From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit 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 --- 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(-) 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 */ -- 2.25.1