3 files changed, 98 insertions, 0 deletions
diff --git a/security/landlock/errata/abi-1.h b/security/landlock/errata/abi-1.h
new file mode 100644
index 000000000..315ea7e0f
--- /dev/null
+++ b/security/landlock/errata/abi-1.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/**
+ * DOC: erratum_3
+ *
+ * Erratum 3: Disconnected directory handling
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This fix addresses an issue with disconnected directories that occur when a
+ * directory is moved outside the scope of a bind mount.  The change ensures
+ * that evaluated access rights include both those from the disconnected file
+ * hierarchy down to its filesystem root and those from the related mount point
+ * hierarchy.  This prevents access right widening through rename or link
+ * actions.
+ *
+ * Impact:
+ *
+ * Without this fix, it was possible to widen access rights through rename or
+ * link actions involving disconnected directories, potentially bypassing
+ * ``LANDLOCK_ACCESS_FS_REFER`` restrictions.  This could allow privilege
+ * escalation in complex mount scenarios where directories become disconnected
+ * from their original mount points.
+ */
+LANDLOCK_ERRATUM(3)
+
+/**
+ * DOC: erratum_4
+ *
+ * Erratum 4: Creation of whiteout objects
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This fix changes the access rights required for the creation of whiteout
+ * objects through :manpage:`mknod(2)`, :manpage:`renameat2(2)`, or
+ * :manpage:`link(2)`.  Creating whiteout objects is now guarded by
+ * ``LANDLOCK_ACCESS_FS_MAKE_REG`` instead of ``LANDLOCK_ACCESS_FS_MAKE_CHAR``.
+ *
+ * Whiteout objects are used in OverlayFS to mark the absence of a file in an
+ * upper file system.  Despite being created with ``S_IFCHR``, whiteout objects
+ * do not count as character devices.
+ *
+ * Impact:
+ *
+ * Sandboxed programs that create OverlayFS whiteouts (such as fuse-overlayfs)
+ * now require ``LANDLOCK_ACCESS_FS_MAKE_REG`` instead of
+ * ``LANDLOCK_ACCESS_FS_MAKE_CHAR``.
+ */
+LANDLOCK_ERRATUM(4)
diff --git a/security/landlock/errata/abi-4.h b/security/landlock/errata/abi-4.h
new file mode 100644
index 000000000..fe11ec7d7
--- /dev/null
+++ b/security/landlock/errata/abi-4.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/**
+ * DOC: erratum_1
+ *
+ * Erratum 1: TCP socket identification
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This fix addresses an issue where IPv4 and IPv6 stream sockets (e.g., SMC,
+ * MPTCP, or SCTP) were incorrectly restricted by TCP access rights during
+ * :manpage:`bind(2)` and :manpage:`connect(2)` operations. This change ensures
+ * that only TCP sockets are subject to TCP access rights, allowing other
+ * protocols to operate without unnecessary restrictions.
+ *
+ * Impact:
+ *
+ * In kernels without this fix, using ``LANDLOCK_ACCESS_NET_BIND_TCP`` or
+ * ``LANDLOCK_ACCESS_NET_CONNECT_TCP`` would incorrectly restrict non-TCP
+ * stream protocols (SMC, MPTCP, SCTP), potentially breaking applications
+ * that rely on these protocols while using Landlock network restrictions.
+ */
+LANDLOCK_ERRATUM(1)
diff --git a/security/landlock/errata/abi-6.h b/security/landlock/errata/abi-6.h
new file mode 100644
index 000000000..5cb1475c7
--- /dev/null
+++ b/security/landlock/errata/abi-6.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/**
+ * DOC: erratum_2
+ *
+ * Erratum 2: Scoped signal handling
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This fix addresses an issue where signal scoping was overly restrictive,
+ * preventing sandboxed threads from signaling other threads within the same
+ * process if they belonged to different domains.  Because threads are not
+ * security boundaries, user space might assume that all threads within the same
+ * process can send signals between themselves (see :manpage:`nptl(7)` and
+ * :manpage:`libpsx(3)`).  Consistent with :manpage:`ptrace(2)` behavior, direct
+ * interaction between threads of the same process should always be allowed.
+ * This change ensures that any thread is allowed to send signals to any other
+ * thread within the same process, regardless of their domain.
+ *
+ * Impact:
+ *
+ * This problem only manifests when the userspace process is itself using
+ * :manpage:`libpsx(3)` or an equivalent mechanism to enforce a Landlock policy
+ * on multiple already-running threads at once.  Programs which enforce a
+ * Landlock policy at startup time and only then become multithreaded are not
+ * affected.  Without this fix, signal scoping could break multi-threaded
+ * applications that expect threads within the same process to freely signal
+ * each other.
+ */
+LANDLOCK_ERRATUM(2)