lkml.org 
[lkml]   [2022]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH v1 09/11] landlock: Document LANDLOCK_ACCESS_FS_REFER and ABI versioning
    On Mon, Feb 21, 2022 at 4:15 PM Mickaël Salaün <mic@digikod.net> wrote:
    >
    > From: Mickaël Salaün <mic@linux.microsoft.com>
    >
    > Add LANDLOCK_ACCESS_FS_REFER in the example and properly check to only
    > use it if the current kernel support it thanks to the Landlock ABI
    > version.
    >
    > Move the file renaming and linking limitation to a new "Previous
    > limitations" section.
    >
    > Improve documentation about the backward and forward compatibility,
    > including the rational for ruleset's handled_access_fs.
    >
    > Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
    > Link: https://lore.kernel.org/r/20220221212522.320243-10-mic@digikod.net
    > ---
    > Documentation/userspace-api/landlock.rst | 124 +++++++++++++++++++----
    > 1 file changed, 104 insertions(+), 20 deletions(-)

    Thanks for remembering to update the docs :) I made a few phrasing
    suggestions below, but otherwise it looks good to me.

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

    > diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
    > index f35552ff19ba..97db09d36a5c 100644
    > --- a/Documentation/userspace-api/landlock.rst
    > +++ b/Documentation/userspace-api/landlock.rst
    > @@ -281,6 +347,24 @@ Memory usage
    > Kernel memory allocated to create rulesets is accounted and can be restricted
    > by the Documentation/admin-guide/cgroup-v1/memory.rst.
    >
    > +Previous limitations
    > +====================
    > +
    > +File renaming and linking (ABI 1)
    > +---------------------------------
    > +
    > +Because Landlock targets unprivileged access controls, it is needed to properly
    ^^^^^
    "... controls, it needs to ..."

    > +handle composition of rules. Such property also implies rules nesting.
    > +Properly handling multiple layers of ruleset, each one of them able to restrict
    ^^^^^^^
    "rulesets,"

    > +access to files, also implies to inherit the ruleset restrictions from a parent
    ^^^^^^^^^^
    "... implies inheritance of the ..."

    > +to its hierarchy. Because files are identified and restricted by their
    > +hierarchy, moving or linking a file from one directory to another implies to
    > +propagate the hierarchy constraints.

    "... one directory to another implies propagation of the hierarchy constraints."

    > + To protect against privilege escalations

    > +through renaming or linking, and for the sake of simplicity, Landlock previously
    > +limited linking and renaming to the same directory. Starting with the Landlock
    > +ABI version 2, it is now possible to securely control renaming and linking
    > +thanks to the new `LANDLOCK_ACCESS_FS_REFER` access right.

    --
    paul-moore.com

    \
     
     \ /
      Last update: 2022-03-17 02:28    [W:4.090 / U:0.172 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site