netdev - Re: [PATCH v9 03/12] landlock: Refactor landlock_find_rule/insert

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Message-ID: <d014f6db-0073-5461-afcd-5b046f3db096@digikod.net>
Date:   Fri, 10 Feb 2023 18:36:48 +0100
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 v9 03/12] landlock: Refactor
 landlock_find_rule/insert_rule


On 16/01/2023 09:58, 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.
> 
> Remove unnecessary inlining.
> 

You need to keep the Co-developed-by before the Signed-off-by for my entry.

> Signed-off-by: Mickaël Salaün <mic@...ikod.net>
> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
> ---
> 
> 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      |  49 ++++++------
>   security/landlock/ruleset.c | 148 +++++++++++++++++++++++++-----------
>   security/landlock/ruleset.h |  65 +++++++++++++---
>   3 files changed, 185 insertions(+), 77 deletions(-)
> 
> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
> index 0ae54a639e16..273ed8549da1 100644
> --- a/security/landlock/fs.c
> +++ b/security/landlock/fs.c

[...]

> @@ -191,12 +193,15 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
>    *
>    * Returns NULL if no rule is found or if @dentry is negative.
>    */
> -static inline const struct landlock_rule *
> +static const struct landlock_rule *

Can you please create a (previous) dedicated patch for all the inlining 
changes?


>   find_rule(const struct landlock_ruleset *const domain,
>   	  const struct dentry *const dentry)
>   {
>   	const struct landlock_rule *rule;
>   	const struct inode *inode;
> +	struct landlock_id id = {
> +		.type = LANDLOCK_KEY_INODE,
> +	};
>   
>   	/* Ignores nonexistent leafs. */
>   	if (d_is_negative(dentry))

[...]

> @@ -652,7 +657,7 @@ static inline int check_access_path(const struct landlock_ruleset *const domain,
>   }
>   
>   static int current_check_access_path(const struct path *const path,
> -					    const access_mask_t access_request)
> +				     const access_mask_t access_request)

This syntax fix should be moved to patch 2/12.


[...]

> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
> index 1f3188b4e313..c5c88a100f74 100644
> --- a/security/landlock/ruleset.c
> +++ b/security/landlock/ruleset.c

[...]

> @@ -285,23 +333,23 @@ static int merge_ruleset(struct landlock_ruleset *const dst,


> -		if (WARN_ON_ONCE(walker_rule->num_layers != 1)) {
> -			err = -EINVAL;
> -			goto out_unlock;
> -		}
> -		if (WARN_ON_ONCE(walker_rule->layers[0].level != 0)) {
> -			err = -EINVAL;
> -			goto out_unlock;
> -		}
> +		if (WARN_ON_ONCE(walker_rule->num_layers != 1))
> +			return -EINVAL;
> +		if (WARN_ON_ONCE(walker_rule->layers[0].level != 0))
> +			return -EINVAL;

This introduces two potential bugs. Why change this code?