From patchwork Fri Nov 20 18:04:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921507 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03EB1C2D0E4 for ; Fri, 20 Nov 2020 18:05:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3C3C2242B for ; Fri, 20 Nov 2020 18:05:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729243AbgKTSEh (ORCPT ); Fri, 20 Nov 2020 13:04:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727959AbgKTSEg (ORCPT ); Fri, 20 Nov 2020 13:04:36 -0500 Received: from smtp-1909.mail.infomaniak.ch (smtp-1909.mail.infomaniak.ch [IPv6:2001:1600:3:17::1909]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 632C8C0613CF; Fri, 20 Nov 2020 10:04:36 -0800 (PST) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FG4VwpzlhGW4; Fri, 20 Nov 2020 19:04:34 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FG2R9Dzlh8T9; Fri, 20 Nov 2020 19:04:34 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 1/9] certs: Fix blacklisted hexadecimal hash string check Date: Fri, 20 Nov 2020 19:04:18 +0100 Message-Id: <20201120180426.922572-2-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün When looking for a blacklisted hash, bin2hex() is used to transform a binary hash to an ascii (lowercase) hexadecimal string. This string is then search for in the description of the keys from the blacklist keyring. When adding a key to the blacklist keyring, blacklist_vet_description() checks the hash prefix and the hexadecimal string, but not that this string is lowercase. It is then valid to set hashes with uppercase hexadecimal, which will be silently ignored by the kernel. Add an additional check to blacklist_vet_description() to check that hexadecimal strings are in lowercase. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- certs/blacklist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 6514f9ebc943..4e1a58170d5c 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -37,7 +37,7 @@ static int blacklist_vet_description(const char *desc) found_colon: desc++; for (; *desc; desc++) { - if (!isxdigit(*desc)) + if (!isxdigit(*desc) || isupper(*desc)) return -EINVAL; n++; } From patchwork Fri Nov 20 18:04:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921505 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75847C83012 for ; Fri, 20 Nov 2020 18:05:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D5FE2242B for ; Fri, 20 Nov 2020 18:05:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729380AbgKTSE5 (ORCPT ); Fri, 20 Nov 2020 13:04:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729368AbgKTSEj (ORCPT ); Fri, 20 Nov 2020 13:04:39 -0500 Received: from smtp-bc0c.mail.infomaniak.ch (smtp-bc0c.mail.infomaniak.ch [IPv6:2001:1600:4:17::bc0c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3845AC0613CF for ; Fri, 20 Nov 2020 10:04:39 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FJ0GQ4zlhThj; Fri, 20 Nov 2020 19:04:36 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FH3RmPzlh8T4; Fri, 20 Nov 2020 19:04:35 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 2/9] certs: Make blacklist_vet_description() more strict Date: Fri, 20 Nov 2020 19:04:19 +0100 Message-Id: <20201120180426.922572-3-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Before exposing this new key type to user space, make sure that only meaningful blacklisted hashes are accepted. This is also checked for builtin blacklisted hashes, but a following commit make sure that the user will notice (at built time) and will fix the configuration if it already included errors. Check that a blacklist key description starts with a valid prefix and then a valid hexadecimal string. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- certs/blacklist.c | 46 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 4e1a58170d5c..961359885881 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -17,6 +17,16 @@ #include #include "blacklist.h" +/* + * According to crypto/asymmetric_keys/x509_cert_parser.c:x509_note_pkey_algo(), + * the size of the currently longest supported hash algorithm is 512 bits, + * which translates into 128 hex characters. + */ +#define MAX_HASH_LEN 128 + +static const char tbs_prefix[] = "tbs"; +static const char bin_prefix[] = "bin"; + static struct key *blacklist_keyring; /* @@ -25,24 +35,40 @@ static struct key *blacklist_keyring; */ static int blacklist_vet_description(const char *desc) { - int n = 0; - - if (*desc == ':') - return -EINVAL; - for (; *desc; desc++) - if (*desc == ':') - goto found_colon; + int i, prefix_len, tbs_step = 0, bin_step = 0; + + /* The following algorithm only works if prefix lenghts match. */ + BUILD_BUG_ON(sizeof(tbs_prefix) != sizeof(bin_prefix)); + prefix_len = sizeof(tbs_prefix) - 1; + for (i = 0; *desc; desc++, i++) { + if (*desc == ':') { + if (tbs_step == prefix_len) + goto found_colon; + if (bin_step == prefix_len) + goto found_colon; + return -EINVAL; + } + if (i >= prefix_len) + return -EINVAL; + if (*desc == tbs_prefix[i]) + tbs_step++; + if (*desc == bin_prefix[i]) + bin_step++; + } return -EINVAL; found_colon: desc++; - for (; *desc; desc++) { + for (i = 0; *desc && i < MAX_HASH_LEN; desc++, i++) { if (!isxdigit(*desc) || isupper(*desc)) return -EINVAL; - n++; } + if (*desc) + /* The hash is greater than MAX_HASH_LEN. */ + return -EINVAL; - if (n == 0 || n & 1) + /* Checks for an even number of hexadecimal characters. */ + if (i == 0 || i & 1) return -EINVAL; return 0; } From patchwork Fri Nov 20 18:04:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921503 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABDDDC83013 for ; Fri, 20 Nov 2020 18:05:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F41E2408E for ; Fri, 20 Nov 2020 18:05:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729176AbgKTSEj (ORCPT ); Fri, 20 Nov 2020 13:04:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729366AbgKTSEj (ORCPT ); Fri, 20 Nov 2020 13:04:39 -0500 Received: from smtp-190d.mail.infomaniak.ch (smtp-190d.mail.infomaniak.ch [IPv6:2001:1600:3:17::190d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5404C0613CF for ; Fri, 20 Nov 2020 10:04:38 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FK01NSzlhMNm; Fri, 20 Nov 2020 19:04:37 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FJ57Hnzlh8T2; Fri, 20 Nov 2020 19:04:36 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 3/9] certs: Factor out the blacklist hash creation Date: Fri, 20 Nov 2020 19:04:20 +0100 Message-Id: <20201120180426.922572-4-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Factor out the blacklist hash creation with the get_raw_hash() helper. This also centralize the "tbs" and "bin" prefixes and make them private, which help to manage them consistently. Cc: David Howells Cc: David S. Miller Cc: David Woodhouse Cc: Herbert Xu Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün --- certs/blacklist.c | 73 ++++++++++++++----- crypto/asymmetric_keys/x509_public_key.c | 3 +- include/keys/system_keyring.h | 14 +++- .../platform_certs/keyring_handler.c | 26 +------ 4 files changed, 70 insertions(+), 46 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 961359885881..0d2c959e9422 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -102,11 +102,43 @@ static struct key_type key_type_blacklist = { .describe = blacklist_describe, }; +static char *get_raw_hash(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) +{ + size_t type_len; + const char *type_prefix; + char *buffer, *p; + + switch (hash_type) { + case BLACKLIST_HASH_X509_TBS: + type_len = sizeof(tbs_prefix) - 1; + type_prefix = tbs_prefix; + break; + case BLACKLIST_HASH_BINARY: + type_len = sizeof(bin_prefix) - 1; + type_prefix = bin_prefix; + break; + default: + WARN_ON_ONCE(1); + return ERR_PTR(-EINVAL); + } + buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + p = memcpy(buffer, type_prefix, type_len); + p += type_len; + *p++ = ':'; + bin2hex(p, hash, hash_len); + p += hash_len * 2; + *p = '\0'; + return buffer; +} + /** - * mark_hash_blacklisted - Add a hash to the system blacklist + * mark_raw_hash_blacklisted - Add a hash to the system blacklist * @hash - The hash as a hex string with a type prefix (eg. "tbs:23aa429783") */ -int mark_hash_blacklisted(const char *hash) +static int mark_raw_hash_blacklisted(const char *hash) { key_ref_t key; @@ -126,29 +158,33 @@ int mark_hash_blacklisted(const char *hash) return 0; } +int mark_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) +{ + const char *buffer; + + buffer = get_raw_hash(hash, hash_len, hash_type); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + kfree(buffer); + return 0; +} /** * is_hash_blacklisted - Determine if a hash is blacklisted * @hash: The hash to be checked as a binary blob * @hash_len: The length of the binary hash - * @type: Type of hash + * @hash_type: Type of hash */ -int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type) +int is_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) { key_ref_t kref; - size_t type_len = strlen(type); - char *buffer, *p; + const char *buffer; int ret = 0; - buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); - if (!buffer) - return -ENOMEM; - p = memcpy(buffer, type, type_len); - p += type_len; - *p++ = ':'; - bin2hex(p, hash, hash_len); - p += hash_len * 2; - *p = 0; - + buffer = get_raw_hash(hash, hash_len, hash_type); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); kref = keyring_search(make_key_ref(blacklist_keyring, true), &key_type_blacklist, buffer, false); if (!IS_ERR(kref)) { @@ -163,7 +199,8 @@ EXPORT_SYMBOL_GPL(is_hash_blacklisted); int is_binary_blacklisted(const u8 *hash, size_t hash_len) { - if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED) + if (is_hash_blacklisted(hash, hash_len, BLACKLIST_HASH_BINARY) == + -EKEYREJECTED) return -EPERM; return 0; @@ -194,7 +231,7 @@ static int __init blacklist_init(void) panic("Can't allocate system blacklist keyring\n"); for (bl = blacklist_hashes; *bl; bl++) - if (mark_hash_blacklisted(*bl) < 0) + if (mark_raw_hash_blacklisted(*bl) < 0) pr_err("- blacklisting failed\n"); return 0; } diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index ae450eb8be14..3b7dba5e4cd9 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -81,7 +81,8 @@ int x509_get_sig_params(struct x509_certificate *cert) if (ret < 0) goto error_2; - ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs"); + ret = is_hash_blacklisted(sig->digest, sig->digest_size, + BLACKLIST_HASH_X509_TBS); if (ret == -EKEYREJECTED) { pr_err("Cert %*phN is blacklisted\n", sig->digest_size, sig->digest); diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index fb8b07daa9d1..b184d8743e23 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -10,6 +10,13 @@ #include +enum blacklist_hash_type { + /* TBSCertificate hash */ + BLACKLIST_HASH_X509_TBS = 1, + /* Raw data hash */ + BLACKLIST_HASH_BINARY = 2, +}; + #ifdef CONFIG_SYSTEM_TRUSTED_KEYRING extern int restrict_link_by_builtin_trusted(struct key *keyring, @@ -32,13 +39,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted( #endif #ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING -extern int mark_hash_blacklisted(const char *hash); +extern int mark_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type); extern int is_hash_blacklisted(const u8 *hash, size_t hash_len, - const char *type); + enum blacklist_hash_type hash_type); extern int is_binary_blacklisted(const u8 *hash, size_t hash_len); #else static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len, - const char *type) + enum blacklist_hash_type hash_type) { return 0; } diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c index c5ba695c10e3..4a78fa1fde53 100644 --- a/security/integrity/platform_certs/keyring_handler.c +++ b/security/integrity/platform_certs/keyring_handler.c @@ -15,35 +15,13 @@ static efi_guid_t efi_cert_x509_sha256_guid __initdata = EFI_CERT_X509_SHA256_GUID; static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID; -/* - * Blacklist a hash. - */ -static __init void uefi_blacklist_hash(const char *source, const void *data, - size_t len, const char *type, - size_t type_len) -{ - char *hash, *p; - - hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL); - if (!hash) - return; - p = memcpy(hash, type, type_len); - p += type_len; - bin2hex(p, data, len); - p += len * 2; - *p = 0; - - mark_hash_blacklisted(hash); - kfree(hash); -} - /* * Blacklist an X509 TBS hash. */ static __init void uefi_blacklist_x509_tbs(const char *source, const void *data, size_t len) { - uefi_blacklist_hash(source, data, len, "tbs:", 4); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS); } /* @@ -52,7 +30,7 @@ static __init void uefi_blacklist_x509_tbs(const char *source, static __init void uefi_blacklist_binary(const char *source, const void *data, size_t len) { - uefi_blacklist_hash(source, data, len, "bin:", 4); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY); } /* From patchwork Fri Nov 20 18:04:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921491 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCA62C64E69 for ; Fri, 20 Nov 2020 18:04:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7DBF12242B for ; Fri, 20 Nov 2020 18:04:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729391AbgKTSEk (ORCPT ); Fri, 20 Nov 2020 13:04:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729408AbgKTSEk (ORCPT ); Fri, 20 Nov 2020 13:04:40 -0500 Received: from smtp-42ad.mail.infomaniak.ch (smtp-42ad.mail.infomaniak.ch [IPv6:2001:1600:3:17::42ad]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5724C0613CF for ; Fri, 20 Nov 2020 10:04:39 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FL12GfzlhQYW; Fri, 20 Nov 2020 19:04:38 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FK66jDzlh8TJ; Fri, 20 Nov 2020 19:04:37 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 4/9] certs: Check that builtin blacklist hashes are valid Date: Fri, 20 Nov 2020 19:04:21 +0100 Message-Id: <20201120180426.922572-5-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Add and use a check-blacklist-hashes.awk script to make sure that the builtin blacklist hashes will be approved by the run time blacklist description checks. This is useful to debug invalid hash formats, and it make sure that previous hashes which could have been loaded in the kernel (but ignored) are now noticed and deal with by the user. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- MAINTAINERS | 1 + certs/.gitignore | 1 + certs/Makefile | 15 +++++++++++- scripts/check-blacklist-hashes.awk | 37 ++++++++++++++++++++++++++++++ 4 files changed, 53 insertions(+), 1 deletion(-) create mode 100755 scripts/check-blacklist-hashes.awk diff --git a/MAINTAINERS b/MAINTAINERS index e451dcce054f..a5b0c59f55a0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4090,6 +4090,7 @@ L: keyrings@vger.kernel.org S: Maintained F: Documentation/admin-guide/module-signing.rst F: certs/ +F: scripts/check-blacklist-hashes.awk F: scripts/extract-cert.c F: scripts/sign-file.c diff --git a/certs/.gitignore b/certs/.gitignore index 2a2483990686..42cc2ac24b93 100644 --- a/certs/.gitignore +++ b/certs/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only +blacklist_hashes_checked x509_certificate_list diff --git a/certs/Makefile b/certs/Makefile index f4c25b67aad9..36d45b85e069 100644 --- a/certs/Makefile +++ b/certs/Makefile @@ -6,7 +6,20 @@ obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"") + +quiet_cmd_check_blacklist_hashes = CHECK $(patsubst "%",%,$(2)) + cmd_check_blacklist_hashes = $(AWK) -f scripts/check-blacklist-hashes.awk $(2); touch $@ + +$(eval $(call config_filename,SYSTEM_BLACKLIST_HASH_LIST)) + +$(obj)/blacklist_hashes.o: $(obj)/blacklist_hashes_checked + +targets += blacklist_hashes_checked +$(obj)/blacklist_hashes_checked: $(SYSTEM_BLACKLIST_HASH_LIST_SRCPREFIX)$(SYSTEM_BLACKLIST_HASH_LIST_FILENAME) scripts/check-blacklist-hashes.awk FORCE + $(call if_changed,check_blacklist_hashes,$(SYSTEM_BLACKLIST_HASH_LIST_SRCPREFIX)$(CONFIG_SYSTEM_BLACKLIST_HASH_LIST)) + obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o + else obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o endif @@ -29,7 +42,7 @@ $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREF $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS)) endif # CONFIG_SYSTEM_TRUSTED_KEYRING -clean-files := x509_certificate_list .x509.list +clean-files := x509_certificate_list .x509.list blacklist_hashes_checked ifeq ($(CONFIG_MODULE_SIG),y) ############################################################################### diff --git a/scripts/check-blacklist-hashes.awk b/scripts/check-blacklist-hashes.awk new file mode 100755 index 000000000000..4d3c676b7aef --- /dev/null +++ b/scripts/check-blacklist-hashes.awk @@ -0,0 +1,37 @@ +#!/usr/bin/awk -f +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright © 2020, Microsoft Corporation. All rights reserved. +# +# Author: Mickaël Salaün +# +# Check that a CONFIG_SYSTEM_BLACKLIST_HASH_LIST file contains a valid array of +# hash strings. Such string must start with a prefix ("tbs" or "bin"), then a +# colon (":"), and finally an even number of hexadecimal lowercase characters +# (up to 128). + +BEGIN { + RS = "," +} +{ + if (!match($0, "^[ \t\n\r]*\"([^\"]*)\"[ \t\n\r]*$", part1)) { + print "Not a string (item " NR "):", $0; + exit 1; + } + if (!match(part1[1], "^(tbs|bin):(.*)$", part2)) { + print "Unknown prefix (item " NR "):", part1[1]; + exit 1; + } + if (!match(part2[2], "^([0-9a-z]+)$", part3)) { + print "Not a lowercase hexadecimal string (item " NR "):", part2[2]; + exit 1; + } + if (length(part3[1]) > 128) { + print "Hash string too long (item " NR "):", part3[1]; + exit 1; + } + if (length(part3[1]) % 2 == 1) { + print "Not an even number of hexadecimal characters (item " NR "):", part3[1]; + exit 1; + } +} From patchwork Fri Nov 20 18:04:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921497 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A87DBC56201 for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 763F52240B for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729569AbgKTSEy (ORCPT ); Fri, 20 Nov 2020 13:04:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729470AbgKTSEm (ORCPT ); Fri, 20 Nov 2020 13:04:42 -0500 Received: from smtp-bc0d.mail.infomaniak.ch (smtp-bc0d.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 601D0C0613CF for ; Fri, 20 Nov 2020 10:04:42 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FM1thyzlhCpj; Fri, 20 Nov 2020 19:04:39 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FL73dLzlh8T2; Fri, 20 Nov 2020 19:04:38 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 5/9] PKCS#7: Fix missing include Date: Fri, 20 Nov 2020 19:04:22 +0100 Message-Id: <20201120180426.922572-6-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Add missing stddef.h for size_t. Cc: David Howells Signed-off-by: Mickaël Salaün --- include/linux/verification.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/verification.h b/include/linux/verification.h index 911ab7c2b1ab..b4a74568c0f0 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -8,6 +8,8 @@ #ifndef _LINUX_VERIFICATION_H #define _LINUX_VERIFICATION_H +#include + /* * Indicate that both builtin trusted keys and secondary trusted keys * should be used. From patchwork Fri Nov 20 18:04:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921501 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 242A2C8300E for ; Fri, 20 Nov 2020 18:05:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F28892245D for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729468AbgKTSEm (ORCPT ); Fri, 20 Nov 2020 13:04:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729447AbgKTSEm (ORCPT ); Fri, 20 Nov 2020 13:04:42 -0500 Received: from smtp-190a.mail.infomaniak.ch (smtp-190a.mail.infomaniak.ch [IPv6:2001:1600:4:17::190a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95287C0613CF; Fri, 20 Nov 2020 10:04:41 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FN2xkHzlhYJt; Fri, 20 Nov 2020 19:04:40 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FN0yKKzlh8TN; Fri, 20 Nov 2020 19:04:40 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 6/9] certs: Fix blacklist flag type confusion Date: Fri, 20 Nov 2020 19:04:23 +0100 Message-Id: <20201120180426.922572-7-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() nor key_alloc(), which only takes KEY_ALLOC_* flags. KEY_FLAG_KEEP has the same value as KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update() uses it. LSMs using the key_alloc hook don't check such flag. KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot write to the blacklist keyring, then it is not possible to remove a key/hash from it. Remove KEY_FLAG_KEEP from the call to keyring_alloc() and set the keyring flags with it. This should not fix a bug with the current implementation but it is required for the next commit to allow to add new hashes to the blacklist without the possibility to remove them. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- certs/blacklist.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 0d2c959e9422..d1e2f69d91c2 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -224,11 +224,11 @@ static int __init blacklist_init(void) (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH, - KEY_ALLOC_NOT_IN_QUOTA | - KEY_FLAG_KEEP, + KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); if (IS_ERR(blacklist_keyring)) panic("Can't allocate system blacklist keyring\n"); + set_bit(KEY_FLAG_KEEP, &blacklist_keyring->flags); for (bl = blacklist_hashes; *bl; bl++) if (mark_raw_hash_blacklisted(*bl) < 0) From patchwork Fri Nov 20 18:04:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921499 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7682EC2D0E4 for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 288352415A for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728891AbgKTSEx (ORCPT ); Fri, 20 Nov 2020 13:04:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729466AbgKTSEn (ORCPT ); Fri, 20 Nov 2020 13:04:43 -0500 Received: from smtp-8faf.mail.infomaniak.ch (smtp-8faf.mail.infomaniak.ch [IPv6:2001:1600:3:17::8faf]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCE04C0617A7; Fri, 20 Nov 2020 10:04:42 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FP431bzlhVg5; Fri, 20 Nov 2020 19:04:41 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FP1txHzlh8T2; Fri, 20 Nov 2020 19:04:41 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 7/9] certs: Allow root user to append signed hashes to the blacklist keyring Date: Fri, 20 Nov 2020 19:04:24 +0100 Message-Id: <20201120180426.922572-8-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Add a kernel option SYSTEM_BLACKLIST_AUTH_UPDATE to enable the root user to dynamically add new keys to the blacklist keyring. This enables to invalidate new certificates, either from being loaded in a keyring, or from being trusted in a PKCS#7 certificate chain. This also enables to add new file hashes to be denied by the integrity infrastructure. Being able to untrust a certificate which could have normaly been trusted is a sensitive operation. This is why adding new hashes to the blacklist keyring is only allowed when these hashes are signed and vouched by the builtin trusted keyring. A blacklist hash is stored as a key description. The PKCS#7 signature of this description must be provided as the key payload. Marking a certificate as untrusted should be enforced while the system is running. It is then forbiden to remove such blacklist keys. Update blacklist keyring and blacklist key access rights: * allows the root user to search for a specific blacklisted hash, which make sense because the descriptions are already viewable; * forbids key update; * restricts kernel rights on the blacklist keyring to align with the root user rights. See the help in tools/certs/print-cert-tbs-hash.sh provided by a following commit. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- certs/Kconfig | 10 ++++++ certs/blacklist.c | 85 ++++++++++++++++++++++++++++++++++++----------- 2 files changed, 76 insertions(+), 19 deletions(-) diff --git a/certs/Kconfig b/certs/Kconfig index c94e93d8bccf..35fe9989e7b9 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -83,4 +83,14 @@ config SYSTEM_BLACKLIST_HASH_LIST wrapper to incorporate the list into the kernel. Each should be a string of hex digits. +config SYSTEM_BLACKLIST_AUTH_UPDATE + bool "Allow root to add signed blacklist keys" + depends on SYSTEM_BLACKLIST_KEYRING + depends on SYSTEM_DATA_VERIFICATION + help + If set, provide the ability to load new blacklist keys at run time if + they are signed and vouched by a certificate from the builtin trusted + keyring. The PKCS#7 signature of the description is set in the key + payload. Blacklist keys cannot be removed. + endmenu diff --git a/certs/blacklist.c b/certs/blacklist.c index d1e2f69d91c2..e869a23f38de 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include "blacklist.h" @@ -24,6 +25,9 @@ */ #define MAX_HASH_LEN 128 +#define BLACKLIST_KEY_PERM (KEY_POS_SEARCH | KEY_POS_VIEW | \ + KEY_USR_SEARCH | KEY_USR_VIEW) + static const char tbs_prefix[] = "tbs"; static const char bin_prefix[] = "bin"; @@ -73,19 +77,46 @@ static int blacklist_vet_description(const char *desc) return 0; } -/* - * The hash to be blacklisted is expected to be in the description. There will - * be no payload. - */ -static int blacklist_preparse(struct key_preparsed_payload *prep) +static int blacklist_key_instantiate(struct key *key, + struct key_preparsed_payload *prep) { - if (prep->datalen > 0) - return -EINVAL; - return 0; +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + int err; +#endif + + /* Sets safe default permissions for keys loaded by user space. */ + key->perm = BLACKLIST_KEY_PERM; + + /* + * Skips the authentication step for builtin hashes, they are not + * signed but still trusted. + */ + if (key->flags & (1 << KEY_FLAG_BUILTIN)) + goto out; + +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + /* + * Verifies the description's PKCS#7 signature against the builtin + * trusted keyring. + */ + err = verify_pkcs7_signature(key->description, + strlen(key->description), prep->data, prep->datalen, + NULL, VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL); + if (err) + return err; +#else + WARN_ON_ONCE(1); + return -EPERM; +#endif + +out: + return generic_key_instantiate(key, prep); } -static void blacklist_free_preparse(struct key_preparsed_payload *prep) +static int blacklist_key_update(struct key *key, + struct key_preparsed_payload *prep) { + return -EPERM; } static void blacklist_describe(const struct key *key, struct seq_file *m) @@ -96,9 +127,8 @@ static void blacklist_describe(const struct key *key, struct seq_file *m) static struct key_type key_type_blacklist = { .name = "blacklist", .vet_description = blacklist_vet_description, - .preparse = blacklist_preparse, - .free_preparse = blacklist_free_preparse, - .instantiate = generic_key_instantiate, + .instantiate = blacklist_key_instantiate, + .update = blacklist_key_update, .describe = blacklist_describe, }; @@ -147,8 +177,7 @@ static int mark_raw_hash_blacklisted(const char *hash) hash, NULL, 0, - ((KEY_POS_ALL & ~KEY_POS_SETATTR) | - KEY_USR_VIEW), + BLACKLIST_KEY_PERM, KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); if (IS_ERR(key)) { @@ -207,25 +236,43 @@ int is_binary_blacklisted(const u8 *hash, size_t hash_len) } EXPORT_SYMBOL_GPL(is_binary_blacklisted); +static int restrict_link_for_blacklist(struct key *dest_keyring, + const struct key_type *type, const union key_payload *payload, + struct key *restrict_key) +{ + if (type != &key_type_blacklist) + return -EPERM; + return 0; +} + /* * Initialise the blacklist */ static int __init blacklist_init(void) { const char *const *bl; + struct key_restriction *restriction; if (register_key_type(&key_type_blacklist) < 0) panic("Can't allocate system blacklist key type\n"); + restriction = kzalloc(sizeof(*restriction), GFP_KERNEL); + if (!restriction) + panic("Can't allocate blacklist keyring restriction\n"); + restriction->check = restrict_link_for_blacklist; + blacklist_keyring = keyring_alloc(".blacklist", KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), - (KEY_POS_ALL & ~KEY_POS_SETATTR) | - KEY_USR_VIEW | KEY_USR_READ | - KEY_USR_SEARCH, - KEY_ALLOC_NOT_IN_QUOTA, - NULL, NULL); + KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | + KEY_POS_WRITE | + KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + | KEY_USR_WRITE +#endif + , KEY_ALLOC_NOT_IN_QUOTA, + restriction, NULL); if (IS_ERR(blacklist_keyring)) panic("Can't allocate system blacklist keyring\n"); set_bit(KEY_FLAG_KEEP, &blacklist_keyring->flags); From patchwork Fri Nov 20 18:04:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921493 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DDE0C64E90 for ; Fri, 20 Nov 2020 18:04:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 659FF2240B for ; Fri, 20 Nov 2020 18:04:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728727AbgKTSEq (ORCPT ); Fri, 20 Nov 2020 13:04:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729488AbgKTSEq (ORCPT ); Fri, 20 Nov 2020 13:04:46 -0500 Received: from smtp-8fa8.mail.infomaniak.ch (smtp-8fa8.mail.infomaniak.ch [IPv6:2001:1600:4:17::8fa8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A6C4C0613CF for ; Fri, 20 Nov 2020 10:04:45 -0800 (PST) Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FR6vGczlhXm5; Fri, 20 Nov 2020 19:04:43 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FQ3LJ6zlh8T3; Fri, 20 Nov 2020 19:04:42 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 8/9] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Date: Fri, 20 Nov 2020 19:04:25 +0100 Message-Id: <20201120180426.922572-9-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Align with the new macros and fix include files. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- certs/blacklist.c | 4 ++-- certs/system_keyring.c | 5 +++-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index e869a23f38de..2404175d76c2 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include "blacklist.h" @@ -263,8 +264,7 @@ static int __init blacklist_init(void) blacklist_keyring = keyring_alloc(".blacklist", - KUIDT_INIT(0), KGIDT_INIT(0), - current_cred(), + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | KEY_POS_WRITE | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 798291177186..4b693da488f1 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -98,7 +99,7 @@ static __init int system_trusted_keyring_init(void) builtin_trusted_keys = keyring_alloc(".builtin_trusted_keys", - KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH), KEY_ALLOC_NOT_IN_QUOTA, @@ -109,7 +110,7 @@ static __init int system_trusted_keyring_init(void) #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING secondary_trusted_keys = keyring_alloc(".secondary_trusted_keys", - KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH | KEY_USR_WRITE), From patchwork Fri Nov 20 18:04:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11921495 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08E4CC71156 for ; Fri, 20 Nov 2020 18:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D36C02245A for ; Fri, 20 Nov 2020 18:04:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728844AbgKTSEs (ORCPT ); Fri, 20 Nov 2020 13:04:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729512AbgKTSEs (ORCPT ); Fri, 20 Nov 2020 13:04:48 -0500 Received: from smtp-bc0d.mail.infomaniak.ch (smtp-bc0d.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79B1BC0613CF for ; Fri, 20 Nov 2020 10:04:47 -0800 (PST) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4Cd4FT0n9mzlhbqG; Fri, 20 Nov 2020 19:04:45 +0100 (CET) Received: from localhost (unknown [94.23.54.103]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4Cd4FS5m3nzlh8T5; Fri, 20 Nov 2020 19:04:44 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Herbert Xu , James Morris , Jarkko Sakkinen , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v1 9/9] tools/certs: Add print-cert-tbs-hash.sh Date: Fri, 20 Nov 2020 19:04:26 +0100 Message-Id: <20201120180426.922572-10-mic@digikod.net> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201120180426.922572-1-mic@digikod.net> References: <20201120180426.922572-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Mickaël Salaün Add a new helper print-cert-tbs-hash.sh to generate a TBSCertificate hash from a given certificate. This is useful to generate a blacklist key description used to forbid loading a specific certificate in a keyring, or to invalidate a certificate provided by a PKCS#7 file. Cc: David Howells Cc: David Woodhouse Signed-off-by: Mickaël Salaün --- MAINTAINERS | 1 + tools/certs/print-cert-tbs-hash.sh | 91 ++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100755 tools/certs/print-cert-tbs-hash.sh diff --git a/MAINTAINERS b/MAINTAINERS index a5b0c59f55a0..af778cb613a0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4093,6 +4093,7 @@ F: certs/ F: scripts/check-blacklist-hashes.awk F: scripts/extract-cert.c F: scripts/sign-file.c +F: tools/certs/ CFAG12864B LCD DRIVER M: Miguel Ojeda Sandonis diff --git a/tools/certs/print-cert-tbs-hash.sh b/tools/certs/print-cert-tbs-hash.sh new file mode 100755 index 000000000000..ad335923ef88 --- /dev/null +++ b/tools/certs/print-cert-tbs-hash.sh @@ -0,0 +1,91 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright © 2020, Microsoft Corporation. All rights reserved. +# +# Author: Mickaël Salaün +# +# Compute and print the To Be Signed (TDS) hash of a certificate. This is used +# as description of keys in the blacklist keyring to identify certificates. +# This output should be redirected, without newline, in a file (hash0.txt) and +# signed to create a PKCS#7 file (hash0.p7s). Both of these files can then be +# loaded in the kernel with. +# +# Exemple on a workstation: +# ./print-cert-tbs-hash.sh certificate-to-invalidate.pem > hash0.txt +# openssl smime -sign -in hash0.txt -inkey builtin-private-key.pem \ +# -signer builtin-certificate.pem -certfile certificate-chain.pem \ +# -noattr -binary -outform DER -out hash0.p7s +# +# Exemple on a managed system: +# keyctl padd blacklist "$(< hash0.txt)" %:.blacklist < hash0.p7s + +set -u -e -o pipefail + +CERT="${1:-}" +BASENAME="$(basename -- "${BASH_SOURCE[0]}")" + +if [ $# -ne 1 ] || [ ! -f "${CERT}" ]; then + echo "usage: ${BASENAME} " >&2 + exit 1 +fi + +# Checks that it is indeed a certificate (PEM or DER encoded) and exclude the +# optional PEM text header. +PEM="$(openssl x509 -inform DER -in "${CERT}" 2>/dev/null || openssl x509 -in "${CERT}")" || { + echo "ERROR: Failed to parse certificate" >&2 + exit 1 +} + +# TBSCertificate starts at the second entry. +# Cf. https://tools.ietf.org/html/rfc3280#section-4.1 +# +# Exemple of first lines printed by openssl asn1parse: +# 0:d=0 hl=4 l= 763 cons: SEQUENCE +# 4:d=1 hl=4 l= 483 cons: SEQUENCE +# 8:d=2 hl=2 l= 3 cons: cont [ 0 ] +# 10:d=3 hl=2 l= 1 prim: INTEGER :02 +# 13:d=2 hl=2 l= 20 prim: INTEGER :3CEB2CB8818D968AC00EEFE195F0DF9665328B7B +# 35:d=2 hl=2 l= 13 cons: SEQUENCE +# 37:d=3 hl=2 l= 9 prim: OBJECT :sha256WithRSAEncryption +RANGE_AND_DIGEST_RE=' +2s/^\s*\([0-9]\+\):d=\s*[0-9]\+\s\+hl=\s*[0-9]\+\s\+l=\s*\([0-9]\+\)\s\+cons:\s*SEQUENCE\s*$/\1 \2/p; +7s/^\s*[0-9]\+:d=\s*[0-9]\+\s\+hl=\s*[0-9]\+\s\+l=\s*[0-9]\+\s\+prim:\s*OBJECT\s*:\(.*\)$/\1/p; +' + +RANGE_AND_DIGEST=($(echo "${PEM}" | \ + openssl asn1parse -in - | \ + sed -n -e "${RANGE_AND_DIGEST_RE}")) + +if [ "${#RANGE_AND_DIGEST[@]}" != 3 ]; then + echo "ERROR: Failed to parse TBSCertificate." >&2 + exit 1 +fi + +OFFSET="${RANGE_AND_DIGEST[0]}" +END="$(( OFFSET + RANGE_AND_DIGEST[1] ))" +DIGEST="${RANGE_AND_DIGEST[2]}" + +# The signature hash algorithm is used by Linux to blacklist certificates. +# Cf. crypto/asymmetric_keys/x509_cert_parser.c:x509_note_pkey_algo() +DIGEST_MATCH="" +while read -r DIGEST_ITEM; do + if [ -z "${DIGEST_ITEM}" ]; then + break + fi + if echo "${DIGEST}" | grep -qiF "${DIGEST_ITEM}"; then + DIGEST_MATCH="${DIGEST_ITEM}" + break + fi +done < <(openssl list -digest-commands | tr ' ' '\n' | sort -ur) + +if [ -z "${DIGEST_MATCH}" ]; then + echo "ERROR: Unknown digest algorithm: ${DIGEST}" >&2 + exit 1 +fi + +echo "${PEM}" | \ + openssl x509 -in - -outform DER | \ + dd "bs=1" "skip=${OFFSET}" "count=${END}" "status=none" | \ + openssl dgst "-${DIGEST_MATCH}" - | \ + awk '{printf "tbs:" $2}'