From patchwork Fri Oct 21 15:26:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014924 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 777AAC43217 for ; Fri, 21 Oct 2022 15:27:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230197AbiJUP1D (ORCPT ); Fri, 21 Oct 2022 11:27:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230322AbiJUP1B (ORCPT ); Fri, 21 Oct 2022 11:27:01 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 029FD175357; Fri, 21 Oct 2022 08:26:56 -0700 (PDT) Received: from frapeml500001.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7Zv5p6kz67Cp9; Fri, 21 Oct 2022 23:25:43 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml500001.china.huawei.com (7.182.85.94) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:26:54 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:26:53 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 01/12] landlock: Make ruleset's access masks more generic Date: Fri, 21 Oct 2022 23:26:33 +0800 Message-ID: <20221021152644.155136-2-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org To support network type rules, this modification renames ruleset's access masks and modifies it's type to access_masks_t. This patch adds filesystem helper functions to add and get filesystem mask. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Refactors commit message. Changes since v6: * Adds a new access_masks_t for struct ruleset. * Renames landlock_set_fs_access_mask() to landlock_add_fs_access_mask() because it OR values. * Makes landlock_add_fs_access_mask() more resilient incorrect values. * Refactors landlock_get_fs_access_mask(). Changes since v6: * Adds a new access_masks_t for struct ruleset. * Renames landlock_set_fs_access_mask() to landlock_add_fs_access_mask() because it OR values. * Makes landlock_add_fs_access_mask() more resilient incorrect values. * Refactors landlock_get_fs_access_mask(). Changes since v5: * Changes access_mask_t to u32. * Formats code with clang-format-14. Changes since v4: * Deletes struct landlock_access_mask. Changes since v3: * Splits commit. * Adds get_mask, set_mask helpers for filesystem. * Adds new struct landlock_access_mask. --- security/landlock/fs.c | 10 +++++----- security/landlock/limits.h | 1 + security/landlock/ruleset.c | 17 +++++++++-------- security/landlock/ruleset.h | 35 +++++++++++++++++++++++++++++++---- security/landlock/syscalls.c | 7 ++++--- 5 files changed, 50 insertions(+), 20 deletions(-) -- 2.25.1 diff --git a/security/landlock/fs.c b/security/landlock/fs.c index adcea0fe7e68..0d57c6479d29 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -178,9 +178,9 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, return -EINVAL; /* Transforms relative access rights to absolute ones. */ - access_rights |= - LANDLOCK_MASK_ACCESS_FS & - ~(ruleset->fs_access_masks[0] | ACCESS_INITIALLY_DENIED); + 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); @@ -294,7 +294,7 @@ get_handled_accesses(const struct landlock_ruleset *const domain) size_t layer_level; for (layer_level = 0; layer_level < domain->num_layers; layer_level++) - access_dom |= domain->fs_access_masks[layer_level]; + access_dom |= landlock_get_fs_access_mask(domain, layer_level); return access_dom & LANDLOCK_MASK_ACCESS_FS; } @@ -336,7 +336,7 @@ init_layer_masks(const struct landlock_ruleset *const domain, * access rights. */ if (BIT_ULL(access_bit) & - (domain->fs_access_masks[layer_level] | + (landlock_get_fs_access_mask(domain, layer_level) | ACCESS_INITIALLY_DENIED)) { (*layer_masks)[access_bit] |= BIT_ULL(layer_level); diff --git a/security/landlock/limits.h b/security/landlock/limits.h index 82288f0e9e5e..bafb3b8dc677 100644 --- a/security/landlock/limits.h +++ b/security/landlock/limits.h @@ -21,6 +21,7 @@ #define LANDLOCK_LAST_ACCESS_FS LANDLOCK_ACCESS_FS_TRUNCATE #define LANDLOCK_MASK_ACCESS_FS ((LANDLOCK_LAST_ACCESS_FS << 1) - 1) #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) +#define LANDLOCK_SHIFT_ACCESS_FS 0 /* clang-format on */ diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 996484f98bfd..1f3188b4e313 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -29,7 +29,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) struct landlock_ruleset *new_ruleset; new_ruleset = - kzalloc(struct_size(new_ruleset, fs_access_masks, num_layers), + kzalloc(struct_size(new_ruleset, access_masks, num_layers), GFP_KERNEL_ACCOUNT); if (!new_ruleset) return ERR_PTR(-ENOMEM); @@ -40,7 +40,7 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) /* * hierarchy = NULL * num_rules = 0 - * fs_access_masks[] = 0 + * access_masks[] = 0 */ return new_ruleset; } @@ -55,7 +55,7 @@ landlock_create_ruleset(const access_mask_t fs_access_mask) return ERR_PTR(-ENOMSG); new_ruleset = create_ruleset(1); if (!IS_ERR(new_ruleset)) - new_ruleset->fs_access_masks[0] = fs_access_mask; + landlock_add_fs_access_mask(new_ruleset, fs_access_mask, 0); return new_ruleset; } @@ -117,11 +117,12 @@ static void build_check_ruleset(void) .num_rules = ~0, .num_layers = ~0, }; - typeof(ruleset.fs_access_masks[0]) fs_access_mask = ~0; + typeof(ruleset.access_masks[0]) access_masks = ~0; BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES); BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS); - BUILD_BUG_ON(fs_access_mask < LANDLOCK_MASK_ACCESS_FS); + BUILD_BUG_ON(access_masks < + (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS)); } /** @@ -281,7 +282,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst, err = -EINVAL; goto out_unlock; } - dst->fs_access_masks[dst->num_layers - 1] = src->fs_access_masks[0]; + 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, @@ -340,8 +341,8 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, goto out_unlock; } /* Copies the parent layer stack and leaves a space for the new layer. */ - memcpy(child->fs_access_masks, parent->fs_access_masks, - flex_array_size(parent, fs_access_masks, parent->num_layers)); + memcpy(child->access_masks, parent->access_masks, + flex_array_size(parent, access_masks, parent->num_layers)); if (WARN_ON_ONCE(!parent->hierarchy)) { err = -EINVAL; diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index d43231b783e4..f2ad932d396c 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -25,6 +25,11 @@ static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); +/* Ruleset access masks. */ +typedef u16 access_masks_t; +/* Makes sure all ruleset access rights can be stored. */ +static_assert(BITS_PER_TYPE(access_masks_t) >= LANDLOCK_NUM_ACCESS_FS); + typedef u16 layer_mask_t; /* Makes sure all layers can be checked. */ static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS); @@ -110,7 +115,7 @@ struct landlock_ruleset { * section. This is only used by * landlock_put_ruleset_deferred() when @usage reaches zero. * The fields @lock, @usage, @num_rules, @num_layers and - * @fs_access_masks are then unused. + * @access_masks are then unused. */ struct work_struct work_free; struct { @@ -137,7 +142,7 @@ struct landlock_ruleset { */ u32 num_layers; /** - * @fs_access_masks: Contains the subset of filesystem + * @access_masks: Contains the subset of filesystem * actions that are restricted by a ruleset. A domain * saves all layers of merged rulesets in a stack * (FAM), starting from the first layer to the last @@ -148,13 +153,13 @@ struct landlock_ruleset { * layers are set once and never changed for the * lifetime of the ruleset. */ - access_mask_t fs_access_masks[]; + access_masks_t access_masks[]; }; }; }; struct landlock_ruleset * -landlock_create_ruleset(const access_mask_t fs_access_mask); +landlock_create_ruleset(const access_mask_t access_mask); void landlock_put_ruleset(struct landlock_ruleset *const ruleset); void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); @@ -177,4 +182,26 @@ static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset) refcount_inc(&ruleset->usage); } +static inline void +landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, + const access_mask_t fs_access_mask, + const u16 layer_level) +{ + access_mask_t fs_mask = fs_access_mask & LANDLOCK_MASK_ACCESS_FS; + + /* Should already be checked in sys_landlock_create_ruleset(). */ + WARN_ON_ONCE(fs_access_mask != fs_mask); + // TODO: Add tests to check "|=" and not "=" + ruleset->access_masks[layer_level] |= + (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); +} + +static inline access_mask_t +landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, + const u16 layer_level) +{ + return (ruleset->access_masks[layer_level] >> + LANDLOCK_SHIFT_ACCESS_FS) & + LANDLOCK_MASK_ACCESS_FS; +} #endif /* _SECURITY_LANDLOCK_RULESET_H */ diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 245cc650a4dc..71aca7f990bc 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -346,10 +346,11 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, } /* * Checks that allowed_access matches the @ruleset constraints - * (ruleset->fs_access_masks[0] is automatically upgraded to 64-bits). + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). */ - if ((path_beneath_attr.allowed_access | ruleset->fs_access_masks[0]) != - ruleset->fs_access_masks[0]) { + if ((path_beneath_attr.allowed_access | + landlock_get_fs_access_mask(ruleset, 0)) != + landlock_get_fs_access_mask(ruleset, 0)) { err = -EINVAL; goto out_put_ruleset; } From patchwork Fri Oct 21 15:26:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014925 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 1F9CBC4321E for ; Fri, 21 Oct 2022 15:27:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230338AbiJUP1F (ORCPT ); Fri, 21 Oct 2022 11:27:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230332AbiJUP1B (ORCPT ); Fri, 21 Oct 2022 11:27:01 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34E3D254764; Fri, 21 Oct 2022 08:26:58 -0700 (PDT) Received: from frapeml100008.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7Zy08TPz689lY; Fri, 21 Oct 2022 23:25:46 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml100008.china.huawei.com (7.182.85.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:26:56 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:26:55 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 02/12] landlock: Refactor landlock_find_rule/insert_rule Date: Fri, 21 Oct 2022 23:26:34 +0800 Message-ID: <20221021152644.155136-3-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Adds a new landlock_key union and landlock_id structure to support 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. get_root() helper chooses red_black tree root depending on a key 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 landlock id argument provided in refactored functions. Co-developed-by: Mickaël Salaün Signed-off-by: Konstantin Meskhidze Signed-off-by: Mickaël Salaün --- 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(-) -- 2.25.1 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) +{ + 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, + 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. + */ + 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). + */ + 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) { From patchwork Fri Oct 21 15:26:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014926 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 9767CC4332F for ; Fri, 21 Oct 2022 15:27:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229978AbiJUP1H (ORCPT ); Fri, 21 Oct 2022 11:27:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230339AbiJUP1C (ORCPT ); Fri, 21 Oct 2022 11:27:02 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52CE924AE22; Fri, 21 Oct 2022 08:27:01 -0700 (PDT) Received: from frapeml100007.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7XX6gMTz67kVR; Fri, 21 Oct 2022 23:23:40 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml100007.china.huawei.com (7.182.85.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:26:59 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:26:58 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 03/12] landlock: Refactor merge/inherit_ruleset functions Date: Fri, 21 Oct 2022 23:26:35 +0800 Message-ID: <20221021152644.155136-4-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Refactors merge_ruleset() and inherit_ruleset() functions to support new rule types. This patch adds merge_tree() and inherit_tree() helpers. Each has key_type argument to choose a particular rb_tree structure in a ruleset. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Adds missed lockdep_assert_held it inherit_tree() and merge_tree(). * Fixes comment. Changes since v6: * Refactors merge_ruleset() and inherit_ruleset() functions to support new rule types. * Renames tree_merge() to merge_tree() (and reorder arguments), and tree_copy() to inherit_tree(). Changes since v5: * Refactors some logic errors. * Formats code with clang-format-14. Changes since v4: * None --- security/landlock/ruleset.c | 108 ++++++++++++++++++++++++------------ 1 file changed, 73 insertions(+), 35 deletions(-) -- 2.25.1 diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 41de17d1869e..961ffe0c709e 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -302,36 +302,22 @@ static void put_hierarchy(struct landlock_hierarchy *hierarchy) } } -static int merge_ruleset(struct landlock_ruleset *const dst, - struct landlock_ruleset *const src) +static int merge_tree(struct landlock_ruleset *const dst, + struct landlock_ruleset *const src, + const enum landlock_key_type key_type) { struct landlock_rule *walker_rule, *next_rule; struct rb_root *src_root; int err = 0; might_sleep(); - /* Should already be checked by landlock_merge_ruleset() */ - if (WARN_ON_ONCE(!src)) - return 0; - /* Only merge into a domain. */ - if (WARN_ON_ONCE(!dst || !dst->hierarchy)) - return -EINVAL; + lockdep_assert_held(&dst->lock); + lockdep_assert_held(&src->lock); - src_root = get_root(src, LANDLOCK_KEY_INODE); + src_root = get_root(src, key_type); 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); - - /* Stacks the new layer. */ - if (WARN_ON_ONCE(src->num_layers != 1 || dst->num_layers < 1)) { - err = -EINVAL; - goto out_unlock; - } - 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) { @@ -340,7 +326,7 @@ static int merge_ruleset(struct landlock_ruleset *const dst, } }; const struct landlock_id id = { .key = walker_rule->key, - .type = LANDLOCK_KEY_INODE, + .type = key_type, }; if (WARN_ON_ONCE(walker_rule->num_layers != 1)) @@ -351,8 +337,39 @@ static int merge_ruleset(struct landlock_ruleset *const dst, err = insert_rule(dst, id, &layers, ARRAY_SIZE(layers)); if (err) - goto out_unlock; + return err; + } + return err; +} + +static int merge_ruleset(struct landlock_ruleset *const dst, + struct landlock_ruleset *const src) +{ + int err = 0; + + might_sleep(); + /* Should already be checked by landlock_merge_ruleset() */ + if (WARN_ON_ONCE(!src)) + return 0; + /* Only merge into a domain. */ + if (WARN_ON_ONCE(!dst || !dst->hierarchy)) + return -EINVAL; + + /* Locks @dst first because we are its only owner. */ + mutex_lock(&dst->lock); + mutex_lock_nested(&src->lock, SINGLE_DEPTH_NESTING); + + /* Stacks the new layer. */ + if (WARN_ON_ONCE(src->num_layers != 1 || dst->num_layers < 1)) { + err = -EINVAL; + goto out_unlock; } + dst->access_masks[dst->num_layers - 1] = src->access_masks[0]; + + /* Merges the @src inode tree. */ + err = merge_tree(dst, src, LANDLOCK_KEY_INODE); + if (err) + goto out_unlock; out_unlock: mutex_unlock(&src->lock); @@ -360,43 +377,64 @@ static int merge_ruleset(struct landlock_ruleset *const dst, return err; } -static int inherit_ruleset(struct landlock_ruleset *const parent, - struct landlock_ruleset *const child) +static int inherit_tree(struct landlock_ruleset *const parent, + struct landlock_ruleset *const child, + const enum landlock_key_type key_type) { struct landlock_rule *walker_rule, *next_rule; struct rb_root *parent_root; int err = 0; might_sleep(); - if (!parent) - return 0; + lockdep_assert_held(&parent->lock); + lockdep_assert_held(&parent->lock); - parent_root = get_root(parent, LANDLOCK_KEY_INODE); + parent_root = get_root(parent, key_type); 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. */ + /* Copies the @parent inode or network tree. */ rbtree_postorder_for_each_entry_safe(walker_rule, next_rule, parent_root, node) { const struct landlock_id id = { .key = walker_rule->key, - .type = LANDLOCK_KEY_INODE, + .type = key_type, }; + err = insert_rule(child, id, &walker_rule->layers, walker_rule->num_layers); if (err) - goto out_unlock; + return err; } + return err; +} + +static int inherit_ruleset(struct landlock_ruleset *const parent, + struct landlock_ruleset *const child) +{ + int err = 0; + + might_sleep(); + if (!parent) + return 0; + + /* Locks @child first because we are its only owner. */ + mutex_lock(&child->lock); + mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING); + + /* Copies the @parent inode tree. */ + err = inherit_tree(parent, child, LANDLOCK_KEY_INODE); + if (err) + goto out_unlock; if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) { err = -EINVAL; goto out_unlock; } - /* Copies the parent layer stack and leaves a space for the new layer. */ + /* + * Copies the parent layer stack and leaves a space + * for the new layer. + */ memcpy(child->access_masks, parent->access_masks, flex_array_size(parent, access_masks, parent->num_layers)); From patchwork Fri Oct 21 15:26:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014927 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 6590AC4167B for ; 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Fri, 21 Oct 2022 16:27:00 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 04/12] landlock: Move unmask_layers() and init_layer_masks() Date: Fri, 21 Oct 2022 23:26:36 +0800 Message-ID: <20221021152644.155136-5-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch moves unmask_layers() and init_layer_masks() helpers to ruleset.c to share with landlock network implementation in following commits. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Refactors commit message. Changes since v6: * Moves get_handled_accesses() helper from ruleset.c back to fs.c, cause it's not used in coming network commits. Changes since v5: * Splits commit. * Moves init_layer_masks() and get_handled_accesses() helpers to ruleset.c and makes then non-static. * Formats code with clang-format-14. --- security/landlock/fs.c | 103 ------------------------------------ security/landlock/ruleset.c | 102 +++++++++++++++++++++++++++++++++++ security/landlock/ruleset.h | 20 +++++++ 3 files changed, 122 insertions(+), 103 deletions(-) -- 2.25.1 diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 710cfa1306de..240e42a8f788 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -226,60 +226,6 @@ find_rule(const struct landlock_ruleset *const domain, return rule; } -/* - * @layer_masks is read and may be updated according to the access request and - * the matching rule. - * - * Returns true if the request is allowed (i.e. relevant layer masks for the - * request are empty). - */ -static inline bool -unmask_layers(const struct landlock_rule *const rule, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) -{ - size_t layer_level; - - if (!access_request || !layer_masks) - return true; - if (!rule) - return false; - - /* - * An access is granted if, for each policy layer, at least one rule - * encountered on the pathwalk grants the requested access, - * regardless of its position in the layer stack. We must then check - * the remaining layers for each inode, from the first added layer to - * the last one. When there is multiple requested accesses, for each - * policy layer, the full set of requested accesses may not be granted - * by only one rule, but by the union (binary OR) of multiple rules. - * E.g. /a/b + /a => /a/b - */ - for (layer_level = 0; layer_level < rule->num_layers; layer_level++) { - const struct landlock_layer *const layer = - &rule->layers[layer_level]; - const layer_mask_t layer_bit = BIT_ULL(layer->level - 1); - const unsigned long access_req = access_request; - unsigned long access_bit; - bool is_empty; - - /* - * Records in @layer_masks which layer grants access to each - * requested access. - */ - is_empty = true; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { - if (layer->access & BIT_ULL(access_bit)) - (*layer_masks)[access_bit] &= ~layer_bit; - is_empty = is_empty && !(*layer_masks)[access_bit]; - } - if (is_empty) - return true; - } - return false; -} - /* * Allows access to pseudo filesystems that will never be mountable (e.g. * sockfs, pipefs), but can still be reachable through @@ -303,55 +249,6 @@ get_handled_accesses(const struct landlock_ruleset *const domain) return access_dom & LANDLOCK_MASK_ACCESS_FS; } -/** - * init_layer_masks - Initialize layer masks from an access request - * - * Populates @layer_masks such that for each access right in @access_request, - * the bits for all the layers are set where this access right is handled. - * - * @domain: The domain that defines the current restrictions. - * @access_request: The requested access rights to check. - * @layer_masks: The layer masks to populate. - * - * Returns: An access mask where each access right bit is set which is handled - * in any of the active layers in @domain. - */ -static inline access_mask_t -init_layer_masks(const struct landlock_ruleset *const domain, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) -{ - access_mask_t handled_accesses = 0; - size_t layer_level; - - memset(layer_masks, 0, sizeof(*layer_masks)); - /* An empty access request can happen because of O_WRONLY | O_RDWR. */ - if (!access_request) - return 0; - - /* Saves all handled accesses per layer. */ - for (layer_level = 0; layer_level < domain->num_layers; layer_level++) { - const unsigned long access_req = access_request; - unsigned long access_bit; - - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { - /* - * Artificially handles all initially denied by default - * access rights. - */ - if (BIT_ULL(access_bit) & - (landlock_get_fs_access_mask(domain, layer_level) | - ACCESS_INITIALLY_DENIED)) { - (*layer_masks)[access_bit] |= - BIT_ULL(layer_level); - handled_accesses |= BIT_ULL(access_bit); - } - } - } - return handled_accesses; -} - /* * Check that a destination file hierarchy has more restrictions than a source * file hierarchy. This is only used for link and rename actions. diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 961ffe0c709e..02ab14439c43 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -572,3 +572,105 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset, } return NULL; } + +/* + * @layer_masks is read and may be updated according to the access request and + * the matching rule. + * + * Returns true if the request is allowed (i.e. relevant layer masks for the + * request are empty). + */ +bool unmask_layers(const struct landlock_rule *const rule, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) +{ + size_t layer_level; + + if (!access_request || !layer_masks) + return true; + if (!rule) + return false; + + /* + * An access is granted if, for each policy layer, at least one rule + * encountered on the pathwalk grants the requested access, + * regardless of its position in the layer stack. We must then check + * the remaining layers for each inode, from the first added layer to + * the last one. When there is multiple requested accesses, for each + * policy layer, the full set of requested accesses may not be granted + * by only one rule, but by the union (binary OR) of multiple rules. + * E.g. /a/b + /a => /a/b + */ + for (layer_level = 0; layer_level < rule->num_layers; layer_level++) { + const struct landlock_layer *const layer = + &rule->layers[layer_level]; + const layer_mask_t layer_bit = BIT_ULL(layer->level - 1); + const unsigned long access_req = access_request; + unsigned long access_bit; + bool is_empty; + + /* + * Records in @layer_masks which layer grants access to each + * requested access. + */ + is_empty = true; + for_each_set_bit(access_bit, &access_req, + ARRAY_SIZE(*layer_masks)) { + if (layer->access & BIT_ULL(access_bit)) + (*layer_masks)[access_bit] &= ~layer_bit; + is_empty = is_empty && !(*layer_masks)[access_bit]; + } + if (is_empty) + return true; + } + return false; +} + +/** + * init_layer_masks - Initialize layer masks from an access request + * + * Populates @layer_masks such that for each access right in @access_request, + * the bits for all the layers are set where this access right is handled. + * + * @domain: The domain that defines the current restrictions. + * @access_request: The requested access rights to check. + * @layer_masks: The layer masks to populate. + * + * Returns: An access mask where each access right bit is set which is handled + * in any of the active layers in @domain. + */ +access_mask_t +init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) +{ + access_mask_t handled_accesses = 0; + size_t layer_level; + + memset(layer_masks, 0, sizeof(*layer_masks)); + /* An empty access request can happen because of O_WRONLY | O_RDWR. */ + if (!access_request) + return 0; + + /* Saves all handled accesses per layer. */ + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) { + const unsigned long access_req = access_request; + unsigned long access_bit; + + for_each_set_bit(access_bit, &access_req, + ARRAY_SIZE(*layer_masks)) { + /* + * Artificially handles all initially denied by default + * access rights. + */ + if (BIT_ULL(access_bit) & + (landlock_get_fs_access_mask(domain, layer_level) | + ACCESS_INITIALLY_DENIED)) { + (*layer_masks)[access_bit] |= + BIT_ULL(layer_level); + handled_accesses |= BIT_ULL(access_bit); + } + } + } + return handled_accesses; +} diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 608ab356bc3e..50baff4fcbb4 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -34,6 +34,16 @@ typedef u16 layer_mask_t; /* Makes sure all layers can be checked. */ static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS); +/* + * All access rights that are denied by default whether they are handled or not + * by a ruleset/layer. This must be ORed with all ruleset->fs_access_masks[] + * entries when we need to get the absolute handled access masks. + */ +/* clang-format off */ +#define ACCESS_INITIALLY_DENIED ( \ + LANDLOCK_ACCESS_FS_REFER) +/* clang-format on */ + /** * struct landlock_layer - Access rights for a given layer */ @@ -246,4 +256,14 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, LANDLOCK_SHIFT_ACCESS_FS) & LANDLOCK_MASK_ACCESS_FS; } + +bool unmask_layers(const struct landlock_rule *const rule, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]); + +access_mask_t +init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]); + #endif /* _SECURITY_LANDLOCK_RULESET_H */ From patchwork Fri Oct 21 15:26:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014928 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 648DBC4167E for ; Fri, 21 Oct 2022 15:27:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230401AbiJUP1Y (ORCPT ); Fri, 21 Oct 2022 11:27:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230339AbiJUP1H (ORCPT ); Fri, 21 Oct 2022 11:27:07 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 509B31EB564; Fri, 21 Oct 2022 08:27:05 -0700 (PDT) Received: from frapeml100005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7Xd0Sqsz67kVR; Fri, 21 Oct 2022 23:23:45 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml100005.china.huawei.com (7.182.85.132) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:27:03 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:27:02 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 05/12] landlock: Refactor unmask_layers() and init_layer_masks() Date: Fri, 21 Oct 2022 23:26:37 +0800 Message-ID: <20221021152644.155136-6-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Adds new key_type argument to init_layer_masks() helper. Adds masks_array_size argument to unmask_layers() helper. These modifications support implementing new rule types in the next Landlock versions. Co-developed-by: Mickaël Salaün Signed-off-by: Konstantin Meskhidze Signed-off-by: Mickaël Salaün --- Changes since v7: * Refactors commit message, adds a co-developer. * Minor fixes. Changes since v6: * Removes masks_size attribute from init_layer_masks(). * Refactors init_layer_masks() with new landlock_key_type. Changes since v5: * Splits commit. * Formats code with clang-format-14. Changes since v4: * Refactors init_layer_masks(), get_handled_accesses() and unmask_layers() functions to support multiple rule types. * Refactors landlock_get_fs_access_mask() function with LANDLOCK_MASK_ACCESS_FS mask. Changes since v3: * Splits commit. * Refactors landlock_unmask_layers functions. --- security/landlock/fs.c | 36 ++++++++++++++++++------------- security/landlock/ruleset.c | 42 ++++++++++++++++++++++++++----------- security/landlock/ruleset.h | 11 +++++----- 3 files changed, 58 insertions(+), 31 deletions(-) -- 2.25.1 diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 240e42a8f788..fe76a11483f8 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -435,16 +435,20 @@ static bool is_access_to_paths_allowed( if (unlikely(dentry_child1)) { unmask_layers(find_rule(domain, dentry_child1), init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - &_layer_masks_child1), - &_layer_masks_child1); + &_layer_masks_child1, + LANDLOCK_KEY_INODE), + &_layer_masks_child1, + ARRAY_SIZE(_layer_masks_child1)); layer_masks_child1 = &_layer_masks_child1; child1_is_directory = d_is_dir(dentry_child1); } if (unlikely(dentry_child2)) { unmask_layers(find_rule(domain, dentry_child2), init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - &_layer_masks_child2), - &_layer_masks_child2); + &_layer_masks_child2, + LANDLOCK_KEY_INODE), + &_layer_masks_child2, + ARRAY_SIZE(_layer_masks_child2)); layer_masks_child2 = &_layer_masks_child2; child2_is_directory = d_is_dir(dentry_child2); } @@ -496,15 +500,16 @@ static bool is_access_to_paths_allowed( } rule = find_rule(domain, walker_path.dentry); - allowed_parent1 = unmask_layers(rule, access_masked_parent1, - layer_masks_parent1); - allowed_parent2 = unmask_layers(rule, access_masked_parent2, - layer_masks_parent2); + allowed_parent1 = unmask_layers( + rule, access_masked_parent1, layer_masks_parent1, + ARRAY_SIZE(*layer_masks_parent1)); + allowed_parent2 = unmask_layers( + rule, access_masked_parent2, layer_masks_parent2, + ARRAY_SIZE(*layer_masks_parent2)); /* Stops when a rule from each layer grants access. */ if (allowed_parent1 && allowed_parent2) break; - jump_up: if (walker_path.dentry == walker_path.mnt->mnt_root) { if (follow_up(&walker_path)) { @@ -543,7 +548,8 @@ static inline int check_access_path(const struct landlock_ruleset *const domain, { layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS] = {}; - access_request = init_layer_masks(domain, access_request, &layer_masks); + access_request = init_layer_masks(domain, access_request, &layer_masks, + LANDLOCK_KEY_INODE); if (is_access_to_paths_allowed(domain, path, access_request, &layer_masks, NULL, 0, NULL, NULL)) return 0; @@ -630,7 +636,7 @@ static bool collect_domain_accesses( return true; access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - layer_masks_dom); + layer_masks_dom, LANDLOCK_KEY_INODE); dget(dir); while (true) { @@ -638,7 +644,8 @@ static bool collect_domain_accesses( /* Gets all layers allowing all domain accesses. */ if (unmask_layers(find_rule(domain, dir), access_dom, - layer_masks_dom)) { + layer_masks_dom, + ARRAY_SIZE(*layer_masks_dom))) { /* * Stops when all handled accesses are allowed by at * least one rule in each layer. @@ -754,7 +761,7 @@ static int current_check_refer_path(struct dentry *const old_dentry, */ access_request_parent1 = init_layer_masks( dom, access_request_parent1 | access_request_parent2, - &layer_masks_parent1); + &layer_masks_parent1, LANDLOCK_KEY_INODE); if (is_access_to_paths_allowed( dom, new_dir, access_request_parent1, &layer_masks_parent1, NULL, 0, NULL, NULL)) @@ -1131,7 +1138,8 @@ static int hook_file_open(struct file *const file) if (is_access_to_paths_allowed( dom, &file->f_path, - init_layer_masks(dom, full_access_request, &layer_masks), + init_layer_masks(dom, full_access_request, &layer_masks, + LANDLOCK_KEY_INODE), &layer_masks, NULL, 0, NULL, NULL)) { allowed_access = full_access_request; } else { diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 02ab14439c43..c7cf54ba4f6d 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -576,13 +576,15 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset, /* * @layer_masks is read and may be updated according to the access request and * the matching rule. + * @masks_array_size must be equal to ARRAY_SIZE(*layer_masks). * * Returns true if the request is allowed (i.e. relevant layer masks for the * request are empty). */ bool unmask_layers(const struct landlock_rule *const rule, const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) + layer_mask_t (*const layer_masks)[], + const size_t masks_array_size) { size_t layer_level; @@ -614,8 +616,7 @@ bool unmask_layers(const struct landlock_rule *const rule, * requested access. */ is_empty = true; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { + for_each_set_bit(access_bit, &access_req, masks_array_size) { if (layer->access & BIT_ULL(access_bit)) (*layer_masks)[access_bit] &= ~layer_bit; is_empty = is_empty && !(*layer_masks)[access_bit]; @@ -626,6 +627,10 @@ bool unmask_layers(const struct landlock_rule *const rule, return false; } +typedef access_mask_t +get_access_mask_t(const struct landlock_ruleset *const ruleset, + const u16 layer_level); + /** * init_layer_masks - Initialize layer masks from an access request * @@ -635,19 +640,33 @@ bool unmask_layers(const struct landlock_rule *const rule, * @domain: The domain that defines the current restrictions. * @access_request: The requested access rights to check. * @layer_masks: The layer masks to populate. + * @key_type: The key type to switch between access masks of different types. * * Returns: An access mask where each access right bit is set which is handled * in any of the active layers in @domain. */ -access_mask_t -init_layer_masks(const struct landlock_ruleset *const domain, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) +access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + const enum landlock_key_type key_type) { access_mask_t handled_accesses = 0; - size_t layer_level; + size_t layer_level, num_access; + get_access_mask_t *get_access_mask; + + switch (key_type) { + case LANDLOCK_KEY_INODE: + get_access_mask = landlock_get_fs_access_mask; + num_access = LANDLOCK_NUM_ACCESS_FS; + break; + default: + WARN_ON_ONCE(1); + return 0; + } + + memset(layer_masks, 0, + array_size(sizeof((*layer_masks)[0]), num_access)); - memset(layer_masks, 0, sizeof(*layer_masks)); /* An empty access request can happen because of O_WRONLY | O_RDWR. */ if (!access_request) return 0; @@ -657,14 +676,13 @@ init_layer_masks(const struct landlock_ruleset *const domain, const unsigned long access_req = access_request; unsigned long access_bit; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { + for_each_set_bit(access_bit, &access_req, num_access) { /* * Artificially handles all initially denied by default * access rights. */ if (BIT_ULL(access_bit) & - (landlock_get_fs_access_mask(domain, layer_level) | + (get_access_mask(domain, layer_level) | ACCESS_INITIALLY_DENIED)) { (*layer_masks)[access_bit] |= BIT_ULL(layer_level); diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 50baff4fcbb4..d9eb79ea9a89 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -259,11 +259,12 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, bool unmask_layers(const struct landlock_rule *const rule, const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]); + layer_mask_t (*const layer_masks)[], + const size_t masks_array_size); -access_mask_t -init_layer_masks(const struct landlock_ruleset *const domain, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]); +access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + const enum landlock_key_type key_type); #endif /* _SECURITY_LANDLOCK_RULESET_H */ From patchwork Fri Oct 21 15:26:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014930 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 935C1C43219 for ; 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Fri, 21 Oct 2022 16:27:04 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 06/12] landlock: Refactor landlock_add_rule() syscall Date: Fri, 21 Oct 2022 23:26:38 +0800 Message-ID: <20221021152644.155136-7-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Modifies landlock_add_rule() syscall to support new rule types in future Landlock versions. Adds add_rule_path_beneath() helper to support current filesystem rules. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * None Changes since v6: * None Changes since v5: * Refactors syscall landlock_add_rule() and add_rule_path_beneath() helper to make argument check ordering consistent and get rid of partial revertings in following patches. * Rolls back refactoring base_test.c seltest. * Formats code with clang-format-14. Changes since v4: * Refactors add_rule_path_beneath() and landlock_add_rule() functions to optimize code usage. * Refactors base_test.c seltest: adds LANDLOCK_RULE_PATH_BENEATH rule type in landlock_add_rule() call. Changes since v3: * Split commit. * Refactors landlock_add_rule syscall. --- security/landlock/syscalls.c | 92 +++++++++++++++++++----------------- 1 file changed, 48 insertions(+), 44 deletions(-) -- 2.25.1 diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 71aca7f990bc..87389d7bfbf2 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -274,6 +274,47 @@ static int get_path_from_fd(const s32 fd, struct path *const path) return err; } +static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, + const void __user *const rule_attr) +{ + struct landlock_path_beneath_attr path_beneath_attr; + struct path path; + int res, err; + u32 mask; + + /* Copies raw user space buffer, only one type for now. */ + res = copy_from_user(&path_beneath_attr, rule_attr, + sizeof(path_beneath_attr)); + if (res) + return -EFAULT; + + /* + * Informs about useless rule: empty allowed_access (i.e. deny rules) + * are ignored in path walks. + */ + if (!path_beneath_attr.allowed_access) + return -ENOMSG; + /* + * Checks that allowed_access matches the @ruleset constraints + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). + */ + mask = landlock_get_fs_access_mask(ruleset, 0); + if ((path_beneath_attr.allowed_access | mask) != mask) + return -EINVAL; + + /* Gets and checks the new rule. */ + err = get_path_from_fd(path_beneath_attr.parent_fd, &path); + if (err) + return err; + + /* Imports the new rule. */ + err = landlock_append_fs_rule(ruleset, &path, + path_beneath_attr.allowed_access); + path_put(&path); + + return err; +} + /** * sys_landlock_add_rule - Add a new rule to a ruleset * @@ -306,10 +347,8 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, const enum landlock_rule_type, rule_type, const void __user *const, rule_attr, const __u32, flags) { - struct landlock_path_beneath_attr path_beneath_attr; - struct path path; struct landlock_ruleset *ruleset; - int res, err; + int err; if (!landlock_initialized) return -EOPNOTSUPP; @@ -323,49 +362,14 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, if (IS_ERR(ruleset)) return PTR_ERR(ruleset); - if (rule_type != LANDLOCK_RULE_PATH_BENEATH) { + switch (rule_type) { + case LANDLOCK_RULE_PATH_BENEATH: + err = add_rule_path_beneath(ruleset, rule_attr); + break; + default: err = -EINVAL; - goto out_put_ruleset; - } - - /* Copies raw user space buffer, only one type for now. */ - res = copy_from_user(&path_beneath_attr, rule_attr, - sizeof(path_beneath_attr)); - if (res) { - err = -EFAULT; - goto out_put_ruleset; + break; } - - /* - * Informs about useless rule: empty allowed_access (i.e. deny rules) - * are ignored in path walks. - */ - if (!path_beneath_attr.allowed_access) { - err = -ENOMSG; - goto out_put_ruleset; - } - /* - * Checks that allowed_access matches the @ruleset constraints - * (ruleset->access_masks[0] is automatically upgraded to 64-bits). - */ - if ((path_beneath_attr.allowed_access | - landlock_get_fs_access_mask(ruleset, 0)) != - landlock_get_fs_access_mask(ruleset, 0)) { - err = -EINVAL; - goto out_put_ruleset; - } - - /* Gets and checks the new rule. */ - err = get_path_from_fd(path_beneath_attr.parent_fd, &path); - if (err) - goto out_put_ruleset; - - /* Imports the new rule. */ - err = landlock_append_fs_rule(ruleset, &path, - path_beneath_attr.allowed_access); - path_put(&path); - -out_put_ruleset: landlock_put_ruleset(ruleset); return err; } From patchwork Fri Oct 21 15:26:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014929 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 27F5FC38A2B for ; Fri, 21 Oct 2022 15:27:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230366AbiJUP1Z (ORCPT ); Fri, 21 Oct 2022 11:27:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230343AbiJUP1V (ORCPT ); Fri, 21 Oct 2022 11:27:21 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 391AE24AE22; Fri, 21 Oct 2022 08:27:09 -0700 (PDT) Received: from frapeml100003.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7Xh68KGz67kVR; Fri, 21 Oct 2022 23:23:48 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml100003.china.huawei.com (7.182.85.60) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:27:07 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:27:06 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 07/12] landlock: Add network rules support Date: Fri, 21 Oct 2022 23:26:39 +0800 Message-ID: <20221021152644.155136-8-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This commit adds network rules support in internal landlock functions (presented in ruleset.c) and landlock_create_ruleset syscall. Refactors user space API to support network actions. Adds new network access flags, network rule and network attributes. Increments Landlock ABI version. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Squashes commits. * Increments ABI version to 4. * Refactors commit message. * Minor fixes. Changes since v6: * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() because it OR values. * Makes landlock_add_net_access_mask() more resilient incorrect values. * Refactors landlock_get_net_access_mask(). * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use LANDLOCK_NUM_ACCESS_FS as value. * Updates access_masks_t to u32 to support network access actions. * Refactors landlock internal functions to support network actions with landlock_key/key_type/id types. Changes since v5: * Gets rid of partial revert from landlock_add_rule syscall. * Formats code with clang-format-14. Changes since v4: * Refactors landlock_create_ruleset() - splits ruleset and masks checks. * Refactors landlock_create_ruleset() and landlock mask setters/getters to support two rule types. * Refactors landlock_add_rule syscall add_rule_path_beneath function by factoring out get_ruleset_from_fd() and landlock_put_ruleset(). Changes since v3: * Splits commit. * Adds network rule support for internal landlock functions. * Adds set_mask and get_mask for network. * Adds rb_root root_net_port. --- include/uapi/linux/landlock.h | 49 ++++++++++++++ security/landlock/limits.h | 6 +- security/landlock/ruleset.c | 55 ++++++++++++++-- security/landlock/ruleset.h | 68 ++++++++++++++++---- security/landlock/syscalls.c | 13 +++- tools/testing/selftests/landlock/base_test.c | 2 +- 6 files changed, 170 insertions(+), 23 deletions(-) -- 2.25.1 diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h index f3223f964691..096b683c6ff3 100644 --- a/include/uapi/linux/landlock.h +++ b/include/uapi/linux/landlock.h @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { * this access right. */ __u64 handled_access_fs; + + /** + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) + * that is handled by this ruleset and should then be forbidden if no + * rule explicitly allow them. + */ + __u64 handled_access_net; }; /* @@ -54,6 +61,11 @@ enum landlock_rule_type { * landlock_path_beneath_attr . */ LANDLOCK_RULE_PATH_BENEATH = 1, + /** + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct + * landlock_net_service_attr . + */ + LANDLOCK_RULE_NET_SERVICE = 2, }; /** @@ -79,6 +91,24 @@ struct landlock_path_beneath_attr { */ } __attribute__((packed)); +/** + * struct landlock_net_service_attr - TCP subnet definition + * + * Argument of sys_landlock_add_rule(). + */ +struct landlock_net_service_attr { + /** + * @allowed_access: Bitmask of allowed access network for services + * (cf. `Network flags`_). + */ + __u64 allowed_access; + /** + * @port: Network port. + */ + __u16 port; + +} __attribute__((packed)); + /** * DOC: fs_access * @@ -173,4 +203,23 @@ struct landlock_path_beneath_attr { #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) /* clang-format on */ +/** + * DOC: net_access + * + * Network flags + * ~~~~~~~~~~~~~~~~ + * + * These flags enable to restrict a sandboxed process to a set of network + * actions. + * + * TCP sockets with allowed actions: + * + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to + * a remote port. + */ +/* clang-format off */ +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) +/* clang-format on */ #endif /* _UAPI_LINUX_LANDLOCK_H */ diff --git a/security/landlock/limits.h b/security/landlock/limits.h index bafb3b8dc677..8a1a6463c64e 100644 --- a/security/landlock/limits.h +++ b/security/landlock/limits.h @@ -23,6 +23,10 @@ #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) #define LANDLOCK_SHIFT_ACCESS_FS 0 -/* clang-format on */ +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS +/* clang-format on */ #endif /* _SECURITY_LANDLOCK_LIMITS_H */ diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index c7cf54ba4f6d..9277c1295114 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -36,6 +36,9 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) refcount_set(&new_ruleset->usage, 1); mutex_init(&new_ruleset->lock); new_ruleset->root_inode = RB_ROOT; +#if IS_ENABLED(CONFIG_INET) + new_ruleset->root_net_port = RB_ROOT; +#endif /* IS_ENABLED(CONFIG_INET) */ new_ruleset->num_layers = num_layers; /* * hierarchy = NULL @@ -46,16 +49,21 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) } struct landlock_ruleset * -landlock_create_ruleset(const access_mask_t fs_access_mask) +landlock_create_ruleset(const access_mask_t fs_access_mask, + const access_mask_t net_access_mask) { struct landlock_ruleset *new_ruleset; /* Informs about useless ruleset. */ - if (!fs_access_mask) + if (!fs_access_mask && !net_access_mask) return ERR_PTR(-ENOMSG); new_ruleset = create_ruleset(1); - if (!IS_ERR(new_ruleset)) + if (IS_ERR(new_ruleset)) + return new_ruleset; + if (fs_access_mask) landlock_add_fs_access_mask(new_ruleset, fs_access_mask, 0); + if (net_access_mask) + landlock_add_net_access_mask(new_ruleset, net_access_mask, 0); return new_ruleset; } @@ -73,6 +81,10 @@ static inline bool is_object_pointer(const enum landlock_key_type key_type) switch (key_type) { case LANDLOCK_KEY_INODE: return true; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + return false; +#endif /* IS_ENABLED(CONFIG_INET) */ } WARN_ON_ONCE(1); return false; @@ -126,6 +138,11 @@ static inline struct rb_root *get_root(struct landlock_ruleset *const ruleset, case LANDLOCK_KEY_INODE: root = &ruleset->root_inode; break; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + root = &ruleset->root_net_port; + break; +#endif /* IS_ENABLED(CONFIG_INET) */ } if (WARN_ON_ONCE(!root)) return ERR_PTR(-EINVAL); @@ -154,7 +171,9 @@ static void build_check_ruleset(void) BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES); BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS); BUILD_BUG_ON(access_masks < - (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS)); + (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS) + + (LANDLOCK_MASK_ACCESS_NET + << LANDLOCK_SHIFT_ACCESS_NET)); } /** @@ -370,7 +389,12 @@ static int merge_ruleset(struct landlock_ruleset *const dst, err = merge_tree(dst, src, LANDLOCK_KEY_INODE); if (err) goto out_unlock; - +#if IS_ENABLED(CONFIG_INET) + /* Merges the @src network port tree. */ + err = merge_tree(dst, src, LANDLOCK_KEY_NET_PORT); + if (err) + goto out_unlock; +#endif /* IS_ENABLED(CONFIG_INET) */ out_unlock: mutex_unlock(&src->lock); mutex_unlock(&dst->lock); @@ -426,7 +450,12 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, err = inherit_tree(parent, child, LANDLOCK_KEY_INODE); if (err) goto out_unlock; - +#if IS_ENABLED(CONFIG_INET) + /* Copies the @parent network port tree. */ + err = inherit_tree(parent, child, LANDLOCK_KEY_NET_PORT); + if (err) + goto out_unlock; +#endif /* IS_ENABLED(CONFIG_INET) */ if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) { err = -EINVAL; goto out_unlock; @@ -459,6 +488,11 @@ static void free_ruleset(struct landlock_ruleset *const ruleset) rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, node) free_rule(freeme, LANDLOCK_KEY_INODE); +#if IS_ENABLED(CONFIG_INET) + rbtree_postorder_for_each_entry_safe(freeme, next, + &ruleset->root_net_port, node) + free_rule(freeme, LANDLOCK_KEY_NET_PORT); +#endif /* IS_ENABLED(CONFIG_INET) */ put_hierarchy(ruleset->hierarchy); kfree(ruleset); } @@ -637,6 +671,9 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset, * Populates @layer_masks such that for each access right in @access_request, * the bits for all the layers are set where this access right is handled. * + * @layer_masks must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET + * elements according to @key_type. + * * @domain: The domain that defines the current restrictions. * @access_request: The requested access rights to check. * @layer_masks: The layer masks to populate. @@ -659,6 +696,12 @@ access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, get_access_mask = landlock_get_fs_access_mask; num_access = LANDLOCK_NUM_ACCESS_FS; break; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + get_access_mask = landlock_get_net_access_mask; + num_access = LANDLOCK_NUM_ACCESS_NET; + break; +#endif /* IS_ENABLED(CONFIG_INET) */ default: WARN_ON_ONCE(1); return 0; diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index d9eb79ea9a89..f272d2cd518c 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -19,16 +19,20 @@ #include "limits.h" #include "object.h" +/* Rule access mask. */ typedef u16 access_mask_t; /* Makes sure all filesystem access rights can be stored. */ static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); +/* Makes sure all network access rights can be stored. */ +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); /* Ruleset access masks. */ -typedef u16 access_masks_t; +typedef u32 access_masks_t; /* Makes sure all ruleset access rights can be stored. */ -static_assert(BITS_PER_TYPE(access_masks_t) >= LANDLOCK_NUM_ACCESS_FS); +static_assert(BITS_PER_TYPE(access_masks_t) >= + LANDLOCK_NUM_ACCESS_FS + LANDLOCK_NUM_ACCESS_NET); typedef u16 layer_mask_t; /* Makes sure all layers can be checked. */ @@ -82,6 +86,13 @@ enum landlock_key_type { * keys. */ LANDLOCK_KEY_INODE = 1, +#if IS_ENABLED(CONFIG_INET) + /** + * @LANDLOCK_KEY_NET_PORT: Type of &landlock_ruleset.root_net_port's + * node keys. + */ + LANDLOCK_KEY_NET_PORT = 2, +#endif /* IS_ENABLED(CONFIG_INET) */ }; /** @@ -156,6 +167,15 @@ struct landlock_ruleset { * reaches zero. */ struct rb_root root_inode; +#if IS_ENABLED(CONFIG_INET) + /** + * @root_net_port: Root of a red-black tree containing &struct + * landlock_rule nodes with network port. 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_net_port; +#endif /* IS_ENABLED(CONFIG_INET) */ /** * @hierarchy: Enables hierarchy identification even when a parent * domain vanishes. This is needed for the ptrace protection. @@ -166,8 +186,8 @@ struct landlock_ruleset { * @work_free: Enables to free a ruleset within a lockless * section. This is only used by * landlock_put_ruleset_deferred() when @usage reaches zero. - * The fields @lock, @usage, @num_rules, @num_layers and - * @access_masks are then unused. + * The fields @lock, @usage, @num_rules, @num_layers, + * @net_access_mask and @access_masks are then unused. */ struct work_struct work_free; struct { @@ -194,13 +214,13 @@ struct landlock_ruleset { */ u32 num_layers; /** - * @access_masks: Contains the subset of filesystem - * actions that are restricted by a ruleset. A domain - * saves all layers of merged rulesets in a stack - * (FAM), starting from the first layer to the last - * one. These layers are used when merging rulesets, - * for user space backward compatibility (i.e. - * future-proof), and to properly handle merged + * @access_masks: Contains the subset of filesystem and + * network actions that are restricted by a ruleset. + * A domain saves all layers of merged rulesets in a + * stack (FAM), starting from the first layer to the + * last one. These layers are used when merging + * rulesets, for user space backward compatibility + * (i.e. future-proof), and to properly handle merged * rulesets without overlapping access rights. These * layers are set once and never changed for the * lifetime of the ruleset. @@ -211,7 +231,8 @@ struct landlock_ruleset { }; struct landlock_ruleset * -landlock_create_ruleset(const access_mask_t access_mask); +landlock_create_ruleset(const access_mask_t access_mask_fs, + const access_mask_t access_mask_net); void landlock_put_ruleset(struct landlock_ruleset *const ruleset); void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); @@ -248,6 +269,20 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); } +static inline void +landlock_add_net_access_mask(struct landlock_ruleset *const ruleset, + const access_mask_t net_access_mask, + const u16 layer_level) +{ + access_mask_t net_mask = net_access_mask & LANDLOCK_MASK_ACCESS_NET; + + /* Should already be checked in sys_landlock_create_ruleset(). */ + WARN_ON_ONCE(net_access_mask != net_mask); + // TODO: Add tests to check "|=" and not "=" + ruleset->access_masks[layer_level] |= + (net_mask << LANDLOCK_SHIFT_ACCESS_NET); +} + static inline access_mask_t landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, const u16 layer_level) @@ -257,6 +292,15 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, LANDLOCK_MASK_ACCESS_FS; } +static inline access_mask_t +landlock_get_net_access_mask(const struct landlock_ruleset *const ruleset, + const u16 layer_level) +{ + return (ruleset->access_masks[layer_level] >> + LANDLOCK_SHIFT_ACCESS_NET) & + LANDLOCK_MASK_ACCESS_NET; +} + bool unmask_layers(const struct landlock_rule *const rule, const access_mask_t access_request, layer_mask_t (*const layer_masks)[], diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 87389d7bfbf2..c5a6ad4e2fca 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -82,8 +82,9 @@ static void build_check_abi(void) * struct size. */ ruleset_size = sizeof(ruleset_attr.handled_access_fs); + ruleset_size += sizeof(ruleset_attr.handled_access_net); BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size); - BUILD_BUG_ON(sizeof(ruleset_attr) != 8); + BUILD_BUG_ON(sizeof(ruleset_attr) != 16); path_beneath_size = sizeof(path_beneath_attr.allowed_access); path_beneath_size += sizeof(path_beneath_attr.parent_fd); @@ -129,7 +130,7 @@ static const struct file_operations ruleset_fops = { .write = fop_dummy_write, }; -#define LANDLOCK_ABI_VERSION 3 +#define LANDLOCK_ABI_VERSION 4 /** * sys_landlock_create_ruleset - Create a new ruleset @@ -188,8 +189,14 @@ SYSCALL_DEFINE3(landlock_create_ruleset, LANDLOCK_MASK_ACCESS_FS) return -EINVAL; + /* Checks network content (and 32-bits cast). */ + if ((ruleset_attr.handled_access_net | LANDLOCK_MASK_ACCESS_NET) != + LANDLOCK_MASK_ACCESS_NET) + return -EINVAL; + /* Checks arguments and transforms to kernel struct. */ - ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs); + ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs, + ruleset_attr.handled_access_net); if (IS_ERR(ruleset)) return PTR_ERR(ruleset); diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c index 792c3f0a59b4..646f778dfb1e 100644 --- a/tools/testing/selftests/landlock/base_test.c +++ b/tools/testing/selftests/landlock/base_test.c @@ -75,7 +75,7 @@ TEST(abi_version) const struct landlock_ruleset_attr ruleset_attr = { .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE, }; - ASSERT_EQ(3, landlock_create_ruleset(NULL, 0, + ASSERT_EQ(4, landlock_create_ruleset(NULL, 0, LANDLOCK_CREATE_RULESET_VERSION)); ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, From patchwork Fri Oct 21 15:26:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014933 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 77734C4332F for ; Fri, 21 Oct 2022 15:27:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230368AbiJUP1b (ORCPT ); Fri, 21 Oct 2022 11:27:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230354AbiJUP1V (ORCPT ); Fri, 21 Oct 2022 11:27:21 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F06F256D12; Fri, 21 Oct 2022 08:27:11 -0700 (PDT) Received: from frapeml100002.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7Xk5YwFz688kD; Fri, 21 Oct 2022 23:23:50 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by frapeml100002.china.huawei.com (7.182.85.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:27:09 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:27:08 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 08/12] landlock: Implement TCP network hooks Date: Fri, 21 Oct 2022 23:26:40 +0800 Message-ID: <20221021152644.155136-9-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch adds support of socket_bind() and socket_connect() hooks. It's possible to restrict binding and connecting of TCP sockets to particular ports. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Minor fixes. * Refactors commit message. Changes since v6: * Updates copyright. * Refactors landlock_append_net_rule() and check_socket_access() functions with landlock_id type. Changes since v5: * Fixes some logic errors. * Formats code with clang-format-14. Changes since v4: * Factors out CONFIG_INET into make file. * Refactors check_socket_access(). * Adds helper get_port(). * Adds CONFIG_IPV6 in get_port(), hook_socket_bind/connect functions to support AF_INET6 family. * Adds AF_UNSPEC family support in hook_socket_bind/connect functions. * Refactors add_rule_net_service() and landlock_add_rule syscall to support network rule inserting. * Refactors init_layer_masks() to support network rules. Changes since v3: * Splits commit. * Adds SECURITY_NETWORK in config. * Adds IS_ENABLED(CONFIG_INET) if a kernel has no INET configuration. * Adds hook_socket_bind and hook_socket_connect hooks. --- security/landlock/Kconfig | 1 + security/landlock/Makefile | 2 + security/landlock/net.c | 164 +++++++++++++++++++++++++++++++++++ security/landlock/net.h | 26 ++++++ security/landlock/setup.c | 2 + security/landlock/syscalls.c | 59 ++++++++++++- 6 files changed, 251 insertions(+), 3 deletions(-) create mode 100644 security/landlock/net.c create mode 100644 security/landlock/net.h -- 2.25.1 diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig index 8e33c4e8ffb8..10c099097533 100644 --- a/security/landlock/Kconfig +++ b/security/landlock/Kconfig @@ -3,6 +3,7 @@ config SECURITY_LANDLOCK bool "Landlock support" depends on SECURITY && !ARCH_EPHEMERAL_INODES + select SECURITY_NETWORK select SECURITY_PATH help Landlock is a sandboxing mechanism that enables processes to restrict diff --git a/security/landlock/Makefile b/security/landlock/Makefile index 7bbd2f413b3e..53d3c92ae22e 100644 --- a/security/landlock/Makefile +++ b/security/landlock/Makefile @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o landlock-y := setup.o syscalls.o object.o ruleset.o \ cred.o ptrace.o fs.o + +landlock-$(CONFIG_INET) += net.o \ No newline at end of file diff --git a/security/landlock/net.c b/security/landlock/net.c new file mode 100644 index 000000000000..39e8a156a1f4 --- /dev/null +++ b/security/landlock/net.c @@ -0,0 +1,164 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Landlock LSM - Network management and hooks + * + * Copyright © 2022 Huawei Tech. Co., Ltd. + * Copyright © 2022 Microsoft Corporation + */ + +#include +#include +#include +#include + +#include "common.h" +#include "cred.h" +#include "limits.h" +#include "net.h" +#include "ruleset.h" + +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, + const u16 port, access_mask_t access_rights) +{ + int err; + const struct landlock_id id = { + .key.data = port, + .type = LANDLOCK_KEY_NET_PORT, + }; + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); + + /* Transforms relative access rights to absolute ones. */ + access_rights |= LANDLOCK_MASK_ACCESS_NET & + ~landlock_get_net_access_mask(ruleset, 0); + + mutex_lock(&ruleset->lock); + err = landlock_insert_rule(ruleset, id, access_rights); + mutex_unlock(&ruleset->lock); + + return err; +} + +static int check_socket_access(const struct landlock_ruleset *const domain, + u16 port, access_mask_t access_request) +{ + bool allowed = false; + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; + const struct landlock_rule *rule; + access_mask_t handled_access; + const struct landlock_id id = { + .key.data = port, + .type = LANDLOCK_KEY_NET_PORT, + }; + + if (WARN_ON_ONCE(!domain)) + return 0; + if (WARN_ON_ONCE(domain->num_layers < 1)) + return -EACCES; + + rule = landlock_find_rule(domain, id); + handled_access = init_layer_masks(domain, access_request, &layer_masks, + LANDLOCK_KEY_NET_PORT); + allowed = unmask_layers(rule, handled_access, &layer_masks, + ARRAY_SIZE(layer_masks)); + + return allowed ? 0 : -EACCES; +} + +static u16 get_port(const struct sockaddr *const address) +{ + /* Gets port value in host byte order. */ + switch (address->sa_family) { + case AF_UNSPEC: + case AF_INET: { + const struct sockaddr_in *const sockaddr = + (struct sockaddr_in *)address; + return ntohs(sockaddr->sin_port); + } +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: { + const struct sockaddr_in6 *const sockaddr_ip6 = + (struct sockaddr_in6 *)address; + return ntohs(sockaddr_ip6->sin6_port); + } +#endif + } + WARN_ON_ONCE(1); + return 0; +} + +static int hook_socket_bind(struct socket *sock, struct sockaddr *address, + int addrlen) +{ + const struct landlock_ruleset *const dom = + landlock_get_current_domain(); + + if (!dom) + return 0; + + /* Check if it's a TCP socket. */ + if (sock->type != SOCK_STREAM) + return 0; + + switch (address->sa_family) { + case AF_UNSPEC: + case AF_INET: +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: +#endif + return check_socket_access(dom, get_port(address), + LANDLOCK_ACCESS_NET_BIND_TCP); + default: + return 0; + } +} + +static int hook_socket_connect(struct socket *sock, struct sockaddr *address, + int addrlen) +{ + const struct landlock_ruleset *const dom = + landlock_get_current_domain(); + + if (!dom) + return 0; + + /* Check if it's a TCP socket. */ + if (sock->type != SOCK_STREAM) + return 0; + + /* Check if the hook is AF_INET* socket's action. */ + switch (address->sa_family) { + case AF_INET: +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: +#endif + return check_socket_access(dom, get_port(address), + LANDLOCK_ACCESS_NET_CONNECT_TCP); + case AF_UNSPEC: { + u16 i; + + /* + * If just in a layer a mask supports connect access, + * the socket_connect() hook with AF_UNSPEC family flag + * must be banned. This prevents from disconnecting already + * connected sockets. + */ + for (i = 0; i < dom->num_layers; i++) { + if (landlock_get_net_access_mask(dom, i) & + LANDLOCK_ACCESS_NET_CONNECT_TCP) + return -EACCES; + } + } + } + return 0; +} + +static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = { + LSM_HOOK_INIT(socket_bind, hook_socket_bind), + LSM_HOOK_INIT(socket_connect, hook_socket_connect), +}; + +__init void landlock_add_net_hooks(void) +{ + security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), + LANDLOCK_NAME); +} diff --git a/security/landlock/net.h b/security/landlock/net.h new file mode 100644 index 000000000000..0da1d9dff5ab --- /dev/null +++ b/security/landlock/net.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Network management and hooks + * + * Copyright © 2022 Huawei Tech. Co., Ltd. + */ + +#ifndef _SECURITY_LANDLOCK_NET_H +#define _SECURITY_LANDLOCK_NET_H + +#include "common.h" +#include "ruleset.h" +#include "setup.h" + +#if IS_ENABLED(CONFIG_INET) +__init void landlock_add_net_hooks(void); + +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, + const u16 port, access_mask_t access_rights); +#else /* IS_ENABLED(CONFIG_INET) */ +static inline void landlock_add_net_hooks(void) +{ +} +#endif /* IS_ENABLED(CONFIG_INET) */ + +#endif /* _SECURITY_LANDLOCK_NET_H */ diff --git a/security/landlock/setup.c b/security/landlock/setup.c index 3f196d2ce4f9..7e4a598177b8 100644 --- a/security/landlock/setup.c +++ b/security/landlock/setup.c @@ -14,6 +14,7 @@ #include "fs.h" #include "ptrace.h" #include "setup.h" +#include "net.h" bool landlock_initialized __lsm_ro_after_init = false; @@ -29,6 +30,7 @@ static int __init landlock_init(void) landlock_add_cred_hooks(); landlock_add_ptrace_hooks(); landlock_add_fs_hooks(); + landlock_add_net_hooks(); landlock_initialized = true; pr_info("Up and running.\n"); return 0; diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index c5a6ad4e2fca..7853f32e8325 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -29,6 +29,7 @@ #include "cred.h" #include "fs.h" #include "limits.h" +#include "net.h" #include "ruleset.h" #include "setup.h" @@ -74,7 +75,8 @@ static void build_check_abi(void) { struct landlock_ruleset_attr ruleset_attr; struct landlock_path_beneath_attr path_beneath_attr; - size_t ruleset_size, path_beneath_size; + struct landlock_net_service_attr net_service_attr; + size_t ruleset_size, path_beneath_size, net_service_size; /* * For each user space ABI structures, first checks that there is no @@ -90,6 +92,11 @@ static void build_check_abi(void) path_beneath_size += sizeof(path_beneath_attr.parent_fd); BUILD_BUG_ON(sizeof(path_beneath_attr) != path_beneath_size); BUILD_BUG_ON(sizeof(path_beneath_attr) != 12); + + net_service_size = sizeof(net_service_attr.allowed_access); + net_service_size += sizeof(net_service_attr.port); + BUILD_BUG_ON(sizeof(net_service_attr) != net_service_size); + BUILD_BUG_ON(sizeof(net_service_attr) != 10); } /* Ruleset handling */ @@ -322,13 +329,54 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, return err; } +static int add_rule_net_service(struct landlock_ruleset *ruleset, + const void __user *const rule_attr) +{ +#if IS_ENABLED(CONFIG_INET) + struct landlock_net_service_attr net_service_attr; + int res; + u32 mask; + + /* Copies raw user space buffer, only one type for now. */ + res = copy_from_user(&net_service_attr, rule_attr, + sizeof(net_service_attr)); + if (res) + return -EFAULT; + + /* + * Informs about useless rule: empty allowed_access (i.e. deny rules) + * are ignored by network actions. + */ + if (!net_service_attr.allowed_access) + return -ENOMSG; + + /* + * Checks that allowed_access matches the @ruleset constraints + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). + */ + mask = landlock_get_net_access_mask(ruleset, 0); + if ((net_service_attr.allowed_access | mask) != mask) + return -EINVAL; + + /* Denies inserting a rule with port 0. */ + if (net_service_attr.port == 0) + return -EINVAL; + + /* Imports the new rule. */ + return landlock_append_net_rule(ruleset, net_service_attr.port, + net_service_attr.allowed_access); +#else /* IS_ENABLED(CONFIG_INET) */ + return -EAFNOSUPPORT; +#endif /* IS_ENABLED(CONFIG_INET) */ +} + /** * sys_landlock_add_rule - Add a new rule to a ruleset * * @ruleset_fd: File descriptor tied to the ruleset that should be extended * with the new rule. - * @rule_type: Identify the structure type pointed to by @rule_attr (only - * %LANDLOCK_RULE_PATH_BENEATH for now). + * @rule_type: Identify the structure type pointed to by @rule_attr: + * %LANDLOCK_RULE_PATH_BENEATH or %LANDLOCK_RULE_NET_SERVICE. * @rule_attr: Pointer to a rule (only of type &struct * landlock_path_beneath_attr for now). * @flags: Must be 0. @@ -339,6 +387,8 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, * Possible returned errors are: * * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; + * - %EAFNOSUPPORT: @rule_type is LANDLOCK_RULE_NET_SERVICE but TCP/IP is not + * supported by the running kernel; * - %EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. * &landlock_path_beneath_attr.allowed_access is not a subset of the * ruleset handled accesses); @@ -373,6 +423,9 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, case LANDLOCK_RULE_PATH_BENEATH: err = add_rule_path_beneath(ruleset, rule_attr); break; + case LANDLOCK_RULE_NET_SERVICE: + err = add_rule_net_service(ruleset, rule_attr); + break; default: err = -EINVAL; break; From patchwork Fri Oct 21 15:26:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014931 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 ED4BCC433FE for ; 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Fri, 21 Oct 2022 16:27:10 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 09/12] selftests/landlock: Share enforce_ruleset() Date: Fri, 21 Oct 2022 23:26:41 +0800 Message-ID: <20221021152644.155136-10-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This commit moves enforce_ruleset() helper function to common.h so that to be used both by filesystem tests and network ones. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Refactors commit message. Changes since v6: * None. Changes since v5: * Splits commit. * Moves enforce_ruleset helper into common.h * Formats code with clang-format-14. --- tools/testing/selftests/landlock/common.h | 10 ++++++++++ tools/testing/selftests/landlock/fs_test.c | 10 ---------- 2 files changed, 10 insertions(+), 10 deletions(-) -- 2.25.1 diff --git a/tools/testing/selftests/landlock/common.h b/tools/testing/selftests/landlock/common.h index d7987ae8d7fc..bafed1c0c2a6 100644 --- a/tools/testing/selftests/landlock/common.h +++ b/tools/testing/selftests/landlock/common.h @@ -256,3 +256,13 @@ static int __maybe_unused send_fd(int usock, int fd_tx) return -errno; return 0; } + +__attribute__((__unused__)) static void +enforce_ruleset(struct __test_metadata *const _metadata, const int ruleset_fd) +{ + ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)); + ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)) + { + TH_LOG("Failed to enforce ruleset: %s", strerror(errno)); + } +} diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index d5dab986f612..20c1ac8485f1 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -563,16 +563,6 @@ static int create_ruleset(struct __test_metadata *const _metadata, return ruleset_fd; } -static void enforce_ruleset(struct __test_metadata *const _metadata, - const int ruleset_fd) -{ - ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)); - ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)) - { - TH_LOG("Failed to enforce ruleset: %s", strerror(errno)); - } -} - TEST_F_FORK(layout1, proc_nsfs) { const struct rule rules[] = { From patchwork Fri Oct 21 15:26:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014932 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 0AB05C3A59E for ; Fri, 21 Oct 2022 15:27:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230365AbiJUP13 (ORCPT ); Fri, 21 Oct 2022 11:27:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230369AbiJUP1W (ORCPT ); Fri, 21 Oct 2022 11:27:22 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D06425ED2A; Fri, 21 Oct 2022 08:27:15 -0700 (PDT) Received: from fraeml744-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7ZY6Ykqz688y7; Fri, 21 Oct 2022 23:25:25 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by fraeml744-chm.china.huawei.com (10.206.15.225) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:27:13 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:27:12 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 10/12] selftests/landlock: Add 10 new test suites dedicated to network Date: Fri, 21 Oct 2022 23:26:42 +0800 Message-ID: <20221021152644.155136-11-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org These test suites try to check edge cases for TCP sockets bind() and connect() actions. socket: * bind_no_restrictions: Tests with non-landlocked ipv4 and ipv6 sockets. * bind_with_restrictions: Tests with mixed landlock rules for ipv4 and ipv6 sockets. * connect_no_restrictions: Tests with non-landlocked ipv4 and ipv6 sockets. * connect_with_restrictions: Tests with mixed landlock rules for ipv4 and ipv6 sockets. * connect_afunspec_no_restrictions: Tests with no landlock restrictions allowing to disconnect already connected socket with AF_UNSPEC socket family. * connect_afunspec_with_restrictions: Tests with landlocked process refusing to disconnect already connected socket. * ruleset_overlap: Tests with overlapping rules for one port. * ruleset_expanding: Tests with expanding rulesets in which rules are gradually added one by one, restricting sockets' connections. * inval: Tests with invalid user space supplied data: - out of range ruleset attribute; - unhandled allowed access; - zero port value; - zero access value; - legitimate access values; layout1: * with_net: Tests with network bind() socket action within filesystem directory access test. Test coverage for security/landlock is 94.3% of 920 lines according to gcc/gcov-11. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Squashes all selftest commits. * Adds fs test with network bind() socket action. * Minor fixes. --- security/landlock/ruleset.h | 2 - tools/testing/selftests/landlock/config | 4 + tools/testing/selftests/landlock/fs_test.c | 65 ++ tools/testing/selftests/landlock/net_test.c | 823 ++++++++++++++++++++ 4 files changed, 892 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/landlock/net_test.c -- 2.25.1 diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index f272d2cd518c..ee1a02a404ce 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -264,7 +264,6 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, /* Should already be checked in sys_landlock_create_ruleset(). */ WARN_ON_ONCE(fs_access_mask != fs_mask); - // TODO: Add tests to check "|=" and not "=" ruleset->access_masks[layer_level] |= (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); } @@ -278,7 +277,6 @@ landlock_add_net_access_mask(struct landlock_ruleset *const ruleset, /* Should already be checked in sys_landlock_create_ruleset(). */ WARN_ON_ONCE(net_access_mask != net_mask); - // TODO: Add tests to check "|=" and not "=" ruleset->access_masks[layer_level] |= (net_mask << LANDLOCK_SHIFT_ACCESS_NET); } diff --git a/tools/testing/selftests/landlock/config b/tools/testing/selftests/landlock/config index 0f0a65287bac..71f7e9a8a64c 100644 --- a/tools/testing/selftests/landlock/config +++ b/tools/testing/selftests/landlock/config @@ -1,3 +1,7 @@ +CONFIG_INET=y +CONFIG_IPV6=y +CONFIG_NET=y +CONFIG_NET_NS=y CONFIG_OVERLAY_FS=y CONFIG_SECURITY_LANDLOCK=y CONFIG_SECURITY_PATH=y diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 20c1ac8485f1..5c52da1a5a69 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -8,14 +8,17 @@ */ #define _GNU_SOURCE +#include #include #include +#include #include #include #include #include #include #include +#include #include #include #include @@ -4366,4 +4369,66 @@ TEST_F_FORK(layout2_overlay, same_content_different_file) } } +#define IP_ADDRESS "127.0.0.1" + +TEST_F_FORK(layout1, with_net) +{ + int sockfd; + int sock_port = 15000; + struct sockaddr_in addr4; + + addr4.sin_family = AF_INET; + addr4.sin_port = htons(sock_port); + addr4.sin_addr.s_addr = inet_addr(IP_ADDRESS); + memset(&addr4.sin_zero, '\0', 8); + + const struct rule rules[] = { + { + .path = dir_s1d2, + .access = ACCESS_RO, + }, + {}, + }; + + struct landlock_ruleset_attr ruleset_attr_net = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + struct landlock_net_service_attr net_service = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = sock_port, + }; + + /* Creates ruleset for network access. */ + const int ruleset_fd_net = landlock_create_ruleset( + &ruleset_attr_net, sizeof(ruleset_attr_net), 0); + ASSERT_LE(0, ruleset_fd_net); + + /* Adds a network rule. */ + ASSERT_EQ(0, + landlock_add_rule(ruleset_fd_net, LANDLOCK_RULE_NET_SERVICE, + &net_service, 0)); + + enforce_ruleset(_metadata, ruleset_fd_net); + ASSERT_EQ(0, close(ruleset_fd_net)); + + const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* Tests on a directory with the network rule loaded. */ + ASSERT_EQ(0, test_open(dir_s1d2, O_RDONLY)); + ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY)); + + sockfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0); + ASSERT_LE(0, sockfd); + /* Binds a socket to port 15000. */ + ASSERT_EQ(0, bind(sockfd, &addr4, sizeof(addr4))); + + /* Closes bounded socket. */ + ASSERT_EQ(0, close(sockfd)); +} + TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c new file mode 100644 index 000000000000..d1548bd7ab60 --- /dev/null +++ b/tools/testing/selftests/landlock/net_test.c @@ -0,0 +1,823 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Landlock tests - Network + * + * Copyright (C) 2022 Huawei Tech. Co., Ltd. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" + +#define MAX_SOCKET_NUM 10 + +#define SOCK_PORT_START 3470 +#define SOCK_PORT_ADD 10 + +#define IP_ADDRESS "127.0.0.1" + +/* Number pending connections queue to be hold. */ +#define BACKLOG 10 + +const struct sockaddr addr_unspec = { .sa_family = AF_UNSPEC }; + +/* Invalid attribute, out of landlock network access range. */ +#define LANDLOCK_INVAL_ATTR 7 + +FIXTURE(socket) +{ + uint port[MAX_SOCKET_NUM]; + struct sockaddr_in addr4[MAX_SOCKET_NUM]; + struct sockaddr_in6 addr6[MAX_SOCKET_NUM]; +}; + +/* struct _fixture_variant_socket */ +FIXTURE_VARIANT(socket) +{ + const bool is_ipv4; +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(socket, ipv4) { + /* clang-format on */ + .is_ipv4 = true, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(socket, ipv6) { + /* clang-format on */ + .is_ipv4 = false, +}; + +static int +create_socket_variant(const struct _fixture_variant_socket *const variant, + const int type) +{ + if (variant->is_ipv4) + return socket(AF_INET, type | SOCK_CLOEXEC, 0); + else + return socket(AF_INET6, type | SOCK_CLOEXEC, 0); +} + +static int bind_variant(const struct _fixture_variant_socket *const variant, + const int sockfd, + const struct _test_data_socket *const self, + const size_t index) +{ + if (variant->is_ipv4) + return bind(sockfd, &self->addr4[index], + sizeof(self->addr4[index])); + else + return bind(sockfd, &self->addr6[index], + sizeof(self->addr6[index])); +} + +static int connect_variant(const struct _fixture_variant_socket *const variant, + const int sockfd, + const struct _test_data_socket *const self, + const size_t index) +{ + if (variant->is_ipv4) + return connect(sockfd, &self->addr4[index], + sizeof(self->addr4[index])); + else + return connect(sockfd, &self->addr6[index], + sizeof(self->addr6[index])); +} + +FIXTURE_SETUP(socket) +{ + int i; + + /* Creates IPv4 socket addresses. */ + for (i = 0; i < MAX_SOCKET_NUM; i++) { + self->port[i] = SOCK_PORT_START + SOCK_PORT_ADD * i; + self->addr4[i].sin_family = AF_INET; + self->addr4[i].sin_port = htons(self->port[i]); + self->addr4[i].sin_addr.s_addr = inet_addr(IP_ADDRESS); + memset(&(self->addr4[i].sin_zero), '\0', 8); + } + + /* Creates IPv6 socket addresses. */ + for (i = 0; i < MAX_SOCKET_NUM; i++) { + self->port[i] = SOCK_PORT_START + SOCK_PORT_ADD * i; + self->addr6[i].sin6_family = AF_INET6; + self->addr6[i].sin6_port = htons(self->port[i]); + inet_pton(AF_INET6, IP_ADDRESS, &(self->addr6[i].sin6_addr)); + } + + set_cap(_metadata, CAP_SYS_ADMIN); + ASSERT_EQ(0, unshare(CLONE_NEWNET)); + ASSERT_EQ(0, system("ip link set dev lo up")); + clear_cap(_metadata, CAP_SYS_ADMIN); +} + +FIXTURE_TEARDOWN(socket) +{ +} + +TEST_F_FORK(socket, bind_no_restrictions) +{ + int sockfd; + + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + + /* Binds a socket to port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + ASSERT_EQ(0, close(sockfd)); +} + +TEST_F_FORK(socket, bind_with_restrictions) +{ + int sockfd; + + struct landlock_ruleset_attr ruleset_attr = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + .port = self->port[0], + }; + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP, + .port = self->port[1], + }; + struct landlock_net_service_attr net_service_3 = { + .allowed_access = 0, + .port = self->port[2], + }; + + const int ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + /* Allows connect and bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + /* Allows connect and deny bind operations to the port[1] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + /* + * Empty allowed_access (i.e. deny rules) are ignored in network actions + * for port[2] socket. + */ + ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_3, 0)); + ASSERT_EQ(ENOMSG, errno); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd); + + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + /* Binds a socket to port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* Closes bounded socket. */ + ASSERT_EQ(0, close(sockfd)); + + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + /* Binds a socket to port[1]. */ + ASSERT_EQ(-1, bind_variant(variant, sockfd, self, 1)); + ASSERT_EQ(EACCES, errno); + + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + /* Binds a socket to port[2]. */ + ASSERT_EQ(-1, bind_variant(variant, sockfd, self, 2)); + ASSERT_EQ(EACCES, errno); +} + +TEST_F_FORK(socket, connect_no_restrictions) +{ + int sockfd, new_fd; + pid_t child; + int status; + + /* Creates a server socket. */ + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + + /* Binds a socket to port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* Makes listening socket. */ + ASSERT_EQ(0, listen(sockfd, BACKLOG)); + + child = fork(); + ASSERT_LE(0, child); + if (child == 0) { + int child_sockfd; + + /* Closes listening socket for the child. */ + ASSERT_EQ(0, close(sockfd)); + /* Creates a stream client socket. */ + child_sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, child_sockfd); + + /* Makes connection to the listening socket with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, child_sockfd, self, 0)); + _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); + return; + } + /* Accepts connection from the child. */ + new_fd = accept(sockfd, NULL, 0); + ASSERT_LE(0, new_fd); + + /* Closes connection. */ + ASSERT_EQ(0, close(new_fd)); + + /* Closes listening socket for the parent. */ + ASSERT_EQ(0, close(sockfd)); + + ASSERT_EQ(child, waitpid(child, &status, 0)); + ASSERT_EQ(1, WIFEXITED(status)); + ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); +} + +TEST_F_FORK(socket, connect_with_restrictions) +{ + int new_fd; + int sockfd_1, sockfd_2; + pid_t child_1, child_2; + int status; + + struct landlock_ruleset_attr ruleset_attr = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + .port = self->port[0], + }; + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + .port = self->port[1], + }; + + const int ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + /* Allows connect and bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + /* Allows connect and deny bind operations to the port[1] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd); + + /* Creates a server socket 1. */ + sockfd_1 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_1); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd_1, self, 0)); + + /* Makes listening socket 1. */ + ASSERT_EQ(0, listen(sockfd_1, BACKLOG)); + + child_1 = fork(); + ASSERT_LE(0, child_1); + if (child_1 == 0) { + int child_sockfd; + + /* Closes listening socket for the child. */ + ASSERT_EQ(0, close(sockfd_1)); + /* Creates a stream client socket. */ + child_sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, child_sockfd); + + /* Makes connection to the listening socket with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, child_sockfd, self, 0)); + _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); + return; + } + /* Accepts connection from the child 1. */ + new_fd = accept(sockfd_1, NULL, 0); + ASSERT_LE(0, new_fd); + + /* Closes connection. */ + ASSERT_EQ(0, close(new_fd)); + + /* Closes listening socket 1 for the parent. */ + ASSERT_EQ(0, close(sockfd_1)); + + ASSERT_EQ(child_1, waitpid(child_1, &status, 0)); + ASSERT_EQ(1, WIFEXITED(status)); + ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); + + /* Creates a server socket 2. */ + sockfd_2 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_2); + + /* Binds the socket 2 to address with port[1]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd_2, self, 1)); + + /* Makes listening socket 2. */ + ASSERT_EQ(0, listen(sockfd_2, BACKLOG)); + + child_2 = fork(); + ASSERT_LE(0, child_2); + if (child_2 == 0) { + int child_sockfd; + + /* Closes listening socket for the child. */ + ASSERT_EQ(0, close(sockfd_2)); + /* Creates a stream client socket. */ + child_sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, child_sockfd); + + /* Makes connection to the listening socket with port[1]. */ + ASSERT_EQ(-1, connect_variant(variant, child_sockfd, self, 1)); + ASSERT_EQ(EACCES, errno); + _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); + return; + } + + /* Closes listening socket 2 for the parent. */ + ASSERT_EQ(0, close(sockfd_2)); + + ASSERT_EQ(child_2, waitpid(child_2, &status, 0)); + ASSERT_EQ(1, WIFEXITED(status)); + ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); +} + +TEST_F_FORK(socket, connect_afunspec_no_restrictions) +{ + int sockfd; + pid_t child; + int status; + + /* Creates a server socket 1. */ + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* Makes connection to the socket with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, sockfd, self, 0)); + + child = fork(); + ASSERT_LE(0, child); + if (child == 0) { + /* Child tries to disconnect already connected socket. */ + ASSERT_EQ(0, connect(sockfd, (struct sockaddr *)&addr_unspec, + sizeof(addr_unspec))); + _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); + return; + } + /* Closes listening socket 1 for the parent. */ + ASSERT_EQ(0, close(sockfd)); + + ASSERT_EQ(child, waitpid(child, &status, 0)); + ASSERT_EQ(1, WIFEXITED(status)); + ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); +} + +TEST_F_FORK(socket, connect_afunspec_with_restrictions) +{ + int sockfd; + pid_t child; + int status; + + struct landlock_ruleset_attr ruleset_attr_1 = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP, + }; + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = self->port[0], + }; + + struct landlock_ruleset_attr ruleset_attr_2 = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + + .port = self->port[0], + }; + + const int ruleset_fd_1 = landlock_create_ruleset( + &ruleset_attr_1, sizeof(ruleset_attr_1), 0); + ASSERT_LE(0, ruleset_fd_1); + + /* Allows bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_1, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd_1); + + /* Creates a server socket 1. */ + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* Makes connection to socket with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, sockfd, self, 0)); + + const int ruleset_fd_2 = landlock_create_ruleset( + &ruleset_attr_2, sizeof(ruleset_attr_2), 0); + ASSERT_LE(0, ruleset_fd_2); + + /* Allows connect and bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_2, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd_2); + + child = fork(); + ASSERT_LE(0, child); + if (child == 0) { + /* Child tries to disconnect already connected socket. */ + ASSERT_EQ(-1, connect(sockfd, (struct sockaddr *)&addr_unspec, + sizeof(addr_unspec))); + ASSERT_EQ(EACCES, errno); + _exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE); + return; + } + /* Closes listening socket 1 for the parent. */ + ASSERT_EQ(0, close(sockfd)); + + ASSERT_EQ(child, waitpid(child, &status, 0)); + ASSERT_EQ(1, WIFEXITED(status)); + ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); +} + +TEST_F_FORK(socket, ruleset_overlap) +{ + int sockfd; + int one = 1; + + struct landlock_ruleset_attr ruleset_attr = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = self->port[0], + }; + + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + + .port = self->port[0], + }; + + int ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + /* Allows bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + /* Allows connect and bind operations to the port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd); + + /* Creates a server socket. */ + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* Binds the socket to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* Makes connection to socket with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, sockfd, self, 0)); + + /* Closes socket. */ + ASSERT_EQ(0, close(sockfd)); + + /* Creates another ruleset layer. */ + ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + /* + * Allows bind operations to the port[0] socket in + * the new ruleset layer. + */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + + /* Enforces the new ruleset. */ + enforce_ruleset(_metadata, ruleset_fd); + + /* Creates a server socket. */ + sockfd = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* Binds the socket to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd, self, 0)); + + /* + * Forbids to connect the socket to address with port[0], + * as just one ruleset layer has connect() access rule. + */ + ASSERT_EQ(-1, connect_variant(variant, sockfd, self, 0)); + ASSERT_EQ(EACCES, errno); + + /* Closes socket. */ + ASSERT_EQ(0, close(sockfd)); +} + +TEST_F_FORK(socket, ruleset_expanding) +{ + int sockfd_1, sockfd_2; + int one = 1; + + struct landlock_ruleset_attr ruleset_attr_1 = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP, + }; + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = self->port[0], + }; + + const int ruleset_fd_1 = landlock_create_ruleset( + &ruleset_attr_1, sizeof(ruleset_attr_1), 0); + ASSERT_LE(0, ruleset_fd_1); + + /* Adds rule to port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_1, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd_1); + ASSERT_EQ(0, close(ruleset_fd_1)); + + /* Creates a socket 1. */ + sockfd_1 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_1); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd_1, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd_1, self, 0)); + + /* Makes connection to socket 1 with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, sockfd_1, self, 0)); + + /* Closes socket 1. */ + ASSERT_EQ(0, close(sockfd_1)); + + /* Creates a socket 2. */ + sockfd_2 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_2); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd_2, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* + * Forbids to bind the socket 2 to address with port[1], + * since there is no rule with bind() access for port[1]. + */ + ASSERT_EQ(-1, bind_variant(variant, sockfd_2, self, 1)); + ASSERT_EQ(EACCES, errno); + + /* Expands network mask. */ + struct landlock_ruleset_attr ruleset_attr_2 = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + + /* Adds connect() access to port[0]. */ + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + + .port = self->port[0], + }; + /* Adds bind() access to port[1]. */ + struct landlock_net_service_attr net_service_3 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = self->port[1], + }; + + const int ruleset_fd_2 = landlock_create_ruleset( + &ruleset_attr_2, sizeof(ruleset_attr_2), 0); + ASSERT_LE(0, ruleset_fd_2); + + /* Adds rule to port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_2, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + /* Adds rule to port[1] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_2, LANDLOCK_RULE_NET_SERVICE, + &net_service_3, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd_2); + ASSERT_EQ(0, close(ruleset_fd_2)); + + /* Creates a socket 1. */ + sockfd_1 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_1); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd_1, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd_1, self, 0)); + + /* Makes connection to socket 1 with port[0]. */ + ASSERT_EQ(0, connect_variant(variant, sockfd_1, self, 0)); + + /* Closes socket 1. */ + ASSERT_EQ(0, close(sockfd_1)); + + /* Creates a socket 2. */ + sockfd_2 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_2); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd_2, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* + * Forbids to bind the socket 2 to address with port[1], + * because just one layer has bind() access rule. + */ + ASSERT_EQ(-1, bind_variant(variant, sockfd_1, self, 1)); + ASSERT_EQ(EACCES, errno); + + /* Expands network mask. */ + struct landlock_ruleset_attr ruleset_attr_3 = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + }; + + /* Restricts connect() access to port[0]. */ + struct landlock_net_service_attr net_service_4 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + + .port = self->port[0], + }; + + const int ruleset_fd_3 = landlock_create_ruleset( + &ruleset_attr_3, sizeof(ruleset_attr_3), 0); + ASSERT_LE(0, ruleset_fd_3); + + /* Adds rule to port[0] socket. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_3, LANDLOCK_RULE_NET_SERVICE, + &net_service_4, 0)); + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd_3); + ASSERT_EQ(0, close(ruleset_fd_3)); + + /* Creates a socket 1. */ + sockfd_1 = create_socket_variant(variant, SOCK_STREAM); + ASSERT_LE(0, sockfd_1); + /* Allows to reuse of local address. */ + ASSERT_EQ(0, setsockopt(sockfd_1, SOL_SOCKET, SO_REUSEADDR, &one, + sizeof(one))); + + /* Binds the socket 1 to address with port[0]. */ + ASSERT_EQ(0, bind_variant(variant, sockfd_1, self, 0)); + + /* + * Forbids to connect the socket 1 to address with port[0], + * as just one layer has connect() access rule. + */ + ASSERT_EQ(-1, connect_variant(variant, sockfd_1, self, 0)); + ASSERT_EQ(EACCES, errno); + + /* Closes socket 1. */ + ASSERT_EQ(0, close(sockfd_1)); +} + +/* clang-format off */ + +#define ACCESS_LAST LANDLOCK_ACCESS_NET_CONNECT_TCP + +#define ACCESS_ALL ( \ + LANDLOCK_ACCESS_NET_BIND_TCP | \ + LANDLOCK_ACCESS_NET_CONNECT_TCP) + +/* clang-format on */ + +TEST_F_FORK(socket, inval) +{ + __u64 access; + + struct landlock_ruleset_attr ruleset_attr = { + .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP + }; + struct landlock_ruleset_attr ruleset_attr_inval = { + .handled_access_net = LANDLOCK_INVAL_ATTR + }; + struct landlock_ruleset_attr ruleset_attr_all = { .handled_access_net = + ACCESS_ALL }; + + struct landlock_net_service_attr net_service_1 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, + .port = self->port[0], + }; + struct landlock_net_service_attr net_service_2 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + .port = 0, + }; + struct landlock_net_service_attr net_service_3 = { + .allowed_access = 0, + .port = self->port[1], + }; + struct landlock_net_service_attr net_service_4 = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + .port = self->port[2], + }; + + struct landlock_net_service_attr net_service_5 = {}; + + /* Checks invalid ruleset attribute. */ + const int ruleset_fd_inv = landlock_create_ruleset( + &ruleset_attr_inval, sizeof(ruleset_attr_inval), 0); + ASSERT_EQ(-1, ruleset_fd_inv); + ASSERT_EQ(EINVAL, errno); + + /* Gets ruleset. */ + const int ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + ASSERT_LE(0, ruleset_fd); + + /* Checks unhandled allowed_access. */ + ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_1, 0)); + ASSERT_EQ(EINVAL, errno); + + /* Checks zero port value. */ + ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_2, 0)); + ASSERT_EQ(EINVAL, errno); + + /* Checks zero access value. */ + ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_3, 0)); + ASSERT_EQ(ENOMSG, errno); + + /* Adds with legitimate values. */ + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service_4, 0)); + + const int ruleset_fd_all = landlock_create_ruleset( + &ruleset_attr_all, sizeof(ruleset_attr_all), 0); + + ASSERT_LE(0, ruleset_fd_all); + + /* Tests access rights for all network rules */ + for (access = 1; access <= ACCESS_LAST; access <<= 1) { + net_service_5.allowed_access = access; + net_service_5.port = self->port[3]; + + ASSERT_EQ(0, landlock_add_rule(ruleset_fd_all, + LANDLOCK_RULE_NET_SERVICE, + &net_service_5, 0)); + } + + /* Enforces the ruleset. */ + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + enforce_ruleset(_metadata, ruleset_fd_all); + ASSERT_EQ(0, close(ruleset_fd_all)); +} +TEST_HARNESS_MAIN From patchwork Fri Oct 21 15:26:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014934 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 4BE19C43219 for ; Fri, 21 Oct 2022 15:27:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230415AbiJUP1e (ORCPT ); Fri, 21 Oct 2022 11:27:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230332AbiJUP1X (ORCPT ); Fri, 21 Oct 2022 11:27:23 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5ABF02565F7; Fri, 21 Oct 2022 08:27:17 -0700 (PDT) Received: from fraeml743-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mv7bK0ZSgz67HtH; Fri, 21 Oct 2022 23:26:05 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by fraeml743-chm.china.huawei.com (10.206.15.224) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 21 Oct 2022 17:27:15 +0200 Received: from mscphis00759.huawei.com (10.123.66.134) 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 15.1.2375.31; Fri, 21 Oct 2022 16:27:14 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 11/12] samples/landlock: Add network demo Date: Fri, 21 Oct 2022 23:26:43 +0800 Message-ID: <20221021152644.155136-12-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This commit adds network demo. It's possible to allow a sandboxer to bind/connect to a list of particular ports restricting network actions to the rest of ports. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Removes network support if ABI < 4. * Removes network support if not set by a user. Changes since v6: * Removes network support if ABI < 3. Changes since v5: * Makes network ports sandboxing optional. * Fixes some logic errors. * Formats code with clang-format-14. Changes since v4: * Adds ENV_TCP_BIND_NAME "LL_TCP_BIND" and ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT" variables to insert TCP ports. * Renames populate_ruleset() to populate_ruleset_fs(). * Adds populate_ruleset_net() and parse_port_num() helpers. * Refactors main() to support network sandboxing. --- samples/landlock/sandboxer.c | 129 +++++++++++++++++++++++++++++++---- 1 file changed, 116 insertions(+), 13 deletions(-) -- 2.25.1 diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c index fd4237c64fb2..68582b0d7c85 100644 --- a/samples/landlock/sandboxer.c +++ b/samples/landlock/sandboxer.c @@ -51,6 +51,8 @@ static inline int landlock_restrict_self(const int ruleset_fd, #define ENV_FS_RO_NAME "LL_FS_RO" #define ENV_FS_RW_NAME "LL_FS_RW" +#define ENV_TCP_BIND_NAME "LL_TCP_BIND" +#define ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT" #define ENV_PATH_TOKEN ":" static int parse_path(char *env_path, const char ***const path_list) @@ -71,6 +73,20 @@ static int parse_path(char *env_path, const char ***const path_list) return num_paths; } +static int parse_port_num(char *env_port) +{ + int i, num_ports = 0; + + if (env_port) { + num_ports++; + for (i = 0; env_port[i]; i++) { + if (env_port[i] == ENV_PATH_TOKEN[0]) + num_ports++; + } + } + return num_ports; +} + /* clang-format off */ #define ACCESS_FILE ( \ @@ -81,8 +97,8 @@ static int parse_path(char *env_path, const char ***const path_list) /* clang-format on */ -static int populate_ruleset(const char *const env_var, const int ruleset_fd, - const __u64 allowed_access) +static int populate_ruleset_fs(const char *const env_var, const int ruleset_fd, + const __u64 allowed_access) { int num_paths, i, ret = 1; char *env_path_name; @@ -143,6 +159,48 @@ static int populate_ruleset(const char *const env_var, const int ruleset_fd, return ret; } +static int populate_ruleset_net(const char *const env_var, const int ruleset_fd, + const __u64 allowed_access) +{ + int num_ports, i, ret = 1; + char *env_port_name; + struct landlock_net_service_attr net_service = { + .allowed_access = 0, + .port = 0, + }; + + env_port_name = getenv(env_var); + if (!env_port_name) { + ret = 0; + goto out_free_name; + } + env_port_name = strdup(env_port_name); + unsetenv(env_var); + num_ports = parse_port_num(env_port_name); + + if (num_ports == 1 && (strtok(env_port_name, ENV_PATH_TOKEN) == NULL)) { + ret = 0; + goto out_free_name; + } + + for (i = 0; i < num_ports; i++) { + net_service.allowed_access = allowed_access; + net_service.port = atoi(strsep(&env_port_name, ENV_PATH_TOKEN)); + if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service, 0)) { + fprintf(stderr, + "Failed to update the ruleset with port \"%d\": %s\n", + net_service.port, strerror(errno)); + goto out_free_name; + } + } + ret = 0; + +out_free_name: + free(env_port_name); + return ret; +} + /* clang-format off */ #define ACCESS_FS_ROUGHLY_READ ( \ @@ -164,41 +222,63 @@ static int populate_ruleset(const char *const env_var, const int ruleset_fd, LANDLOCK_ACCESS_FS_REFER | \ LANDLOCK_ACCESS_FS_TRUNCATE) +#define ACCESS_NET_BIND_CONNECT ( \ + LANDLOCK_ACCESS_NET_BIND_TCP | \ + LANDLOCK_ACCESS_NET_CONNECT_TCP) + /* clang-format on */ -#define LANDLOCK_ABI_LAST 3 +#define LANDLOCK_ABI_LAST 4 int main(const int argc, char *const argv[], char *const *const envp) { const char *cmd_path; char *const *cmd_argv; int ruleset_fd, abi; + char *env_port_name; __u64 access_fs_ro = ACCESS_FS_ROUGHLY_READ, - access_fs_rw = ACCESS_FS_ROUGHLY_READ | ACCESS_FS_ROUGHLY_WRITE; + access_fs_rw = ACCESS_FS_ROUGHLY_READ | ACCESS_FS_ROUGHLY_WRITE, + access_net_tcp = ACCESS_NET_BIND_CONNECT; struct landlock_ruleset_attr ruleset_attr = { .handled_access_fs = access_fs_rw, + .handled_access_net = access_net_tcp, }; if (argc < 2) { fprintf(stderr, - "usage: %s=\"...\" %s=\"...\" %s [args]...\n\n", - ENV_FS_RO_NAME, ENV_FS_RW_NAME, argv[0]); + "usage: %s=\"...\" %s=\"...\" %s=\"...\" %s=\"...\"%s " + " [args]...\n\n", + ENV_FS_RO_NAME, ENV_FS_RW_NAME, ENV_TCP_BIND_NAME, + ENV_TCP_CONNECT_NAME, argv[0]); fprintf(stderr, "Launch a command in a restricted environment.\n\n"); - fprintf(stderr, "Environment variables containing paths, " - "each separated by a colon:\n"); + fprintf(stderr, + "Environment variables containing paths and ports " + "each separated by a colon:\n"); fprintf(stderr, "* %s: list of paths allowed to be used in a read-only way.\n", ENV_FS_RO_NAME); fprintf(stderr, - "* %s: list of paths allowed to be used in a read-write way.\n", + "* %s: list of paths allowed to be used in a read-write way.\n\n", ENV_FS_RW_NAME); + fprintf(stderr, + "Environment variables containing ports are optional " + "and could be skipped.\n"); + fprintf(stderr, + "* %s: list of ports allowed to bind (server).\n", + ENV_TCP_BIND_NAME); + fprintf(stderr, + "* %s: list of ports allowed to connect (client).\n", + ENV_TCP_CONNECT_NAME); fprintf(stderr, "\nexample:\n" "%s=\"/bin:/lib:/usr:/proc:/etc:/dev/urandom\" " "%s=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" " + "%s=\"9418\" " + "%s=\"80:443\" " "%s bash -i\n\n", - ENV_FS_RO_NAME, ENV_FS_RW_NAME, argv[0]); + ENV_FS_RO_NAME, ENV_FS_RW_NAME, ENV_TCP_BIND_NAME, + ENV_TCP_CONNECT_NAME, argv[0]); fprintf(stderr, "This sandboxer can use Landlock features " "up to ABI version %d.\n", @@ -240,7 +320,10 @@ int main(const int argc, char *const argv[], char *const *const envp) case 2: /* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */ ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE; - + __attribute__((fallthrough)); + case 3: + /* Removes network support for ABI < 4 */ + ruleset_attr.handled_access_net &= ~ACCESS_NET_BIND_CONNECT; fprintf(stderr, "Hint: You should update the running kernel " "to leverage Landlock features " @@ -259,16 +342,36 @@ int main(const int argc, char *const argv[], char *const *const envp) access_fs_ro &= ruleset_attr.handled_access_fs; access_fs_rw &= ruleset_attr.handled_access_fs; + /* Removes bind access attribute if not supported by a user. */ + env_port_name = getenv(ENV_TCP_BIND_NAME); + if (!env_port_name) { + access_net_tcp &= ~LANDLOCK_ACCESS_NET_BIND_TCP; + } + /* Removes connect access attribute if not supported by a user. */ + env_port_name = getenv(ENV_TCP_CONNECT_NAME); + if (!env_port_name) { + access_net_tcp &= ~LANDLOCK_ACCESS_NET_CONNECT_TCP; + } + ruleset_attr.handled_access_net &= access_net_tcp; + ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); if (ruleset_fd < 0) { perror("Failed to create a ruleset"); return 1; } - if (populate_ruleset(ENV_FS_RO_NAME, ruleset_fd, access_fs_ro)) { + if (populate_ruleset_fs(ENV_FS_RO_NAME, ruleset_fd, access_fs_ro)) { + goto err_close_ruleset; + } + if (populate_ruleset_fs(ENV_FS_RW_NAME, ruleset_fd, access_fs_rw)) { + goto err_close_ruleset; + } + if (populate_ruleset_net(ENV_TCP_BIND_NAME, ruleset_fd, + LANDLOCK_ACCESS_NET_BIND_TCP)) { goto err_close_ruleset; } - if (populate_ruleset(ENV_FS_RW_NAME, ruleset_fd, access_fs_rw)) { + if (populate_ruleset_net(ENV_TCP_CONNECT_NAME, ruleset_fd, + LANDLOCK_ACCESS_NET_CONNECT_TCP)) { goto err_close_ruleset; } if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) { From patchwork Fri Oct 21 15:26:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Konstantin Meskhidze (A)" X-Patchwork-Id: 13014935 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 49D27C433FE for ; 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Fri, 21 Oct 2022 16:27:19 +0100 From: Konstantin Meskhidze To: CC: , , , , , Subject: [PATCH v8 12/12] landlock: Document Landlock's network support Date: Fri, 21 Oct 2022 23:26:44 +0800 Message-ID: <20221021152644.155136-13-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.66.134] X-ClientProxiedBy: mscpeml100002.china.huawei.com (7.188.26.75) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Describes network access rules for TCP sockets. Adds network access example in the tutorial. Points out AF_UNSPEC socket family behaviour. Adds kernel configuration support for network. Signed-off-by: Konstantin Meskhidze --- Changes since v7: * Fixes documentaion logic errors and typos as Mickaёl suggested: https://lore.kernel.org/netdev/9f354862-2bc3-39ea-92fd-53803d9bbc21@digikod.net/ Changes since v6: * Adds network support documentaion. --- Documentation/userspace-api/landlock.rst | 72 +++++++++++++++++++----- 1 file changed, 59 insertions(+), 13 deletions(-) -- 2.25.1 diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst index d8cd8cd9ce25..d0610ec9ce05 100644 --- a/Documentation/userspace-api/landlock.rst +++ b/Documentation/userspace-api/landlock.rst @@ -11,10 +11,10 @@ Landlock: unprivileged access control :Date: October 2022 The goal of Landlock is to enable to restrict ambient rights (e.g. global -filesystem access) for a set of processes. Because Landlock is a stackable -LSM, it makes possible to create safe security sandboxes as new security layers -in addition to the existing system-wide access-controls. This kind of sandbox -is expected to help mitigate the security impact of bugs or +filesystem or network access) for a set of processes. Because Landlock +is a stackable LSM, it makes possible to create safe security sandboxes as new +security layers in addition to the existing system-wide access-controls. This +kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves. @@ -30,18 +30,20 @@ Landlock rules A Landlock rule describes an action on an object. An object is currently a file hierarchy, and the related filesystem actions are defined with `access -rights`_. A set of rules is aggregated in a ruleset, which can then restrict -the thread enforcing it, and its future children. +rights`_. Since ABI version 4 a port data appears with related network actions +for TCP socket families. A set of rules is aggregated in a ruleset, which +can then restrict the thread enforcing it, and its future children. Defining and enforcing a security policy ---------------------------------------- We first need to define the ruleset that will contain our rules. For this example, the ruleset will contain rules that only allow read actions, but write -actions will be denied. The ruleset then needs to handle both of these kind of +actions will be denied. The ruleset then needs to handle both of these kind of actions. This is required for backward and forward compatibility (i.e. the kernel and user space may not know each other's supported restrictions), hence -the need to be explicit about the denied-by-default access rights. +the need to be explicit about the denied-by-default access rights. Also ruleset +will have network rules for specific ports, so it should handle network actions. .. code-block:: c @@ -62,6 +64,9 @@ the need to be explicit about the denied-by-default access rights. LANDLOCK_ACCESS_FS_MAKE_SYM | LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_TRUNCATE, + .handled_access_net = + LANDLOCK_ACCESS_NET_BIND_TCP | + LANDLOCK_ACCESS_NET_CONNECT_TCP, }; Because we may not know on which kernel version an application will be @@ -70,14 +75,18 @@ should try to protect users as much as possible whatever the kernel they are using. To avoid binary enforcement (i.e. either all security features or none), we can leverage a dedicated Landlock command to get the current version of the Landlock ABI and adapt the handled accesses. Let's check if we should -remove the ``LANDLOCK_ACCESS_FS_REFER`` or ``LANDLOCK_ACCESS_FS_TRUNCATE`` -access rights, which are only supported starting with the second and third -version of the ABI. +remove the `LANDLOCK_ACCESS_FS_REFER` or `LANDLOCK_ACCESS_FS_TRUNCATE` or +network access rights, which are only supported starting with the second, +third and fourth version of the ABI. .. code-block:: c int abi; + #define ACCESS_NET_BIND_CONNECT ( \ + LANDLOCK_ACCESS_NET_BIND_TCP | \ + LANDLOCK_ACCESS_NET_CONNECT_TCP) + abi = landlock_create_ruleset(NULL, 0, LANDLOCK_CREATE_RULESET_VERSION); if (abi < 0) { /* Degrades gracefully if Landlock is not handled. */ @@ -92,6 +101,9 @@ version of the ABI. case 2: /* Removes LANDLOCK_ACCESS_FS_TRUNCATE for ABI < 3 */ ruleset_attr.handled_access_fs &= ~LANDLOCK_ACCESS_FS_TRUNCATE; + case 3: + /* Removes network support for ABI < 4 */ + ruleset_attr.handled_access_net &= ~ACCESS_NET_BIND_CONNECT; } This enables to create an inclusive ruleset that will contain our rules. @@ -143,8 +155,22 @@ for the ruleset creation, by filtering access rights according to the Landlock ABI version. In this example, this is not required because all of the requested ``allowed_access`` rights are already available in ABI 1. +For network part we can add number of rules containing a port number and actions +that a process is allowed to do for certian ports. + +.. code-block:: c + + struct landlock_net_service_attr net_service = { + .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, + .port = 8080, + }; + + err = landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE, + &net_service, 0); + We now have a ruleset with one rule allowing read access to ``/usr`` while -denying all other handled accesses for the filesystem. The next step is to +denying all other handled accesses for the filesystem. The ruleset also contains +a rule allowing to bind current proccess to the port 8080. The next step is to restrict the current thread from gaining more privileges (e.g. thanks to a SUID binary). @@ -296,6 +322,13 @@ not. It is also possible to pass such file descriptors between processes, keeping their Landlock properties, even when these processes do not have an enforced Landlock ruleset. +AF_UNSPEC socket family +----------------------- + +Sockets of AF_UNSPEC family types are treated as AF_INET(IPv4) socket for bind() +action. But connect() one is not allowed by Landlock for AF_UNSPEC sockets. This +logic prevents from disconnecting already connected sockets. + Compatibility ============= @@ -355,7 +388,7 @@ Access rights ------------- .. kernel-doc:: include/uapi/linux/landlock.h - :identifiers: fs_access + :identifiers: fs_access net_access Creating a new ruleset ---------------------- @@ -374,6 +407,7 @@ Extending a ruleset .. kernel-doc:: include/uapi/linux/landlock.h :identifiers: landlock_rule_type landlock_path_beneath_attr + landlock_net_service_attr Enforcing a ruleset ------------------- @@ -451,6 +485,13 @@ always allowed when using a kernel that only supports the first or second ABI. Starting with the Landlock ABI version 3, it is now possible to securely control truncation thanks to the new ``LANDLOCK_ACCESS_FS_TRUNCATE`` access right. +Network support (ABI < 4) +------------------------- + +Starting with the Landlock ABI version 4, it is now possible to restrict TCP +sockets' bind() and connect() actions for specific ports allowing processes +to establish restricted connections. + .. _kernel_support: Kernel support @@ -469,6 +510,11 @@ still enable it by adding ``lsm=landlock,[...]`` to Documentation/admin-guide/kernel-parameters.rst thanks to the bootloader configuration. +To be able to explicitly allow TCP operations (e.g., adding a network rule with +`LANDLOCK_ACCESS_NET_TCP_BIND`), the kernel must support TCP (`CONFIG_INET=y`). +Otherwise, sys_landlock_add_rule() returns an `EAFNOSUPPORT` error, which can +safely be ignored because this kind of TCP operation is already not possible. + Questions and answers =====================