From: "Mickaël Salaün" <mic@digikod.net>
To: Kees Cook <keescook@chromium.org>
Cc: "James Morris" <jmorris@namei.org>,
"Jann Horn" <jannh@google.com>,
"Serge E . Hallyn" <serge@hallyn.com>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Andy Lutomirski" <luto@amacapital.net>,
"Anton Ivanov" <anton.ivanov@cambridgegreys.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Casey Schaufler" <casey@schaufler-ca.com>,
"David Howells" <dhowells@redhat.com>,
"Jeff Dike" <jdike@addtoit.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Michael Kerrisk" <mtk.manpages@gmail.com>,
"Richard Weinberger" <richard@nod.at>,
"Shuah Khan" <shuah@kernel.org>,
"Vincent Dagonneau" <vincent.dagonneau@ssi.gouv.fr>,
kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org,
linux-security-module@vger.kernel.org, x86@kernel.org,
"Mickaël Salaün" <mic@linux.microsoft.com>
Subject: Re: [PATCH v30 02/12] landlock: Add ruleset and domain management
Date: Fri, 19 Mar 2021 20:03:22 +0100 [thread overview]
Message-ID: <acda4be1-4076-a31d-fcfd-27764dd598c8@digikod.net> (raw)
In-Reply-To: <202103191114.C87C5E2B69@keescook>
On 19/03/2021 19:40, Kees Cook wrote:
> On Tue, Mar 16, 2021 at 09:42:42PM +0100, Mickaël Salaün wrote:
>> From: Mickaël Salaün <mic@linux.microsoft.com>
>>
>> A Landlock ruleset is mainly a red-black tree with Landlock rules as
>> nodes. This enables quick update and lookup to match a requested
>> access, e.g. to a file. A ruleset is usable through a dedicated file
>> descriptor (cf. following commit implementing syscalls) which enables a
>> process to create and populate a ruleset with new rules.
>>
>> A domain is a ruleset tied to a set of processes. This group of rules
>> defines the security policy enforced on these processes and their future
>> children. A domain can transition to a new domain which is the
>> intersection of all its constraints and those of a ruleset provided by
>> the current process. This modification only impact the current process.
>> This means that a process can only gain more constraints (i.e. lose
>> accesses) over time.
>>
>> Cc: James Morris <jmorris@namei.org>
>> Cc: Jann Horn <jannh@google.com>
>> Cc: Kees Cook <keescook@chromium.org>
>> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
>> Acked-by: Serge Hallyn <serge@hallyn.com>
>> Link: https://lore.kernel.org/r/20210316204252.427806-3-mic@digikod.net
>
> (Aside: you appear to be self-adding your Link: tags -- AIUI, this is
> normally done by whoever pulls your series. I've only seen Link: tags
> added when needing to refer to something else not included in the
> series.)
It is an insurance to not lose history. :)
>
>> [...]
>> +static void put_rule(struct landlock_rule *const rule)
>> +{
>> + might_sleep();
>> + if (!rule)
>> + return;
>> + landlock_put_object(rule->object);
>> + kfree(rule);
>> +}
>
> I'd expect this to be named "release" rather than "put" since it doesn't
> do any lifetime reference counting.
It does decrement rule->object->usage .
>
>> +static void build_check_ruleset(void)
>> +{
>> + const struct landlock_ruleset ruleset = {
>> + .num_rules = ~0,
>> + .num_layers = ~0,
>> + };
>> +
>> + BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES);
>> + BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS);
>> +}
>
> This is checking that the largest possible stored value is correctly
> within the LANDLOCK_MAX_* macro value?
Yes, there is builtin checks for all Landlock limits.
>
>> [...]
>
> The locking all looks right, and given your test coverage and syzkaller
> work, it's hard for me to think of ways to prove it out any better. :)
Thanks!
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
>
>
next prev parent reply other threads:[~2021-03-19 19:03 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 20:42 [PATCH v30 00/12] Landlock LSM Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 01/12] landlock: Add object management Mickaël Salaün
2021-03-19 18:13 ` Kees Cook
2021-03-19 18:57 ` Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 02/12] landlock: Add ruleset and domain management Mickaël Salaün
2021-03-19 18:40 ` Kees Cook
2021-03-19 19:03 ` Mickaël Salaün [this message]
2021-03-19 19:15 ` Kees Cook
2021-03-24 20:31 ` James Morris
2021-03-25 9:29 ` Mickaël Salaün
2021-03-23 0:13 ` Jann Horn
2021-03-16 20:42 ` [PATCH v30 03/12] landlock: Set up the security framework and manage credentials Mickaël Salaün
2021-03-19 18:45 ` Kees Cook
2021-03-19 19:07 ` Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 04/12] landlock: Add ptrace restrictions Mickaël Salaün
2021-03-19 18:45 ` Kees Cook
2021-03-16 20:42 ` [PATCH v30 05/12] LSM: Infrastructure management of the superblock Mickaël Salaün
2021-03-19 17:24 ` Kees Cook
2021-03-16 20:42 ` [PATCH v30 06/12] fs,security: Add sb_delete hook Mickaël Salaün
2021-03-19 17:24 ` Kees Cook
2021-03-16 20:42 ` [PATCH v30 07/12] landlock: Support filesystem access-control Mickaël Salaün
2021-03-18 23:10 ` James Morris
2021-03-19 18:57 ` Kees Cook
2021-03-19 19:19 ` Mickaël Salaün
2021-03-23 19:30 ` Mickaël Salaün
2021-03-23 0:13 ` Jann Horn
2021-03-23 15:55 ` Mickaël Salaün
2021-03-23 17:49 ` Jann Horn
2021-03-23 19:22 ` Mickaël Salaün
2021-03-24 3:10 ` Jann Horn
2021-03-16 20:42 ` [PATCH v30 08/12] landlock: Add syscall implementations Mickaël Salaün
2021-03-19 19:06 ` Kees Cook
2021-03-19 21:53 ` Mickaël Salaün
2021-03-24 15:03 ` Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 09/12] arch: Wire up Landlock syscalls Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 10/12] selftests/landlock: Add user space tests Mickaël Salaün
2021-03-19 17:56 ` Kees Cook
2021-03-19 18:41 ` Mickaël Salaün
2021-03-19 19:11 ` Kees Cook
2021-03-19 21:57 ` Mickaël Salaün
2021-03-16 20:42 ` [PATCH v30 11/12] samples/landlock: Add a sandbox manager example Mickaël Salaün
2021-03-19 17:26 ` Kees Cook
2021-03-16 20:42 ` [PATCH v30 12/12] landlock: Add user and kernel documentation Mickaël Salaün
2021-03-19 18:03 ` Kees Cook
2021-03-19 18:54 ` Mickaël Salaün
2021-03-23 19:25 ` Mickaël Salaün
2021-03-24 16:21 ` Mickaël Salaün
2021-03-18 23:26 ` [PATCH v30 00/12] Landlock LSM James Morris
2021-03-19 15:52 ` Mickaël Salaün
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