On 28/11/2022 07:44, Konstantin Meskhidze (A) wrote:
11/17/2022 9:44 PM, Mickaël Salaün пишет:
On 21/10/2022 17:26, Konstantin Meskhidze wrote:
Describes network access rules for TCP sockets. Adds network access
example in the tutorial. Points out AF_UNSPEC socket family behaviour.
Adds kernel configuration support for network.
Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx>
---
Changes since v7:
* Fixes documentaion logic errors and typos as Mickaёl suggested:
https://lore.kernel.org/netdev/9f354862-2bc3-39ea-92fd-53803d9bbc21@xxxxxxxxxxx/
Changes since v6:
* Adds network support documentaion.
---
Documentation/userspace-api/landlock.rst | 72 +++++++++++++++++++-----
1 file changed, 59 insertions(+), 13 deletions(-)
diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
index d8cd8cd9ce25..d0610ec9ce05 100644
--- a/Documentation/userspace-api/landlock.rst
+++ b/Documentation/userspace-api/landlock.rst
@@ -11,10 +11,10 @@ Landlock: unprivileged access control
:Date: October 2022
The goal of Landlock is to enable to restrict ambient rights (e.g. global
-filesystem access) for a set of processes. Because Landlock is a stackable
-LSM, it makes possible to create safe security sandboxes as new security layers
-in addition to the existing system-wide access-controls. This kind of sandbox
-is expected to help mitigate the security impact of bugs or
+filesystem or network access) for a set of processes. Because Landlock
+is a stackable LSM, it makes possible to create safe security sandboxes as new
+security layers in addition to the existing system-wide access-controls. This
+kind of sandbox is expected to help mitigate the security impact of bugs or
unexpected/malicious behaviors in user space applications. Landlock empowers
any process, including unprivileged ones, to securely restrict themselves.
@@ -30,18 +30,20 @@ Landlock rules
A Landlock rule describes an action on an object. An object is currently a
file hierarchy, and the related filesystem actions are defined with `access
-rights`_. A set of rules is aggregated in a ruleset, which can then restrict
-the thread enforcing it, and its future children.
+rights`_. Since ABI version 4 a port data appears with related network actions
+for TCP socket families. A set of rules is aggregated in a ruleset, which
+can then restrict the thread enforcing it, and its future children.
Defining and enforcing a security policy
----------------------------------------
We first need to define the ruleset that will contain our rules. For this
example, the ruleset will contain rules that only allow read actions, but write
-actions will be denied. The ruleset then needs to handle both of these kind of
+actions will be denied. The ruleset then needs to handle both of these kind of
actions. This is required for backward and forward compatibility (i.e. the
kernel and user space may not know each other's supported restrictions), hence
-the need to be explicit about the denied-by-default access rights.
+the need to be explicit about the denied-by-default access rights. Also ruleset
+will have network rules for specific ports, so it should handle network actions.
.. code-block:: c
@@ -62,6 +64,9 @@ the need to be explicit about the denied-by-default access rights.
LANDLOCK_ACCESS_FS_MAKE_SYM |
LANDLOCK_ACCESS_FS_REFER |
LANDLOCK_ACCESS_FS_TRUNCATE,
+ .handled_access_net =
+ LANDLOCK_ACCESS_NET_BIND_TCP |
+ LANDLOCK_ACCESS_NET_CONNECT_TCP,
};
Because we may not know on which kernel version an application will be
@@ -70,14 +75,18 @@ should try to protect users as much as possible whatever the kernel they are
using. To avoid binary enforcement (i.e. either all security features or
none), we can leverage a dedicated Landlock command to get the current version
of the Landlock ABI and adapt the handled accesses. Let's check if we should
-remove the ``LANDLOCK_ACCESS_FS_REFER`` or ``LANDLOCK_ACCESS_FS_TRUNCATE``
-access rights, which are only supported starting with the second and third
-version of the ABI.
+remove the `LANDLOCK_ACCESS_FS_REFER` or `LANDLOCK_ACCESS_FS_TRUNCATE` or
+network access rights, which are only supported starting with the second,
This is a bad rebase.
Sorry. Did not get it.
This hunk (and maybe others) changes unrelated things (e.g. back quotes).
+third and fourth version of the ABI.
.. code-block:: c
int abi;
+ #define ACCESS_NET_BIND_CONNECT ( \
+ LANDLOCK_ACCESS_NET_BIND_TCP | \
+ LANDLOCK_ACCESS_NET_CONNECT_TCP)
Please add a 4-spaces prefix for these two lines.
Like this??
#define ACCESS_NET_BIND_CONNECT ( \
LANDLOCK_ACCESS_NET_BIND_TCP | \
LANDLOCK_ACCESS_NET_CONNECT_TCP)
Like for other indentations in the documentation (e.g. ruleset_attr
definition):
#define ACCESS_NET_BIND_CONNECT ( \
LANDLOCK_ACCESS_NET_BIND_TCP | \
LANDLOCK_ACCESS_NET_CONNECT_TCP)
