PCR values, so keys are easily migrated to new pcr values, such as -when the kernel and initramfs are updated. The same key can have many saved -blobs under different PCR values, so multiple boots are easily supported. -TPM 1.2 -------- +Trust Source +============ -By default, trusted keys are sealed under the SRK, which has the default -authorization value (20 zeros). This can be set at takeownership time with the -trouser's utility: "tpm_takeownership -u -z". +Trust Source provides the source of security for the Trusted Keys, on which +basis Trusted Keys establishes a Trust model with its user. A Trust Source could +differ from one system to another depending on its security requirements. It +could be either an off-chip device or an on-chip device. Following section +demostrates a list of supported devices along with their security properties/ +guarantees: -TPM 2.0 -------- + * Root of trust for storage -The user must first create a storage key and make it persistent, so the key is -available after reboot. This can be done using the following commands. + (1) TPM (Trusted Platform Module: hardware device) + + Rooted to Storage Root Key (SRK) which never leaves the TPM that + provides crypto operation to establish root of trust for storage. + + (2) TEE (Trusted Execution Environment: OP-TEE based on Arm TrustZone) + + Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip + fuses and is accessible to TEE only. + + * Execution isolation + + (1) TPM + + Fixed set of operations running in isolated execution environment. + + (2) TEE + + Customizable set of operations running in isolated execution + environment verified via Secure/Trusted boot process. + + * Optional binding to platform integrity state + + (1) TPM + + Keys can be optionally sealed to specified PCR (integrity measurement) + values, and only unsealed by the TPM, if PCRs and blob integrity + verifications match. A loaded Trusted Key can be updated with new + (future) PCR values, so keys are easily migrated to new PCR values, + such as when the kernel and initramfs are updated. The same key can + have many saved blobs under different PCR values, so multiple boots are + easily supported. + + (2) TEE + + Relies on Secure/Trusted boot process for platform integrity. It can + be extended with TEE based measured boot process. + + * On-chip versus off-chip + + (1) TPM + + Off-chip device connected via serial bus (like I2C, SPI etc.) exposing + physical access which represents an attack surface that can be + mitigated via tamper detection. + + (2) TEE + + On-chip functionality, immune to this attack surface. + + * Memory attacks (DRAM based like attaching a bus monitor etc.) + + (1) TPM + + Immune to these attacks as it doesn’t make use of system DRAM. + + (2) TEE + + An implementation based on TrustZone protected DRAM is susceptible to + such attacks. In order to mitigate these attacks one needs to rely on + on-chip secure RAM to store secrets or have the entire TEE + implementation based on on-chip secure RAM. An alternative mitigation + would be to use encrypted DRAM. + + * Side-channel attacks (cache, memory, CPU or time based) + + (1) TPM + + Immune to side-channel attacks as its resources are isolated from the + main OS. + + (2) TEE + + A careful implementation is required to mitigate against these attacks + for resources which are shared (eg. shared memory) with the main OS. + Cache and CPU based side-channel attacks can be mitigated via + invalidating caches and CPU registers during context switch to and from + the secure world. + To mitigate against time based attacks, one needs to have time + invariant implementations (like crypto algorithms etc.). + + * Resistance to physical attacks (power analysis, electromagnetic emanation, + probes etc.) + + (1) TPM + + Provides limited protection utilizing tamper resistance. + + (2) TEE + + Provides no protection by itself, relies on the underlying platform for + features such as tamper resistance. + + +Key Generation +============== + +Trusted Keys +------------ + +New keys are created from trust source generated random numbers, and are +encrypted/decrypted using trust source storage root key. + + * TPM (hardware device) based RNG + + Strength of random numbers may vary from one device manufacturer to + another. + + * TEE (OP-TEE based on Arm TrustZone) based RNG + + RNG is customizable as per platform needs. It can either be direct output + from platform specific hardware RNG or a software based Fortuna CSPRNG + which can be seeded via multiple entropy sources. + +Encrypted Keys +-------------- + +Encrypted keys do not depend on a trust source, and are faster, as they use AES +for encryption/decryption. New keys are created from kernel generated random +numbers, and are encrypted/decrypted using a specified ‘master’ key. The +‘master’ key can either be a trusted-key or user-key type. The main disadvantage +of encrypted keys is that if they are not rooted in a trusted key, they are only +as secure as the user key encrypting them. The master user key should therefore +be loaded in as secure a way as possible, preferably early in boot. + + +Usage +===== + +Trusted Keys usage: TPM +----------------------- + +TPM 1.2: By default, trusted keys are sealed under the SRK, which has the +default authorization value (20 zeros). This can be set at takeownership time +with the TrouSerS utility: "tpm_takeownership -u -z". + +TPM 2.0: The user must first create a storage key and make it persistent, so the +key is available after reboot. This can be done using the following commands. With the IBM TSS 2 stack:: @@ -79,14 +210,21 @@ TPM_STORED_DATA format. The key length for new keys are always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits), the upper limit is to fit within the 2048 bit SRK (RSA) keylength, with all necessary structure/padding. -Encrypted keys do not depend on a TPM, and are faster, as they use AES for -encryption/decryption. New keys are created from kernel generated random -numbers, and are encrypted/decrypted using a specified 'master' key. The -'master' key can either be a trusted-key or user-key type. The main -disadvantage of encrypted keys is that if they are not rooted in a trusted key, -they are only as secure as the user key encrypting them. The master user key -should therefore be loaded in as secure a way as possible, preferably early in -boot. +Trusted Keys usage: TEE +----------------------- + +Usage:: + + keyctl add trusted name "new keylen" ring + keyctl add trusted name "load hex_blob" ring + keyctl print keyid + +"keyctl print" returns an ascii hex copy of the sealed key, which is in format +specific to TEE device implementation. The key length for new keys are always +in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). + +Encrypted Keys usage +-------------------- The decrypted portion of encrypted keys can contain either a simple symmetric key or a more complex structure. The format of the more complex structure is @@ -104,8 +242,8 @@ Where:: format:= 'default | ecryptfs | enc32' key-type:= 'trusted' | 'user' - Examples of trusted and encrypted key usage: +-------------------------------------------- Create and save a trusted key named "kmk" of length 32 bytes. @@ -151,7 +289,7 @@ Load a trusted key from the saved blob:: f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b e4a8aea2b607ec96931e6f4d4fe563ba -Reseal a trusted key under new pcr values:: +Reseal (TPM specific) a trusted key under new PCR values:: $ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`" $ keyctl print 268728824 @@ -165,11 +303,12 @@ Reseal a trusted key under new pcr values:: 7ef6a24defe4846104209bf0c3eced7fa1a672ed5b125fc9d8cd88b476a658a4434644ef df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f06b3b8 + The initial consumer of trusted keys is EVM, which at boot time needs a high -quality symmetric key for HMAC protection of file metadata. The use of a +quality symmetric key for HMAC protection of file metadata. The use of a trusted key provides strong guarantees that the EVM key has not been -compromised by a user level problem, and when sealed to specific boot PCR -values, protects against boot and offline attacks. Create and save an +compromised by a user level problem, and when sealed to a platform integrity +state, protects against boot and offline attacks. Create and save an encrypted key "evm" using the above trusted key "kmk": option 1: omitting 'format':: From patchwork Thu Sep 17 13:46:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sumit Garg X-Patchwork-Id: 11782609 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 2577814F6 for ; Thu, 17 Sep 2020 14:19:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F020E21D43 for ; Thu, 17 Sep 2020 14:19:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="zfzwax3P" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727251AbgIQOMt (ORCPT ); Thu, 17 Sep 2020 10:12:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727249AbgIQN6l (ORCPT ); Thu, 17 Sep 2020 09:58:41 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD55FC0610D6 for ; Thu, 17 Sep 2020 06:47:44 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id d19so1174017pld.0 for ; Thu, 17 Sep 2020 06:47:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=+R0CfwNbMgOaTG4ScznT7OJX0b8ugIojVEfeSnnqNTc=; b=zfzwax3PpdhSOHwd1Dziyh/EVuvLFMJgWgUyuNomMMIfOy+ltMgttpjv2PkG0QUrMg VQ4tkC9yB0StxHOspic8lBEaytG89CvgXfNpG01BM65wRcafv1kgrlPLj2GCQY94wTgE zMNTKBDl6YPTGmySD1a74bYQ5eCzuSljS+Xze4jq2M4G23zm2MM6oTyfwCwJdDnwWzFS hSRNWA3rzc6ZJT5GuNLKkUue9ferEZlkW82DuXD+E8Su8oaJCTy5uj93w/vR2eM1e+LZ OdZsqPF0JYLGzk0yeFhD0uDG4zhhs/QSWomdvTcDXSvQQtWEbM9IysNVgavJZt0qoVNB SByQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=+R0CfwNbMgOaTG4ScznT7OJX0b8ugIojVEfeSnnqNTc=; b=VjqigLlDFllLPNGKWvbsva+FRcVLy/r70mfTyq7w0eQ3tLIUJcoDwzc6zifEZzfhKN m+XQh9pPotnNfPoWOtcO0CqSLkpbzRKayMrxsiSscIkVc89KWoY2bo7fV4xbo+nGPd+u oYuEw+BkE5exA6AOpy0J2UZNlhk5ftV0UjWhKAz75xMq4/8TBRog7FRBOVuR6kce5HbK MIw7DIAbGNafNikFugG05Djd3hi2qpHxccJ0HgdJPFX1h35qTwYwYhm0couBHx3XFVx1 bNW5SzPEZKj+0C/4klHzFnIN7GKGPoI6PC+BKmjOdbx3S/mD+/OBYe72WeIZCEUIiY4T Tx7w== X-Gm-Message-State: AOAM5302e1rJPqm5zLw0yna1UPgWz4xwWHzI4HaHbrV1CQswaQtr6yiN 47MlDlDx4//GHUQUJVDFSVT+eg== X-Google-Smtp-Source: ABdhPJyvy8jjWm23ZilkLS4jB5OQY9gVJSrgQpws0JzwxO3vK5veKrElGyPGUmVKb+AhTbMGL/UX9g== X-Received: by 2002:a17:902:8305:b029:d1:cbfc:79b7 with SMTP id bd5-20020a1709028305b02900d1cbfc79b7mr17679996plb.33.1600350464395; Thu, 17 Sep 2020 06:47:44 -0700 (PDT) Received: from localhost.localdomain ([117.252.66.163]) by smtp.gmail.com with ESMTPSA id i73sm6821120pfe.67.2020.09.17.06.47.35 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Sep 2020 06:47:43 -0700 (PDT) From: Sumit Garg To: jarkko.sakkinen@linux.intel.com, zohar@linux.ibm.com, jejb@linux.ibm.com Cc: dhowells@redhat.com, jens.wiklander@linaro.org, corbet@lwn.net, jmorris@namei.org, serge@hallyn.com, casey@schaufler-ca.com, janne.karhunen@gmail.com, daniel.thompson@linaro.org, Markus.Wamser@mixed-mode.de, lhinds@redhat.com, keyrings@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org, Sumit Garg Subject: [PATCH v6 4/4] MAINTAINERS: Add entry for TEE based Trusted Keys Date: Thu, 17 Sep 2020 19:16:38 +0530 Message-Id: <1600350398-4813-5-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> References: <1600350398-4813-1-git-send-email-sumit.garg@linaro.org> Precedence: bulk List-ID: Add MAINTAINERS entry for TEE based Trusted Keys framework. Signed-off-by: Sumit Garg Acked-by: Jarkko Sakkinen --- MAINTAINERS | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 0d0862b..0a913ba 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9668,6 +9668,14 @@ F: include/keys/trusted-type.h F: include/keys/trusted_tpm.h F: security/keys/trusted-keys/ +KEYS-TRUSTED-TEE +M: Sumit Garg +L: linux-integrity@vger.kernel.org +L: keyrings@vger.kernel.org +S: Supported +F: include/keys/trusted_tee.h +F: security/keys/trusted-keys/trusted_tee.c + KEYS/KEYRINGS M: David Howells M: Jarkko Sakkinen