From mboxrd@z Thu Jan 1 00:00:00 1970 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=-24.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 D2369C11F69 for ; Thu, 1 Jul 2021 16:13:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3E7A613F9 for ; Thu, 1 Jul 2021 16:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232577AbhGAQQX (ORCPT ); Thu, 1 Jul 2021 12:16:23 -0400 Received: from linux.microsoft.com ([13.77.154.182]:32808 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229664AbhGAQQV (ORCPT ); Thu, 1 Jul 2021 12:16:21 -0400 Received: from [10.137.112.111] (unknown [131.107.147.111]) by linux.microsoft.com (Postfix) with ESMTPSA id E9A1A20B7178; Thu, 1 Jul 2021 09:13:50 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E9A1A20B7178 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1625156031; bh=L0TFBV45yon3Rax3W70wgo6HwymisAJAqsNQm2qWezc=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=km8QtdZuDizjDu70EM5Pg7ct9SBQ7RD6pX+X10Qea3rARjFBc7QBzzTVhbQZodeAm w7uLbWEvoh2Ur3bhLb/ua6Npz6EfwWmjnv7VigLWF01zbc9fMFeNWFLScM2kHu6QMl vakqTtk+0CKI8QjLnvvB9DN1fQwSmXMuu5EYKogY= Subject: Re: [PATCH v2 2/3] ima: Return int in the functions to measure a buffer To: Roberto Sassu , zohar@linux.ibm.com, paul@paul-moore.com Cc: stephen.smalley.work@gmail.com, prsriva02@gmail.com, tusharsu@linux.microsoft.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, selinux@vger.kernel.org References: <20210701125552.2958008-1-roberto.sassu@huawei.com> <20210701125552.2958008-3-roberto.sassu@huawei.com> From: Lakshmi Ramasubramanian Message-ID: <75bf7a3f-fd0e-177b-5725-e5f8b1f68966@linux.microsoft.com> Date: Thu, 1 Jul 2021 09:15:46 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210701125552.2958008-3-roberto.sassu@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/1/2021 5:55 AM, Roberto Sassu wrote: > ima_measure_critical_data() and process_buffer_measurement() currently > don't return a result. A caller wouldn't be able to know whether those > functions were executed successfully. > > This patch modifies the return type from void to int, and returns 0 if the > buffer has been successfully measured, a negative value otherwise. > > Also, this patch does not modify the behavior of existing callers by > processing the returned value. Instead, the value is stored in a variable > marked as __maybe_unused. > > Signed-off-by: Roberto Sassu > --- > include/linux/ima.h | 15 +++--- > security/integrity/ima/ima.h | 10 ++-- > security/integrity/ima/ima_appraise.c | 4 +- > security/integrity/ima/ima_asymmetric_keys.c | 4 +- > security/integrity/ima/ima_init.c | 6 ++- > security/integrity/ima/ima_main.c | 48 ++++++++++++-------- > security/integrity/ima/ima_queue_keys.c | 15 +++--- > security/selinux/ima.c | 10 ++-- > 8 files changed, 66 insertions(+), 46 deletions(-) > > diff --git a/include/linux/ima.h b/include/linux/ima.h > index 81e830d01ced..60492263aa64 100644 > --- a/include/linux/ima.h > +++ b/include/linux/ima.h > @@ -35,10 +35,10 @@ extern void ima_post_path_mknod(struct user_namespace *mnt_userns, > extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); > extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size); > extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); > -extern void ima_measure_critical_data(const char *event_label, > - const char *event_name, > - const void *buf, size_t buf_len, > - bool hash); > +extern int ima_measure_critical_data(const char *event_label, > + const char *event_name, > + const void *buf, size_t buf_len, > + bool hash); > > #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM > extern void ima_appraise_parse_cmdline(void); > @@ -144,10 +144,13 @@ static inline int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size > > static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} > > -static inline void ima_measure_critical_data(const char *event_label, > +static inline int ima_measure_critical_data(const char *event_label, > const char *event_name, > const void *buf, size_t buf_len, > - bool hash) {} > + bool hash) > +{ > + return -ENOENT; > +} > > #endif /* CONFIG_IMA */ > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index f0e448ed1f9f..03db221324c3 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -264,11 +264,11 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, > struct evm_ima_xattr_data *xattr_value, > int xattr_len, const struct modsig *modsig, int pcr, > struct ima_template_desc *template_desc); > -void process_buffer_measurement(struct user_namespace *mnt_userns, > - struct inode *inode, const void *buf, int size, > - const char *eventname, enum ima_hooks func, > - int pcr, const char *func_data, > - bool buf_hash); > +int process_buffer_measurement(struct user_namespace *mnt_userns, > + struct inode *inode, const void *buf, int size, > + const char *eventname, enum ima_hooks func, > + int pcr, const char *func_data, > + bool buf_hash); > void ima_audit_measurement(struct integrity_iint_cache *iint, > const unsigned char *filename); > int ima_alloc_init_template(struct ima_event_data *event_data, > diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c > index ef9dcfce45d4..275a2377743f 100644 > --- a/security/integrity/ima/ima_appraise.c > +++ b/security/integrity/ima/ima_appraise.c > @@ -345,6 +345,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, > enum hash_algo hash_algo; > const u8 *digest = NULL; > u32 digestsize = 0; > + int process_rc __maybe_unused; > int rc = 0; > > if (!(iint->flags & IMA_CHECK_BLACKLIST)) > @@ -355,7 +356,8 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, > > rc = is_binary_blacklisted(digest, digestsize); > if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) > - process_buffer_measurement(&init_user_ns, NULL, digest, digestsize, > + process_rc = process_buffer_measurement(&init_user_ns, I think there is no need to make this change now. If and when ima_check_blacklist() needs to look at the return value of p_b_m(), this change can be made. > + NULL, digest, digestsize, > "blacklisted-hash", NONE, > pcr, NULL, false); > } > diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c > index c985418698a4..910367cdd920 100644 > --- a/security/integrity/ima/ima_asymmetric_keys.c > +++ b/security/integrity/ima/ima_asymmetric_keys.c > @@ -31,6 +31,7 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, > unsigned long flags, bool create) > { > bool queued = false; > + int ret __maybe_unused; > > /* Only asymmetric keys are handled by this hook. */ > if (key->type != &key_type_asymmetric) > @@ -60,7 +61,8 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, > * if the IMA policy is configured to measure a key linked > * to the given keyring. > */ > - process_buffer_measurement(&init_user_ns, NULL, payload, payload_len, > + ret = process_buffer_measurement(&init_user_ns, NULL, > + payload, payload_len, Same comment as in ima_check_blacklist() - this change be made when needed. > keyring->description, KEY_CHECK, 0, > keyring->description, false); > } > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c > index 5076a7d9d23e..6790eea88db8 100644 > --- a/security/integrity/ima/ima_init.c > +++ b/security/integrity/ima/ima_init.c > @@ -118,6 +118,7 @@ void __init ima_load_x509(void) > > int __init ima_init(void) > { > + int measure_rc __maybe_unused; > int rc; > > ima_tpm_chip = tpm_default_chip(); > @@ -153,8 +154,9 @@ int __init ima_init(void) > > ima_init_key_queue(); > > - ima_measure_critical_data("kernel_info", "kernel_version", > - UTS_RELEASE, strlen(UTS_RELEASE), false); > + measure_rc = ima_measure_critical_data("kernel_info", "kernel_version", > + UTS_RELEASE, strlen(UTS_RELEASE), > + false); Same comment as in ima_check_blacklist() - this change be made when needed. > > return rc; > } > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index 8ef1fa357e0c..3386e7436440 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -827,7 +827,7 @@ int ima_post_load_data(char *buf, loff_t size, > return 0; > } > > -/* > +/** > * process_buffer_measurement - Measure the buffer or the buffer data hash > * @mnt_userns: user namespace of the mount the inode was found from > * @inode: inode associated with the object being measured (NULL for KEY_CHECK) > @@ -840,12 +840,15 @@ int ima_post_load_data(char *buf, loff_t size, > * @buf_hash: measure buffer data hash > * > * Based on policy, either the buffer data or buffer data hash is measured > + * > + * Return: 0 if the buffer has been successfully measured, a negative value > + * otherwise. > */ > -void process_buffer_measurement(struct user_namespace *mnt_userns, > - struct inode *inode, const void *buf, int size, > - const char *eventname, enum ima_hooks func, > - int pcr, const char *func_data, > - bool buf_hash) > +int process_buffer_measurement(struct user_namespace *mnt_userns, > + struct inode *inode, const void *buf, int size, > + const char *eventname, enum ima_hooks func, > + int pcr, const char *func_data, > + bool buf_hash) > { > int ret = 0; > const char *audit_cause = "ENOMEM"; > @@ -867,7 +870,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns, > u32 secid; > > if (!ima_policy_flag) > - return; > + return -ENOENT; > > template = ima_template_desc_buf(); > if (!template) { > @@ -889,7 +892,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns, > secid, 0, func, &pcr, &template, > func_data); > if (!(action & IMA_MEASURE)) > - return; > + return -ENOENT; > } > > if (!pcr) > @@ -937,7 +940,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns, > func_measure_str(func), > audit_cause, ret, 0, ret); > > - return; > + return ret; > } > > /** > @@ -951,6 +954,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns, > void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > { > struct fd f; > + int ret __maybe_unused; > > if (!buf || !size) > return; > @@ -959,9 +963,10 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > if (!f.file) > return; > > - process_buffer_measurement(file_mnt_user_ns(f.file), file_inode(f.file), > - buf, size, "kexec-cmdline", KEXEC_CMDLINE, 0, > - NULL, false); > + ret = process_buffer_measurement(file_mnt_user_ns(f.file), > + file_inode(f.file), buf, size, > + "kexec-cmdline", KEXEC_CMDLINE, 0, > + NULL, false); Since the return value of p_b_m() is not used here, this change can be made when needed. > fdput(f); > } > > @@ -977,18 +982,21 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > * and extend the pcr. Examples of critical data could be various data > * structures, policies, and states stored in kernel memory that can > * impact the integrity of the system. > + * > + * Return: 0 if the buffer has been successfully measured, a negative value > + * otherwise. > */ > -void ima_measure_critical_data(const char *event_label, > - const char *event_name, > - const void *buf, size_t buf_len, > - bool hash) > +int ima_measure_critical_data(const char *event_label, > + const char *event_name, > + const void *buf, size_t buf_len, > + bool hash) > { > if (!event_name || !event_label || !buf || !buf_len) > - return; > + return -ENOPARAM; > > - process_buffer_measurement(&init_user_ns, NULL, buf, buf_len, event_name, > - CRITICAL_DATA, 0, event_label, > - hash); > + return process_buffer_measurement(&init_user_ns, NULL, buf, buf_len, > + event_name, CRITICAL_DATA, 0, > + event_label, hash); > } > > static int __init init_ima(void) > diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c > index 979ef6c71f3d..e3047ce64f39 100644 > --- a/security/integrity/ima/ima_queue_keys.c > +++ b/security/integrity/ima/ima_queue_keys.c > @@ -134,6 +134,7 @@ void ima_process_queued_keys(void) > { > struct ima_key_entry *entry, *tmp; > bool process = false; > + int ret __maybe_unused; > > if (ima_process_keys) > return; > @@ -159,13 +160,13 @@ void ima_process_queued_keys(void) > > list_for_each_entry_safe(entry, tmp, &ima_keys, list) { > if (!timer_expired) > - process_buffer_measurement(&init_user_ns, NULL, > - entry->payload, > - entry->payload_len, > - entry->keyring_name, > - KEY_CHECK, 0, > - entry->keyring_name, > - false); > + ret = process_buffer_measurement(&init_user_ns, NULL, > + entry->payload, > + entry->payload_len, > + entry->keyring_name, > + KEY_CHECK, 0, > + entry->keyring_name, > + false); Same comment as above. > list_del(&entry->list); > ima_free_key_entry(entry); > } > diff --git a/security/selinux/ima.c b/security/selinux/ima.c > index 34d421861bfc..4db9fa211638 100644 > --- a/security/selinux/ima.c > +++ b/security/selinux/ima.c > @@ -75,6 +75,7 @@ void selinux_ima_measure_state_locked(struct selinux_state *state) > char *state_str = NULL; > void *policy = NULL; > size_t policy_len; > + int measure_rc __maybe_unused; > int rc = 0; > > WARN_ON(!mutex_is_locked(&state->policy_mutex)); > @@ -85,8 +86,9 @@ void selinux_ima_measure_state_locked(struct selinux_state *state) > return; > } > > - ima_measure_critical_data("selinux", "selinux-state", > - state_str, strlen(state_str), false); > + measure_rc = ima_measure_critical_data("selinux", "selinux-state", > + state_str, strlen(state_str), > + false); Since the return value of ima_measure_critical_data() is not used here, this change can be made when needed. > > kfree(state_str); > > @@ -102,8 +104,8 @@ void selinux_ima_measure_state_locked(struct selinux_state *state) > return; > } > > - ima_measure_critical_data("selinux", "selinux-policy-hash", > - policy, policy_len, true); > + measure_rc = ima_measure_critical_data("selinux", "selinux-policy-hash", > + policy, policy_len, true); Same comment as above. -lakshmi > > vfree(policy); > } >