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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E4A3CCA47B for ; Fri, 8 Jul 2022 13:10:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237832AbiGHNK0 (ORCPT ); Fri, 8 Jul 2022 09:10:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237442AbiGHNKZ (ORCPT ); Fri, 8 Jul 2022 09:10:25 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9114226AD7; Fri, 8 Jul 2022 06:10:22 -0700 (PDT) Received: from fraeml737-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LfYWm4J8Kz6GDHm; Fri, 8 Jul 2022 21:09:08 +0800 (CST) Received: from lhreml745-chm.china.huawei.com (10.201.108.195) by fraeml737-chm.china.huawei.com (10.206.15.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 8 Jul 2022 15:10:19 +0200 Received: from [10.122.132.241] (10.122.132.241) by lhreml745-chm.china.huawei.com (10.201.108.195) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 8 Jul 2022 14:10:18 +0100 Message-ID: <7735ae47-9088-be29-2696-c5170031d7c2@huawei.com> Date: Fri, 8 Jul 2022 16:10:17 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v6 02/17] landlock: refactors landlock_find/insert_rule Content-Language: ru To: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= CC: , , , , , References: <20220621082313.3330667-1-konstantin.meskhidze@huawei.com> <20220621082313.3330667-3-konstantin.meskhidze@huawei.com> <0bbbcf21-1e7d-5585-545f-bf89d8ebd527@digikod.net> From: "Konstantin Meskhidze (A)" In-Reply-To: <0bbbcf21-1e7d-5585-545f-bf89d8ebd527@digikod.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.122.132.241] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To lhreml745-chm.china.huawei.com (10.201.108.195) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 7/7/2022 7:44 PM, Mickaël Salaün пишет: > > On 21/06/2022 10:22, Konstantin Meskhidze wrote: >> Adds a new object union to support a socket port >> rule type. Refactors landlock_insert_rule() and >> landlock_find_rule() to support coming network >> modifications. Now adding or searching a rule >> in a ruleset depends on a rule_type argument >> provided in refactored functions mentioned above. >> >> Signed-off-by: Konstantin Meskhidze >> --- >> >> Changes since v5: >> * Formats code with clang-format-14. >> >> Changes since v4: >> * Refactors insert_rule() and create_rule() functions by deleting >> rule_type from their arguments list, it helps to reduce useless code. >> >> Changes since v3: >> * Splits commit. >> * Refactors landlock_insert_rule and landlock_find_rule functions. >> * Rename new_ruleset->root_inode. >> >> --- >> security/landlock/fs.c | 7 ++- >> security/landlock/ruleset.c | 105 ++++++++++++++++++++++++++---------- >> security/landlock/ruleset.h | 27 +++++----- >> 3 files changed, 96 insertions(+), 43 deletions(-) >> >> diff --git a/security/landlock/fs.c b/security/landlock/fs.c >> index e6da08ed99d1..46aedc2a05a8 100644 >> --- a/security/landlock/fs.c >> +++ b/security/landlock/fs.c >> @@ -173,7 +173,8 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, >> if (IS_ERR(object)) >> return PTR_ERR(object); >> mutex_lock(&ruleset->lock); >> - err = landlock_insert_rule(ruleset, object, access_rights); >> + err = landlock_insert_rule(ruleset, object, 0, access_rights, >> + LANDLOCK_RULE_PATH_BENEATH); >> mutex_unlock(&ruleset->lock); >> /* >> * No need to check for an error because landlock_insert_rule() >> @@ -204,7 +205,9 @@ find_rule(const struct landlock_ruleset *const domain, >> inode = d_backing_inode(dentry); >> rcu_read_lock(); >> rule = landlock_find_rule( >> - domain, rcu_dereference(landlock_inode(inode)->object)); >> + domain, >> + (uintptr_t)rcu_dereference(landlock_inode(inode)->object), >> + LANDLOCK_RULE_PATH_BENEATH); >> rcu_read_unlock(); >> return rule; >> } >> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c >> index a3fd58d01f09..5f13f8a12aee 100644 >> --- a/security/landlock/ruleset.c >> +++ b/security/landlock/ruleset.c >> @@ -35,7 +35,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) >> return ERR_PTR(-ENOMEM); >> refcount_set(&new_ruleset->usage, 1); >> mutex_init(&new_ruleset->lock); >> - new_ruleset->root = RB_ROOT; >> + new_ruleset->root_inode = RB_ROOT; >> new_ruleset->num_layers = num_layers; >> /* >> * hierarchy = NULL >> @@ -69,7 +69,8 @@ static void build_check_rule(void) >> } >> >> static struct landlock_rule * >> -create_rule(struct landlock_object *const object, >> +create_rule(struct landlock_object *const object_ptr, >> + const uintptr_t object_data, >> const struct landlock_layer (*const layers)[], const u32 num_layers, >> const struct landlock_layer *const new_layer) >> { >> @@ -90,8 +91,15 @@ create_rule(struct landlock_object *const object, >> if (!new_rule) >> return ERR_PTR(-ENOMEM); >> RB_CLEAR_NODE(&new_rule->node); >> - landlock_get_object(object); >> - new_rule->object = object; >> + >> + if (object_ptr) { >> + landlock_get_object(object_ptr); >> + new_rule->object.ptr = object_ptr; >> + } else if (object_ptr && object_data) { > > Something is wrong with this second check: else + object_ptr? Sorry. Do you mean logical error here? I got your point. You are right! I think it must be refactored like this: if (object_ptr && !object_data) { landlock_get_object(object_ptr); new_rule->object.ptr = object_ptr; } else if (object_ptr && object_data) { ... } Plus, I will add a test for this case. > > >> + WARN_ON_ONCE(1); >> + return ERR_PTR(-EINVAL); >> + } >> + >> new_rule->num_layers = new_num_layers; >> /* Copies the original layer stack. */ >> memcpy(new_rule->layers, layers, >> @@ -107,7 +115,7 @@ static void free_rule(struct landlock_rule *const rule) >> might_sleep(); >> if (!rule) >> return; >> - landlock_put_object(rule->object); >> + landlock_put_object(rule->object.ptr); >> kfree(rule); >> } >> >> @@ -143,26 +151,42 @@ static void build_check_ruleset(void) >> * access rights. >> */ >> static int insert_rule(struct landlock_ruleset *const ruleset, >> - struct landlock_object *const object, >> + struct landlock_object *const object_ptr, >> + uintptr_t object_data, u16 rule_type, > > Use landlock_rule_type instead of u16, everywhere. It was part of my > review/patch two versions ago (with other things), please take them into > account: > https://lore.kernel.org/r/92d498f0-c598-7413-6b7c-d19c5aec6cab@digikod.net > > >> const struct landlock_layer (*const layers)[], >> size_t num_layers) >> { >> struct rb_node **walker_node; >> struct rb_node *parent_node = NULL; >> struct landlock_rule *new_rule; >> + struct rb_root *root; >> >> might_sleep(); >> lockdep_assert_held(&ruleset->lock); >> - if (WARN_ON_ONCE(!object || !layers)) >> + if (WARN_ON_ONCE(!layers)) >> return -ENOENT; >> - walker_node = &(ruleset->root.rb_node); >> + if (WARN_ON_ONCE(object_ptr && object_data)) >> + return -EINVAL; >> + /* Chooses rb_tree structure depending on a rule type. */ >> + switch (rule_type) { >> + case LANDLOCK_RULE_PATH_BENEATH: >> + if (WARN_ON_ONCE(!object_ptr)) >> + return -ENOENT; >> + object_data = (uintptr_t)object_ptr; >> + root = &ruleset->root_inode; >> + break; >> + default: >> + WARN_ON_ONCE(1); >> + return -EINVAL; >> + } >> + walker_node = &root->rb_node; >> while (*walker_node) { >> struct landlock_rule *const this = >> rb_entry(*walker_node, struct landlock_rule, node); >> >> - if (this->object != object) { >> + if (this->object.data != object_data) { >> parent_node = *walker_node; >> - if (this->object < object) >> + if (this->object.data < object_data) >> walker_node = &((*walker_node)->rb_right); >> else >> walker_node = &((*walker_node)->rb_left); >> @@ -194,11 +218,16 @@ static int insert_rule(struct landlock_ruleset *const ruleset, >> * Intersects access rights when it is a merge between a >> * ruleset and a domain. >> */ >> - new_rule = create_rule(object, &this->layers, this->num_layers, >> - &(*layers)[0]); >> + switch (rule_type) { >> + case LANDLOCK_RULE_PATH_BENEATH: >> + new_rule = create_rule(object_ptr, 0, &this->layers, >> + this->num_layers, &(*layers)[0]); >> + break; >> + } >> if (IS_ERR(new_rule)) >> return PTR_ERR(new_rule); >> - rb_replace_node(&this->node, &new_rule->node, &ruleset->root); >> + rb_replace_node(&this->node, &new_rule->node, >> + &ruleset->root_inode); >> free_rule(this); >> return 0; >> } >> @@ -207,11 +236,15 @@ static int insert_rule(struct landlock_ruleset *const ruleset, >> build_check_ruleset(); >> if (ruleset->num_rules >= LANDLOCK_MAX_NUM_RULES) >> return -E2BIG; >> - new_rule = create_rule(object, layers, num_layers, NULL); >> + switch (rule_type) { >> + case LANDLOCK_RULE_PATH_BENEATH: >> + new_rule = create_rule(object_ptr, 0, layers, num_layers, NULL); >> + break; >> + } >> if (IS_ERR(new_rule)) >> return PTR_ERR(new_rule); >> rb_link_node(&new_rule->node, parent_node, walker_node); >> - rb_insert_color(&new_rule->node, &ruleset->root); >> + rb_insert_color(&new_rule->node, &ruleset->root_inode); >> ruleset->num_rules++; >> return 0; >> } >> @@ -229,8 +262,9 @@ static void build_check_layer(void) >> >> /* @ruleset must be locked by the caller. */ >> int landlock_insert_rule(struct landlock_ruleset *const ruleset, >> - struct landlock_object *const object, >> - const access_mask_t access) >> + struct landlock_object *const object_ptr, >> + const uintptr_t object_data, >> + const access_mask_t access, const u16 rule_type) >> { >> struct landlock_layer layers[] = { { >> .access = access, >> @@ -239,7 +273,8 @@ int landlock_insert_rule(struct landlock_ruleset *const ruleset, >> } }; >> >> build_check_layer(); >> - return insert_rule(ruleset, object, &layers, ARRAY_SIZE(layers)); >> + return insert_rule(ruleset, object_ptr, object_data, rule_type, &layers, >> + ARRAY_SIZE(layers)); >> } >> >> static inline void get_hierarchy(struct landlock_hierarchy *const hierarchy) >> @@ -284,8 +319,8 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> dst->access_masks[dst->num_layers - 1] = src->access_masks[0]; >> >> /* Merges the @src tree. */ >> - rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, &src->root, >> - node) { >> + rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, >> + &src->root_inode, node) { >> struct landlock_layer layers[] = { { >> .level = dst->num_layers, >> } }; >> @@ -299,7 +334,8 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> goto out_unlock; >> } >> layers[0].access = walker_rule->layers[0].access; >> - err = insert_rule(dst, walker_rule->object, &layers, >> + err = insert_rule(dst, walker_rule->object.ptr, 0, >> + LANDLOCK_RULE_PATH_BENEATH, &layers, >> ARRAY_SIZE(layers)); >> if (err) >> goto out_unlock; >> @@ -327,8 +363,9 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, >> >> /* Copies the @parent tree. */ >> rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, >> - &parent->root, node) { >> - err = insert_rule(child, walker_rule->object, >> + &parent->root_inode, node) { >> + err = insert_rule(child, walker_rule->object.ptr, 0, >> + LANDLOCK_RULE_PATH_BENEATH, >> &walker_rule->layers, >> walker_rule->num_layers); >> if (err) >> @@ -361,7 +398,8 @@ static void free_ruleset(struct landlock_ruleset *const ruleset) >> struct landlock_rule *freeme, *next; >> >> might_sleep(); >> - rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root, node) >> + rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, >> + node) >> free_rule(freeme); >> put_hierarchy(ruleset->hierarchy); >> kfree(ruleset); >> @@ -453,20 +491,29 @@ landlock_merge_ruleset(struct landlock_ruleset *const parent, >> */ >> const struct landlock_rule * >> landlock_find_rule(const struct landlock_ruleset *const ruleset, >> - const struct landlock_object *const object) >> + const uintptr_t object_data, const u16 rule_type) >> { >> const struct rb_node *node; >> >> - if (!object) >> + if (!object_data) >> return NULL; >> - node = ruleset->root.rb_node; >> + >> + switch (rule_type) { >> + case LANDLOCK_RULE_PATH_BENEATH: >> + node = ruleset->root_inode.rb_node; >> + break; >> + default: >> + WARN_ON_ONCE(1); >> + return NULL; >> + } >> + >> while (node) { >> struct landlock_rule *this = >> rb_entry(node, struct landlock_rule, node); >> >> - if (this->object == object) >> + if (this->object.data == object_data) >> return this; >> - if (this->object < object) >> + if (this->object.data < object_data) >> node = node->rb_right; >> else >> node = node->rb_left; >> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h >> index bd7ab39859bf..a22d132c32a7 100644 >> --- a/security/landlock/ruleset.h >> +++ b/security/landlock/ruleset.h >> @@ -53,15 +53,17 @@ struct landlock_rule { >> */ >> struct rb_node node; >> /** >> - * @object: Pointer to identify a kernel object (e.g. an inode). This >> - * is used as a key for this ruleset element. This pointer is set once >> - * and never modified. It always points to an allocated object because >> - * each rule increments the refcount of its object. >> - */ >> - struct landlock_object *object; >> - /** >> - * @num_layers: Number of entries in @layers. >> + * @object: A union to identify either a kernel object (e.g. an inode) or >> + * a raw data value (e.g. a network socket port). This is used as a key >> + * for this ruleset element. This pointer/@object.ptr/ is set once and >> + * never modified. It always points to an allocated object because each >> + * rule increments the refcount of its object (for inodes).; >> */ >> + union { >> + struct landlock_object *ptr; >> + uintptr_t data; >> + } object; >> + >> u32 num_layers; >> /** >> * @layers: Stack of layers, from the latest to the newest, implemented >> @@ -98,7 +100,7 @@ struct landlock_ruleset { >> * nodes. Once a ruleset is tied to a process (i.e. as a domain), this >> * tree is immutable until @usage reaches zero. >> */ >> - struct rb_root root; >> + struct rb_root root_inode; >> /** >> * @hierarchy: Enables hierarchy identification even when a parent >> * domain vanishes. This is needed for the ptrace protection. >> @@ -160,8 +162,9 @@ void landlock_put_ruleset(struct landlock_ruleset *const ruleset); >> void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); >> >> int landlock_insert_rule(struct landlock_ruleset *const ruleset, >> - struct landlock_object *const object, >> - const access_mask_t access); >> + struct landlock_object *const object_ptr, >> + const uintptr_t object_data, >> + const access_mask_t access, const u16 rule_type); >> >> struct landlock_ruleset * >> landlock_merge_ruleset(struct landlock_ruleset *const parent, >> @@ -169,7 +172,7 @@ landlock_merge_ruleset(struct landlock_ruleset *const parent, >> >> const struct landlock_rule * >> landlock_find_rule(const struct landlock_ruleset *const ruleset, >> - const struct landlock_object *const object); >> + const uintptr_t object_data, const u16 rule_type); >> >> static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset) >> { >> -- >> 2.25.1 >> > .