From patchwork Tue Jan 7 19:43:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11321691 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 3E96A109A for ; Tue, 7 Jan 2020 19:44:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C73E2187F for ; Tue, 7 Jan 2020 19:44:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="s6lo+isQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728727AbgAGTn7 (ORCPT ); Tue, 7 Jan 2020 14:43:59 -0500 Received: from linux.microsoft.com ([13.77.154.182]:34200 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728440AbgAGTnz (ORCPT ); Tue, 7 Jan 2020 14:43:55 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id 7D31F20B4798; Tue, 7 Jan 2020 11:43:54 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7D31F20B4798 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1578426234; bh=TkQ5nY0p46xtuOLS8IYT3yF4T4Gc66FJ+Oz2GWcSYYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s6lo+isQbjMpv5lJHSZ1s/KupcraJoe1FhWSKHouXvSF3sM9wPHka/KiupN9vZPTK KFuEmslIXdKDuluEKlBT8frKFkANzYzJqKHrLB0E/m0cr03xEJlSETOMWSjEFxf+Ul ABeG/nc13EoMBU/u2opabS+Hv8zkxyIs6wSSDUJA= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 1/4] IMA: Define an IMA hook to measure keys Date: Tue, 7 Jan 2020 11:43:47 -0800 Message-Id: <20200107194350.3782-2-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200107194350.3782-1-nramas@linux.microsoft.com> References: <20200107194350.3782-1-nramas@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Measure asymmetric keys used for verifying file signatures, certificates, etc. This patch defines a new IMA hook namely ima_post_key_create_or_update() to measure the payload used to create a new asymmetric key or update an existing asymmetric key. Added a new config CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS that is enabled when CONFIG_IMA and CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE are defined. Asymmetric key structure is defined only when CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE is defined. Since the IMA hook measures asymmetric keys, the IMA hook is defined in a new file namely ima_asymmetric_keys.c which is built only if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is defined. Signed-off-by: Lakshmi Ramasubramanian Reported-by: kbuild test robot # ima_asymmetric_keys.c is built as a kernel module when it is actually not. Fixes: 88e70da170e8 ("IMA: Define an IMA hook to measure keys") --- security/integrity/ima/Kconfig | 9 ++++ security/integrity/ima/Makefile | 1 + security/integrity/ima/ima_asymmetric_keys.c | 52 ++++++++++++++++++++ 3 files changed, 62 insertions(+) create mode 100644 security/integrity/ima/ima_asymmetric_keys.c diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 838476d780e5..73a3974712d8 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -310,3 +310,12 @@ config IMA_APPRAISE_SIGNED_INIT default n help This option requires user-space init to be signed. + +config IMA_MEASURE_ASYMMETRIC_KEYS + bool "Enable measuring asymmetric keys on key create or update" + depends on IMA=y + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y + default y + help + This option enables measuring asymmetric keys when + the key is created or updated. diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 31d57cdf2421..3e9d0ad68c7b 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -12,3 +12,4 @@ ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o +obj-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c new file mode 100644 index 000000000000..994d89d58af9 --- /dev/null +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 Microsoft Corporation + * + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) + * + * File: ima_asymmetric_keys.c + * Defines an IMA hook to measure asymmetric keys on key + * create or update. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include "ima.h" + +/** + * ima_post_key_create_or_update - measure asymmetric keys + * @keyring: keyring to which the key is linked to + * @key: created or updated key + * @payload: The data used to instantiate or update the key. + * @payload_len: The length of @payload. + * @flags: key flags + * @create: flag indicating whether the key was created or updated + * + * Keys can only be measured, not appraised. + * The payload data used to instantiate or update the key is measured. + */ +void ima_post_key_create_or_update(struct key *keyring, struct key *key, + const void *payload, size_t payload_len, + unsigned long flags, bool create) +{ + /* Only asymmetric keys are handled by this hook. */ + if (key->type != &key_type_asymmetric) + return; + + if (!payload || (payload_len == 0)) + return; + + /* + * keyring->description points to the name of the keyring + * (such as ".builtin_trusted_keys", ".ima", etc.) to + * which the given key is linked to. + * + * The name of the keyring is passed in the "eventname" + * parameter to process_buffer_measurement() and is set + * in the "eventname" field in ima_event_data for + * the key measurement IMA event. + */ + process_buffer_measurement(payload, payload_len, + keyring->description, KEY_CHECK, 0); +} From patchwork Tue Jan 7 19:43:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11321685 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 51CCE138C for ; Tue, 7 Jan 2020 19:43:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30A0B20848 for ; Tue, 7 Jan 2020 19:43:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="ZLFFRMIh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728665AbgAGTnz (ORCPT ); Tue, 7 Jan 2020 14:43:55 -0500 Received: from linux.microsoft.com ([13.77.154.182]:34212 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728457AbgAGTnz (ORCPT ); Tue, 7 Jan 2020 14:43:55 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id A6CBD20B479A; Tue, 7 Jan 2020 11:43:54 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A6CBD20B479A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1578426234; bh=yA5LFjSLBWVUP9TbZOq+D/2tmitmwjc/aS91KwfLW6Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZLFFRMIhtrM0dtheX1wT/8OLGYBWwcScPXgBiIpgLm2I0onLHlwuo5o5p7jJmIxql N0wLB85js/eg5T/7HST8Ui+ZZS1wROO7siJsssn5EVcAU4lGe6mMDTIcuvoj0wkkQW MjMJDkjJ9BMG+iaevZLcLUUzy/JiE4T6iBkX7/I4= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 2/4] KEYS: Call the IMA hook to measure keys Date: Tue, 7 Jan 2020 11:43:48 -0800 Message-Id: <20200107194350.3782-3-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200107194350.3782-1-nramas@linux.microsoft.com> References: <20200107194350.3782-1-nramas@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Call the IMA hook from key_create_or_update() function to measure the payload when a new key is created or an existing key is updated. This patch adds the call to the IMA hook from key_create_or_update() function to measure the key on key create or update. Signed-off-by: Lakshmi Ramasubramanian Cc: David Howells Cc: Jarkko Sakkinen Reported-by: kbuild test robot # ima_asymmetric_keys.c is built as a kernel module when it is actually not. Fixes: cb1aa3823c92 ("KEYS: Call the IMA hook to measure keys") --- include/linux/ima.h | 14 ++++++++++++++ security/keys/key.c | 10 ++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/ima.h b/include/linux/ima.h index 6d904754d858..f4644c54f648 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -101,6 +101,20 @@ static inline void ima_add_kexec_buffer(struct kimage *image) {} #endif +#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS +extern void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, size_t plen, + unsigned long flags, bool create); +#else +static inline void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, + size_t plen, + unsigned long flags, + bool create) {} +#endif /* CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS */ + #ifdef CONFIG_IMA_APPRAISE extern bool is_ima_appraise_enabled(void); extern void ima_inode_post_setattr(struct dentry *dentry); diff --git a/security/keys/key.c b/security/keys/key.c index 764f4c57913e..718bf7217420 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include "internal.h" @@ -936,6 +937,9 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, goto error_link_end; } + ima_post_key_create_or_update(keyring, key, payload, plen, + flags, true); + key_ref = make_key_ref(key, is_key_possessed(keyring_ref)); error_link_end: @@ -965,6 +969,12 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, } key_ref = __key_update(key_ref, &prep); + + if (!IS_ERR(key_ref)) + ima_post_key_create_or_update(keyring, key, + payload, plen, + flags, false); + goto error_free_prep; } EXPORT_SYMBOL(key_create_or_update); From patchwork Tue Jan 7 19:43:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11321689 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 DAF99138C for ; Tue, 7 Jan 2020 19:44:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A12E4214D8 for ; Tue, 7 Jan 2020 19:44:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="SL6AW4CD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728731AbgAGTn7 (ORCPT ); Tue, 7 Jan 2020 14:43:59 -0500 Received: from linux.microsoft.com ([13.77.154.182]:34234 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728607AbgAGTnz (ORCPT ); Tue, 7 Jan 2020 14:43:55 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id D28F320B479C; Tue, 7 Jan 2020 11:43:54 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D28F320B479C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1578426234; bh=s+Zmgddx5AD2JWjCVm06VmtkMsj4CxUiQH6gDbhgmxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SL6AW4CDhIAUptYWQwcTD7CFARyO6jxQXB1soIX08LDi+zEsj9a7lW52YaoYZLIsS dx28qbMroZLHVTQfX7Kr8EIzwxHujqe6keEoAEo8TB78uvlfoYmsgmQFZed+bscUO/ UoXc6uWiXMXHlY34M2EKClFXQK+tblCfu4fV5Wsk= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 3/4] IMA: Add support to limit measuring keys Date: Tue, 7 Jan 2020 11:43:49 -0800 Message-Id: <20200107194350.3782-4-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200107194350.3782-1-nramas@linux.microsoft.com> References: <20200107194350.3782-1-nramas@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Limit measuring keys to those keys being loaded onto a given set of keyrings only and when the user id (uid) matches if uid is specified in the policy. This patch defines a new IMA policy option namely "keyrings=" that can be used to specify a set of keyrings. If this option is specified in the policy for "measure func=KEY_CHECK" then only the keys loaded onto a keyring given in the "keyrings=" option are measured. If uid is specified in the policy then the key is measured only if the current user id matches the one specified in the policy. Added a new parameter namely "keyring" (name of the keyring) to process_buffer_measurement(). The keyring name is passed to ima_get_action() to determine the required action. ima_match_rules() is updated to check keyring in the policy, if specified, for KEY_CHECK function. Signed-off-by: Lakshmi Ramasubramanian Fixes: e9085e0ad38a ("IMA: Add support to limit measuring keys") --- Documentation/ABI/testing/ima_policy | 10 +++- security/integrity/ima/ima.h | 8 ++- security/integrity/ima/ima_api.c | 8 ++- security/integrity/ima/ima_appraise.c | 4 +- security/integrity/ima/ima_asymmetric_keys.c | 8 ++- security/integrity/ima/ima_main.c | 9 +-- security/integrity/ima/ima_policy.c | 62 ++++++++++++++++++-- 7 files changed, 91 insertions(+), 18 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 066d32797500..cd572912c593 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -25,7 +25,7 @@ Description: lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] option: [[appraise_type=]] [template=] [permit_directio] - [appraise_flag=] + [appraise_flag=] [keyrings=] base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] @@ -42,6 +42,9 @@ Description: appraise_flag:= [check_blacklist] Currently, blacklist check is only for files signed with appended signature. + keyrings:= list of keyrings + (eg, .builtin_trusted_keys|.ima). Only valid + when action is "measure" and func is KEY_CHECK. template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value @@ -117,3 +120,8 @@ Description: Example of measure rule using KEY_CHECK to measure all keys: measure func=KEY_CHECK + + Example of measure rule using KEY_CHECK to only measure + keys added to .builtin_trusted_keys or .ima keyring: + + measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index fe6c698617bd..f06238e41a7c 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -208,7 +208,8 @@ struct modsig; /* LIM API function definitions */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, - struct ima_template_desc **template_desc); + struct ima_template_desc **template_desc, + const char *keyring); int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func); int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file, void *buf, loff_t size, @@ -220,7 +221,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct ima_template_desc *template_desc); void process_buffer_measurement(const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr); + int pcr, const char *keyring); void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename); int ima_alloc_init_template(struct ima_event_data *event_data, @@ -235,7 +236,8 @@ const char *ima_d_path(const struct path *path, char **pathbuf, char *filename); /* IMA policy related functions */ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, - struct ima_template_desc **template_desc); + struct ima_template_desc **template_desc, + const char *keyring); void ima_init_policy(void); void ima_update_policy(void); void ima_update_policy_flag(void); diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 610759fe63b8..f6bc00914aa5 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -169,12 +169,13 @@ void ima_add_violation(struct file *file, const unsigned char *filename, * @func: caller identifier * @pcr: pointer filled in if matched measure policy sets pcr= * @template_desc: pointer filled in if matched measure policy sets template= + * @keyring: keyring name used to determine the action * * The policy is defined in terms of keypairs: * subj=, obj=, type=, func=, mask=, fsmagic= * subj,obj, and type: are LSM specific. * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK - * | KEXEC_CMDLINE + * | KEXEC_CMDLINE | KEY_CHECK * mask: contains the permission mask * fsmagic: hex value * @@ -183,14 +184,15 @@ void ima_add_violation(struct file *file, const unsigned char *filename, */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, - struct ima_template_desc **template_desc) + struct ima_template_desc **template_desc, + const char *keyring) { int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH; flags &= ima_policy_flag; return ima_match_policy(inode, cred, secid, func, mask, flags, pcr, - template_desc); + template_desc, keyring); } /* diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 300c8d2943c5..a9649b04b9f1 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -55,7 +55,7 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func) security_task_getsecid(current, &secid); return ima_match_policy(inode, current_cred(), secid, func, mask, - IMA_APPRAISE | IMA_HASH, NULL, NULL); + IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL); } static int ima_fix_xattr(struct dentry *dentry, @@ -330,7 +330,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) process_buffer_measurement(digest, digestsize, "blacklisted-hash", NONE, - pcr); + pcr, NULL); } return rc; diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index 994d89d58af9..fea2e7dd3b09 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -46,7 +46,13 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, * parameter to process_buffer_measurement() and is set * in the "eventname" field in ima_event_data for * the key measurement IMA event. + * + * The name of the keyring is also passed in the "keyring" + * parameter to process_buffer_measurement() to check + * if the IMA policy is configured to measure a key linked + * to the given keyring. */ process_buffer_measurement(payload, payload_len, - keyring->description, KEY_CHECK, 0); + keyring->description, KEY_CHECK, 0, + keyring->description); } diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 9b35db2fc777..2272c3255c7d 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -215,7 +215,7 @@ static int process_measurement(struct file *file, const struct cred *cred, * Included is the appraise submask. */ action = ima_get_action(inode, cred, secid, mask, func, &pcr, - &template_desc); + &template_desc, NULL); violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) && (ima_policy_flag & IMA_MEASURE)); if (!action && !violation_check) @@ -632,12 +632,13 @@ int ima_load_data(enum kernel_load_data_id id) * @eventname: event name to be used for the buffer entry. * @func: IMA hook * @pcr: pcr to extend the measurement + * @keyring: keyring name to determine the action to be performed * * Based on policy, the buffer is measured into the ima log. */ void process_buffer_measurement(const void *buf, int size, const char *eventname, enum ima_hooks func, - int pcr) + int pcr, const char *keyring) { int ret = 0; struct ima_template_entry *entry = NULL; @@ -668,7 +669,7 @@ void process_buffer_measurement(const void *buf, int size, if (func) { security_task_getsecid(current, &secid); action = ima_get_action(NULL, current_cred(), secid, 0, func, - &pcr, &template); + &pcr, &template, keyring); if (!(action & IMA_MEASURE)) return; } @@ -721,7 +722,7 @@ void ima_kexec_cmdline(const void *buf, int size) { if (buf && size != 0) process_buffer_measurement(buf, size, "kexec-cmdline", - KEXEC_CMDLINE, 0); + KEXEC_CMDLINE, 0, NULL); } static int __init init_ima(void) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 3f3928b3db99..7667ca546ce9 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -79,6 +79,7 @@ struct ima_rule_entry { int type; /* audit type */ } lsm[MAX_LSM_RULES]; char *fsname; + char *keyrings; /* Measure keys added to these keyrings */ struct ima_template_desc *template; }; @@ -356,6 +357,50 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, return NOTIFY_OK; } +/** + * ima_match_keyring - determine whether the keyring matches the measure rule + * @rule: a pointer to a rule + * @keyring: name of the keyring to match against the measure rule + * @cred: a pointer to a credentials structure for user validation + * + * Returns true if keyring matches one in the rule, false otherwise. + */ +static bool ima_match_keyring(struct ima_rule_entry *rule, + const char *keyring, const struct cred *cred) +{ + char *keyrings, *next_keyring, *keyrings_ptr; + bool matched = false; + + if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) + return false; + + if (!rule->keyrings) + return true; + + if (!keyring) + return false; + + keyrings = kstrdup(rule->keyrings, GFP_KERNEL); + if (!keyrings) + return false; + + /* + * "keyrings=" is specified in the policy in the format below: + * keyrings=.builtin_trusted_keys|.ima|.evm + */ + keyrings_ptr = keyrings; + while ((next_keyring = strsep(&keyrings_ptr, "|")) != NULL) { + if (!strcmp(next_keyring, keyring)) { + matched = true; + break; + } + } + + kfree(keyrings); + + return matched; +} + /** * ima_match_rules - determine whether an inode matches the measure rule. * @rule: a pointer to a rule @@ -364,18 +409,23 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, * @secid: the secid of the task to be validated * @func: LIM hook identifier * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) + * @keyring: keyring name to check in policy for KEY_CHECK func * * Returns true on rule match, false on failure. */ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, const struct cred *cred, u32 secid, - enum ima_hooks func, int mask) + enum ima_hooks func, int mask, + const char *keyring) { int i; if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) { - if ((rule->flags & IMA_FUNC) && (rule->func == func)) + if ((rule->flags & IMA_FUNC) && (rule->func == func)) { + if (func == KEY_CHECK) + return ima_match_keyring(rule, keyring, cred); return true; + } return false; } if ((rule->flags & IMA_FUNC) && @@ -479,6 +529,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) * @pcr: set the pcr to extend * @template_desc: the template that should be used for this rule + * @keyring: the keyring name, if given, to be used to check in the policy. + * keyring can be NULL if func is anything other than KEY_CHECK. * * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) * conditions. @@ -489,7 +541,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) */ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, enum ima_hooks func, int mask, int flags, int *pcr, - struct ima_template_desc **template_desc) + struct ima_template_desc **template_desc, + const char *keyring) { struct ima_rule_entry *entry; int action = 0, actmask = flags | (flags << 1); @@ -503,7 +556,8 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, if (!(entry->action & actmask)) continue; - if (!ima_match_rules(entry, inode, cred, secid, func, mask)) + if (!ima_match_rules(entry, inode, cred, secid, func, mask, + keyring)) continue; action |= entry->flags & IMA_ACTION_FLAGS; From patchwork Tue Jan 7 19:43:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11321697 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 0A34D109A for ; Tue, 7 Jan 2020 19:44:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBC8E20848 for ; Tue, 7 Jan 2020 19:44:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="b8NkhnkW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728723AbgAGTn7 (ORCPT ); Tue, 7 Jan 2020 14:43:59 -0500 Received: from linux.microsoft.com ([13.77.154.182]:34272 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728660AbgAGTnz (ORCPT ); Tue, 7 Jan 2020 14:43:55 -0500 Received: from nramas-ThinkStation-P520.corp.microsoft.com (unknown [131.107.174.108]) by linux.microsoft.com (Postfix) with ESMTPSA id 08ACF20B479D; Tue, 7 Jan 2020 11:43:55 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 08ACF20B479D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1578426235; bh=vKopEemioZDxxkhIIhSrX9LVxTYuu1tqhtvTwXFOlw8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b8NkhnkW15jpOvwrsK2vCU2avcMqxoWfj7dFv01AQww+lucA4+JhSNjxL845MgVrt /2zrxEA1T7oS2TqQrLBAyBpYvOXrajBEKhDihs6ARkRhYiUZ4yMHiDU5dS9RZdc8SU ZRF2oHLjWMor95mHprMl9e8tm04ZaFhzcRjr2t2E= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 4/4] IMA: Read keyrings= option from the IMA policy Date: Tue, 7 Jan 2020 11:43:50 -0800 Message-Id: <20200107194350.3782-5-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200107194350.3782-1-nramas@linux.microsoft.com> References: <20200107194350.3782-1-nramas@linux.microsoft.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Read "keyrings=" option, if specified in the IMA policy, and store in the list of IMA rules when the configured IMA policy is read. This patch defines a new policy token enum namely Opt_keyrings and an option flag IMA_KEYRINGS for reading "keyrings=" option from the IMA policy. Updated ima_parse_rule() to parse "keyrings=" option in the policy. Updated ima_policy_show() to display "keyrings=" option. The following example illustrates how key measurement can be verified. Sample "key" measurement rule in the IMA policy: measure func=KEY_CHECK uid=0 keyrings=.ima|.evm template=ima-buf Display "key" measurement in the IMA measurement list: cat /sys/kernel/security/ima/ascii_runtime_measurements 10 faf3...e702 ima-buf sha256:27c915b8ddb9fae7214cf0a8a7043cc3eeeaa7539bcb136f8427067b5f6c3b7b .ima 308202863082...4aee Verify "key" measurement data for a key added to ".ima" keyring: cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | grep -m 1 "\.ima" | cut -d' ' -f 6 | xxd -r -p |tee ima-cert.der | sha256sum | cut -d' ' -f 1 The output of the above command should match the template hash of the first "key" measurement entry in the IMA measurement list for the key added to ".ima" keyring. The file namely "ima-cert.der" generated by the above command should be a valid x509 certificate (in DER format) and should match the one that was used to import the key to the ".ima" keyring. The certificate file can be verified using openssl tool. Signed-off-by: Lakshmi Ramasubramanian Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy") --- security/integrity/ima/ima_policy.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 7667ca546ce9..8f2ca487753b 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -34,6 +34,7 @@ #define IMA_EUID 0x0080 #define IMA_PCR 0x0100 #define IMA_FSNAME 0x0200 +#define IMA_KEYRINGS 0x0400 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */ @@ -820,7 +821,8 @@ enum { Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt, Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt, Opt_appraise_type, Opt_appraise_flag, - Opt_permit_directio, Opt_pcr, Opt_template, Opt_err + Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, + Opt_err }; static const match_table_t policy_tokens = { @@ -856,6 +858,7 @@ static const match_table_t policy_tokens = { {Opt_permit_directio, "permit_directio"}, {Opt_pcr, "pcr=%s"}, {Opt_template, "template=%s"}, + {Opt_keyrings, "keyrings=%s"}, {Opt_err, NULL} }; @@ -1105,6 +1108,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) result = 0; entry->flags |= IMA_FSNAME; break; + case Opt_keyrings: + ima_log_string(ab, "keyrings", args[0].from); + + if ((entry->keyrings) || + (entry->action != MEASURE) || + (entry->func != KEY_CHECK)) { + result = -EINVAL; + break; + } + entry->keyrings = kstrdup(args[0].from, GFP_KERNEL); + if (!entry->keyrings) { + result = -ENOMEM; + break; + } + result = 0; + entry->flags |= IMA_KEYRINGS; + break; case Opt_fsuuid: ima_log_string(ab, "fsuuid", args[0].from); @@ -1480,6 +1500,13 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, " "); } + if (entry->flags & IMA_KEYRINGS) { + if (entry->keyrings != NULL) + snprintf(tbuf, sizeof(tbuf), "%s", entry->keyrings); + seq_printf(m, pt(Opt_keyrings), tbuf); + seq_puts(m, " "); + } + if (entry->flags & IMA_PCR) { snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr); seq_printf(m, pt(Opt_pcr), tbuf);