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 12D23C433FE for ; Mon, 28 Nov 2022 02:58:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229718AbiK1C6p (ORCPT ); Sun, 27 Nov 2022 21:58:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229509AbiK1C6n (ORCPT ); Sun, 27 Nov 2022 21:58:43 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35FBD7651; Sun, 27 Nov 2022 18:58:42 -0800 (PST) Received: from frapeml500007.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4NL98H0clRz67vrS; Mon, 28 Nov 2022 10:55:59 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml500007.china.huawei.com (7.182.85.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 28 Nov 2022 03:58:40 +0100 Received: from [10.122.132.241] (10.122.132.241) by lhrpeml500004.china.huawei.com (7.191.163.9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Mon, 28 Nov 2022 02:58:39 +0000 Message-ID: Date: Mon, 28 Nov 2022 05:58:38 +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 v8 02/12] landlock: Refactor landlock_find_rule/insert_rule Content-Language: ru To: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= CC: , , , , , References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> <20221021152644.155136-3-konstantin.meskhidze@huawei.com> <5c6c99f7-4218-1f79-477e-5d943c9809fd@digikod.net> From: "Konstantin Meskhidze (A)" In-Reply-To: <5c6c99f7-4218-1f79-477e-5d943c9809fd@digikod.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.122.132.241] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 11/17/2022 9:41 PM, Mickaël Salaün пишет: > > On 21/10/2022 17:26, Konstantin Meskhidze wrote: >> Adds a new landlock_key union and landlock_id structure to support > > Add a new… Ok. Thanks. > >> a socket port rule type. A struct landlock_id identifies a unique entry >> in a ruleset: either a kernel object (e.g inode) or typed data (e.g TCP >> port). There is one red-black tree per key type. >> >> This patch also adds is_object_pointer() and get_root() helpers. >> is_object_pointer() one checks whether key type is LANDLOCK_KEY_INODE. > > is_object_pointer() returns true if the key type is LANDLOCK_KEY_INODE. > Got it. >> get_root() helper chooses red_black tree root depending on a key type. > > get_root() returns a red_black tree root pointer according to a key type. Ok. Thanks. > >> >> Refactors landlock_insert_rule() and landlock_find_rule() to support coming > > Refactor… Ok. > >> network modifications. Now adding or searching a rule in a ruleset depends > > … Adding or searching a rule in a ruleset can now be done > >> on a landlock id argument provided in refactored functions. > > thanks to a Landlock ID argument passed to these helpers. > I will rewrite it. Thanks. >> >> Co-developed-by: Mickaël Salaün > > Signed-off-by: Mickaël Salaün > > >> Signed-off-by: Konstantin Meskhidze >> --- >> >> Changes since v7: >> * Completes all the new field descriptions landlock_key, >> landlock_key_type, landlock_id. >> * Refactors commit message, adds a co-developer. >> >> Changes since v6: >> * Adds union landlock_key, enum landlock_key_type, and struct >> landlock_id. >> * Refactors ruleset functions and improves switch/cases: create_rule(), >> insert_rule(), get_root(), is_object_pointer(), free_rule(), >> landlock_find_rule(). >> * Refactors landlock_append_fs_rule() functions to support new >> landlock_id type. >> >> 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 | 21 ++++-- >> security/landlock/ruleset.c | 146 +++++++++++++++++++++++++----------- >> security/landlock/ruleset.h | 64 +++++++++++++--- >> 3 files changed, 169 insertions(+), 62 deletions(-) >> >> diff --git a/security/landlock/fs.c b/security/landlock/fs.c >> index 0d57c6479d29..710cfa1306de 100644 >> --- a/security/landlock/fs.c >> +++ b/security/landlock/fs.c >> @@ -168,7 +168,9 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, >> access_mask_t access_rights) >> { >> int err; >> - struct landlock_object *object; >> + struct landlock_id id = { >> + .type = LANDLOCK_KEY_INODE, >> + }; >> >> /* Files only get access rights that make sense. */ >> if (!d_is_dir(path->dentry) && >> @@ -181,17 +183,17 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, >> access_rights |= LANDLOCK_MASK_ACCESS_FS & >> ~(landlock_get_fs_access_mask(ruleset, 0) | >> ACCESS_INITIALLY_DENIED); >> - object = get_inode_object(d_backing_inode(path->dentry)); >> - if (IS_ERR(object)) >> - return PTR_ERR(object); >> + id.key.object = get_inode_object(d_backing_inode(path->dentry)); >> + if (IS_ERR(id.key.object)) >> + return PTR_ERR(id.key.object); >> mutex_lock(&ruleset->lock); >> - err = landlock_insert_rule(ruleset, object, access_rights); >> + err = landlock_insert_rule(ruleset, id, access_rights); >> mutex_unlock(&ruleset->lock); >> /* >> * No need to check for an error because landlock_insert_rule() >> * increments the refcount for the new object if needed. >> */ >> - landlock_put_object(object); >> + landlock_put_object(id.key.object); >> return err; >> } >> >> @@ -208,6 +210,9 @@ find_rule(const struct landlock_ruleset *const domain, >> { >> const struct landlock_rule *rule; >> const struct inode *inode; >> + struct landlock_id id = { >> + .type = LANDLOCK_KEY_INODE, >> + }; >> >> /* Ignores nonexistent leafs. */ >> if (d_is_negative(dentry)) >> @@ -215,8 +220,8 @@ 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)); >> + id.key.object = rcu_dereference(landlock_inode(inode)->object); >> + rule = landlock_find_rule(domain, id); >> rcu_read_unlock(); >> return rule; >> } >> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c >> index 1f3188b4e313..41de17d1869e 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 >> @@ -68,8 +68,18 @@ static void build_check_rule(void) >> BUILD_BUG_ON(rule.num_layers < LANDLOCK_MAX_NUM_LAYERS); >> } >> >> +static inline bool is_object_pointer(const enum landlock_key_type key_type) > > Let's remove all "inline" keywords in all .c files. This should be > simple for the compiler to inline them automatically, and it makes the > code cleaner. Got it. > > >> +{ >> + switch (key_type) { >> + case LANDLOCK_KEY_INODE: >> + return true; >> + } >> + WARN_ON_ONCE(1); >> + return false; >> +} >> + >> static struct landlock_rule * >> -create_rule(struct landlock_object *const object, >> +create_rule(const struct landlock_id id, >> const struct landlock_layer (*const layers)[], const u32 num_layers, >> const struct landlock_layer *const new_layer) >> { >> @@ -90,8 +100,13 @@ 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 (is_object_pointer(id.type)) { >> + /* This should be catched by insert_rule(). */ >> + WARN_ON_ONCE(!id.key.object); >> + landlock_get_object(id.key.object); >> + } >> + >> + new_rule->key = id.key; >> new_rule->num_layers = new_num_layers; >> /* Copies the original layer stack. */ >> memcpy(new_rule->layers, layers, >> @@ -102,12 +117,29 @@ create_rule(struct landlock_object *const object, >> return new_rule; >> } >> >> -static void free_rule(struct landlock_rule *const rule) >> +static inline struct rb_root *get_root(struct landlock_ruleset *const ruleset, > > Please remove "inline". Got it. Thanks. > >> + const enum landlock_key_type key_type) >> +{ >> + struct rb_root *root = NULL; >> + >> + switch (key_type) { >> + case LANDLOCK_KEY_INODE: >> + root = &ruleset->root_inode; >> + break; >> + } >> + if (WARN_ON_ONCE(!root)) >> + return ERR_PTR(-EINVAL); >> + return root; >> +} >> + >> +static void free_rule(struct landlock_rule *const rule, >> + const enum landlock_key_type key_type) >> { >> might_sleep(); >> if (!rule) >> return; >> - landlock_put_object(rule->object); >> + if (is_object_pointer(key_type)) >> + landlock_put_object(rule->key.object); >> kfree(rule); >> } >> >> @@ -129,8 +161,8 @@ static void build_check_ruleset(void) >> * insert_rule - Create and insert a rule in a ruleset >> * >> * @ruleset: The ruleset to be updated. >> - * @object: The object to build the new rule with. The underlying kernel >> - * object must be held by the caller. >> + * @id: The ID to build the new rule with. The underlying kernel object, if >> + * any, must be held by the caller. >> * @layers: One or multiple layers to be copied into the new rule. >> * @num_layers: The number of @layers entries. >> * >> @@ -144,26 +176,37 @@ static void build_check_ruleset(void) >> * access rights. >> */ >> static int insert_rule(struct landlock_ruleset *const ruleset, >> - struct landlock_object *const object, >> + const struct landlock_id id, >> const struct landlock_layer (*const layers)[], >> - size_t num_layers) >> + const 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 (is_object_pointer(id.type)) { >> + if (WARN_ON_ONCE(!id.key.object)) >> + return -ENOENT; >> + } >> + >> + root = get_root(ruleset, id.type); >> + if (IS_ERR(root)) >> + return PTR_ERR(root); >> + >> + 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->key.data != id.key.data) { >> parent_node = *walker_node; >> - if (this->object < object) >> + if (this->key.data < id.key.data) >> walker_node = &((*walker_node)->rb_right); >> else >> walker_node = &((*walker_node)->rb_left); >> @@ -195,24 +238,24 @@ 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, >> + new_rule = create_rule(id, &this->layers, this->num_layers, >> &(*layers)[0]); >> if (IS_ERR(new_rule)) >> return PTR_ERR(new_rule); >> - rb_replace_node(&this->node, &new_rule->node, &ruleset->root); >> - free_rule(this); >> + rb_replace_node(&this->node, &new_rule->node, root); >> + free_rule(this, id.type); >> return 0; >> } >> >> - /* There is no match for @object. */ >> + /* There is no match for @id. */ >> build_check_ruleset(); >> if (ruleset->num_rules >= LANDLOCK_MAX_NUM_RULES) >> return -E2BIG; >> - new_rule = create_rule(object, layers, num_layers, NULL); >> + new_rule = create_rule(id, layers, num_layers, NULL); >> 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, root); >> ruleset->num_rules++; >> return 0; >> } >> @@ -230,7 +273,7 @@ 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 struct landlock_id id, >> const access_mask_t access) >> { >> struct landlock_layer layers[] = { { >> @@ -240,7 +283,7 @@ 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, id, &layers, ARRAY_SIZE(layers)); >> } >> >> static inline void get_hierarchy(struct landlock_hierarchy *const hierarchy) >> @@ -263,6 +306,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> struct landlock_ruleset *const src) >> { >> struct landlock_rule *walker_rule, *next_rule; >> + struct rb_root *src_root; >> int err = 0; >> >> might_sleep(); >> @@ -273,6 +317,10 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> if (WARN_ON_ONCE(!dst || !dst->hierarchy)) >> return -EINVAL; >> >> + src_root = get_root(src, LANDLOCK_KEY_INODE); >> + if (IS_ERR(src_root)) >> + return PTR_ERR(src_root); >> + >> /* Locks @dst first because we are its only owner. */ >> mutex_lock(&dst->lock); >> mutex_lock_nested(&src->lock, SINGLE_DEPTH_NESTING); >> @@ -285,23 +333,23 @@ 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, >> + rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, src_root, >> node) { >> struct landlock_layer layers[] = { { >> .level = dst->num_layers, >> } }; >> + const struct landlock_id id = { >> + .key = walker_rule->key, >> + .type = LANDLOCK_KEY_INODE, >> + }; >> >> - if (WARN_ON_ONCE(walker_rule->num_layers != 1)) { >> - err = -EINVAL; >> - goto out_unlock; >> - } >> - if (WARN_ON_ONCE(walker_rule->layers[0].level != 0)) { >> - err = -EINVAL; >> - goto out_unlock; >> - } >> + if (WARN_ON_ONCE(walker_rule->num_layers != 1)) >> + return -EINVAL; >> + if (WARN_ON_ONCE(walker_rule->layers[0].level != 0)) >> + return -EINVAL; >> layers[0].access = walker_rule->layers[0].access; >> - err = insert_rule(dst, walker_rule->object, &layers, >> - ARRAY_SIZE(layers)); >> + >> + err = insert_rule(dst, id, &layers, ARRAY_SIZE(layers)); >> if (err) >> goto out_unlock; >> } >> @@ -316,21 +364,29 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, >> struct landlock_ruleset *const child) >> { >> struct landlock_rule *walker_rule, *next_rule; >> + struct rb_root *parent_root; >> int err = 0; >> >> might_sleep(); >> if (!parent) >> return 0; >> >> + parent_root = get_root(parent, LANDLOCK_KEY_INODE); >> + if (IS_ERR(parent_root)) >> + return PTR_ERR(parent_root); >> + >> /* Locks @child first because we are its only owner. */ >> mutex_lock(&child->lock); >> mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING); >> >> /* Copies the @parent tree. */ >> rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, >> - &parent->root, node) { >> - err = insert_rule(child, walker_rule->object, >> - &walker_rule->layers, >> + parent_root, node) { >> + const struct landlock_id id = { >> + .key = walker_rule->key, >> + .type = LANDLOCK_KEY_INODE, >> + }; >> + err = insert_rule(child, id, &walker_rule->layers, >> walker_rule->num_layers); >> if (err) >> goto out_unlock; >> @@ -362,8 +418,9 @@ 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) >> - free_rule(freeme); >> + rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, >> + node) >> + free_rule(freeme, LANDLOCK_KEY_INODE); >> put_hierarchy(ruleset->hierarchy); >> kfree(ruleset); >> } >> @@ -454,20 +511,23 @@ 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 struct landlock_id id) >> { >> + const struct rb_root *root; >> const struct rb_node *node; >> >> - if (!object) >> + root = get_root((struct landlock_ruleset *)ruleset, id.type); >> + if (IS_ERR(root)) >> return NULL; >> - node = ruleset->root.rb_node; >> + node = root->rb_node; >> + >> while (node) { >> struct landlock_rule *this = >> rb_entry(node, struct landlock_rule, node); >> >> - if (this->object == object) >> + if (this->key.data == id.key.data) >> return this; >> - if (this->object < object) >> + if (this->key.data < id.key.data) >> node = node->rb_right; >> else >> node = node->rb_left; >> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h >> index f2ad932d396c..608ab356bc3e 100644 >> --- a/security/landlock/ruleset.h >> +++ b/security/landlock/ruleset.h >> @@ -49,6 +49,46 @@ struct landlock_layer { >> access_mask_t access; >> }; >> >> +/** >> + * union landlock_key - Key of a ruleset's red-black tree >> + */ >> +union landlock_key { >> + /** >> + * @object: Pointer to identify a kernel object (e.g. an inode). >> + */ >> + struct landlock_object *object; >> + /** >> + * @data: A raw data value to identify a network socket port. > > "Raw data to identify an arbitrary 32-bit value (e.g. a TCP port)." > Ok. > >> + */ >> + uintptr_t data; >> +}; >> + >> +/** >> + * enum landlock_key_type - Type of &union landlock_key >> + */ >> +enum landlock_key_type { >> + /** >> + * @LANDLOCK_KEY_INODE: Type of &landlock_ruleset.root_inode's node >> + * keys. >> + */ >> + LANDLOCK_KEY_INODE = 1, >> +}; >> + >> +/** >> + * struct landlock_id - Unique rule identifier for a ruleset >> + */ >> +struct landlock_id { >> + /** >> + * @key: A union to identify either a kernel object (e.g. an inode) or >> + * a raw data value (e.g. a network socket port). > > "a 32-bit value (e.g. a TCP port)." Ok. Got it. > > >> + */ >> + union landlock_key key; >> + /** >> + * @type: A enumerator to identify the type of landlock_ruleset's root tree. >> + */ >> + const enum landlock_key_type type; >> +}; >> + >> /** >> * struct landlock_rule - Access rights tied to an object >> */ >> @@ -58,12 +98,13 @@ 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. >> + * @key: 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. The 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; >> + union landlock_key key; >> /** >> * @num_layers: Number of entries in @layers. >> */ >> @@ -99,11 +140,12 @@ struct landlock_hierarchy { >> */ >> struct landlock_ruleset { >> /** >> - * @root: Root of a red-black tree containing &struct landlock_rule >> - * nodes. Once a ruleset is tied to a process (i.e. as a domain), this >> - * tree is immutable until @usage reaches zero. >> + * @root_inode: Root of a red-black tree containing &struct >> + * landlock_rule nodes with inode object. 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. >> @@ -165,7 +207,7 @@ 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 struct landlock_id id, >> const access_mask_t access); >> >> struct landlock_ruleset * >> @@ -174,7 +216,7 @@ 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 struct landlock_id id); >> >> static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset) >> { >> -- >> 2.25.1 >> > .