From patchwork Mon Aug 29 17:03:44 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: 12958219 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 EDACFC6FA85 for ; Mon, 29 Aug 2022 17:04:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231244AbiH2REO (ORCPT ); Mon, 29 Aug 2022 13:04:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229939AbiH2REN (ORCPT ); Mon, 29 Aug 2022 13:04:13 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D33B49BB52; Mon, 29 Aug 2022 10:04:11 -0700 (PDT) Received: from fraeml737-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4MGcGK2R6Nz67x0N; Tue, 30 Aug 2022 01:03:37 +0800 (CST) Received: from lhrpeml500004.china.huawei.com (7.191.163.9) by fraeml737-chm.china.huawei.com (10.206.15.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 29 Aug 2022 19:04:10 +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 15.1.2375.24; Mon, 29 Aug 2022 18:04:09 +0100 From: Konstantin Meskhidze To: CC: , , , , , , , Subject: [PATCH v7 01/18] landlock: rename access mask Date: Tue, 30 Aug 2022 01:03:44 +0800 Message-ID: <20220829170401.834298-2-konstantin.meskhidze@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220829170401.834298-1-konstantin.meskhidze@huawei.com> References: <20220829170401.834298-1-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 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 | 7 ++++--- security/landlock/limits.h | 1 + security/landlock/ruleset.c | 17 +++++++++-------- security/landlock/ruleset.h | 37 ++++++++++++++++++++++++++++++++---- security/landlock/syscalls.c | 7 ++++--- 5 files changed, 51 insertions(+), 18 deletions(-) -- 2.25.1 diff --git a/security/landlock/fs.c b/security/landlock/fs.c index c57f581a9cd5..e2d1cc28729a 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -168,7 +168,8 @@ 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_rights |= LANDLOCK_MASK_ACCESS_FS & + ~landlock_get_fs_access_mask(ruleset, 0); object = get_inode_object(d_backing_inode(path->dentry)); if (IS_ERR(object)) return PTR_ERR(object); @@ -287,7 +288,7 @@ get_handled_accesses(const struct landlock_ruleset *const domain) for (layer_level = 0; layer_level < domain->num_layers; layer_level++) { - if (domain->fs_access_masks[layer_level] & + if (landlock_get_fs_access_mask(domain, layer_level) & BIT_ULL(access_bit)) { access_dom |= BIT_ULL(access_bit); break; @@ -317,7 +318,7 @@ init_layer_masks(const struct landlock_ruleset *const domain, for_each_set_bit(access_bit, &access_req, ARRAY_SIZE(*layer_masks)) { - if (domain->fs_access_masks[layer_level] & + if (landlock_get_fs_access_mask(domain, layer_level) & BIT_ULL(access_bit)) { (*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..647d44284080 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 +182,28 @@ static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset) refcount_inc(&ruleset->usage); } +/* A helper function to set a filesystem mask. */ +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); +} + +/* A helper function to get a filesystem mask. */ +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 f4d6fc7ed17f..6593381466e0 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; }