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 4F59BC4332F for ; Thu, 17 Nov 2022 18:42:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240652AbiKQSmf (ORCPT ); Thu, 17 Nov 2022 13:42:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240677AbiKQSmc (ORCPT ); Thu, 17 Nov 2022 13:42:32 -0500 Received: from smtp-42aa.mail.infomaniak.ch (smtp-42aa.mail.infomaniak.ch [IPv6:2001:1600:4:17::42aa]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB0C986A78 for ; Thu, 17 Nov 2022 10:42:27 -0800 (PST) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4NCpgP3xcYzMpyVB; Thu, 17 Nov 2022 19:42:25 +0100 (CET) Received: from ns3096276.ip-94-23-54.eu (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4NCpgN6Hw2zMpnPj; Thu, 17 Nov 2022 19:42:24 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1668710545; bh=JbD1rvQPFQDyU0dJCl5FWDSFg5W5urU90kWUl0DiaJM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=WPh57jfhJlVrecGJwkSEuYk0UswH56KOklm6U/xtezHzMDiv14h6uTquaADtGHd5P KDUKPiKx5frQm/FWI1WPTZgO+cVB80Rlt596OsjDRtb8+AHTdDortLP4YorqbjZgDu UjgYUwS572ceti+FBYdV8aQGq75qLo0uEvqa1Zis= Message-ID: Date: Thu, 17 Nov 2022 19:42:24 +0100 MIME-Version: 1.0 User-Agent: Subject: Re: [PATCH v8 05/12] landlock: Refactor unmask_layers() and init_layer_masks() Content-Language: en-US To: Konstantin Meskhidze Cc: willemdebruijn.kernel@gmail.com, gnoack3000@gmail.com, linux-security-module@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, artem.kuzin@huawei.com References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> <20221021152644.155136-6-konstantin.meskhidze@huawei.com> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= In-Reply-To: <20221021152644.155136-6-konstantin.meskhidze@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: On 21/10/2022 17:26, Konstantin Meskhidze wrote: > Adds new key_type argument to init_layer_masks() helper. Add a new key_type argument to the… > Adds masks_array_size argument to unmask_layers() helper. Add a masks_array_size argument to the… The name of these helpers need to be prefixed with "landlock_". > These modifications support implementing new rule types in the next > Landlock versions. > > Co-developed-by: Mickaël Salaün Signed-off-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 >