diff --git a/share/man/man7/mitigations.7 b/share/man/man7/mitigations.7 --- a/share/man/man7/mitigations.7 +++ b/share/man/man7/mitigations.7 @@ -25,7 +25,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd October 6, 2023 +.Dd May 31, 2024 .Dt MITIGATIONS 7 .Os .Sh NAME @@ -234,8 +234,26 @@ .\" .\".Ss Stack Smashing Protection (SSP) .\" -.\".Ss Supervisor mode memory protection -.\" +.Ss Supervisor mode memory protection +Certain processors include features that prevent unintended access to memory +pages accessible to userspace (non-privileged) code, while in a privileged +mode. +One feature prevents execution, intended to mitigate exploitation of kernel +vulnerabilities from userland. +Another feature prevents unintended reads from or writes to user space memory +from the kernel. +This also provides effective protection against NULL pointer dereferences from +kernel. +.Bl -column -offset indent "Architecture" "Feature" "Access Type Prevented" +.It Sy Architecture Ta Sy Feature Ta Sy Access Type Prevented +.It amd64 Ta SMAP Ta Read / Write +.It amd64 Ta SMEP Ta Execute +.It arm64 Ta PAN Ta Read / Write +.It arm64 Ta PXN Ta Execute +.El +.Pp +These features are automatically used by the kernel. +There is no user-facing configuration. .Ss Hardware vulnerability controls See .Xr security 7