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[v1,11/11] landlock: Add design choices documentation for filesystem access rights

Message ID 20220221212522.320243-12-mic@digikod.net (mailing list archive)
State New, archived
Headers show
Series Landlock: file linking and renaming support | expand

Commit Message

Mickaël Salaün Feb. 21, 2022, 9:25 p.m. UTC 
From: Mickaël Salaün <mic@linux.microsoft.com>

Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Link: https://lore.kernel.org/r/20220221212522.320243-12-mic@digikod.net
---
 Documentation/security/landlock.rst | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

Comments

Paul Moore March 17, 2022, 1:27 a.m. UTC | #1 
On Mon, Feb 21, 2022 at 4:15 PM Mickaël Salaün <mic@digikod.net> wrote:
>
> From: Mickaël Salaün <mic@linux.microsoft.com>
>
> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
> Link: https://lore.kernel.org/r/20220221212522.320243-12-mic@digikod.net
> ---
>  Documentation/security/landlock.rst | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)

Reviewed-by: Paul Moore <paul@paul-moore.com>

--
paul-moore.com
diff mbox series

Patch

diff --git a/Documentation/security/landlock.rst b/Documentation/security/landlock.rst
index 3df68cb1d10f..621b2c1ac514 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: February 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
 =====