From patchwork Mon Feb 21 21:25:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 12754146 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 EB33BC4332F for ; Mon, 21 Feb 2022 21:15:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234363AbiBUVPp (ORCPT ); Mon, 21 Feb 2022 16:15:45 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:41096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234294AbiBUVPm (ORCPT ); Mon, 21 Feb 2022 16:15:42 -0500 Received: from smtp-8fa9.mail.infomaniak.ch (smtp-8fa9.mail.infomaniak.ch [IPv6:2001:1600:3:17::8fa9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADABD24084 for ; Mon, 21 Feb 2022 13:15:14 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4K2Znr6sSwzMqHjD; Mon, 21 Feb 2022 22:15:12 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4K2Znr4VDvzljTgK; Mon, 21 Feb 2022 22:15:12 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: James Morris , "Serge E . Hallyn" Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Al Viro , Jann Horn , Kees Cook , Konstantin Meskhidze , Paul Moore , Shuah Khan , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= Subject: [PATCH v1 03/11] landlock: Create find_rule() from unmask_layers() Date: Mon, 21 Feb 2022 22:25:14 +0100 Message-Id: <20220221212522.320243-4-mic@digikod.net> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221212522.320243-1-mic@digikod.net> References: <20220221212522.320243-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Mickaël Salaün This refactoring will be useful in a following commit. Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20220221212522.320243-4-mic@digikod.net Reviewed-by: Paul Moore --- security/landlock/fs.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 4048e3c04d75..0bcb27f2360a 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -180,23 +180,36 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, /* Access-control management */ -static inline layer_mask_t unmask_layers( +/* + * The lifetime of the returned rule is tied to @domain. + * + * Returns NULL if no rule is found or if @dentry is negative. + */ +static inline const struct landlock_rule *find_rule( const struct landlock_ruleset *const domain, - const struct path *const path, - const access_mask_t access_request, layer_mask_t layer_mask) + const struct dentry *const dentry) { const struct landlock_rule *rule; const struct inode *inode; - size_t i; - if (d_is_negative(path->dentry)) - /* Ignore nonexistent leafs. */ - return layer_mask; - inode = d_backing_inode(path->dentry); + /* Ignores nonexistent leafs. */ + if (d_is_negative(dentry)) + return NULL; + + inode = d_backing_inode(dentry); rcu_read_lock(); rule = landlock_find_rule(domain, rcu_dereference(landlock_inode(inode)->object)); rcu_read_unlock(); + return rule; +} + +static inline layer_mask_t unmask_layers( + const struct landlock_rule *const rule, + const access_mask_t access_request, layer_mask_t layer_mask) +{ + size_t layer_level; + if (!rule) return layer_mask; @@ -207,8 +220,9 @@ static inline layer_mask_t unmask_layers( * the remaining layers for each inode, from the first added layer to * the last one. */ - for (i = 0; i < rule->num_layers; i++) { - const struct landlock_layer *const layer = &rule->layers[i]; + 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); /* Checks that the layer grants access to the full request. */ @@ -266,8 +280,9 @@ static int check_access_path(const struct landlock_ruleset *const domain, while (true) { struct dentry *parent_dentry; - layer_mask = unmask_layers(domain, &walker_path, - access_request, layer_mask); + layer_mask = unmask_layers(find_rule(domain, + walker_path.dentry), access_request, + layer_mask); if (layer_mask == 0) { /* Stops when a rule from each layer grants access. */ allowed = true;