netdev - Re: [PATCH v11 03/12] landlock: Refactor landlock_find_rule/insert

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Date: Mon, 26 Jun 2023 20:40:12 +0200
From: Mickaël Salaün <mic@...ikod.net>
To: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
Cc: willemdebruijn.kernel@...il.com, gnoack3000@...il.com,
 linux-security-module@...r.kernel.org, netdev@...r.kernel.org,
 netfilter-devel@...r.kernel.org, yusongping@...wei.com,
 artem.kuzin@...wei.com
Subject: Re: [PATCH v11 03/12] landlock: Refactor
 landlock_find_rule/insert_rule


On 15/05/2023 18:13, Konstantin Meskhidze wrote:
> Add a new landlock_key union and landlock_id structure to support
> a socket port rule type. A struct landlock_id identifies a unique entry
> in a ruleset: either a kernel object (e.g inode) or typed data (e.g TCP
> port). There is one red-black tree per key type.
> 
> This patch also adds is_object_pointer() and get_root() helpers.
> is_object_pointer() returns true if key type is LANDLOCK_KEY_INODE.
> get_root() helper returns a red_black tree root pointer according to
> a key type.
> 
> Refactor landlock_insert_rule() and landlock_find_rule() to support coming
> network modifications. Adding or searching a rule in ruleset can now be
> done thanks to a Landlock ID argument passed to these helpers.
> 
> Co-developed-by: Mickaël Salaün <mic@...ikod.net>
> Signed-off-by: Mickaël Salaün <mic@...ikod.net>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
> ---
> 
> Changes since v10:
> * None.
> 
> Changes since v9:
> * Splits commit.
> * Refactors commit message.
> * Minor fixes.
> 
> Changes since v8:
> * Refactors commit message.
> * Removes inlining.
> * Minor fixes.
> 
> Changes since v7:
> * Completes all the new field descriptions landlock_key,
>    landlock_key_type, landlock_id.
> * Refactors commit message, adds a co-developer.
> 
> Changes since v6:
> * Adds union landlock_key, enum landlock_key_type, and struct
>    landlock_id.
> * Refactors ruleset functions and improves switch/cases: create_rule(),
>    insert_rule(), get_root(), is_object_pointer(), free_rule(),
>    landlock_find_rule().
> * Refactors landlock_append_fs_rule() functions to support new
>    landlock_id type.
> 
> Changes since v5:
> * Formats code with clang-format-14.
> 
> Changes since v4:
> * Refactors insert_rule() and create_rule() functions by deleting
> rule_type from their arguments list, it helps to reduce useless code.
> 
> Changes since v3:
> * Splits commit.
> * Refactors landlock_insert_rule and landlock_find_rule functions.
> * Rename new_ruleset->root_inode.
> 
> ---
>   security/landlock/fs.c      |  21 +++---
>   security/landlock/ruleset.c | 134 ++++++++++++++++++++++++++----------
>   security/landlock/ruleset.h |  65 ++++++++++++++---
>   3 files changed, 166 insertions(+), 54 deletions(-)

[...]

> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
> index 1f3188b4e313..deab37838f5b 100644
> --- a/security/landlock/ruleset.c
> +++ b/security/landlock/ruleset.c

[...]

> @@ -316,21 +368,29 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,
>   			   struct landlock_ruleset *const child)
>   {
>   	struct landlock_rule *walker_rule, *next_rule;
> +	struct rb_root *parent_root;
>   	int err = 0;
> 
>   	might_sleep();
>   	if (!parent)
>   		return 0;
> 
> +	parent_root = get_root(parent, LANDLOCK_KEY_INODE);
> +	if (IS_ERR(parent_root))
> +		return PTR_ERR(parent_root);
> +
>   	/* Locks @child first because we are its only owner. */
>   	mutex_lock(&child->lock);
>   	mutex_lock_nested(&parent->lock, SINGLE_DEPTH_NESTING);
> 
>   	/* Copies the @parent tree. */
>   	rbtree_postorder_for_each_entry_safe(walker_rule, next_rule,
> -					     &parent->root, node) {
> -		err = insert_rule(child, walker_rule->object,
> -				  &walker_rule->layers,
> +					     parent_root, node) {
> +		const struct landlock_id id = {
> +			.key = walker_rule->key,
> +			.type = LANDLOCK_KEY_INODE,
> +		};

Please add a line break here instead of in a the following refactoring 
commit.


> +		err = insert_rule(child, id, &walker_rule->layers,
>   				  walker_rule->num_layers);
>   		if (err)
>   			goto out_unlock;