4 files changed, 28 insertions, 1 deletions
diff --git a/security/landlock/errata/abi-1.h b/security/landlock/errata/abi-1.h
index e8a2bff2e5b6..3f099555f059 100644
--- a/security/landlock/errata/abi-1.h
+++ b/security/landlock/errata/abi-1.h
@@ -12,5 +12,13 @@
  * 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)
diff --git a/security/landlock/errata/abi-4.h b/security/landlock/errata/abi-4.h
index c052ee54f89f..fe11ec7d7ddf 100644
--- a/security/landlock/errata/abi-4.h
+++ b/security/landlock/errata/abi-4.h
@@ -11,5 +11,12 @@
  * :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
index 5113a829f87e..5cb1475c7ea8 100644
--- a/security/landlock/errata/abi-6.h
+++ b/security/landlock/errata/abi-6.h
@@ -15,5 +15,15 @@
  * 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)
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index 3e4e99deb7f9..0d66a68677b7 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -158,9 +158,11 @@ static const struct file_operations ruleset_fops = {
 /*
  * The Landlock ABI version should be incremented for each new Landlock-related
  * user space visible change (e.g. Landlock syscalls).  This version should
- * only be incremented once per Linux release, and the date in
+ * only be incremented once per Linux release.  When incrementing, the date in
  * Documentation/userspace-api/landlock.rst should be updated to reflect the
  * UAPI change.
+ * If the change involves a fix that requires userspace awareness, also update
+ * the errata documentation in Documentation/userspace-api/landlock.rst .
  */
 const int landlock_abi_version = 8;