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Message-ID: <ea1bfc93-77fc-ce1e-81a9-c69c7ae1f47b@huawei.com>
Date: Sat, 10 Sep 2022 20:20:38 +0300
From: "Konstantin Meskhidze (A)" <konstantin.meskhidze@...wei.com>
To: Mickaël Salaün <mic@...ikod.net>
CC: <willemdebruijn.kernel@...il.com>, <gnoack3000@...il.com>,
<linux-security-module@...r.kernel.org>, <netdev@...r.kernel.org>,
<netfilter-devel@...r.kernel.org>, <anton.sirazetdinov@...wei.com>
Subject: Re: [PATCH v7 05/18] landlock: refactor helper functions
9/6/2022 11:07 AM, Mickaël Salaün пишет:
> You can improve the subject with: "landlock: Refactor unmask_layers()
> and init_layer_masks()"
Got it. I will change it.
>
> On 29/08/2022 19:03, Konstantin Meskhidze wrote:
>> Adds new key_type argument to init_layer_masks() helper functions.
>> This modification supports implementing new rule types in the next
>> Landlock versions.
>>
>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
>
> As for patch 2/18, you can append:
> Co-developed-by: Mickaël Salaün <mic@...ikod.net>
Ok. I will append. Thanks.>
>
>> ---
>>
>> 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 | 33 +++++++++++++++++-----------
>> security/landlock/ruleset.c | 44 +++++++++++++++++++++++++++----------
>> security/landlock/ruleset.h | 11 +++++-----
>> 3 files changed, 58 insertions(+), 30 deletions(-)
>>
>> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
>> index b03d6153f628..a4d9aea539cd 100644
>> --- a/security/landlock/fs.c
>> +++ b/security/landlock/fs.c
>> @@ -439,16 +439,20 @@ static int check_access_path_dual(
>> 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);
>> }
>> @@ -500,15 +504,16 @@ static int check_access_path_dual(
>> }
>>
>> 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)) {
>> @@ -564,7 +569,8 @@ 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);
>> return check_access_path_dual(domain, path, access_request,
>> &layer_masks, NULL, 0, NULL, NULL);
>> }
>> @@ -648,7 +654,7 @@ 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) {
>> @@ -656,7 +662,8 @@ 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.
>> @@ -772,7 +779,7 @@ 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);
>> return check_access_path_dual(dom, new_dir,
>> access_request_parent1,
>> &layer_masks_parent1, NULL, 0,
>> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
>> index 671a95e2a345..84fcd8eb30d4 100644
>> --- a/security/landlock/ruleset.c
>> +++ b/security/landlock/ruleset.c
>> @@ -574,7 +574,8 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset,
>> */
>
> You missed another hunk from my patch… Please do a diff with it.
Sorry. What did I miss here?
>
>
>> 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;
>>
>> @@ -606,8 +607,7 @@ 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];
>> @@ -618,15 +618,36 @@ bool unmask_layers(const struct landlock_rule *const rule,
>> return false;
>> }
>>
>> -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])
>> +typedef access_mask_t
>> +get_access_mask_t(const struct landlock_ruleset *const ruleset,
>> + const u16 layer_level);
>> +
>> +/*
>> + * @layer_masks must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET
>> + * elements according to @key_type.
>> + */
>> +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;
>> @@ -636,9 +657,8 @@ 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)) {
>> - if (landlock_get_fs_access_mask(domain, layer_level) &
>> + for_each_set_bit(access_bit, &access_req, num_access) {
>> + if (get_access_mask(domain, layer_level) &
>> BIT_ULL(access_bit)) {
>> (*layer_masks)[access_bit] |=
>> BIT_ULL(layer_level);
>> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
>> index d7d9b987829c..2083855bf42d 100644
>> --- a/security/landlock/ruleset.h
>> +++ b/security/landlock/ruleset.h
>> @@ -238,11 +238,12 @@ 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
>>
> .
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