All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Mickaël Salaün" <mic@digikod.net>
To: James Morris <jmorris@namei.org>, "Serge E . Hallyn" <serge@hallyn.com>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	"Jann Horn" <jannh@google.com>,
	"John Johansen" <john.johansen@canonical.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Konstantin Meskhidze" <konstantin.meskhidze@huawei.com>,
	"Paul Moore" <paul@paul-moore.com>,
	"Shuah Khan" <shuah@kernel.org>,
	"Tetsuo Handa" <penguin-kernel@I-love.SAKURA.ne.jp>,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: [PATCH v3 12/12] landlock: Add design choices documentation for filesystem access rights
Date: Fri,  6 May 2022 18:11:02 +0200	[thread overview]
Message-ID: <20220506161102.525323-13-mic@digikod.net> (raw)
In-Reply-To: <20220506161102.525323-1-mic@digikod.net>

Summarize the rationale of filesystem access rights according to the
file type.

Update the document date.

Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-13-mic@digikod.net
---

Changes since v2:
* Add more explanation in the commit message.
* Update date.

Changes since v1:
* Add Reviewed-by: Paul Moore.
* Update date.
---
 Documentation/security/landlock.rst | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/Documentation/security/landlock.rst b/Documentation/security/landlock.rst
index 3df68cb1d10f..5c77730b4479 100644
--- a/Documentation/security/landlock.rst
+++ b/Documentation/security/landlock.rst
@@ -7,7 +7,7 @@ Landlock LSM: kernel documentation
 ==================================
 
 :Author: Mickaël Salaün
-:Date: March 2021
+:Date: May 2022
 
 Landlock's goal is to create scoped access-control (i.e. sandboxing).  To
 harden a whole system, this feature should be available to any process,
@@ -42,6 +42,21 @@ Guiding principles for safe access controls
 * Computation related to Landlock operations (e.g. enforcing a ruleset) shall
   only impact the processes requesting them.
 
+Design choices
+==============
+
+Filesystem access rights
+------------------------
+
+All access rights are tied to an inode and what can be accessed through it.
+Reading the content of a directory doesn't imply to be allowed to read the
+content of a listed inode.  Indeed, a file name is local to its parent
+directory, and an inode can be referenced by multiple file names thanks to
+(hard) links.  Being able to unlink a file only has a direct impact on the
+directory, not the unlinked inode.  This is the reason why
+`LANDLOCK_ACCESS_FS_REMOVE_FILE` or `LANDLOCK_ACCESS_FS_REFER` are not allowed
+to be tied to files but only to directories.
+
 Tests
 =====
 
-- 
2.35.1


  parent reply	other threads:[~2022-05-06 16:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06 16:10 [PATCH v3 00/12] Landlock: file linking and renaming support Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 01/12] landlock: Define access_mask_t to enforce a consistent access mask size Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 02/12] landlock: Reduce the maximum number of layers to 16 Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 03/12] landlock: Create find_rule() from unmask_layers() Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 04/12] landlock: Fix same-layer rule unions Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 05/12] landlock: Move filesystem helpers and add a new one Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 06/12] LSM: Remove double path_rename hook calls for RENAME_EXCHANGE Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 07/12] landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 08/12] selftests/landlock: Add 11 new test suites dedicated to file reparenting Mickaël Salaün
2022-05-06 16:10 ` [PATCH v3 09/12] samples/landlock: Add support for " Mickaël Salaün
2022-05-06 16:11 ` [PATCH v3 10/12] landlock: Document LANDLOCK_ACCESS_FS_REFER and ABI versioning Mickaël Salaün
2022-05-06 16:11 ` [PATCH v3 11/12] landlock: Document good practices about filesystem policies Mickaël Salaün
2022-05-06 16:11 ` Mickaël Salaün [this message]
2022-05-06 16:31 ` [PATCH v3 00/12] Landlock: file linking and renaming support Mickaël Salaün

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220506161102.525323-13-mic@digikod.net \
    --to=mic@digikod.net \
    --cc=jannh@google.com \
    --cc=jmorris@namei.org \
    --cc=john.johansen@canonical.com \
    --cc=keescook@chromium.org \
    --cc=konstantin.meskhidze@huawei.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=paul@paul-moore.com \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=serge@hallyn.com \
    --cc=shuah@kernel.org \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH v3 12/12] landlock: Add design choices documentation for filesystem access rights' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.