diff --git a/man/systemd-system.conf.xml b/man/systemd-system.conf.xml
index 9351c6ec52..bb28debbf2 100644
--- a/man/systemd-system.conf.xml
+++ b/man/systemd-system.conf.xml
@@ -553,6 +553,10 @@
shared libraries (mmap_file), and write-to-execute transitions such as JIT
compilation (file_mprotect).
+ The policy also enforces W^X system-wide: no mapping may be writable and executable at the
+ same time, and a private file mapping that has been modified through copy-on-write may not be made
+ executable afterwards.
+
Since v262, files on overlayfs mounts are resolved to the layer that hosts their data, so
execution from an overlay whose data resides on a signed dm-verity device is permitted, while files
in a writable upper layer are denied. This requires kernel v7.2 or newer; on older kernels execution from
@@ -561,13 +565,11 @@
btrfs are unsupported.
Note that, without further measures to secure the system, kexec can be used to circumvent
- this. Writable and executable memory mappings can also be used to circumvent this, so they need to
- be blocked, which can be achieved using other LSMs, or on a per-service basis by using the
- MemoryDenyWriteExecute= setting.
+ this.
This requires the kernel to be booted with dm_verity.require_signatures=1
- on the kernel command line and with BPF LSM enabled (lsm=...,bpf). If either
- prerequisite is not met, PID 1 will refuse to complete startup.
+ and proc_mem.force_override=never on the kernel command line, and with BPF LSM
+ enabled (lsm=...,bpf).
The value yes is equivalent to exec. Additional
modes may be added in the future.