netdev - Re: [PATCH v8 07/12] landlock: Add network rules support

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Message-ID: <53a55630-c4db-a79d-7be5-dc6026f92673@digikod.net>
Date:   Mon, 28 Nov 2022 21:26:07 +0100
From:   Mickaël Salaün <mic@...ikod.net>
To:     "Konstantin Meskhidze (A)" <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, artem.kuzin@...wei.com,
        Linux API <linux-api@...r.kernel.org>,
        "Alejandro Colomar (man-pages)" <alx.manpages@...il.com>
Subject: Re: [PATCH v8 07/12] landlock: Add network rules support


On 28/11/2022 05:01, Konstantin Meskhidze (A) wrote:
> 
> 
> 11/17/2022 9:43 PM, Mickaël Salaün пишет:
>>
>> On 21/10/2022 17:26, Konstantin Meskhidze wrote:
>>> This commit adds network rules support in internal landlock functions
>>> (presented in ruleset.c) and landlock_create_ruleset syscall.
>>
>> …in the ruleset management helpers and the landlock_create_ruleset syscall.
>>
>>
>>> Refactors user space API to support network actions. Adds new network
>>
>> Refactor…
>>
>>> access flags, network rule and network attributes. Increments Landlock
>>
>> Increment…
> 
>     The commit's message will be fixed. Thank you!
>>
>>> ABI version.
>>>
>>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
>>> ---
>>>
>>> Changes since v7:
>>> * Squashes commits.
>>> * Increments ABI version to 4.
>>> * Refactors commit message.
>>> * Minor fixes.
>>>
>>> Changes since v6:
>>> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask()
>>>     because it OR values.
>>> * Makes landlock_add_net_access_mask() more resilient incorrect values.
>>> * Refactors landlock_get_net_access_mask().
>>> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use
>>>     LANDLOCK_NUM_ACCESS_FS as value.
>>> * Updates access_masks_t to u32 to support network access actions.
>>> * Refactors landlock internal functions to support network actions with
>>>     landlock_key/key_type/id types.
>>>
>>> Changes since v5:
>>> * Gets rid of partial revert from landlock_add_rule
>>> syscall.
>>> * Formats code with clang-format-14.
>>>
>>> Changes since v4:
>>> * Refactors landlock_create_ruleset() - splits ruleset and
>>> masks checks.
>>> * Refactors landlock_create_ruleset() and landlock mask
>>> setters/getters to support two rule types.
>>> * Refactors landlock_add_rule syscall add_rule_path_beneath
>>> function by factoring out get_ruleset_from_fd() and
>>> landlock_put_ruleset().
>>>
>>> Changes since v3:
>>> * Splits commit.
>>> * Adds network rule support for internal landlock functions.
>>> * Adds set_mask and get_mask for network.
>>> * Adds rb_root root_net_port.
>>>
>>> ---
>>>    include/uapi/linux/landlock.h                | 49 ++++++++++++++
>>>    security/landlock/limits.h                   |  6 +-
>>>    security/landlock/ruleset.c                  | 55 ++++++++++++++--
>>>    security/landlock/ruleset.h                  | 68 ++++++++++++++++----
>>>    security/landlock/syscalls.c                 | 13 +++-
>>>    tools/testing/selftests/landlock/base_test.c |  2 +-
>>>    6 files changed, 170 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
>>> index f3223f964691..096b683c6ff3 100644
>>> --- a/include/uapi/linux/landlock.h
>>> +++ b/include/uapi/linux/landlock.h
>>> @@ -31,6 +31,13 @@ struct landlock_ruleset_attr {
>>>    	 * this access right.
>>>    	 */
>>>    	__u64 handled_access_fs;
>>> +
>>> +	/**
>>> +	 * @handled_access_net: Bitmask of actions (cf. `Network flags`_)
>>> +	 * that is handled by this ruleset and should then be forbidden if no
>>> +	 * rule explicitly allow them.
>>> +	 */
>>> +	__u64 handled_access_net;
>>>    };
>>>
>>>    /*
>>> @@ -54,6 +61,11 @@ enum landlock_rule_type {
>>>    	 * landlock_path_beneath_attr .
>>>    	 */
>>>    	LANDLOCK_RULE_PATH_BENEATH = 1,
>>> +	/**
>>> +	 * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct
>>> +	 * landlock_net_service_attr .
>>> +	 */
>>> +	LANDLOCK_RULE_NET_SERVICE = 2,
>>>    };
>>>
>>>    /**
>>> @@ -79,6 +91,24 @@ struct landlock_path_beneath_attr {
>>>    	 */
>>>    } __attribute__((packed));
>>>
>>> +/**
>>> + * struct landlock_net_service_attr - TCP subnet definition
>>> + *
>>> + * Argument of sys_landlock_add_rule().
>>> + */
>>> +struct landlock_net_service_attr {
>>> +	/**
>>> +	 * @allowed_access: Bitmask of allowed access network for services
>>> +	 * (cf. `Network flags`_).
>>> +	 */
>>> +	__u64 allowed_access;
>>> +	/**
>>> +	 * @port: Network port.
>>> +	 */
>>> +	__u16 port;
>>
>>    From an UAPI point of view, I think the port field should be __be16, as
>> for sockaddr_in->port and other network-related APIs. This will require
>> some kernel changes to please sparse: make C=2 security/landlock/ must
>> not print any warning.
> 
>     Is sparse a default checker?

You should be able to easily install it with your Linux distro.