[v13,01/12] landlock: Make ruleset's access masks more generic

Message ID	20231016015030.1684504-2-konstantin.meskhidze@huawei.com (mailing list archive)
State	Superseded
Delegated to:	Netdev Maintainers
Headers	show Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52CB2185C for <netdev@vger.kernel.org>; Mon, 16 Oct 2023 01:50:45 +0000 (UTC) From: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> To: <mic@digikod.net> CC: <willemdebruijn.kernel@gmail.com>, <gnoack3000@gmail.com>, <linux-security-module@vger.kernel.org>, <netdev@vger.kernel.org>, <netfilter-devel@vger.kernel.org>, <yusongping@huawei.com>, <artem.kuzin@huawei.com> Subject: [PATCH v13 01/12] landlock: Make ruleset's access masks more generic Date: Mon, 16 Oct 2023 09:50:19 +0800 Message-ID: <20231016015030.1684504-2-konstantin.meskhidze@huawei.com> In-Reply-To: <20231016015030.1684504-1-konstantin.meskhidze@huawei.com> References: <20231016015030.1684504-1-konstantin.meskhidze@huawei.com> Precedence: bulk MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit
Series	Network support for Landlock \| expand [v13,00/12] Network support for Landlock [v13,01/12] landlock: Make ruleset's access masks more generic [v13,02/12] landlock: Allow FS topology changes for domains without such rule type [v13,03/12] landlock: Refactor landlock_find_rule/insert_rule [v13,04/12] landlock: Refactor merge/inherit_ruleset functions [v13,05/12] landlock: Move and rename layer helpers [v13,06/12] landlock: Refactor layer helpers [v13,07/12] landlock: Refactor landlock_add_rule() syscall [v13,08/12] landlock: Add network rules and TCP hooks support [v13,09/12] selftests/landlock: Share enforce_ruleset() [v13,10/12] selftests/landlock: Add 7 new test variants dedicated to network [v13,11/12] samples/landlock: Add network demo [v13,12/12] landlock: Document Landlock's network support

Context	Check	Description
netdev/tree_selection	success	Not a local patch, async

diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 1c0c198f6fdb..6953801619ac 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 55b1df8f66a8..e19c7a99dfc6 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 +182,25 @@ 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); + 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..7ec6bbed7117 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -310,6 +310,7 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, struct path path; struct landlock_ruleset *ruleset; int res, err; + access_mask_t mask; if (!landlock_initialized) return -EOPNOTSUPP; @@ -346,10 +347,10 @@ 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]) { + mask = landlock_get_fs_access_mask(ruleset, 0); + if ((path_beneath_attr.allowed_access | mask) != mask) { err = -EINVAL; goto out_put_ruleset; }

[v13,01/12] landlock: Make ruleset's access masks more generic

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